Possible Cheaper Solution For Making Casts

[haji]

Ive been experimenting with ghetto casting for the last week and cant seem to find the best release agent.



So I theorized that you could use 1 or 2 sample size orders of Rebound 25 for the first layer on a helmet. Then for the thicker layers: you could use silicone caulk found at homedepot/lowes/walmart with the combination of silicone thickner.



Inputs?



What could go wrong? only the first layer of rebound 25 will be making contact with the helmet

 

[mroreo123]

Although a release agent helps prolong the life of your mold, a release agent shouldn't actually be necessary to get your casts out of a silicone mold.



I'm no expert on molding (yet!), but I would imagine that the stresses applied to the rubber when demolding will cause the two different silicones to delaminate from each other when you pull the mold off the master/casts, especially for a glove mold which is what many people are doing for helmet molds. The silicone caulk may not even stick to the Rebound. If you haven't already, I'd experiment with a box mold first and stretch/flex it to see what happens to the combo. If that works, you might be able to do a multi-part mold if a glove mold doesn't work so well.

 

[Chazodude]

Dont you mean making molds?



Casts are what you 'pull' from a mold if my terminology is correct =P



I tried ghetto casting. Dont go their, in the end its so much better doing the real thing!

I used one trial kit of rebound on an early helmet I made and I think its enough.



You can try the other method you suggest but I dont recommend it. Go for real products designed for this use. They are expensive for a reason!





Charlie

 

[haji]

haha, my bad on the terminology





adhesive silicone sticks like a mug (thats why you HAVE to use a release agent to get it off when ghetto casting). So silicone caulk over rebound 25 will go together fine. Im pretty sure Thi vex will work with the silicone caulk aswell.



I know i cant use the glove method, but i could use razor to make a partial incision on the back to pull out the cast. If it leaves a seam, i can always sand it



This honestly looks like a big money saver. I really cant see any faults. but ill find out in a month if there are any



So the question is, is a sample size rebound 25 enough to make the first layer?

 

[Walter Spase]

Silicone caulk over rebound 25 will go together fine. Im pretty sure Thi vex will work with the silicone caulk aswell.

So you have put Silicone Caulk over Rebound 25 and it will go together fine, but you are still asking how much rebound to buy. I'm a bit confused, you have tried this and it does work, or you haven't tried it and you assume it works?

 

[UNSC Leatherneck]

And let's not forget that you can make molds out of latex, which is REALLY cheap. Just throwing that out there.

 

[bboyfresco]

And let's not forget that you can make molds out of latex, which is REALLY cheap. Just throwing that out there.

but also take forever to make (5-7 days) and the life of the mold is no where near as long as the life of the silicone mold though



Mold release is awesome, It really helps from my experience to slide the rubber off the item you're molding without alot of stress to the mold itself

 

[UNSC Leatherneck]

but also take forever to make (5-7 days) and the life of the mold is no where near as long as the life of the silicone mold though

Yes, it takes forever, but the ridiculously low price of materials makes up for any shorter mold life. It can cost well over $100 in materials to make a silicone mold, as opposed to $25 in materials to make a latex mold (and that INCLUDES the mother mold!) You can just make another mold. I have seen latex molds that have ten pulls from them and are showing zero degradation. How many pulls are most people going to make from a mold. Probably not that many, so the economics are very good.