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Landseer
02-03-2006, 09:05 PM
In a previous thread I posted about this original CA 1890 terra cotta multi-piece architectural panel, (left) and that I have a mold only of the center winged dragon.
I sculpted from water clay- (Middle) a replica of the right-hand section using measurements and photos, and have the left-hand section partially done.
As long as I have that silicone rubber container opened I will go ahead and make a mold of this tomorrow along with a piece of cast iron.

I also scaled out and printed a multi-page copy of this 6 foot tall Art Deco panel to use soon to make a clay replica 12-1/2" wide and 21" tall, and maybe 2-1/2" deep.

I guess I can make the panel design either of two ways- rolling out a slab, maybe with a little texture impressed in it, and either applying strips of clay to the surface for the design, or rolling out a slab and just cutting the design down.
I like the idea of the first method because even though the background surface is pretty minimal, it IS there and it would look better if the background is even and flat in every area, whereas trying to sculpt down by removing clay to MAKE the background might look uneven.
Drawback of adding on strips and flats is I want to incize the design on the clay from the printed drawing to get all the curves and forms right.

I think I have one bag of clay left so I'll have to order more probably.
The design appears in an ad for Conkling-Armstrong terra cotta company in Philly. The 1/2 page ad is in a 1930 issues of "Architecture."

The ad says they used a soft grey underglaze on all of the terra cotta, with the backgrounds on these panels done in a darker shade to emphasize the ornamentation. That is an interesting concept, and amazing that simply for a little more effect they had to carefully apply two different underglazes on these which of course increased the labor costs.
I am still trying to find out where this Public School this is on in the Bronx is located, it was once PS 98 but that number has been reassigned to another school in Manhattan. I'm hoping to find photos.

Added: I just removed the rubber off my clay model, looks like it turned out fine other than a few thin spots in the rubber, the stuff has always been difficult to determine how thick you are getting it on the model and highlights and corners have always been troublesome, but the QM140 silicone worked well on dry water clay sprayed with clear lacquer.
The rubber peeled right off the model so easy despite all the deep undercuts, that the original clay (unfired) model was left intact except for one fragile leaf tip that I had pulled against and broke off.

I will hang on to the model, doubt I will fire it as it was never meant to be fired and now coated with lacquer who knows, might blow up in the kiln.
I just cast the mold for the first time.
Added the right hand photo showing the center and my cast from the new mold;

Landseer
02-16-2006, 12:17 AM
With the gallon of silicone I ordered, might be here today even... I'll be setting this terra cotta keystone up to mold this weekend, it might take the whole gallon. I don't plan to restore the damage on the top corners- it's part of her history and was likely caused by falling ice.

In another thread about marble's deterioration in the weather, the terra cotta weathers fine and is as crisp as the day it was sculpted, even the sculptor's tool marks and a few remnants of the seam of the plaster piece mold can be seen where it wasn't completely smoothed out.
It IS funny that back in the 1880's when these pieces were first made to replace carved stone on buildings, the stone carvers were all upset and tried to convince architects and everyone that the terra cotta would never last, ironic how it turned out to be exactly the oposite- the stonework is all wearing away, cracking, and spalling- especially brown sandstone but also limestone, and the terra cotta remains as crisp and impervious as the day it was installed- not even the acid rain bothers it.

Merlion
02-16-2006, 02:17 AM
... the terra cotta remains as crisp and impervious as the day it was installed- not even the acid rain bothers it.

Is it correct if terra cotta clay is fired at a sufficiently hight temperature, it is not porus ? If so, it is like other ceramics and should last.

By the way, on a different matter. Have you tried expanded polyurethane foam as the backing mold of such one piece flexible mold ? Unlike plaster, it is very light. And it can be cut easily later on into, say two halves for removal.

I've seen it done once, and just now I've purchased some to try out.

Landseer
02-18-2006, 05:59 PM
Is it correct if terra cotta clay is fired at a sufficiently hight temperature, it is not porus ? If so, it is like other ceramics and should last.
It is my understanding that these architectural sculptures were fired at a pretty high cone and have little, but some absorption qualities. In the later period after about 1900 they were often given a matt underglaze, this one included was given a matt underglaze, a neutral cement grey or white color usually.
Some were made of a yellow clay with a lot of grog and given a red matt
underglaze to make them appear to be the same color clay as the red brick. It was my understanding this was done because of some inherent issues with red clay for strength and shrinkage.


By the way, on a different matter. Have you tried expanded polyurethane foam as the backing mold of such one piece flexible mold ? Unlike plaster, it is very light. And it can be cut easily later on into, say two halves for removal.

I've seen it done once, and just now I've purchased some to try out.
I responded in another thread where you posted photos of that, good photos by the way!

I haven't tried that for molds- just insulating the house :) my personal thought on this foam is I don't like it- working with that stickey gooey foamy stuff insulating cracks is bad enough! I still prefer the old fashioned plaster piece shells and usually design them so the largest section simply stays put on the work table and only the smaller sides are removed.

It's good to experiment with new materials Merlion, so if your test on this works okay for you then it's a good deal and I'm glad you posted about it with photos.
I get really picky about how my casts look, I don't even like to repair old damage on the originals to do the molds because I like the casts to come out exactly the same and no matter how much I try to blend in a plasticene patch *I* can still see the texture difference in the casts. So too I like th eplaster piece shells because then I know the rubber is perfectly supported all around, nothing is going to bulge, "give" warp or change, it's good and solid and that too is important for my larger pieces- especially if I fill the mold with concrete.

I never found the weight to really be any kind of headache but I guess a disabled person, or someone who has lost an arm or hand, or has arthritis would really need the lightest material possible, and then this might work for them.

Landseer
02-18-2006, 06:10 PM
I have both pieces above going now, the rubber arrived yesterday. The lady keystone is mounted on a board and sealed, ready for work on her tomorrow. For today I am finishing building up the rubber on one half of the iron finial.
On the finial, once I get the mold done, I plan to pour a cast in one half of it with plaster and use that to make a wall plaque with the design on it.
I was thinking that if I do some work on that plaque design, I could maybe sculpt in a background scene, with the finial in the "foreground", I have seen this done especially in low bas relief on medals and coins of course, and it looks very effective, more so if the background design is done with an angle perspective- something similar to this bronze medal I own pictured below is the idea I had in mind.

I suspect this is not as easy an effect as it seems, because the sculptor has to rely strictly on the illusion of depth with angles and foreshortening techniques- especially true with die struck medals where the raised portions can only be a certain amount maximum and no undercuts.

I have pictures of the church from a number of view points, old and new, so I might be able to come up with something.

As an aside, as far as silicone costs, using QM140 v/s window caulk @ $5 a tube - the one half of the rubber mold for this finial used 600 gms of rubber (the 10# pail +1# curative is 4,889 gms) so when I do the other side I will use up only 1200 gms- about one quart, or 1/4 of the total, so the mold will cost me about $25 for the rubber.

I applied the rubber in 5 applications and carefully built up thickness around the protrusions as well as the keyed "flange" so the plaster shell can be made in two halves and remove easy, and the two halves of rubber will fit well and accurately together.

Tomorrow I start on the big mold of the lady keystone, that certainly will be an all afternoon affair.

Landseer
02-19-2006, 08:07 PM
I just finished the rubber portion of the lady keystone above, it took 4100 gms = 9 lbs.
I mixed it up in 440 and then 550 gm batches (500 base +50 catalist) since I don't like to mix a lot up all at once and the plastic bowls I have to mix in will hold just about 550 gms and is a nice size to work with.

It took 2 batches to apply each coat and I built it up with 4 coats, allowing some time - about an hour or so between for the previous applications to stiffen a bit.
The working time/pot life is very long, so it doesn't start curing while I'm applying it.
I need to get another gallon to finish the other half of that finial which seemed to take 2#, and then find something else I need to make a mold of to use the rest of that up.

Going back to cost of rubber, then you can see this one cost me about $75 for the silicone, but it's a BIG mold, the keystone is about 20" long.

Landseer
02-26-2006, 01:12 AM
The large mold came out well, I finished it today. The shell used 90# of plaster in 6 pieces. One pic shows the first shell piece, I didn't take sequential pics because by the time I got around to doing more on it the sun set and the pics don't turn out as well under the florescent light.

But the one piece was mirrored on the other side, another piece was made on the top, 2 small pieces on either side of the lady's helmet where it was undercut, and then one big section covering the whole face.

2nd photo shows the mold not cleaned up or trimmed yet, next to the original.
I will cast the first one tomorrow, so we'll see how much it takes to fill the mold!

I made the mold full depth so I can use it two ways- filled with concrete for those who want one of these to build into a wall, and filled only half way with hydrocal for a minimum depth lighter weight wall decoration. Later I'll make a second mold of the shallower depth cast for that.

The silicone rubber came off real easy and it was of good thickness

http://i23.photobucket.com/albums/b375/Randall2/PICT1149.jpg

http://i23.photobucket.com/albums/b375/Randall2/PICT1150.jpg
http://i23.photobucket.com/albums/b375/Randall2/PICT1155.jpg

daaub
02-26-2006, 12:37 PM
I made the mold full depth so I can use it two ways- filled with concrete for those who want one of these to build into a wall, and filled only half way with hydrocal for a minimum depth lighter weight wall decoration. Later I'll make a second mold of the shallower depth cast for that.

Hi Landseer,

When you cast in concrete do you make your own mix or use that ready-mix stuff? By ready-mix i mean the kind that already has the portland cement, agregate, sand, ect. all ready to go - the just add water kind. I have been playing around with a few mixes and still prefer a heavy stone mix mainly for the strength but also appereance. I prefer variations in color and texture of the surface.
In one recent test with just portland cement and a very very small amount of sand, i noticed some hair line fractures develop on the surface a few days after it was completely dry. I was curious how a pure portland mix would look with little to no agregate. I assume this surface cracking is because using too little sand and way too much water. With such little agregare used, the stuff got very hot while curing, much hotter then any other mix ive used. Could the heating and cooling be what caused the cracking surface?
Have you ever tried mixing in different materials such as metal filings, ect. to get variations on color and texture. In a piece that size, do you use any reinforcement in the concrete. Also, what do you use to seal the concrete pieces you sell?

Thanks,

Landseer
04-07-2006, 12:52 PM
I did some more work on the left side piece for my winged dragon panel, having gotten busy with other molds and all, it sat wrapped in plastic since last summer, but I got it out over the weekend and did some more finishing work on it. I need to get the right edge a little closer to the existing shape so they fit together closer, part of the gap is just they way they were laid on the floor for the photo and part is oversize to allow for the shrinkage of drying.
This isn't a big deal in any case since the original terra cotta architectural pieces were sized to allow a gap for the mortar, so they never had a "jigsaw puzzle fit" in any case, it was the mortar that filled gaps.

I'm hoping to have it done this weekend since it only needs a little more refining, smoothing and then the burlap texture impressed and worked onto the background to match the other two pieces, and then it's ready to let dry slowly.


The center and right are hydrocal, the left is water clay, both sides are recreated from photos;

http://www.lostnewyorkcity.com/store/537-3pc.jpg

Landseer
04-25-2006, 07:28 PM
The roughed out egg and dart molding for the above panel, roughed out, the bead and reel sub-design on the bottom is just rough as well.

The Egg and dart block is about 12" long and when done I'll make a silicone rubber mold of it to make enough plaster casts to create the border around the whole, modifying the corners to fit, and then making a mold of the entire assembly to make casts.
Not particularly difficult, but a bit tricky to get even as well as giving it the convex shape.

Edit in: Swopped images with the latest.

http://i23.photobucket.com/albums/b375/Randall2/egg-dart-latest.jpg

Landseer
05-08-2006, 09:32 PM
I am pretty happy with the egg and dart molding, so next weekend I hope to clean it up a bit more when the clay is a bit stiffer, and call it done.
I'm going to order two pails of silicone rubber so I can finish this molding, cast what I need to finish the panel border, the left side piece which was done a while back, and then mold the whole assembly.

I'll also make a mold of that big lion.

I ordered more water clay from Georgies, and I rec'd my order of tools from Dick Blick. The tools look very nice- calipers, a set of boxwood, and a set of 12 stainless steel wax/plaster carving tools shown here;

http://www.dickblick.com/zz330/59/

Plaster is murder on tools but while these are inexpensive they look like they will work well for fine detailing and final cleanup purposes which is what I selected them for- not carving down a whole block!

Landseer
05-20-2006, 05:43 PM
I started this large mold this afternoon;

http://i23.photobucket.com/albums/b375/Randall2/PICT1245.jpg



Here's one of the QM140 silicone kits, 10#, about a gallon plus the purple catalist. I have them add the thixo into the catalist in advance to save me from having to add this component myself. It otherwise comesas a third part which you can vary the amount of thixo properties with, I happen to find the amount they add at the plant for me is PERFECT for my use.
My little digital kitchen gram scale is also shown, it works well, very sensitive though the iluminated readout can be a little hard to see. On top of the scale is one of a stack of cheap hard plastic bowls I picked up at Duckwalls, I think they were a dollar each and comfortably hold 450 gms of QM140 plus the 45 gms of cat per batch.

I coated this large mold with 6 batches- about 6-1/2 pounds- 3 batches the first coat and 3 the second, I COULD add a 7th batch over all the corners and high spots to strengthen these areas which do tend to be thin if you don't take care to ensure rubber is laid up well on these areas, but I'll look in a few minutes and see if it's good as it is.

It is fairly thin and I skimped on adding my usual wide flange because this mold will only be used once to make a plaster master cast from, so the plaster supporting shell likewise will be made fairly thin and with that single use in mind.
To do it right and build up a nice thickness of rubber I would (and will on the next one) use the whole 10# kit.

I started around 12:30 PM and applied the 6 batches, had a lunch and break for a couple of hours, and finished it by 4:30, so it took about 2 hours to apply all of the rubber.

If this was latex I would have the first or maybe the second of 20 coats applied right now :)
Meanwhile, I could consider this mold DONE and ready to have the plaster shell on tomorrow morning, which means I could have my cast out of this tomorrow afternoon. If this was latex I might be on the 4th coat by then, just 16 more to go then ;)

http://i23.photobucket.com/albums/b375/Randall2/PICT1246.jpg

ahirschman
05-20-2006, 09:24 PM
Hi Landseer, thanks for all the pics, and great detail. I tend to be more wasteful of rubber, making simpler molds (Trading material for time), but my next one will follow what you have done. My molds are getting too big to continue in this style of mold making.

Thanks for taking the time to post all these images and the write ups.

Ari.

ahirschman
05-20-2006, 09:29 PM
Hi Landseer, thanks for all the pics, and great detail. I tend to be more wasteful of rubber, making simpler molds (Trading material for time), but my next one will follow what you have done. My molds are getting too big to continue in this style of mold making.

Thanks for taking the time to post all these images and the write ups.

Ari.

Landseer
05-21-2006, 11:18 AM
Well it's certainly my pleasure Ari!
With $100 a gallon material you really need to be on the conservative side with it's use while not skimping which can cause other issues.

I went back over the mold with a 7th batch after I posted, just to be sure the points, corners and other areas had enough thickness so there shouldn't be many weak areas. I will be starting the plaster shell right about now and everyone will tag along for the "ride" through that process today.

When it's done I'll carefully remove the rubber as it will be prety thin and I didn't expend much rubber making sure it's REALLY as thick as it should be, I did fill in a few undercuts though which will make the shell building easier.

Landseer
05-21-2006, 11:59 AM
First we start with coating the mold rubber with liquid soap, I just use the cheapest dish soap which in this case happened to be "Joy", coating the mold all over helps get the plaster shell off a lot easier.

http://i23.photobucket.com/albums/b375/Randall2/PICT1252.jpg






Next, these two images shows two areas of opposing planes between the lion's mouth and some of the raised fur details which would cause difficulty getting the shell off- it would be locked in these areas good and tight!

http://i23.photobucket.com/albums/b375/Randall2/PICT1251.jpg


http://i23.photobucket.com/albums/b375/Randall2/PICT1250.jpg


So the work around is to divide the areas in half with two small filler sections which are carefully rounded and smooth because these will be covered with another section. Once hard they are soaped WELL, and should they not want to remove easily because they are embedded in the next section and you can't get a grip, then working the larger overshell almost always separates them in any case, especially if the undercut or opposing angle is creating more resistance than the adhesion between the soap and the plaster.

I COULD have filled these areas in a bit with thick rubber and filled the fairly minor undercuts there in in such a way as the opposing planes are eliminated, but that takes more expensive rubber, so depending on the mold it's a decision you have to make there about which will be better. In this case, a use-once mold- I opted for the cheaper method, the time factor being about the same.

http://i23.photobucket.com/albums/b375/Randall2/PICT1253.jpg

Now ready for the next section!

Landseer
05-21-2006, 12:39 PM
The next section is done, were this to be a permanent mold the section would be made squared off, a bit thicker and neater.

http://i23.photobucket.com/albums/b375/Randall2/PICT1254.jpg

Landseer
05-21-2006, 02:17 PM
4th section now molded in place, the brown blob is plasticene, it allows for inserting a flat knife in if needed to pry the bottom section off without having to hammer in something;

http://i23.photobucket.com/albums/b375/Randall2/PICT1255.jpg

Now turned around to get the top;

http://i23.photobucket.com/albums/b375/Randall2/PICT1256.jpg

And the top section now in place;

http://i23.photobucket.com/albums/b375/Randall2/PICT1257.jpg

On this section I incorporated some shreaded plastic excelsior which is like the use of chopped hemp in the old days, it lightens the section and gives it more strength since it's only an inch thick. It also enabled me to start applying the plaster earlier since the intermixed strands kept it together almost like a spackle paste. First time I tried this since i have about 30 bags of the stuff free from work to use for packing material, worked well.

Back to the last section!

Landseer
05-21-2006, 02:57 PM
And now turned back around, the last section is completed, the so called "base" I refer to elsewhere that the rest of the sections sit on top of and are held together by.

The whole shell took 75# of plaster- about 5 pails worth- the base then is about 30# of that total and it stays on the bench, or would if it was a permanent mold, and only moved when the mold is stored away.
Right now however it's quite heavier than 75# because there is about 7 gallons of WATER or about 60# involved, some of that is chemically combined, most will evaporate out over time.

http://i23.photobucket.com/albums/b375/Randall2/PICT1258.jpg

So now at 3:00, and with a few breaks between, the shell took maybe 2 hours to complete, the rubber about 2 hours, and in about one hour from now I'll have a cast.
Keeping in mind the mold was started just about 25 hours ago, and if this was latex mold I might be on coat #6, with "just" 14 more to go or so :)

Costs:

2 hours set up
2 hours rubber
2 hours shell
TOTAL; 6 hours

6-1/2# of rubber with prorated shipping cost; $76.00
3 bags (75#) plaster @ $16.00 a bag $48.00
TOTAL; $124.00

My plaster is much more expensive than it should be, but I'm limited to access for it right now to a local hardware store- a year ago it was $10.49 a bag... This makes it MORE expensive than hydrocal but I need that long plastic state Plaster of Paris has that hydrocal doesn't, so unless I can get a cheaper source I can maybe mix the two to cut costs.

I have tried adding hydrocal to the plaster, and without controlled measuring or scientific testing it seems that once I added more than about 20% the setting action was more like the hydrocal- shorter and fairly sudden and the texture is courser in that plastic state probably due to the fact that it's rapidly forming it's crystals to harden.

And now at 4:30 I just finished splash casting the lion after determining it would take ten gallons of slurry to fill the mold, so I mixed 5 gallons worth and cast it hollow with the mouth area being filled solid to the top. I don't like doing this way because the weight of the plaster clinging to the sides of the rubber can pull the rubber away from the shell and make it dip inward, but I have a lot of rework to do on this-including fixing the already warpy, bumpy and out of parallel/square sides. If it comes out too bad then I'll have to go ahead and cast it solid then, hoping to avoid that as the cast will be around 100#, closer to 160 wet and that would be a real chore getting that upstairs!

Landseer
05-21-2006, 06:35 PM
Here's the cast, I have already begin the repair/restoration process, as can now be seen I have carved out the lion's mouth leaving the fangs full round as the original carved stone was, I like it so much better already!

Over further on the right at 3 o'clock position, the lion's cheeks which had an undercut originally- had been filled in and, and in his whiskers some odd surfaces show, maybe welding or mold seams on the cheap aluminum reproduction cast, all of this has to be removed and carefully restored back.

http://i23.photobucket.com/albums/b375/Randall2/PICT1259.jpg

Good shot of the lion's mouth, per further down I have carved out the lion's mouth, adding back the original details and configuration of the original stone carving.
As can be seen on top of the back of the lion's tongue there are carving marks, in tribute to the original late carver plus I'm obsessive enough about originality in every way including textures that I bought a 4 tooth stone carving chisel which very closely matches the 4 tooth pattern of some of the existing original carving marks, but will need a little 'blunting' to eliminate the "sharpness" of the new tool to better match the original.

I also drilled out both nostrils which had been totally filled in, and they now match the original's. The original nostrils when viewed in the old photo shows they actually did not match exactly which is rather curious since it was very obvious, same for the eyes- there are differences though not major. My guess is since this was on the third floor of the building's facade the level of accuracy to perfection was not deemed necessary. No attempt will be made to change that aspect.



http://i23.photobucket.com/albums/b375/Randall2/PICT1260.jpg

And this photo shows what else I want to correct- all those idiotic looking fake carving lines scratched into the surface are not original, the carving marks between the nostrils and upper teeth are original as are those directly to the left in the background by the lion's lower jaw, and on the bridge of his nose- compared to the added in scratches in his mane (they go diagonally from the 5 to 10 O'clock position in the photo are obviously of a different texture, spacing etc.

Going by the photo of the original carved stone lion, all of those clumps of hair forming the lion's mane had some fairly deep undercuts, so whomever reproduced this in aluminum filled ALL of those undercuts in along with the lion's mouth and scratched in the fake details.


http://i23.photobucket.com/albums/b375/Randall2/PICT1261.jpg

Landseer
05-22-2006, 10:54 PM
I started work on this last night, and did some more today on it, the lion's mane on the upper right coming down half way is where I started adding back the undercutting.
I did that according to the enlarged photos of the original carving which I had displayed on the computer monitor in the studio so I could refer to it as I worked.
Comparing the right side with the almost intact left shows a pretty dramatic difference and how much of the original detail had been covered up or filled in.
As mentioned earlier but more obvious in this photo- the right nostril is smaller than the left. that's how it was on the original stone and while I could fix it now I won't.

I'm finding I rather like carving plaster, wonder how it might be to carve limestone and how long it would take to carve something like this!


http://i23.photobucket.com/albums/b375/Randall2/PICT1264.jpg

Landseer
05-27-2006, 01:21 PM
Moving right along :)

I spent some more quality time working on the lion, I had to soak it in the bath tub a bit as it was drying out, and then I had to let it sit a couple of days to dry off the excess as the surface seemed to be TOO soft when it was that saturated.

I came home last night from work and did the rubber mold for my egg and dart molding and now I'll go finish that and need to cast 8-10 of them in plaster and start fitting them around the 3 pieces of my dragon panel. The corners all need to be mitered 45º and some of the blocks no doubt will need their lengths modified to fit.

I figured the easiest most accurate way to cut these is trying it on my chop saw outside, we'll see if it works with the blocks fresh wet out of the mold or if they have to be dry first.
It will be murder on the blade but that's what the cheap blades that come with saws are best used for- they are disposable :)

Now that I think of it, I think the blade is already dulled from a few nails...

I also have my Art Deco panel to work on, I already have the first cast of it considered sold to a client.

Now that I have a couple of casts of the egg-dart block I fit them side by side and they fit perfectly and look good. I was a little concerned the left and right half eggs would not match up well when the individual blocks were assembled, but I must have measured and sculpted the height, curvature, width of both ends and their half eggs pretty well.
Now that I know the weight of each egg-dart block, the whole assembly in hydrocal will likely weigh about 55#

ro_z21
05-27-2006, 05:01 PM
this is bloody brilliant!!!
thanks for taking the time to explain your process.
we do alot of casting at the art school i go to, and generally as students we like to keep costs down, and end up using latex. good for the pocket, but not good for time factor, nor any knowledge of other products that are out there.

what is the rubber stuff you use? whats it made from and whats the brand name? where can i get it from?

sometimes we would use alginate. but it can get quite expensive and the mold shrinks reasonably quickly and doesnt really last long. but dentist alginate is good for making molds of insides of mouth :)

also i find it interesting that you even put a rubber coating on. if this kind of thing was to be cast by any of my classmates, we would just build a clay wall,(with keys), one at a time though for each section of the mold, , vas up the object and start flicking the plaster on. the flick technique while the plaster is still quite runny is important to get all the detail and illiminate airbubbles. but i like your way better, no matter how careful i am i still get airbubbles, and theres no messing around with clay walls and you dont have to worry about the seams of the mold!

do you think hot wax could be poured into that rubber stuff? maybe thats why we dont use it...

Landseer
05-27-2006, 05:25 PM
Thank you for the comments, glad you find the info of use!

I use QM 140 silicone, it's sold here;

http://www.quantumsilicones.com/products.php

It's working out well, I took the egg-dart block out of it, and the original unfired water clay model was left totally intact- the silicone doesn't stick at all to it when sealed with a little spray lacquer.

I took the rubber off after only about a 14 hour cure, now that's rushing things a bit but the rubber is tough.

I'm confused about your process with the clay walls and flicking plaster, and not using rubber?


Alginate is an old time product, long ago obsoleted but some places like Sculpture house still sell it more out of tradition than anything else.
I need to cast a few more blocks, likely I'll post some pictures in a few hours.
I tried cutting some of the blocks on the miter saw and they just cut slick as can be with no chipping, looks like it will take about 4 more blocks than I thought to complete the border since some of them are being cut in half for the corners and the other half discarded as too short.

Landseer
05-28-2006, 05:35 PM
Posted in images folder