Injection Molding Idea

[yf]

Can a large hot melt glue gun be used for one off injection molding?

If you don't need to mold too many parts it might be an alternative to building a dedicated machine.

One could probably buy .25" dia. plastic rod of whatever plastic needed and just feed through the gun. Make up the mold to accept the tip of the gun or modify it to thread on or???

Has anyone tried this?

[brunneng]

I have seen hot glue used in small molds to make a part that didn't need much strength or was just an appearance piece.

I believe hot glue melts at something like 150-200 deg? Whereas most molding plastics are in the 400-500 deg range. The gun would melt around the barrel (which I've had happen).

A dedicated HSM sized piston machine is actually pretty easy to build and most of the work does not need to be very precise.

[ibewgypsie]

TRY.. www.synair.com for a castable plastic, I toyed with the ideal about injection, but this worked so great hardens to a 93 rockwell, you can tap it machine it.
On the curing, no water can be present, it starts setting up with lil white lines, then POOF... it smokes and turns white. I was running out of the shop the first time I cast it. Casted projects have been belt drive gears and small robotic manipulators. YOU CAN make anything from this, and it is pretty cheap.

[brunneng]

Which component of theirs is the one you used? Part #?

[ibewgypsie]

Por-a-cast and I used por-a-mold once.. but found rubber mold replication not my style. I made a mold of the browning xl gear from lead (poured it around the gear then tapped it and pushed if from the mold.
They have some bugs on thier site, huh? well try this one then buy direct.. http://www.bare-metal.com/ hobby supplies.

[Techtchr]

The hydraulic pressure that a small home-made piston type machine can generate , can't be duplicated by a glue gun. You need the pressure as well as the softened plastic to fill a mold. As brunneng says, they aren't that hard to build.
Matt