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View Full Version : Polyurethane, plastics, and plaster of Paris: Does silicone hate them?!



Suzy Specter
09-07-2016, 08:58 PM
Hi there! I'm new to the MerNetwork, so forgive me but but after hours of hunting I couldn't really find my answer.

I'm embarking on my first silicone tail adventure! *@_@* terror!

I'm a cosplay enthusiast, and I've even made vacuum sealed storm trooper armor (plastics melted over a mold) so I have a GENERAL working knowledge of plastics and polymers to an extent.

I resin cast and do about 5000 other crafts, but before I start my fin fun, I have a question.

I had someone cast my lower body with plaster of Paris strips. I now have a life like mold from under my rib cage to my feet in two parts (front and back). We used Vaseline as a release agent, and I wore some plastic wrap on... My lady bits, in order to protect me.

I haven't decided what method to use yet, and I'm keeping my concept kinda secret cause I also vlog and I want this to be a surprise! (I've been filming to whole process).

Anyway, I wanted to know... The mold lifted the details of the plastic wrap and obviously where my knees and things and such were cast there's a trench. I need to build around or scuplt the outside (if I decide to do a pour of sorts) and / or to smooth out or fix the imperfections on the inside.

If I do a mesh / scale by scale method, I can still seal the mold and fill it with insulating foam, but that will still leave the trench like indentations on the outside, and I don't want to have bags in my tail!

I have a Dremel and I was wondering is it possible to use like, fiberglass resin or polyurethane to sculpt / smooth the imperfections on the inside, or will that effect the silicone? Or let's say I want to sculpt the outside (like a full positive) for a pour or something... What kind of material can I use for that?

Did any of that make sense at all?! Lol

I have a few photos but I'm using the mobile site to post this so I can't see how to show them *twitch*.

Regardless of method I plan on sculpting the fins and fluke in clay, and will most likely use appropriate DragonSkin or some such for the tail. That's my plan, anyway.

Anyway, thanks for reading. Hopefully it doesn't sound cray lol.

Iamonlyme@me.com
09-07-2016, 09:06 PM
Maybe I am missing something because I am also knew to this but if the imperfections are on the inside of the mold why would it matter? My understanding is that you would seal the two halves together and place your power mesh/spandex/naprene what ever you choose over the plaster legs and than pin the scales on and seal.


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Suzy Specter
09-07-2016, 09:31 PM
Technically they are one both sides due to there being strips laid across and the fact that we used layers so there's a seam of sorts as well in some areas. I'm just wondering how I can smooth those out in case I paint over the mold for a form fitting silicone lol. So many possibilities! I want to avoid pinning / casting one scale at a time if I can 😰

Iamonlyme@me.com
09-07-2016, 09:34 PM
Ok I see now :) I don't think I can help much sorry :( maybe paint plaster over the put side to fill in areas layer by layer?


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Suzy Specter
09-07-2016, 09:35 PM
http://mernetwork.com/index/webkit-fake-url://75202831-d169-43b0-8e6f-894073f81d3b/imagejpeg

Iamonlyme@me.com
09-07-2016, 09:39 PM
http://mernetwork.com/index/webkit-fake-url://75202831-d169-43b0-8e6f-894073f81d3b/imagejpeg

Sorry I can't see picture


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Trident True
09-08-2016, 04:27 AM
Ok so from what i can gather you want to fill the creases in the mold due to the glad wrap? you could use polyfilla. its a paste used to fill in holes in walls etc. its a plaster. you can buy it premixed. to answer your Q. polyurethane and urethane will not inhibit cure once cured.

KaraLenae
09-09-2016, 10:49 AM
I did foam scales then poured plaster of Paris over for my mold. I noticed some 'imperfections' where my scales didn't lift out perfectly. I used my dremel to smooth out the bumps and lumps. How about using burlap dipped in plaster of paris to 'fill in' the creases. Then you can use the dremel sander tip to smooth out. I used vaseline as a release before I poured the dragon skin silicone. Hope my rambling helps!!! Good luck :-)

"It's the good girls who keep diaries, the bad ones never have the time." Tallulah Bankhead