Silicone Mold Cast Release

[Druid]

For those of you that use silicone molds for casting pen, bottle stopper, and other molds, what release agent do you use (if any)? Is it a spray, wax, or brush applied compound? I will be casting with both Alumilite Clear & Similar 41 clear casting.

Look forward to your reply

Cheers

 

[its_virgil]

I use no release agent and the blanks pop out quite easily. I cast polyester resin so I can't answer for the alumilite.
Do a good turn daily!
Don

For those of you that use silicone molds for casting pen, bottle stopper, and other molds, what release agent do you use (if any)? Is it a spray, wax, or brush applied compound? I will be casting with both Alumilite Clear & Similar 41 clear casting.

Look forward to your reply

Cheers

 

[Longfellow]

Casting Release

Back in the 70's when I did resin casting in RTV molds I used PVA,( Poly Vinyl Alcohol). It was brushed on. Not sure if it is still available or if it will work on your casting.

 

[toolcrazy]

I have done a few cast on sili mold. And didn't use anything. It seemed that nothing stuck to them.

 

[hughbie]

i use silicone and plastic medicine bottles.....i've never had to use a release agent at all. i pour polyester resin and i have used alumite....no problems at all
just go for it

 

[td]

What they said..... No release agent needed or either PR or Alumilite

 

[ldb2000]

I use several of Gadgets silicone molds and have never had to use a relase agent with either Alumilite or PR , nothing sticks to silicone .

 

[Darley]

I don't use any release agent for my PR event for the 7/8" mold I did, blanks pop easy out

 

[Druid]

Thanks for the info, you validated what I thought. I keep seeing mold release agents advertised for silicone molds and couldnt figure it out.

 

[Glass Scratcher]

Thanks for the info, you validated what I thought. I keep seeing mold release agents advertised for silicone molds and couldnt figure it out.

Mold release agents are needed if, for example, your silicone molds are a tin type of silicone and you are using a type of polyeurethane that requires platinum cure silicone molds, you will have a surface cure inhibition, or a fogging of the resin where it contacts the mold, unless you wax the mold or use another type of mold release as a contact buffer.

Release agents also protect tin cure silicone molds from the styrene and MEKp that are used with polyester resins. It gives the molds a longer in-use lifespan.

If you are making a multi-part silicone mold then you need a mold release agent to prevent the silicone from sticking to itself.

It never hurts to wax your molds when they go back on the shelf/library between uses.

 

[sbell111]

I used to cast some really detailed items in alumilite using silicone molds. I didn't use a release agent. When the molds were new, I would have no problems, but as they aged they would begin to stick in the detailed areas, casusing small bits of the mold to remain on the cast item. When this began to happen, I would repour the mold.

I have had no such problems with the simple molds for pen blanks using PR.