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Post by hawkeye15 on Jun 11, 2015 22:21:41 GMT -5
I am using the Alumilite performance 65D to cast a prototype of a human hand and had some questions regarding products function or if
I am doing something wrong. I am casting into an algenate product not unlike the dental algenate used by dentists. I mixed equal parts of
A and B together mixed very well with drill and paddle, then poured into cast slowly. I shook to remove as many bubbles as possible when half way
poured then finished pouring. The product heated up then expanded out of the mold about one inch above opening almost like it was boiling.
After a couple hrs I removed it and hand appears to have very many bubbles in it (somewhat clear). My question is this normal or did I screw up
the process? new to this so many questions here. Thanks!
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Post by mike on Jun 12, 2015 14:05:02 GMT -5
Alginate molds are basically powder and water. Any water that comes in contact with a urethane makes foam. So basically the water in the alginate mold reacted with the Perf 65 as it was curing and started foaming. I've never heard of anyone being able to successfully cast urethane parts in an alginate mold. Most of the time people will pour plaster or cement or some other water base product in alginate molds. Then, the water in the alginate mold will assist the cure rather than contaminate it.
I would suggest trying a silicone rubber mold instead of alginate. If you have to use alginate, pour a plaster reproduction, then make a silicone mold off of the plaster reproduction and then cast Perf 65D.
Mike
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Post by hawkeye15 on Jun 12, 2015 15:57:14 GMT -5
I see, did not know that Mike. I will go the way of the silicon rubber then! thanks so much for your response.
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Post by hawkeye15 on Jul 20, 2015 15:40:43 GMT -5
What type of release agent would I use if I was using silicon rubber mold?
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Post by mike on Jul 21, 2015 11:06:50 GMT -5
You don't have to use any mold release when pouring a urethane resin into a silicone rubber mold as urethanes will not bond or adhere to silicone. Really, nothing other than another silicone will bond to silicone. That is why you are required to use mold release when making a two piece silicone rubber mold. Nothing sticks to it other than another silicone.
With that said, if you want to make your molds last as long as possible, people will often spray a silicone base mold release into their silicone rubber mold to release urethanes and other resins so they last much longer before eventually drying out and sticking.
We sell two releases ... Stoner Urethane Mold Release and our UMR which is more of a do all release which is also paintable. These two will help your silicone last longer and produce more Perf 65D parts out of it before wearing out.
Mike
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Post by hawkeye15 on Jul 21, 2015 16:31:52 GMT -5
what about polyurethane rubber molds using the urethane performance 65d? does the stoner release agent work for those as well?
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Post by carol - Alumilite Corp on Jul 22, 2015 9:00:01 GMT -5
If you already have a urethane mold and don't want to make a silicone mold, yes the Stoner Release will work for urethane to urethane. Make sure all areas of the mold are sprayed well before pouring urethane into urethane.
If you have to make a mold ... typically silicone is the way to go when using urethane as a casting medium.
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