Mold box

[porschercr]

Kind of a "newbie" question, sorry....

I'm curious what the best material would be for making a mold box? 

 

Trevor

[TarheelRick]

Almost anything that will hold your mold material will work.  Many people use Lego's to build up a box, with clay around the bottom to prevent seepage.  I have built boxes from cardboard and tape, and they work just as well.  I have also used such things as empty pudding cups for small items, empty margarine tubs, etc., of course you have to be sure to spray them with mold release.  Simply use your imagination.

[Mark]

I've used plastic caps from syrup bottles (the one that snaps over the spout) for small items like wheels.  I've found vacuum formed packing material (small sheets with various shape bubbles formed into it) that could be cut apart and used.  These things have a very slight taper which lets you peel the mold out without tearing it.  

For larger parts like hoods, I have used scrap pieces of clear acrylic like Plexiglas.  I use clear so I can see if there are air pockets anywhere (there shouldn't be, as I fill the mold slowly).  The same mold box sides can be used for different size parts by letting one end (and only one end) overlap the adjacent side.  Tough to explain, but easy to figure out once you have the pieces in your hands.  Mold release isn't needed except on two-piece molds where you are pouring new silicone onto existing silicone.  Then, it is vital to being able to get your original part out without wrecking the mold.

I've tried Lego pieces; they're handy but sometimes you end up making the mold bigger than absolutely needed, using more silicone.  Just my opinion though...your mileage may vary...  

[Aaronw]

Legos

 

You can buy the bricks individually direct from Lego. I had a nice set color coded by size / shape until my Dad and son got into them and mixed them in with his Legos. I haven't got around to reordering another batch, but it isn't terribly expensive. The only time I've had Mark's issue of having to make a bigger box than I would like was when dealing with a random selection where I didn't have the best choice of options.

 

I have a plastic HDPE cutting board I use as a base, it has a slightly pebbly texture that the clay can get a good grip on.

 

I have never used mold release except for the silicone to silicone contact of two part molds, and I use petroleum jelly for that.  

[oldcarfan]

I bought a big sheet of foam poster board and just cut off however much I need to make a box.

[porschercr]

Thanks all. Much appreciated.

[1320wayne]

Here's my 2cents. For smaller molds I use Lego blocks, like mentioned above. For larger molds for bodies I have two mold boxes that were created out of wood and designed to be disassembled after curing and re-used when needed. They sit on a wooden base and sealed to the base using tube caulking or gasket sealer.