Best method for replicating prop in silicone and resin

Don't want to see this ad? Sign up for anRPF Premium Membershiptoday. Support the community. Stop the ads.

CharlesHouse

Active Member
I have a few props I built I want to make silicone and resin copies of using silicone molds. I am looking at Mold Star or Mold Max for the mold and rubber props. I haven't found a resin that would be best yet. I have read you can save silicone by brushing it on. What would make up the bulk of the mold? What else should I consider? Thank you!
 

Don't want to see this ad? Sign up for anRPF Premium Membershiptoday. Support the community. Stop the ads.

brandomack

Sr Member
RPF PREMIUM MEMBER
Depends on the prop in question. It also depends on how many "pulls" or casts you want out of it.

so to make matters easier, and ultimately more successful....what are we talking about?
 

CharlesHouse

Active Member
I guess that is the point, we aren't talking about one item. We have a dozen props in our apartment we'd like to make copies of because of how damaged they get in use. Guns, hard costume parts, etc. Most things smaller than 12x6. As far as pulls, more than 5, fewer than 50.
 

detenten

Active Member
I'm honestly a fangirl of the Dragonskin series of platinum cure silicones from Smooth On. They are not the cheapest, but I find the cost difference negligible, since I am not a mass-producing shop looking to shave margins. I'll also admit I haven't worked with much else-- I used OOMOO once and hated it (the mold tore, but in all fairness, I did about 50 castings in it, but it just doesn't release like Dragonskin does). I've used Rebound 40 for a brush on mold, and it was OK.

I find them very easy to use and have yet to have trouble with them-- which goes a long way in my book for learning a new skill with minimal frustration. The 1:1 mix ratio by volume means it's quite forgiving, and the bubble release is decent enough without having to have a vacuum degasser.

I tend to thin it with Silicone Thinner and make pour-molds (uses more rubber), but you can also thicken it with Thi-vex, brush on, and make a mother mold around that with plaster bandages. Honestly, you could probably make a decent brush mold without the thickener if you choose Medium or Fast. Slow will give the best pour-moulds, since the cure time is longer to allow for bubble release.

Another plus for me in Dragonskin molds is they release really, really well, so when I'm making a resin casting I know I need to paint, I prefer them. I won't have to spray them with mold release, and then subsequently have to wash, wash, wash my casting to make sure my paint will stick!

For casting resin:

I've used both Smoothcast 300 and 325. They both are also a forgiving 1:1 mix ratio.

300 comes out bright white and cures all at once-- the thermal reaction starts and the whole thing goes solid very quickly. It's great resin, bright white, paints nicely.

325 is my personal preference now, though-- I can pigment it anything I'd like with the sampler set, and it has a "gel" phase of curing, so I can slush cast it if I want to. I find it a little more versatile for my purposes, but your applications might be different.


When you buy, I also suggest choosing something with a longer pot life-- so you have a little more time to mix and pour. With more experience you'll be happier to use faster setting stuff.
 

CharlesHouse

Active Member
How much would you say you spend on a cast? I have seen people make and sell casts for $5-35 from small to rather large, but considering $100 for a gallon of resin and $200 for a gallon of silicone, that seems like your costs would be really high.
 

Don't want to see this ad? Sign up for anRPF Premium Membershiptoday. Support the community. Stop the ads.

Don't want to see this ad? Sign up for anRPF Premium Membershiptoday. Support the community. Stop the ads.

Top