molding original sculpture

[oldterryr]

i sculpted a coyote head form and made a mold from fiberglass (resin and bondo) - i have tried 3 times and i still cant get it to seal on seams - foam googes everywhere - is there another product i can use for the mold - cant figure out what i am doing wrong

[Doug Bridges]

You need to use fiberglass cloth and resin for the mold. Start with a resin coat, then light glass cloth and then the heavy stuff. Then drill holes in the flanges for bolting the halfs or pieces together. You have to bolt it in order to get a good seal and stop the foam from  busting the mold apart.

[oldterryr]

hav already done that and i stll cant get seal

[Bruce Foster]

Terry..........the use of fiberglass cloth, only adds strength to your mold, and in know way hinders leakage around the seams.......you needed to put a channel grove in your mold half's........try running a bead of latex caulk around your mold shelf........put to two halves together, and clamp them down all away around your mold with either nuts and bolts. c-clamps or vise grips........then pour your foam.....add a tad of water to your foam mix......this will give you better expansion and density.......once the foam sets, you should still be able to break you mold apart........if you relieve the pressure from the poured foam positive to soon, you foam could collapse into what looks like a giant raisin...hope this helps

[AndyO]

How are you securing the two halves together? For fiberglass I use a lot of bolts (1 bolt every two-three inches) all the way around the mold. For a plaster mold I use clamps. I embed wood into the mold so there is something for the clamps to grab.

You really never explained how you built the mold so it is hard to say why your not getting a good seal.

[rodlrock]

post some open and closed photos, then we can help you a lot better (we will see were the problen is) .

[oldterryr]

bruce i have done THOSE EXACT steps and still cant get seal - is there another medium i could use

[Bruce Foster]

Terry.......if your mold shelf is tight, with no open voids, other than the small space normally between the mold halves, then you should have no problem.......if, there is any unevenness or clear open voids in the mold halves, then try folding paper towels and use as a gasket around the mold shelf........you can also seal the after the towels the seam with duct tape, before you clamp the mold.......sounds to me Terry, without pictures, that the mold shelves for each half might not have a tight fit, allowing the caulk seal to be broken because of the amount of foam that is displacing it......hard to tell without seeing it

[bill@hogheaven]

Terry, If you used a lot of resin (you only need enough to wet out the mat) the heat produced may have caused the mold to warp. It has happened to me.

[oldterryr]

thanks for help - i will try the paper towels - i have a ton of time invested in the mold(s) - this is my second try - not sure the sculpture will hold up for anohter tryu

[newbirdman]

  You guys a missing the point . If hes losing foam then he doesn't have the flanges made properly . Nothing he cant do will stop the foam from leaking unless he fixes the flanges . When you made the first part of your mold , did you let it cure and then wax the flange and mold the other side ?
   Now for Andy , if your using bolts to hold your mold together your wasting a lot of time . You can buy packs of cheap vice grips 3 / $6.00 and clamp the mold this way .It takes forever to use nuts and bolts .  Rick

[AndyO]

Your probably right Rick. I learned how to build antler molds by reading Erich Carters Taxidermy Today articles. Thats what he used so I did the same. I thought the vice grips would be pretty heavy on the flanges so I never tried.

[TrailsEnd]

I am just giving a little thought to it. Are you placing a cut out piece of plywood into the back of the mold to create back pressure when you pour the foam in?  I also have flanges in this area so that I can " C"  clamp a piece of 2x2 wood over the plywood to get backpressure and density in the foam. Just thought it would help you if you aren't doing so.
Chuck

[Jaffery]

What I could understand from ur question is that the foam leaks out of the mold's seamline. There may be only two reasons (1) U could not make a nice and clean seamline (2) The foam pressure makes a gap between the two parts of the mold.
SOLUTIONS: 1)Try to make a very smooth seamline 2) Unless u use any system to lock both the parts u will always face this type of problems.