Melting 5+ kg plastic all at once


We are doing experiments in sand casting, and are planning on making a solid plastic bench in one piece. The bench should end up weighing around 5 kgs or more.

Any ideas on how to melt and cast big amounts of plastic all at once?


Could we put it all in a rotating oil barrel with a bonfire underneath, like a heated concrete mixer?

Or a really big stock pot with a gas stove underneath?


Attached a couple of photos of what we are looking to scale up.





Have you tried melting the plastic in an oven? The only thing to keep in mind is that you need to keep the temperature withing the melting point of the plastic to avoid burning it. It’s pretty much the same principle of the Compression machine.

If you are going to use an oven or a custom heated enclosure, I would find a way to have a lot of convection in there to help eliminate hot spots that will burn the plastic. Think along the lines of a large air fryer or a hotter version of a dehydrator. You can do this with a metal fan blade with a shaft to a motor outside.

I’m looking forward to results from your sand molds. It is an interesting and unique technique.

We’ve tried melting plastic in the oven in steel bowls with lids , but the plastic melts very un-evenly, and burns along the edges.


Maybe it would be easier to melt in a big tub in the oven?