How much silicone is needed to make a stormtrooper helmet mold?

[EvilSteve]

I'm considering buying the Smooth-On Silicone Starter Kit https://www.smooth-on.com/products/brush-on-silicone-starter-kit/

It has everything I need, but I'm worried it won't be enough. The trial unit of the Rebound 25 silicone is 2lbs/ 0.91kg. Is that too much? Not nearly enough? Just right? I have absolutely no idea.

I'd love to hear from someone with more experience than me.

 

[Zlurpo]

In my experience, a helmet sized thing needs about 8oz (weight, not liquid oz volume) for the first layer, and about 12 (with the thickener) for each subsequent layer. I usually do 4-5 layers, some may say that's more than enough but it's my preference. That's 56 oz, getting near twice that weight.

If you want that kit because you also want the resin, and the plasti-paste, go for it. But if you just want to get the silicone you can buy it cheaper other places.

 

[EvilSteve]

@Zlurop - Thanks for the reply. The kit seems handy because it comes with everything I need. However, if the amount of silicone included is only about half what I need, I'm now wondering if there will be enough resin and plasti-paste.

 

[Kevin Gossett]

It's a trial kit for a reason. Not intended for a mold (or casts for that matter) of that size. If you're not familiar with how much is necessary, there's a good chance you're not familiar with molding and casting in the first place, and a full helmet mold probably isn't the best project to cut your teeth on. I would suggest getting the trial kit to practice on smaller objects, to get a feel for the materials and how they're used, then work your way up to the helmet.

 

[EvilSteve]

It's a trial kit for a reason. Not intended for a mold (or casts for that matter) of that size. If you're not familiar with how much is necessary, there's a good chance you're not familiar with molding and casting in the first place, and a full helmet mold probably isn't the best project to cut your teeth on. I would suggest getting the trial kit to practice on smaller objects, to get a feel for the materials and how they're used, then work your way up to the helmet.

I think you are 100% correct.

The last thing I want is to spend hundreds of pounds on molding supplies and make an arse of it all.