Silicone sticking to resin, why?
- Thread starter gallman37
- Start date
David Moeller
Active Member
A couple of thoughts, depending on the silicone, tin or platinum, something from the resin might be reacting, causing it to stick. If I remember correctly, the tin based will stick to glass as well. You might want to spray a clear coat to seal it then give it a try.
Another problem I had before, some uncured silicone was on the part, when I then put in in a silicon mold, the resin stuck. I had to destroy the mold getting the part out. If this is the case, try cleaning the part (scrub with alcohol.)
Another problem I had before, some uncured silicone was on the part, when I then put in in a silicon mold, the resin stuck. I had to destroy the mold getting the part out. If this is the case, try cleaning the part (scrub with alcohol.)
It is a tin silicone and the piece has a very smooth/shiney surface. I will try sanding it first. Will that help or should I just clear coat it?
David Moeller
Active Member
Sanding will not make a difference. The mold will pick up any kind of texture. Smoother is better. When it sticks, how does it stick? Is it almost bonded to the surface? Does it tear the mold when you pull it away?
Also, do you use a mold release? If not try Mann Ease Release 500 Mold Release and Dry Lubricant. After you cast the part, you will have to wash it with comet so the paint will stick.
If this is a part that someone else did, they may have put fillers in it and that may be what is sticking. Warp Models does this all the time, that is why when you sand it thousands of small bubbles appear in the resin. A royal pain in the A$$! :angry
I would clean the part (like you did), inspect it and fill any small bubbles, clear coat it to seal it, then use mold release. When you make a cast, you might want to keep the first one for making future molds if necessary. I have made parts off of poorly cast parts and thrown the original parts out because they were junk.
I hope this helps, I don't use the tin stuff anymore, it is too finicky. If you try to make clear parts, the resin does not cure where it is touching the RTV and you end up with a big sticky mess. :cry
Good luck,:cool
Dave
Also, do you use a mold release? If not try Mann Ease Release 500 Mold Release and Dry Lubricant. After you cast the part, you will have to wash it with comet so the paint will stick.
If this is a part that someone else did, they may have put fillers in it and that may be what is sticking. Warp Models does this all the time, that is why when you sand it thousands of small bubbles appear in the resin. A royal pain in the A$$! :angry
I would clean the part (like you did), inspect it and fill any small bubbles, clear coat it to seal it, then use mold release. When you make a cast, you might want to keep the first one for making future molds if necessary. I have made parts off of poorly cast parts and thrown the original parts out because they were junk.
I hope this helps, I don't use the tin stuff anymore, it is too finicky. If you try to make clear parts, the resin does not cure where it is touching the RTV and you end up with a big sticky mess. :cry
Good luck,:cool
Dave
vaderdarth
Master Member
I had a similar problem when learning to fiberglass. A resident expert on the subject advised me that I needed to simply brush talcum powder into the mould prior to casting. The talcum powder is a wonderful silicon/resin separating agent. He told me it is especially needed for the first few castings from the mould.
Dave
Dave
