Reductions

[Giotto]

Hi Everyone,

I face a common problem. I prefer to sculpt (realistic, figurative) in 30" or larger scale. I can get the kind of detail I want in that scale. This is often too big for the market place so I need or reduce the scale by 50% or more. The ways I have tried so far are:

1) Reducit
This is a product that shrinks and you get a 40% reduction after a month of "drying". Big problems with distortion and cracking on anything thicker than 1/2 "

2) Silicone and solvent.
Works reasonably well for a 5 - 20% reduction

2) Re sculpting with a macchinetta or pointing machine
Too time consuming. I would rather spend the time creating new work.

3) Digital modeling and 3D printing
This is a area I haven't explored. I have seen some remarkable and detailed reproductions but I am think cost may be the limiting factor. If any of you have had experience with having a clay master digitized reduced and printed I would like to know about your experiences.

Cheers,
G

[grommet]

smaller tools... and a magnifier... with a light

[The Forge]

Hi Giotto,
Do you use a gas kiln to fire the pieces? After you do the initial firing, refire the piece using a 'high temperature reduction'. That usually reduces the piece by 40% and gives a dark color to the clay.

[Giotto]

Hi Grommet

I already use magnifiers and small tools on the 30" scale.....See my eyesight isn't what it used to be....and I really don't like moving tiny bits of clay around. also I have noticed that putting lots of detail into small figures comes out looking cartoonish. Other people can do it but it's just not my thing...maybe too much coffee.

Hi Forge

I have a kiln but I don't fire the clay. I use oil based clay and then make molds

thank you both
G

[Andrew Werby]

Hi Giotto,
Do you use a gas kiln to fire the pieces? After you do the initial firing, refire the piece using a 'high temperature reduction'. That usually reduces the piece by 40% and gives a dark color to the clay.

[Have you ever actually done this, or is it something you just heard about? I've done a lot of ceramics and I don't know of any clay that shrinks 40%, no matter what the atmosphere in the kiln is like. And while refiring can cause a clay sculpture to crack, it doesn't normally make it shrink further.

"High temperature reduction" refers to an atmosphere that has a lot of carbon in it, due to the presence of unburned fuel gas. This will darken (unglazed) clay bodies and cause metallic oxides in the glazes to revert to a metallic (de-oxidized) state, but it's not associated (as far as I know) with any further reduction in size, more than the normal 10-15% shrinkage that is normal between the raw and high-fired stages of ceramics.

But I'm always willing to learn new things - do you have any sources for this I can look up, or maybe some before-and-after pictures with yardsticks to show the rate of shrinkage?]

Andrew Werby
www.unitedartworks.com

[The Forge]

When I was at Hofstra University, there was a ceramicist teaching there who liked to try new formulations of clays for firing. We would compound and pug mill our own clays. The 'high fire reductions' were used primarily to bring out different colors in the glazes. I chose to put a pre-fired piece in the kiln and see what would happen. It was a mixture with a lot of iron in it. It started a light pink color and came out a deep, dark brown and shrunk. I was surprised how much it had reduced at least 25% in size. That's all I can tell you about it.

[Andrew Werby]

When I was at Hofstra University, there was a ceramicist teaching there who liked to try new formulations of clays for firing. We would compound and pug mill our own clays. The 'high fire reductions' were used primarily to bring out different colors in the glazes. I chose to put a pre-fired piece in the kiln and see what would happen. It was a mixture with a lot of iron in it. It started a light pink color and came out a deep, dark brown and shrunk. I was surprised how much it had reduced at least 25% in size. That's all I can tell you about it.

[That's interesting. Yes, I can see how a mix with a lot of iron oxide in it (which takes up more space than metallic iron) could shrink more than a normal clay body in a reduction atmosphere. I've certainly seen the opposite happen, where iron expands as it rusts, and sheds any concrete that's covering it. Maybe there's a new formula in there, for a special "shrinko" body. And 25% sounds more likely than 40%. ]

Andrew Werby
www.computersculpture.com

[Harryman]

3) Digital modeling and 3D printing
This is a area I haven't explored. I have seen some remarkable and detailed reproductions but I am think cost may be the limiting factor. If any of you have had experience with having a clay master digitized reduced and printed I would like to know about your experiences.

I scan pieces and modify them (scale, mirror, clean up etc.) quite often. Most of my work is really small and I have a CNC mill that I then mill them on, but I've also enlarged to over life sized and sent them out to be milled in foam. RP is also an option for smaller pieces, just keep in mind the higher the resolution and detail, the higher the cost.

[Mold Man Mike]

I used a shrinking urethane rubber system from Polytek Development on a 7 inch model and after 14 days the reduction is 50%. All of the detail is still there. I don't know if it is done shrinking yet. It is a fast setting product, so you have to work quickly. If this is done shrinking and it still isn't small enough for my liking, I can make a mold of this smaller model and pour more shrinking rubber in that and reduce it another %.

[Giotto]

I used a shrinking urethane rubber system from Polytek Development on a 7 inch model and after 14 days the reduction is 50%. All of the detail is still there. I don't know if it is done shrinking yet. It is a fast setting product, so you have to work quickly. If this is done shrinking and it still isn't small enough for my liking, I can make a mold of this smaller model and pour more shrinking rubber in that and reduce it another %.

Wow...hi Mold man.

Did you have any problems with the product cracking ? I tried "reducit" and found I was limited to 1/2" thickness or the cracking got extreme.

Thanks,
G

[Mold Man Mike]

Did not crack at room temp. I put a copy I made in an oven at 150F for 24 hrs and it shrank at 40% overnight, but cracked. Room temp and 2 weeks worked out well. No detail was lost through shrinkage.

[Mold Man Mike]

In addition to the "reduction" rubber I have used from Polytek, I also used a "growing" rubber. Through a few times of casting a part, soaking in water to grow, making another mold of the bigger part, making another part to soak in water to grow (you get the picture), I made this small cameo increase in size to roughly 600% without losing any detail.

[rika]

Wow, Mold Man, very interesting experiments!

[The Forge]

I am having difficulty understanding why a 30" well detailed figure will not sell. Yes, smaller ones are probably more marketable. But, if you do not want to sculpt smaller, why would you accept a smaller copy, which will lose much of your desired detail, as a true representation of your work? :confused:

[Giotto]

I am having difficulty understanding why a 30" well detailed figure will not sell. Yes, smaller ones are probably more marketable. But, if you do not want to sculpt smaller, why would you accept a smaller copy, which will lose much of your desired detail, as a true representation of your work? :confused:

It's strictly a market thing...I am being told that smaller bronzes sell better...probably because they can sit on a desk, bookshelf, side table etc as opposed to a stand alone pedestal...also there is the multiplying aspect of (my costs + foundry) x 2 (gallery market up) putting the cost above the typical buyer....from a fine art point of view I agree with you.

G

[Synappsys]

3) Digital modeling and 3D printing
This is a area I haven't explored. I have seen some remarkable and detailed reproductions but I am think cost may be the limiting factor. If any of you have had experience with having a clay master digitized reduced and printed I would like to know about your experiences.

Cheers,
G


Scan cost is anywhere from $500-$1000

Plan on $25 Cu/in for the print in wax

hope this helps

[The Forge]

Check www.dirdim.com. They do all that type of work.

[Mold Man Mike]

My part shrank even more since my last posting June 4th and kept all of the detail.

[Giotto]

Thank you Synappsys and Forge for the digital info. It is expensive as I thought.

Mike,
I ordered some of that shrinking compound today. If I get good shrinkage with no distortion or cracking then I have to say Polytek has a hot product at $90/gal.
Thank you

G

[Mold Man Mike]

A gallon goes a long way. The product gets mixed with a solvent (I used paint thinner) and water. The stuff is fast to go from liquid to a rubber. I suggest mixing the solvent with the product using a mechanical mixer (I used a drill and a turbo mixer), add water and mix and pour in 25 seconds.

[WillPaq]

This stuff is great but it does go off faster than any compound I have ever used. The first time I used it I didn't even have time fully pour- the stuff gelled as I was pouring it.

I recommend putting it in the fridge and using ice cold water, as that does give a little extra time to mix and pour. When de-molding your pieces, be advised that the material is pretty unstable and will tear easily until it shrinks.

[deuxpan]

Hi Everyone,

3) Digital modeling and 3D printing
This is a area I haven't explored. I have seen some remarkable and detailed reproductions but I am think cost may be the limiting factor. If any of you have had experience with having a clay master digitized reduced and printed I would like to know about your experiences.

Cheers,
G

I'll chime in on this as it's something that our company does rather often.
For good-quality and most importantly accurate reductions 3D scanning and printing is your only solution.

Someone already mentioned some prices which seem pretty spot on. But let me give a little explanation which might make those prices seem more affordable.

1. 3D Laser scanning cost - Once a 3D laser scan is completed you will always have it. You can use it for archiving purposes so if the original is broken or the sculpture is lost a new one can always be printed using the scan. If your sculpted clay is 30" and you're scanning to create a 12" piece for marketing purposes or whatever it may be, you can then use that scan to have a company like ours enlarge it to life-size or greater for a monumental sculpture. Using the 3D scanning services to their full potential from reduction and enlargement standpoints together or trying to achieve a larger variety of sizes the cost of the scanning starts to be dispersed.

2. 3D Printing - There is variation of different 3D printing machines but I personally have the most experience with ZCorp 3D printers so I'll talk about them. Synappsys mentioned a cost of $25/cu in which is spot on with what we charge for 3D printing using Zcorp printers which produce a plaster-like model which is great because having the plaster properties allows it to be tooled and "scraped" so modifying the model by hand (if you feel necessary for any reason) is done easily and quickly. We have some infiltration processes that also allow the "plaster" model to be drilled, tapped, etc.

I can't say about other printing processes but with our 3D printing service we can print the sculpture (if the shape allows) hollow. So while the $25/cu in price applies the volume of the sculpture gets decreased to only a relatively thin shell (roughly 5mm for stability purposes). You only get charged for the volume of that shell and not the whole model. So if lets say you had a box that was 2 x 2 x 2". That's 8 cu in and thus $200. But if we hollow that box to 5mm thickness and leave one side open (one side open would be no problem as it would sit on that side and would not be seen) now the volume becomes 3.35 cu in making it $84.

I know of too many people that did some guesstimate volume calculations (by eye) of their sculptures and eliminated 3D printing as a viable option (due to monetary concerns). Don't do those mistakes, talk to me or another company of your choice that does similar services so we can go over all the options and making these truly helpful services fit within your budget.

You can contact me with questions at deuxpan@deuxpan.com .

Here are a couple examples of what we have done:

http://deuxpan.com/Portfolio/portfolio1/images/1.jpg
In this photo we're showing the "workability" of the material so you can refine or change the model using simple tools.

http://deuxpan.com/Portfolio/portfolio5/images/2.jpg
This reduction was done for Mr. MacDonald, you can see the 12" 3D printed model next to the original 36" plaster. If you look very closely at the reduced sculpture you can see the tiny signature.

http://deuxpan.com/Portfolio/portfolio8/images/3.jpg
This was actually an enlargement from 12" to 20" and as you can see, all details transfer over perfectly.

http://deuxpan.com/Portfolio/portfolio2_2/images/4.jpg
This is a perfect example of alleviating scanning cost. The artist had us create the large-scale angel using our robotic-routing service and also had a small 12" model 3D printed. The same 3D scan was used to create both.

[SPRINGFIELD]

Hi Grommet

I already use magnifiers and small tools on the 30" scale.....See my eyesight isn't what it used to be....and I really don't like moving tiny bits of clay around. also I have noticed that putting lots of detail into small figures comes out looking cartoonish. Other people can do it but it's just not my thing...maybe too much coffee.

Hi Forge

I have a kiln but I don't fire the clay. I use oil based clay and then make molds

thank you both
G

I'm wondering what kind of oil based clay you use. I used to use soft clays like Jolly King and Van Aken. They were fast to use but hard to get detail.
Now I use Chavant NSP Medium Gray and NSP Hard Gray.

The new clays are slower working but I can get much better detail and my
sculpting has improved overall.
My eyesight isn't so good either. I usually heat up the NSP clays a little than
rough out my sculpture. Than I use warm metal tools and some reading glases
to get the detail.
Also have you ever tried Chavant's Y2 Clay? It's kind of like a clay and a wax.
I have trouble with the color of Y2 Clay though it's a dark brown.

[john wendelbo]

you can't beat 3D laser scanning combined with rapid prototyping, we do it all the time with our minolta vivid 9i 3d scanner and do the rapid proto dirt cheap (10$ / cubic inch) on a ZCorp printer (ie comes out in plaster) - when there isn't too much detail we even print out of wax (which goes straight to shelling and gets cast, ie no mold). It all works beautifully.

by "we" I mean carolina bronze http://www.carolinabronze.com.

you can also see some rapid proto stuff at my website in the "sculpture" and "dimension 2.5" sections http://www.johnwendelbo.com

incidentally for a 12" figurative we charge 800$ for the high res scan.

cheers

[john wendelbo]

by the way - the guesstimate to get the volume for rapid prototyping purposes is to evaluate the surface area of you piece in square inches, and divide that number by 4 - that gives you the volume for a 1/4in thick shell, which is what is typically used for rapid proto pieces, that gives you the material volume in cubic inches, you can then multiply that by $15-$25 which is quite a common price per cubic inch for RP processes -

hope this helps...

[Mold Man Mike]

Here is 3 1/2 months. I think it is done shrinking. All detail perfect.

[mantrid]

3 1/2 months! It would be better to just sculpt it again from fresh. In that time you could have made dozens of them.

[Mold Man Mike]

Giotto
How did the product you bought work for you? Did you use it yet?

[Mold Man Mike]

Mantrid

That is an option

[David Kim]

I'm arriving into this conversation very late, but if you guys are still around, I wanted to ask what was the name of the products from Polytek?