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Old Mar 24, 2011, 10:45 AM
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warhead_71's Avatar
Chicago, IL
Joined Dec 2006
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I use Alumilite brand silicone mold and PU resin. I'm not sure I understand what you are asking though... the PU is not supposed to stick to the silicone mold. To get the resin evenly distributed over the inside of your mold, you have to do rotational casting... meaning you have to rotate your mold in all axes as the PU hardens. The fast-drying resin I use starts to harden after just 3-4 minutes. I don't use a "rotation machine", I just slowly fill my mold with the right amount of resin (to avoid bubbles), seal it, then rotate it by hand to get good coverage. After a minute of rotating it by hand, I start to juggle it in the air... just spinning it and tossing it like a baseball, to keep the resin from sagging. After about 4 minutes, I am done.

P.S. - check my blog. I have another pilot nearing completion. I'll post some pics here when he's all done.
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Old Mar 24, 2011, 11:49 AM
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Sverige, SkŚne Lšn, MalmŲ
Joined Sep 2010
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Quote:
Originally Posted by warhead_71 View Post
I use Alumilite brand silicone mold and PU resin. I'm not sure I understand what you are asking though... the PU is not supposed to stick to the silicone mold. To get the resin evenly distributed over the inside of your mold, you have to do rotational casting... meaning you have to rotate your mold in all axes as the PU hardens. The fast-drying resin I use starts to harden after just 3-4 minutes. I don't use a "rotation machine", I just slowly fill my mold with the right amount of resin (to avoid bubbles), seal it, then rotate it by hand to get good coverage. After a minute of rotating it by hand, I start to juggle it in the air... just spinning it and tossing it like a baseball, to keep the resin from sagging. After about 4 minutes, I am done.

P.S. - check my blog. I have another pilot nearing completion. I'll post some pics here when he's all done.

Hi Warhead!

Well,...it has to stick just a little,...in My case the resin leaves small clear
areas. Just like water on a newly waxed car......

I've tried with different releaseagents to no avail

Otherwise I use the same procedure as You do. Sometime I use My rotocaster, but mostly My hands.

To sum it up,...I need some kind of "releaseagent" that makes the resin stick a little, but not to much,...

Kind regards
Seejay
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Old Mar 24, 2011, 02:10 PM
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Good stuff. I need to read up on it. thanks.
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Old Mar 26, 2011, 01:33 PM
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USA, TX, Fort Worth
Joined Sep 2004
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Another victim sucked in

Like many others who have added to this thread, I have been drawn in and I had to give it a try. Itís so different from anything I have done before, but I canít seem to quit fiddling with it! I see it as two distinct challenges. First, creating a sculpted figure, and second, reproducing it with a mold and some sort of casting. I think Iíve done better on the first part (sculpting) and am still struggling with the second (casting) but Iím getting better. Although I am happy with my results, the main lesson is this takes time and experimentation. Iíve had a pretty steep learning curve. However, each one I did showed clear improvement and I found it addictive. Iím convinced that anyone can do this given enough time. The main lesson I think is that if the process itself doesnít appeal to you itís better just to buy a pilot. Iíve never posted here with pictures so I apologize if this posting doesnít turn out.
Creating a sculpted figure: Iíve never sculpted anything, so I decided to start with something and then modify it. I have children around with way too many toys. It didnít take much time in the toy box to find a couple of victims to start with. Basically I coated them with Vaseline and used 100% silicone caulking from the hardware store to make a basic mold. I brushed the silicone on in thin layers and then used plaster of paris to add a rigid backing.
If you are just looking for something basic, this might be all you have to do. Make a mold, use tissue and wood glue to cast a figure, paint it and go.
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Old Mar 26, 2011, 01:34 PM
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With a mold made with the method above, I then took some Super Sculpey and squeezed it into each side to cast a figure to work on. I put a popsicle stick in the middle of the two sides to hold on to while I worked it. With some photos in front of me and a little practice, I was able to come up with some acceptable results. Once I had results I liked, I could make another mold of my sculpture and then use Super Sculpey to make a second or third generation figure for further improvements or changes. After a couple of generations on and you can barely see the original. Without the crutch of using a toy figure as a place to start, I donít think I could have come up with my results.
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Old Mar 26, 2011, 01:36 PM
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Sorry I meant to include these photos with the last post
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Old Mar 26, 2011, 01:56 PM
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Molding and Casting

I did a lot of experimentation with this. I could have just bought the bottle of casting silicone, but then what would ezone be without a bunch of experimentation and DIY searching (and cheapskates)? To make the first molds, I used ordinary silicone and experimented with some recipes on the net for thinning it and getting it to set up in thicker applications. The only advice that I thought worth anything in the end was the idea of mixing a spoon of cornstarch and a dab of acrylic paint to a cup of silicone. This gave me the possibility of mixing up a thick batch of silicone and it would cure all the way through in no time. It made a good backing material for a higher quality silicone I used to capture the surface detail. For the initial mold layer, I found ďMold Max StrokeĒ from Smooth On to be easy to work with and for 24$ trial size, a little bit has gone a long way. The last few molds Iíve made were just a couple of layers of Stroke and then a plaster backing to lend support, and Iíve been very happy with the results. I do the mold in two sides, using the method with clay. It takes practice, but I think Iíve got it down.

Once I had molds, I tried lots of things to cast the figures. Silicone is so forgiving, you can pour just about anything in there! Light weight spackle, a few layers of tissue and glue, pouring latex paint into the mold a few times and drying between layers, and then various mixtures of all of the above.

While these are not quick drying and can take some effort at layering, they offer good results in weight, and the materials are right around the house for anyone to try. To dry each layer, I would put the mold over the heater or use a hair dryer. With more experimentation I think thereís some combination of these home materials that would do a good job, but not if you wanted to do a large batch of professional quality figures. Also, you need more patience than me. I always want to peek too soon. Lately Iíve settled on the low density two part foam from Smooth On ďFoam It!Ē at 3 lb density. This is the only foam Iíve tried. Itís too expensive for me to experiment with the huge amount of casting and molding materials out there (thatís why this thread has been such a help). I found it to be OK, but not great for casting all by itself. The weight is good, but the skin wasnít all that great. My answer has been to coat the mold with auto primer to give it a nice skin and give the final cast plenty of time to cure. When I can keep from peeking, this has turned out to be the best for me. This guy is about 1/18th scale and is under 2 grams. The 1/12th scale guys weigh around 3 grams.
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Old Mar 26, 2011, 01:58 PM
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Questions

!!!!!!Questions for others out there:
Goggles are driving me insane. Working on faces and clothing is forgiving because thereís fudge room in the symmetry. Thereís so much variation in faces and folds that I find it easier to produce acceptable results. Goggles are symmetric and machine made and if you donít get those angles and sizes right it looks like Elton John as someone else in the thread has said. I would like to mold some goggles separately to attach, but Iím having a devil of a time figuring out how to make acceptable ones. Super Sculpy is so difficult to work this small. Any pointers? Iíve seen some really good ones on the thread.
I wonder what other casting foams are like and how they would be different from the one I tried. Any favorites? Anyone tried the lightweight PolyTek foam?
http://www.polytek.com/cart/index.ph...ategory_id=270

All the best,
Josh
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Old Mar 26, 2011, 02:53 PM
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mistairjoe's Avatar
lake orion mi
Joined Sep 2002
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If I made some scale goggles and cast them in bronze or brass would that be a good idea?With out straps or lenses of course.Joe
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Old Mar 26, 2011, 08:11 PM
Zach
Illinois
Joined Feb 2004
806 Posts
I have done some experimenting with separate goggles and oxygen masks.

I sculpt them with Sculpy's Bend and Bake. It's a type of Sculpy clay that stays rubbery after you bake it. This prevents the thin pieces from breaking.
You can also mix the Bend and Bake clay with other Sculpy clay to get a mixture you like. Even at less than 1/4 Bend and Bake a clay mix is still flexible after it is baked and I think, easier to work with.

I sculpt the goggles on a casting of the head they are for and then bake them still on the head at a low temperature. Maybe about 150 or so. You will have to experiment to see what works best for you. Before baking I try to loosen the goggles a little from the head to make removal easier after it has been baked.

I'm experimenting with a resin called Task 14 from Smooth On. It is a rubbery like material when dried. It's suppose to be black but when cast very thin it is transparent but it takes paint well. Getting good castings has been a challenge though.
It's a work in progress.

Zach
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Old Mar 26, 2011, 08:14 PM
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Joe, Not having any idea what steps would go into such a procedure, what other possible response can I offer other than, "Of course, that sounds fantastic!" Would you like me to send you a couple of my amateur castings to mess around with?
Josh
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Old Mar 26, 2011, 09:24 PM
Zach
Illinois
Joined Feb 2004
806 Posts
Josh,
I checked my notes and your foam is producing some good numbers in the weight department.

I'm doing rotational casting with Smooth On Smooth Cast 305. The lowest I can get my 1/12 pilot is 9.4 grams and my 1/16 pilot is 2.8 grams. That's the least amount of resin I can use and still get a casting without holes in it.

Zach
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Old Mar 26, 2011, 11:05 PM
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Zach, That's a good idea with the bendy sculpey. I might try to find something firmer too. The super sculpey I work with is just too soft for those tiny frames. I went back to double check the weights and here's what they are unpainted. The 1/12th is just under 3g and the 1/18th (I think, maybe 1/16th?) is just over 1 1/2 grams. Another one I did in the same mold came in closer to 1 gram. I am happy with the results.
All the best,
Josh
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Old Mar 27, 2011, 07:57 AM
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lake orion mi
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Making goggles involves designing masters in Rhino in different scales,milling them on a small CNC mill in wax,[i own a mill] and then taking a silastic mold and casting in metal or resin.Joe
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