Injection Molding

[Tree Reaper]

I was playing with this idea of using expanding insulating foam to wet form leather projects.

This is going to be a guitar pick case, it just requires trimming now and I'm pleased with the results.

[HellfireJack]

You actually used the force of the expanding foam to mold the leather?

Not only an awesome idea but you wind up with a A:B mold if you don't want to use the foam injection later.

I used to work with the urethane marine foam when I worked at a fiberglass boat shop as a kid. I remember it being as hard as cement when fully cured. Is the spray can stuff the same way?

[particle]

That's impressive! I can't believe it exerted enough pressure to form the leather that well!

[Tree Reaper]

Yes, I used the foam to expand the leather and now I have a foam mold that will seat the leather into the wood mold time after time.

The top block was screwed to the bottom block, I had two holes pre drilled in the top block to insert the plastic tube from the can of foam.

I placed a piece of plastic bag over the leather to protect it from the foam and filled the block with foam, sealed the two holes and let it expand.

The foam is rigid but not real hard although it's hard enough for repeated use.

Edited July 13, 2012 by Tree Reaper

[LNLeather]

Hey TR, that was Very Clever... Are you an Engineer?

I think you might have come up with an idea, with different designs for different items,

that could make you a lot of $$... ??

Edited July 14, 2012 by LNLeather

[cem]

This is a cool idea thanks for sharing Tree Reaper, I've got an interest in this sort of stuff after making silicone molds and the like for a number of years.

Cheers,

Clair

[Tree Reaper]

Thank you all, not an engineer but I think it's in everyone to dream stuff up.

Just know that this foam can be messy, requires acetone for cleaning and rubber gloves.

[BIGGUNDOCTOR]

Expanding foam can exert tons of pressure. Im high school one of the students made a mold for a larger item, and braced it with 2x4's. He mixed the foam's A & B, and poured it in. Soon afterwards the 2x4's were breaking under the pressure.

Look into Smooth-On's products for mold building. They have lots of options.

A friend used a can of expanding foam to get home after one of the airbags of his truck's suspension had a fatal air leak form. The airbag was toast, and the foam held for a long time, even after getting back home hundreds of miles away.

Edited July 14, 2012 by BIGGUNDOCTOR

[Tree Reaper]

The case is finished and should work well.

Edited July 14, 2012 by Tree Reaper

[Tree Reaper]

I tried a round mold and it works just as well.

I can cut this in half and get two pouch faces with it.