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Post by maverick on Feb 5, 2015 23:09:38 GMT -5
I have a mold done in plaster. Vaseline was used as the release agent for the plaster from the model. There is still some residue inside the mold and the surface is uneven. Will Vaseline make a suitable mold release for SF 320? Will it affect the expansion or react with the product?
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Post by Brian on Feb 7, 2015 23:03:20 GMT -5
.....You could also use hair spray...I use it with the RTV rubber....but as with everything test it first to see if it will work for your purpose
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Post by maverick on Feb 8, 2015 18:59:55 GMT -5
Interesting! I'd still have to fill in the mold or risk destructive removal using just hair spray... perhaps with the right clay...
I get the feeling some experiments are in order. Thanks for the tip.
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Post by Brian on Feb 9, 2015 19:35:01 GMT -5
...Also be aware that spray mold release has a shelf life...as I found out this week end...should have stayed with Vaseline....I have been pouring on and off for a few years and still experiment.
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Post by mike on Feb 10, 2015 10:09:21 GMT -5
A thin layer for Vaseline should work great ... Vaseline really helps seal the porosity of the plaster and is a great option.
Mike
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Post by maverick on Feb 10, 2015 11:18:11 GMT -5
I made a new mold in the same plaster to test with. The areas with Vaseline worked quite well. The areas with anything else... well lets just say I'm quite pleased with the resilience of the Super Foam 320 product when banging plaster off with a claw hammer. The test mold is now dust, but the casting is perfect and now I know what to use for the mold I really would like to save from destruction. Mold material: DAP Plaster of Paris - Professional Grade, Dry Mix + Rayon-polyester blend latex free rolled gauze casting material: Super Foam 320 Mold release trials: - Vaseline - a clear winner in every way
- Alumilite UMR Mold Release (spray can for rubber to rubber, rubber to resin, resin to resin) - no perceivable impact, also can be difficult to judge application at the bottom of large mold
- Hair spray - several brands - all areas seemed to have either no impact or made the expanding foam stick worse.
- Polymer clay - prevented sticking to mold the most effectively, however recovery from the casting proved to be somewhat more difficult. This did work well for filling imperfections on the inside of the mold, though next time I might cover the clay in shrink wrap or Vaseline
Thanks for all the input! Working with new materials is always fun. |
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Post by Brian on Feb 10, 2015 22:39:58 GMT -5
...I have only used hair spray (with good results) as a rubber to rubber mold release....I cast some very small pieces so the sprays (either hair spray or the real deal mold release) are what I prefer over Vaseline since the Vaseline could cause unwanted lines and etc. from being brushed on......and in some cases it's difficult to clean the cast up properly with an X-Acto knife or sand paper due to it's small size so absolute cleanliness ,from start to finish, is a must.
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Post by maverick on Feb 11, 2015 11:19:56 GMT -5
Exactly. Rubbers and acrylics will show every detail and imperfection and I would not use Vaseline in those cases either. I will be giving the hairspray trick a try for those cases in the future and I'm most grateful for the tip.
In this case I'm using expanding foam which does not preserve as much surface detail and cleanliness is nearly impossible. Ive got plaster molds of human torsos and the low density yet sturdy expanding foam is being used to cast a mannequin body. It will be skinned in a textile and used as a sewing mannequin by a friend who wanted custom and affordable. So I'm not as concerned about details as I am concerned about preserving the mold as it would be difficult (but fun) to recreate a mold each time.
If you haven't worked with Super Foam 320 before, it's a very fast (<60 sec working time), 20x expansion, sticky as the stuff in a can from Lowes. Man, it's a lot of fun!!
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Post by samuelgmaurer on Apr 23, 2015 15:46:00 GMT -5
What about talcum powder, does that work well?
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Post by mike on Apr 27, 2015 12:38:39 GMT -5
Talc powder or baby powder does work for most silicones but I would not depend on it when using it with 320 foam.
Mike
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