Does Future inhibit cure of platinum rubber?

kenno3 · Post by **kenno3** » Thu Jan 05, 2012 1:16 am

I read a discussion in a very old thread about using Future in a mold. But the old thread topic wasnt completely related.

If I put Future polish on my Master part, then make a mold using platinum cure rubber (Mold Star 15), will the Future inhibit the cure of the rubber? Or does Future peal off surfaces when pressed tight against mold rubber?

I want the parts that come from the mold, to be glossy and have a glass like surface (ill be casting clear Epoxy resin), thats why im thinking of putting Future on my Master part. Or is there a better way? I sanded the Master part up to 2500 grit.
Thanks.

skymods · Post by **skymods** » Sat Jan 07, 2012 1:56 am

If you already have the Mold Star on hand, you could do a small test. Spray some future on something and pour a small amount of rubber over it to see what happens.

If not give Smooth On a call. I have never had any problem getting a quick answer to any technical problem.

kenno3 · Post by **kenno3** » Sat Jan 07, 2012 2:35 am

A small test is curing now, but Im new to Future so I wanted to ask for tips first. I was trying to find the ingredients in Future and some people have said its acrylic. And another site mentioned acrylic-latex something as a possible inhibitor to platinum. Ill update when the rubber cure time is over.

"Guarding against potential inhibitors/poisons of
platinum-catalyzed addition-cure release coatings."
http://www.dowcorning.com/content/publi ... 053-01.pdf

Kylwell · Post by **Kylwell** » Sat Jan 07, 2012 10:54 am

It's acrylic. The confusion probably stems from latex house paint actually being acrylic and containing no latex. Latex wouldn't last long on a floor.

novahobbies · Post by **novahobbies** » Sat Jan 07, 2012 12:14 pm

You shouldn't have any problems - I've molded against Future with a platinum based rubber. But if it's glass-smooth finishes you're after, nothing beats wet sanding down to superfine grades. Future doesn't *always* cure perfectly smooth.

irishtrek · Post by **irishtrek** » Sun Jan 08, 2012 12:22 am

Heck, why not just spray the Future onto the parts after they have been removed from the mold??

kenno3 · Post by **kenno3** » Sun Jan 08, 2012 3:07 am

Here are my results: I painted 1/2 of an acrylic rhinestone with Future as a test. Then I put the rhinestone on Double Sided Scotch tape and put this on top of a cured piece of platinum rubber (Mold Star 15). Then I painted Vaseline (cut with paint thinner) onto the cured rubber. Then I poured liquid platinum rubber onto all of this and also on a piece of wood - as a test for my own use mostly. I read that some tapes and wood inhibit cure, and the guy I bought the rubber from - doubted that Vaseline would work to make 2 part molds.
All the area of the new rubber cured fine, and it didn't stick to the old rubber.

irishtrek wrote:Heck, why not just spray the Future onto the parts after they have been removed from the mold??

I am not sure what exactly Future is capable of, or how it cures (hard or it can rub off?). I asked in the Finishing forum.
I only have up to 2500 grit sand paper, and Novus polish, 1,2 and 3.

I was thinking of using Novus 2 and 1 on my Master part, then putting Future over it to fill micro scratches. Then I would make a mold of this so all the replicas would have a smooth surface, and I would not need to "waste" or use Future on all the replicas. The Master isnt transparent but the replicas will be made with clear epoxy resin. Is this a good idea? Or would I have to put Future on the replicas anyways to bring back some shine and clarity? The final part will be handled a lot.

kenlilly106 · Post by **kenlilly106** » Sun Jan 08, 2012 1:58 pm

Future cures fairly hard after about 24 hours (more or less depending on local conditions) at this point I've never know it to flake or rub off, if you have to remove it at this stage either household ammonia or rubbing alcohol will remove it.

Sanding out the masters to 2500 and then polishing them out to a mirror finish is standard for getting clear parts to cast as clear as possible.

I know of a few companies doing replacement aircraft canopies in clear resin and they typically dip theirs in Future after casting to make them as clear as possible, course if your master will allow for sanding and polishing the whole thing then you may not need to Future them after demolding.

If you can get a good coat of Future on the master without any runs or drips or dust I'd personally go ahead and do it, anything to make the master as smooth as possible can't hurt.

Ken

irishtrek · Post by **irishtrek** » Sun Jan 08, 2012 11:39 pm

Or why not add the future to what's going into the mold???

Kylwell · Post by **Kylwell** » Sun Jan 08, 2012 11:55 pm

irishtrek wrote:Or why not add the future to what's going into the mold???

You mean mix the Future into the resin?

irishtrek · Post by **irishtrek** » Mon Jan 09, 2012 1:38 pm

Kylwell wrote:
irishtrek wrote:Or why not add the future to what's going into the mold???
You mean mix the Future into the resin?

Yep.

Kylwell · Post by **Kylwell** » Mon Jan 09, 2012 1:40 pm

Why? It wouldn't smooth anything and potentually would contaminate the resin.

modelnutz · Post by **modelnutz** » Mon Jan 09, 2012 2:19 pm

irishtrek wrote:Or why not add the future to what's going into the mold???

If there is any water in the Future...you will get foamed resin.

irishtrek · Post by **irishtrek** » Mon Jan 09, 2012 7:58 pm

Those 2 posts asnwers my question.