Patina Suppliers and methods

[sculptorsam]

I may be in the position of applying some patinas to bronze for the first time in the near future so I thought I'd ask how the regulars do it. Do most out there mix the raw chemicals themselves? Purchase pre-mixed patinas? Hot or cold application? And who do you buy the supplies from?

I was never very good in chemistry class and some of those prepared patinas at Compleat Sculptor look pretty nice. Relatedly, what's your favorite kind of wax?

[fritchie]

Sam - As a chemist (Surprise!), I always have mixed my own. Originally, I used a somewhat wider variety of materials, but lately it has been simply liver of sulfur (potassium sulfide), cupric nitrate (in a typical crystalline hydrated form), and sometimes a little ferric nitrate (ditto hydrate). Nothing more. I always start with the liver of sulfur, because I feel this gives greater stability to the patina.

I make both concentrated and dilute versions of each material, and apply with separate small brushes for each type. I heat the piece to the point when applied liquid evaporates quickly, and keep it more or less at this temperature, rotating and skipping over the piece fairly rapidly, and I apply wax immediately on cessation of patining. After the piece has cooled, generally over a couple of hours, I buff with soft cloth and sometimes also a soft shoebrush.

I’ve used various waxes over the years. On recommendation of a professional patinist in a demonstration when I began, about 1988, I bought some pure white “artificial beeswax”, and when this ran out about 2 - 3 years ago, I was desperate to get something similar, but couldn’t. After trying several other mixes, I located some pale cream beeswax at a reasonable price, and I use that now. It seem similar, but maybe not quite as hard.

You are right that commercial mixes probably do a very good job.

I'll have to check on supplier. It was an artists' supply house in the San Francisco area, that I believe still is in business, but one jar is more than a lifetime supply, so it’s been a good ten years ago that I bought these materials.

[warren01]

Sam,
Liver of sulfur as mentioned, you cannot go wrong if looking for tones of brown. Many household products work too for patinas. Things like fertilizer, (Miracle Grow or whatever it is called) can give tints of blue. Regular bleach can give some green colors. Vinegar can give an orange or light brown color.
For other patinas, since I am not a chemist either I usually use the pre-mix patinas from Ron Young. Some work pretty good, others I think, give a fake or painted look, just depends on the look you want to accomplish. Buy the sample kit and play.
Hot or cold depends again on what you are trying to achieve and what chemicals.
For a wax I have been very happy with Butcher's Bowling Alley wax, do not let the name fool you, it is a very good wax on metals and recommended too for some art restorations.

warren

[sculptorsam]

That's a good idea to get a sample kit to try the pre-mixed out. I googled Ron Young and easily found his website too. Looks great, I'll have to spend some time later going through it all. I was just reading about patinas with acid and those without. Any idea if one or the other tends to give a more fake or painted look? On first glance the Vista series looks interesting as well as the Japanese Brown in the traditional patinas. Who knew there were so many choices?!

[warren01]

Any idea if one or the other tends to give a more fake or painted look.

Now I am not knocking them, just my opinion for what it is worth. However, I think the universal patinas. It probably is the fact that they are opaque. If you put a clear lacquer on them, they are not too bad. I just like seeing the metal through the patina and just use wax.

warren

[sculptorsam]

I understood what you meant and realize it's about preference. I too prefer the look of metal itself, which is probably why I like Cor-ten so much. I hate finishes that feel "plastic-y" and put a barrier between the viewer and the object.

Looks like $60 for a kit of all Ron Young's bronze patinas. Not too bad I guess.

[fritchie]

Sam - I remembered that I posted this supplier as part of an earlier conversation. It’s Bryant Labs, a long-time supplier to artists.
Here’s (http://www.sculpture.net/community/showthread.php?t=625&page=2&pp=25) the earlier post. I also gave quite a bit of detail on my patining methods in the late summer, with images, in the Figurative section as I recall.

For this first piece, you probably are wise to start with a widely accepted material. I do need to add a few points to my earlier comments and others. Most importantly, liver of sulfur can go from light brown all the way to full black. It probably is the source of all black patinas before about 1920 to 1930, largely because of its stability.

Secondly, I prefer a texture to my patinas, and that is a reason for the brushes. People who like uniform patinas use a spray or misting application, but otherwise I think my description is followed - keep the piece always nearly dry. and warm to hot.

[sculptorsam]

Thanks for the link, fritchie. I'll have to go back and read through your figurative posts as well. When I read for practical reasons and not simply theoretical, it's amazing how much I realize I missed before. And thanks for pointing out the brush vs. spray effect. I think I'd like a slightly textured effect and suspect it would be a more efficient use of the patina as well. I'd imagine you'd lose some in overspray misting it. As for heating the work up, is putting it in the stove turned on low a good idea? Seems too simple to work.

What's your favorite method for prepping the metal? Sandblasting, 3M pad, wire wheel?

I think I'd enjoy this more if there wasn't a deadline. I still need to decide on a foundry and get the pieces cast and back to me for finishing by the end of March. I've been trying to make some more smaller ones to choose from for a starter piece as well. Problem is, I just keep making more. I've made a sculpture a day for the last 5 work days now. For me, that's just crazy.

[fritchie]

Thanks for the link, fritchie. I'll have to go back and read through your figurative posts as well. When I read for practical reasons and not simply theoretical, it's amazing how much I realize I missed before. And thanks for pointing out the brush vs. spray effect. I think I'd like a slightly textured effect and suspect it would be a more efficient use of the patina as well. I'd imagine you'd lose some in overspray misting it. As for heating the work up, is putting it in the stove turned on low a good idea? Seems too simple to work.

What's your favorite method for prepping the metal? Sandblasting, 3M pad, wire wheel?

I think I'd enjoy this more if there wasn't a deadline. I still need .......

For prepping, I use a soak, generally overnight, in an extremely dilute muriatic (hydrochloric) acid solution - about 2 ounces to a large garbage pail of water (30 gallons ?). The casts from my foundry, in a raw state, typically are partly to fully black with “fire scale”, which probably is a copper oxide or sulfide, produced from the mold materials and heat.

Most sculptors find acid treatment abhorrent, but I follow this with a soak in water, at least 3 - 5 hours, then a soak in similarly dilute ammonia, and then preferably an overnight soak in water. All this takes day or so, but I don’t like the idea of brushing or scrubbing.

I was told from my earliest work that cast bronze contains tiny pores, from whatever cause, and that acid might work away from the inside. I doubted this, but it certainly is true, as I have seen areas that “bleed” water when I am heating for the patina process. All the same, I think my neutralization processes, as described, get the metal into a suitably clean state. Some of my pieces now are over ten years old, and I can see the applied patina gradually converting into a patina of age, with no noticeable corrosion from acid.

As for a stove, I have two radiant natural-gas heaters in my studio, and I heat the pieces in front of one of these until it is hot to the touch before starting the patina process, to save on bottled gas. For the patina process, I use one of those quart-sized bottles of propane. People here working with larger pieces will use a torch fed with natural gas (which is principally methane).

[ExNihiloStudio]

If you use abrasive methods you'll get a clean piece without the problems of unwanted chemical reactions like the ones fritchie mentioned, but abrasion removes some of the bronze which changes the look of the piece. Steel wire wheels and sand will definitely obliterate detail. I personally am interested in chemical stripping for this very reason. A chemically stripped piece will show the chrystaline structure of the cast metal which resembles galvanizing. A problem with using chemicals is they're hazardous. I have read that glass bead blasting will clean a piece with minimal abrasion, but I've never tried this method.

[fritchie]

If you use abrasive methods you'll get a clean piece without the problems of unwanted chemical reactions like the ones fritchie mentioned, but abrasion removes some of the bronze which changes the look of the piece. Steel wire wheels and sand will definitely obliterate detail. I personally am interested in chemical stripping for this very reason. A chemically stripped piece will show the chrystaline structure of the cast metal which resembles galvanizing. A problem with using chemicals is they're hazardous. I have read that glass bead blasting will clean a piece with minimal abrasion, but I've never tried this method.

ExNihilo (Mark) is right about this, to a degree. If the acid treatment is extremely mild - what I attempt - the blackish firescale will be removed, but none of the very thin amorphous surface of the cast. Earlier in my work, when I was willing to work more slowly, I routinely removed most of the black color without revealing the crystalline structure. More recently, I have just guessed acid concentration, and commonly use a little too much.

In the way of background, when bronze, or most other metals are cast, an extremely thin layer that hits the mold first is amorphous, or internally packed in a random fashion. Everything afterward, for 99.99+ percent of the cast, is crystalline, with irregularly shaped, interlocking single crystals. Metallurgists discovered a century or more ago that they could study this internal crystal configuration with a light acid etch - a surface treatment that doesn’t disturb the piece overall, but that removes this thin amorphous layer.

Much of my work for the last 2 - 3 years shows this crystalline etch, with individual crystals about 2 - 3 mm. or 1/8 to 3/16 inch wide. They appear as speckles on the surface, because each crystal reflects light in a slightly different way. I don’t think this result detracts from either the stability or the appearance of the pieces, so I haven’t altered my approach. The speckles show because I like a patina that basically is transparent - it lets most of the reflected light through, and adds only a light brown color. Similarly, I try to retain part of the original black firescale, as I think this enriches the overall color and appearance.

[sculptorsam]

Similarly, I try to retain part of the original black firescale, as I think this enriches the overall color and appearance.

So the reason for removing the firescale is largely aesthetic? There is no inherent instablility of it on the surface, it's more an issue of an even patina application?

Since my work consists of ground planes with pockets of exposed welds, the agressive removal via sandblasting wouldn't bother me as much. I anticipate going over some of the smoother parts with a sanding disk again anyway to clean things up. But I do know that different grades of sand will affect the surface different ways. For the basic blasting on my steel works, I use a local company which uses a rather rough sand. But at the shop, we have a small portable unit that uses a fine silica sand which isn't nearly as abrasive. I think I'll run a test with it when I get a chance.

[fritchie]

So the reason for removing the firescale is largely aesthetic? There is no inherent instablility of it on the surface, it's more an issue of an even patina application?

Since my work consists of ground planes with pockets of exposed welds, the agressive removal via sandblasting wouldn't bother me as much. I anticipate going over some of the smoother parts with a sanding disk again anyway to clean things up. But I do know that different grades of sand will affect the surface different ways. For the basic blasting on my steel works, I use a local company which uses a rather rough sand. But at the shop, we have a small portable unit that uses a fine silica sand which isn't nearly as abrasive. I think I'll run a test with it when I get a chance.

All my work is with bronze, but in that case, the answer is yes, to my knowledge, at least most of the time - 99%, say. l occasionally have seen fairly thick firescale, maybe 0.1 to 0.2 mm, and I don’t know what causes this. In these cases, the scale resists even acid removal, though I sometimes have dabbed it away with cotton swabs and more concentrated muriatic acid, followed by local washing with water. I believe the scale is copper sulfide or copper oxide, the same patina that would develop over decades or centuries on its own, and I see mo reason why it would not be stable.

[sculptorsam]

Got my patina kit from Sculpt Nouveau today so I was experimenting a bit. I was surprised how varied the acid's reaction to the bronze was. Some, like the Darkening Patina, reacted very quickly. Others, like the Ferric Nitrate, had to be applied repeatedly to darken the metal. I do like the dark red/brown that it eventually achieved, as well as the textured look, but I think I'd have to patina full time to achieve a good result. The Mahogany is another that I think I'd like but it reacted very slowly. Anyway to speed things up? I was applying it hot with the occasional dancing of flame over to maintain the temp.

[fritchie]

Sam - Welcome to the wonderful world of patining! Ferric nitrate actually is a mild acid when applied hot, and will remove earlier layers of color. It sounds like you are maintaining about the correct temperature. I don’t know of any way to accelerate the process beyond keeping things just about the point where the liquid steams off when applied. Good luck with all of this.

[sculptorsam]

That explains a lot, fritchie. The most frustrating part about trying to apply the ferric nitrate was that it seemed to wash itself away when I added more. So should I try to use fewer layers with more time between applications or even a lower temperature?

[sculptorsam]

I almost forgot, what's the best way to clean a bristle brush after applying an acid patina?

[fritchie]

I have to admit I've had real problems with ferric nitrate, and I have used less and less with time. My general procedure these days is to apply liver of sulfur to a light or medium brown, then add a smattering of cupric nitrate for blues, and interwoven with the cupric, possibly some ferric nitrate. I find ferric has to be applied lightly, with drying between applications.

Another problem with ferric nitrate is that it will form a purplish, and sometimes almost metallic, reflective color that is very hard to change, if the surface is overheated. People say that cupric and ferric nitrates can be mixed as liquids and applied together, and in theory that ought to be OK, but I never have tried this. In the past (maybe 5 - 8 years ago) I did get some good reddish tones over the sulfide browns with ferric, but the difficulties have led me mostly to skip it. I would recommend you keep trying ferric, maybe with lower concentration and lower heat, drying between applications. The colors CAN be beautiful.

[tom blatt]

Anyone know if it's possible to apply a patana to bronze without first sandblasting? i was always tought to sandblast the piece first then apply the patina.
I.m working in a very
'bare bones" enviornment and don't have access to a sandblaster! Could i sand the bronze to a 120 or 220 grit surface and then apply the patina and still get a good result?
tom

[JAZ]

Another question: Isn't it necessary to neutralize the patinas once applied? It sounds from the above that you apply the patina with heat, then (other than waxing) you're done.
JAZ

[fritchie]

Anyone know if it's possible to apply a patana to bronze without first sandblasting? i was always tought to sandblast the piece first then apply the patina.
I.m working in a very
'bare bones" enviornment and don't have access to a sandblaster! Could i sand the bronze to a 120 or 220 grit surface and then apply the patina and still get a good result?
tom

This principally depends on what you want. I’ve been finishing my own bronzes, cast elsewhere, for about 15 years, and I’ve not sandblasted a single one. My founder for about 95% of this work has been in the business about 40 years, and I don’t think he ever has sandblasted either, though he may have beadblasted (with glass beads, which are rounded and less erosive than sand) a few times.

In both cases, we like the color variation that comes with the casting process, toned down a bit either by grinding during the finish process (in his work) or by an extremely mild acid etch (in my work).

Most commercial foundries, and many art schools do insist on sandblasting to get a uniform color before patining. The method of casting also is significant. He uses the older casting process of investment molding, where the mold is made of silica flour (finely ground sand) and plaster of Paris, applied by hand.

The newer, more mechanical process of ceramic shell molding, where the wax is dipped repeatedly into a ceramic slip, actually MAY require sandblasting, or so I have been told. The ceramic mold adheres more tightly to the cast bronze, and the last traces may have to be blasted away. I suspect a mild acid etch might remove these ceramic bits also, but never have seen this process in action, so I don’t know.

[sculptorsam]

The foundry I just found uses ceramic shell and he told me you have to sandblast it to remove it. When I mentioned removal via an acid, he said it was possible but that the acid required (I forget the name, of course) was so terrible he just shook his head.

And JAZ, the instructions that came with my Sculpt Nouveau patinas don't mention needing a nuetralizer at all. Just apply the patina, then a wax when still warm, and you're good to go. It's my understanding that the patina will continue to change over time without the wax or sealant of some type to "lock" it in.

And I was thinking that perhaps you don't even need to clean a bristle brush when done applying patina? Would the acids eat the bristle? I bought a decent brush and don't want it to go to waste.

[warren01]

Sam,
I do not how big of brush that you are using but I buy those little acid brushes. The ones with the metal tube as the handle. Usually can buy for under a buck each. I just throw them away when done using. The ones that I have kept around the bristles seem okay but the metal tube rusts. I also buy some cheap hobby style paintbrushes if doing really small stuff, again throw aways. I do not think it is worth it to spend for good brushes, it is not like painting where you are looking for the elimination of brush strokes.
For a little larger applications I like using a squirt bottle. There are these little ones that gals use to mist their hair and are around a buck. Just have to watch out for plugging on some of the chemicals. I have found out that the big expensive ones that say you can use for chemicals are a waste of money. Still plug and the squirter still fail. The little ones make it easier to use small amounts. It is surprising how much area one of those little bottles will handle. For instance if using liver of sulfur, you have to have the solution hot, making a little batch works better.

warren

[fritchie]

The foundry I just found uses ceramic shell and he told me you have to sandblast it to remove it. When I mentioned removal via an acid, he said it was possible but that the acid required (I forget the name, of course) was so terrible he just shook his head.

And JAZ, the instructions that came with my Sculpt Nouveau patinas don't mention needing a nuetralizer at all. Just apply the patina, then a wax when still warm, and you're good to go. It's my understanding that the patina will continue to change over time without the wax or sealant of some type to "lock" it in.

And I was thinking that perhaps you don't even need to clean a bristle brush when done applying patina? Would the acids eat the bristle? I bought a decent brush and don't want it to go to waste.

Sam - The acid this guy mentioned might have been hydrofluoric acid. That will dissolve glass (the only acid to do so), and so might be used for the ceramic shell material.

What I had in mind was ordinary muriatic acid or hydrochloric acid, which would work not by dissolving the shell itself, but by dissolving a very tiny layer of the bronze. (Muriatic acid is available by the gallon in hardware stores, and commonly is used by bricklayers to clean extra mortar from the faces of the brick after buildup of each layer.) That always happens, with sandblasting, acid, or any other cleaning method. You might have to scrub a bit with stiff bristles, but I think it would work and might be preferable to sandblasting.

On your question regarding the brush, acid will attack the metal band holding the bristles, not the bristles themselves. I, too, bought good quality brushes, and still have most after a dozen or so years, but with slightly rusty ends. The few I have replaced have gone because of my burning the bristles with my handtorch.

[sculptorsam]

Yeah, that is the acid he mentioned.

I did use some disposable brushes when I was testing out the acids. They worked pretty good, but I did order a nice brush with the patinas just to see what it was like. I'll probably end up using a combination.

I'll definitely check out one of those little bottles, warren. Thanks for the tip.

[tom blatt]

This principally depends on what you want. I’ve been finishing my own bronzes, cast elsewhere, for about 15 years, and I’ve not sandblasted a single one. My founder for about 95% of this work has been in the business about 40 years, and I don’t think he ever has sandblasted either, though he may have beadblasted (with glass beads, which are rounded and less erosive than sand) a few times.

In both cases, we like the color variation that comes with the casting process, toned down a bit either by grinding during the finish process (in his work) or by an extremely mild acid etch (in my work).

Most commercial foundries, and many art schools do insist on sandblasting to get a uniform color before patining. The method of casting also is significant. He uses the older casting process of investment molding, where the mold is made of silica flour (finely ground sand) and plaster of Paris, applied by hand.

The newer, more mechanical process of ceramic shell molding, where the wax is dipped repeatedly into a ceramic slip, actually MAY require sandblasting, or so I have been told. The ceramic mold adheres more tightly to the cast bronze, and the last traces may have to be blasted away. I suspect a mild acid etch might remove these ceramic bits also, but never have seen this process in action, so I don’t know.



So what your saying is just the chasing itself and a little muratic acid [do you use it stright out of the bottle?] and then apply the patina? Thanks for the info. Does anyone know of a blue patina thats not too complicated and thats good for an outdoor piece? And thanks again for the info.
tom

[fritchie]

So what your saying is just the chasing itself and a little muratic acid [do you use it stright out of the bottle?] and then apply the patina? Thanks for the info. Does anyone know of a blue patina thats not too complicated and thats good for an outdoor piece? And thanks again for the info.
tom

The chasing and muriatic acid is just to get ready for patining. And definitely don’t use muriatic acid right of the bottle. That’s something like 35% acid, and will chew up the bronze badly. I’ve described my process in more detail elsewhere here, and will add a link here or in a new message shortly.

However, in brief, I add a milliliter or so (roughly a whisky shot glass) to a plastic garbage pail (probably 40 gallons??) of water. This is VERY dilute, and the sculpture is allowed to soak overnight, or for at least 5 – 6 hours. If the concentration is right, the black firescale still will be present after the soak, but loose enough so that scrubbing with a stiff brush, and a toothbrush in tight corners, will remove all or most of the black. A touch or two of a more concentrated acid, usually with the same stiff brush or even with a cotton swab may be needed to get the last scale.

THEN, the cleaned bronze is soaked for the same time in a very dilute solution of ammonia for complete neutralization of acid, and finally in pure (tap) water to remove all traces of ammonia. Only then is it ready to begin patining.

[fritchie]

Here’s (http://www.sculpture.net/community/showpost.php?p=5661&postcount=14) at least a bit more detail on my method of removing firescale with dilute acid and then neutralizing the acid. It’s part of a miniblog from last summer, and this link should be to post 14 in the thread, the first that clearly discusses the acid treating.

[mtd]

fritchie,
Thanks for all the science behind patinas. I'm also getting ready to do my first bronze/patina and this info is amazing!

I found this place on line for very inexpensive chip brushes. I saw someone using a chip brush to apply a patina (looked like it worked well to me, in my limited knowledge). Any way, here's the site.

cheers,
MD

http://www.torringtonbrush.com/

[sculptorsam]

And here they are. I ended up using Potash (Liver of Sulfer) and clear Butcher's Wax. Any comments would be appreciated. I think I've been around my work so much lately I can't even see it anymore.

[JAZ]

Very nice, Sam. They look small. That probably means that you did not need the interior rod/armature you use on the bigger ones? The blend of organic with geometric and the good relationship between positive and negative space make the forms intriguing. While the three hold together well, if the one in the middle was on its own it would be passive. Passive and complex, so for me although all three are beautiful, the middle one isn't as Noguchi as the other two.
JAZ

[sculptorsam]

Thanks JAZ. Yeah, these are small. 14" tall for the first one, 11" wide by 2" tall the second one and 3.5" tall the third. I ended up making 3-4 casts of each right now to take to a show next week (fingers are crossed). The middle one is quite different from the other two, but it has it's own charm I think. It was difficult to photograph because it's so linear. Whenever I see the two smaller ones, I'm compelled to pick them up, turn them around, and set them down in a different position. I wanted them to be true "objects," interesting from every angle.

I hadn't really thought about the Noguchi influence, but thanks for pointing that out. I sort of "discovered" him in the last year or so. Probably since my sculpture tour really. Now I'm wishing I had found him earlier. Better late than never I guess.

[fritchie]

I like all three, Sam., and I see what JAZ means about the middle one, but I have a different "take".

One of the problems with sculptures is that they are subject to the rules of gravity, like everything else around us. I like to think in terms of pure form, outside of surrounding space or influences such as this when I’m dealing with nonobjective sculpture, and in those terms, I think all three are quite successful. I think JAZ sees the middle one as weak because it is lying flat.

I think you are saying something along my lines, when you say you feel compelled to pick them up and set them down in another position. My “take” on really good, nonobjective sculpture is that it should look as if it dropped from outer space, with no real reference to anything here on Earth. That’s a bit extreme, I know, but I feel that otherwise the concepts tend to be weak.

[JAZ]

Actually, I didn't mean that the middle one was weak. It isn't. But I do prefer the other two. It's funny that I thought you fabricated these. Of course. It makes more sense that they were cast. The surfaces are luscious. Good luck with your show.
JAZ

[JAZ]

"...I’ve used various waxes over the years. On recommendation of a professional patinist in a demonstration when I began, about 1988, I bought some pure white “artificial beeswax”, and when this ran out about 2 - 3 years ago, I was desperate to get something similar, but couldn’t. After trying several other mixes, I located some pale cream beeswax at a reasonable price, and I use that now. It seem similar, but maybe not quite as hard..." Fritchie

Fritchie, the information in this thread is specific to indoor pieces? Is there some different patination method or wax that's used for outdoor pieces?
JAZ

[warren01]

Sam, those are turned out very nice. Good color and I like the highlighted edges.

Jaz, the wax that Sam used also works very well outside. Like how do you rate a wax? I have some pieces that are three Michigan winters old and wax still holding up okay. Probably will have to do a little housekeeping though this summer. So is that good or bad? :rolleyes:

warren

[fritchie]

"...I’ve used various waxes over the years. On recommendation of a professional patinist in a demonstration when I began, about 1988, I bought some pure white “artificial beeswax”, and when this ran out about 2 - 3 years ago, I was desperate to get something similar, but couldn’t. After trying several other mixes, I located some pale cream beeswax at a reasonable price, and I use that now. It seem similar, but maybe not quite as hard..." Fritchie

Fritchie, the information in this thread is specific to indoor pieces? Is there some different patination method or wax that's used for outdoor pieces?
JAZ

JAZ - None of my pieces ever has gone outdoors, but I had the impression from that early demonstration that this coating might be OK outside.

On a different note, I have to report that a large, very prominently displayed figurative bronze here in New Orleans was “cleaned, restored (depatinated and then repatinated), and rewaxed” about fifteen years ago, after having withstood the elements for probably 60 - 80 years or more in a condition I would describe as “not bad”, maybe “fair to middling”. Within about two years of the “improvement”, the piece looked worse than ever, with increased corrosion.

After maybe 4 - 5 years in that condition, it seems to have been stabilized in a condition not too different from before the treatment.

I’m not at all familiar with “Butcher’s “ wax, which I’ve also seen spelled “Bucher’s - as in bookers -wax, but that was recommended specifically many years ago. I have looked in vain for it off and on, so Sam, if you have a supplier, how about a plug? I have heard that it is used in bowling alley’s, so it ought to be sturdy, and people do recommend it for outdoor use, I think.

And, on the question of patina, Sam has used a sulfide, probably the sturdiest, most stable patina available indoors or outdoors for bronze. He calls it “potash”, and that may be OK as a general term, but my dictionary describes potash as a carbonate or oxide of potassium, and the patining material actually is potassium sulfide. Sulfur (as in sulfide) is the critical material here.

Sulfide combines with the copper in bronze to make a very stable material. Copper sulfides probably have been the most common patinas for bronzes since antiquity. In fact, the Mediterranean island of Cyprus gets its name from cuprum, the Latin name for copper. The island held extensive deposits of copper sulfide, a common ore and early source of metallic copper.

[JAZ]

Your story about the restoration is scary.
I have a can of regular Butcher's wax, which is meant for regular floors and a sibling of the bowling alley one. I got it at the hardware store. I'll have to look to see if they have the bowling alley one.
The sulfide definitely sounds like something to consider becasue stability should be the primary concern with outdoor stuff. Meanwhile, since the new bronze is so gorgeous on its own, I'm having a hard time coming to grips with the idea of darkening it so much for the piece that I'm fabricating now. (Even the studio dirt from grinding and cutting is a nice color.) Maybe it would be better aesthetically than I'm visualizing.
Fritchie, thank you for all of your expertise in this and other threads here about bronze and patinas. None of us really wants to find out stuff the hard way because bronze is such an expensive investment.
JAZ

[fritchie]

Your story about the restoration is scary.
I have a can of regular Butcher's wax, which is meant for regular floors and a sibling of the bowling alley one. I got it at the hardware store. I'll have to look to see if they have the bowling alley one.
The sulfide definitely sounds like something to consider becasue stability should be the primary concern with outdoor stuff. Meanwhile, since the new bronze is so gorgeous on its own, I'm having a hard time coming to grips with the idea of darkening it so much for the piece that I'm fabricating now. (Even the studio dirt from grinding and cutting is a nice color.) Maybe it would be better aesthetically than I'm visualizing.
Fritchie, thank you for all of your expertise in this and other threads here about bronze and patinas. None of us really wants to find out stuff the hard way because bronze is such an expensive investment.
JAZ

JAZ - I hadn’t realized you were working with bronze. I guess I missed a post somewhere. Is this fabricated or cast bronze? And, you should realize, in case it’s not clear, that all my bronzes have sulfide (via liver of sulfur, potassium sulfide) as the main element.

This material can produce a coat from the lightest “tan” all the way though to full black, with increasing concentration or repeated applications. I do recommend repeated light coats for control of color. And, BE VERY AWARE of your light source during the patining process. These sulfide coats are quite transparent with lighter applications, and the color will look quite different with incandescent lights, halogen lights, fluorescent lights, or full sunlight. I typically use a mixture primarily of incandescent and halogen, but normally the overhead fluorescents also are on. Halogen is a good approximation to full sunlight.

[sculptorsam]

The show went pretty well. I didn't sell any of the bronzes but I did sell one larger steel works which made it worth while. From talking to some of the other sculptors at the show (the Winter Park Art Festival in Orlando, Florida), darker bronzes like mine didn't do well at all, while "brighter" works in aluminum/stainless or bronzes in greens/blues did very well. I find regional quirks like this very interesting.

Here's the link to where I found the Butcher's wax: http://www.bwccompany.com/

[sculptorsam]

I figured I'd resurrect this thread for a problem that has arisen. I had a larger small work of mine cast in bronze a couple months back. I finished it with Liver of Sulfer just like the other small works. I applied it a bit darker than before, getting an incredibly rich brown with some very nice marbling effects with whisps of lighter color. I applied two coats of wax as usual and took it to a couple festivals a week and two later.

After about a week, I noticed a couple "spots" appear the same color as the lighter marbling effects. With a bit of effort, I could rub them off with my hand. I applied another coat of wax, thinking I just hadn't used enough. About a week after that, I noticed more. They kinda look like water droplets, and I did get a couple drops on it when it sprinkled outside, but the spots don't quite correspond like they should with the water spots so I don't think that's the problem. Besides, the wax should be protecting it. These spots appear to be almost coming from below the wax. I know Liver of Sulfer will continue to darken and age over time, even with wax, but this seems incredibly fast and odd.

Has anyone else had a similar problem? It's a beautiful sculpture but I don't even want to let it out of the house until I can figure this out.

Thanks.

[Araich]

Was it hot when you first waxed it? It could be that there is a cavity holding moisture.

Myself, I have only ever 'cut-back' liver, to reveal a brighter edge and give some character - and in doing so have run water over the surface washing away any excess before re-heating and waxing hot.

It is possible that you have dried chemicals on the surface that are absorbing moisture???

[ExNihiloStudio]

It's probably a chemical reaction and it will probably continue until it's stabilized. To get rid of it you'll have to strip the wax, rub it out, and wait. If it doesn't come back in 2 - 4 weeks it should be all set.

[sculptorsam]

It was hot when I applied the wax, but I didn't rinse if off after applying the patina. I came across conflicting info on whether that was needed or not and since this was a larger work that wouldn't fit in the sink, I didn't. In the future I'll find a way to do it.

I will probably end up re-applying some heat and wiping the wax away. Maybe I'll rinse it as well and wait a while. I suspect I'll lose the nice marble effects in the process. That was partly my concern about rinsing it off before waxing as well.

[Jamo]

Carnuba paste wax. harder than beeswax and is clear. buffs shiny when cooled after hot wax application. I wouldn't use bees wax too soft doesn't last as long.

[fritchie]

Sam - I'm not sure what's going on, but as Araich says, it may be something appearing from tiny holes or "bubbles" in the cast metal. The only thing I can recall that is similar is tiny spots, usually whitish, that rarely have appeared over a period of a year or more, and they typically are easy to wipe away. Sometimes, they require scraping with a point, such as a needle. They’re pretty obviously bits of residual plaster that might have broken off during the pour and gotten caught near the surface. I’ve been told by bronze workers with years’ experience that sometimes happens, and the “efflorescence” will stop with time.

If the repair is obvious, I will remove the wax locally with solvent and/or heat, then repatine as in the first case.

On initial patining: I‘ve always applied a fairly heavy coat of protective wax while the sculpture is hot from patining. I used a batch of pure white, artificial beeswax for about the first ten years, until it ran out. Then I tried many things without finding anything as good. About 2 years ago, I found some fairly light yellow, natural beeswax, and I’ve used that ever since. Carnuba and Bucher’s were recommended, but I could find only yellow in the former, and the latter not at all.

[Araich]

Sam, on your spotting issue, I've done some reading and asking around and I think that it is definitely trapped potassium sulphide (Sulphurated Potash). Apparently, during heating small cavities can open up and trap the chemical, only to resurface down the line, showing through whatever method used to seal.
It was recommended to me to apply it cold to avoid this, though I have not seen this done (will try on next piece) AND you should rinse it before warming for the first wax.

One error I've been making is to use tap water to make up my batches. I'll now be buying some distilled water as I've no idea of the PH of Sydney tap water in a drought.

[fritchie]

Sam, on your spotting issue, I've done some reading and asking around and I think that it is definitely trapped potassium sulphide (Sulphurated Potash). Apparently, during heating small cavities can open up and trap the chemical, only to resurface down the line, showing through whatever method used to seal.

One error I've been making is to use tap water to make up my batches. I'll now be buying some distilled water as I've no idea of the PH of Sydney tap water in a drought.

Sam and Araich - The potassium sulfide theory may be correct, depending on the concentrations used. I‘ve never encountered color changes like this, and I do apply my patina solutions warm, waxing immediately after the final flame-drying, while the sculpture still is warm to the touch. This warm application of wax allows the wax to find its way at least partly into any small cavities, and that may help with the sealing.

In more detail, I use 2 concentrations of potassium sulfide, and if I’m also using cupric nitrate and/or ferric nitrate, I have 2 concentrations of those as well. With the sulfide, the concentrated solution is a fairly deep brown at the beginning, and the dilute solution is a fairly pale yellow. (Cupric and ferric are not at issue here, but the colors are deep and pale blue for cupric; and, for the ferric, medium and pale yellow-brown.) It is very wise to use distilled water. I find it cheaply at supermarkets. Separate brushes also should be used for each concentration and each solution, and it’s good procedure to wash the brushes after final use. Tap water is fine for this.

As the patining progresses, both concentrated and dilute sulfide solutions tend to turn dark, even blackish, from traces of copper dissolved from the sculpture and brought back by the brush. This doesn’t affect the process. (These sulfide solutions cannot be stored, and must be made fresh, directly from the crystals, with each use.)

Unless Sam used extremely concentrated potassium sulfide, though, I think there may be another explanation. In short, I always do just what he said he did, except possibly that his solutions are more concentrated. To describe my procedure a little more, I warm the whole piece with flame from a hand-held tank of propane or a separate gas heater. I place it on a turntable in good light, and then rotate it slowly while dabbing with either concentrated or dilute sulfide. When I’ve gone round the piece this way to a first degree of satisfaction, I heat lightly with no more application of solution until the piece is fully dry and is uniformly warm again, and then I repeat the whole process until I’m satisfied.

A couple of cautionary notes with this: (1) Applying concentrated potassium sulfide can give much darker colors than intended unless the application is a bit slow. There is an “incubation period” for the color to appear and darken, so it is wise to watch for the color to develop. (2) I’ve almost always found that some areas of the cast stay damp longer than others, and I’m assuming these are slightly “spongy", or places with more that the average concentration of tiny internal holes. I wait for all areas to dry at each step, and these persistently damp areas never seem to look different in the final piece.

[sculptorsam]

Thanks for both the follow ups. I do indeed use distilled water. It costs almost nothing and just seemed to make sense. For the concentration, I used what was printed on the package. Off the top of my head, I think it was a teaspoon per pint of water, but don't quote me on that. I applied it with a fresh brush by heating up a small area at a time instead of the whole piece. I didn't let it dry at all after finishing the patina, I just applied the wax warm right away. It may very well be some trapped in spongier sections, I noticed some on the surface of the cast. But the "blemishes" showing up seem to bear no relation to any surface imperfections where patina could be trapped. In fact, they're on some of the smoother surfaces.

I just looked at it today (I'm just letting it sit for a while to see what happens) and it seems to have stabilized. The blemishes aren't expanding or increasing in number. If it is possible to "dry" excess patina that is causing the problem, then it would seem to make sense to re-apply heat to the whole work, rub off the wax, perhaps let it dry, re-heat and reapply wax. I don't think it'll be going anywhere for a while so it's interesting to me to just watch it and tinker with it for a bit.

[fritchie]

Thanks for both the follow ups. I do indeed use distilled water. It costs almost nothing and just seemed to make sense. For the concentration, I used what was printed on the package. Off the top of my head, I think it was a teaspoon per pint of water, but don't quote me on that. Etc.

Sam - A teaspoon per pint probably is close to my more concentrated solution. I generally use about 3 - 4 liquid ounces of distilled water to perhaps a quarter-teaspoon of crystals. I use clear plastic cups for all these solutions, simply because they are convenient and cheap. They can be reused after washing, with the same solution always in a given cup. Generally, I make the dilute solution by pouring some of the concentrated into another cup and diluting something like ten to one. Nothing is measured carefully.

If you do decide to remove wax and go from there, I’ve found that it is necessary to scrub the area (maybe the whole sculpture in your case) with a good wax solvent such as xylene (hardware store) or perhaps naphtha (same source, but quite flammable). Unless all the wax is removed from a section, the solution will bead and not “wet” the surface or be effective.

As your solution seem comparable to my concentrated version, that’s what I find turns a warm area extremely dark brown to black within 20 - 30 seconds. If you don’t get near-black that way, I would guess it’s because your piece isn’t as warm as mine. I generally apply just a quick dab, and aim for the area to dry within 5 - 30 seconds, maybe with further flaming. Obviously, application will vary person to person, but I agree that you may have trapped raw liquid in some tiny holes.

[Louie Arce]

I recently attended a patina workshop in California. The instructor is a sculptor that has his own patina supply company"Sculpt Nuevou" His name is Ron Young from Escondito california. Do a Google seach and you will find him. He hase great products and great tech advice.....Metal_sculpt@hotmail.com

[Buster]

Louie, sounds like you got a lot of useful information from the workshop then?
That's good to hear because I have been signed up for the one he will be offering here in Phoenix in October. I've been using his products for about 5 years and absolutely love them! Can't wait to learn more about different application techniques and affects that can be achieved.

[Louie Arce]

another good source for large brushes are restaurant suppliers. Get the large brushes they use for baseting bread and meats with. Another good tip for techtures and paterns with patinas. #1: Tortois shell pattern...is tadidtionally done with hot patinas. However it can be done cold. How you say? Take that bubble wrap you got your X-mas present in and lay it over the cold patina(pop the bubbles) and let set for the desired time and repeat as much as you want.It works! Tip #2: You can many nice effects allso with plastic wrap. wet the metal with desired chemicals and wrinkle up the surface.What this does is allow for oxygen and and chemicals to fume in the ridges. Very nice technique to use. its just like fumeing a piece under a container...good luck have fun. And one last thing....use accetone to get rid of moisture on your metals before waxing this will help insure the longevity of the coating whatever you use...wax...etc....Louie

[Bill Heineken]

Hello all,

Iu was actually doing a search for Chemical etching, but found your discussion. I do larger commercial "ART WALLS" in copper, and bronze. For interiors I just use a product called Renaissance Wax. For exteriors I use permalac, or incralac. They are made by a company called stan-chem. It is a acrylic lacquer, a with UV inhibiters. I apply these with hvlp guns, and let dry for 20-25 minutes. They do offer a cutting agent for semi satin look. I do not use that method, but what I do do is this.

I apply a .5mill coating, let dry, scuff with grey scotchbright by hand, and apply wax for added protection, and finger print control.

Works very well.

To stop a patina, I have used acetone. It draws out the moisture.

I too have taken two of Rons, classes here at a local foundry. Very informative. Ron,a nd Debbie are very helpful with questions. I have a cor-ten project,a nd was having some issues with what I wanted to achieve. They sent me samples from their recommendations. I highly recommend the few books he offers for patinas. I have all of them.

I am not a huge fan of the LOS method, and tend to use the birchwood casey products for a base patina.

Good luck all.

Bill

[furby]

Think the vista ones have oxides in them thus sort of dye the piece, so unless i want no remnant of the fact its bronze, the real acid ones are better. i took to buying these cos its just about impossible to get your own chemicals here. they're quite OK colourwise & more predictable than real chemicals & making yr own (at least the "artistic" way i used to do it). You use almost nothing for a coat so a small bottle lasts ages.

[ara]

Sam - As a chemist (Surprise!), I always have mixed my own. Originally, I used a somewhat wider variety of materials, but lately it has been simply liver of sulfur (potassium sulfide), cupric nitrate (in a typical crystalline hydrated form), and sometimes a little ferric nitrate (ditto hydrate). Nothing more. I always start with the liver of sulfur, because I feel this gives greater stability to the patina.

I make both concentrated and dilute versions of each material, and apply with separate small brushes for each type. I heat the piece to the point when applied liquid evaporates quickly, and keep it more or less at this temperature, rotating and skipping over the piece fairly rapidly, and I apply wax immediately on cessation of patining. After the piece has cooled, generally over a couple of hours, I buff with soft cloth and sometimes also a soft shoebrush.

I’ve used various waxes over the years. On recommendation of a professional patinist in a demonstration when I began, about 1988, I bought some pure white “artificial beeswax”, and when this ran out about 2 - 3 years ago, I was desperate to get something similar, but couldn’t. After trying several other mixes, I located some pale cream beeswax at a reasonable price, and I use that now. It seem similar, but maybe not quite as hard.

You are right that commercial mixes probably do a very good job.

I'll have to check on supplier. It was an artists' supply house in the San Francisco area, that I believe still is in business, but one jar is more than a lifetime supply, so it’s been a good ten years ago that I bought these materials.

Fritchie you use the same 3 chemicals I am about to purchase from a local supplier..could you tell me what protection you use and if you have had any accidents/injuries?

Can it be stored safely in a shed which gets hot in the summer?

All help appreciated.