I have been practicing casting Platsil gel-10 and Ecoflex-30 and have run into an issue with the casts seeping oil. At first the cast appears great and seems to have cured fine, but after leaving it out of the mold for several hours it accumulates quite a bit of oil on the surface. I've wiped it off several times but it keeps seeping out.
I tried a test cast using my mold and only platsil gel and the cast did not seep oil. This gives me some confidence that my mold is not contaminated. I also tried a test cast using only ecoflex and it did not seep oil (though this was not done in my mold, but in a cup). The issue SEEMS to be when there is a Platsil gel-10 skin backed with ecoflex30. Like te ecoflex is leeching oil only through the platsil gel skin
I'm not sure what I've done wrong, here is what i'm working with:
My mold is made of ultracal30. The mold came out rather porous, causing the silicone to stick so I brushed on a little Johnson's Paste Wax diluted with VM&P Naptha. Before casting I sprayed a bit of Mann 200 mold release into the mold as well.
I then brushed on two layers of lightly tinted Platsil-Gel thickened with very little Thivex silicone thickener. The cast was then filled with lightly tinted Ecoflex-30 (which i mixed very well to incorporate the solids that settled in the tub).. no retarders or dilutants.
Would it be safe to continue to wipe off the oil using naptha, until it stop seeping? It seems to seep less as I continue to wipe it down. Do you think it would accept paint after a week or so of wiping the skin down repeatedly?
Thanks for reading!
Reading this thread through again, I am more than ever convinced that your Gel 10 was diluted with oil, perhaps it was actually Gel 25 and they thought adding some thinner would make it like Gel 10. Make sure you buy from a reputable seller.