Plastic heat welding for acrylic parts?

I had a problem where the plastic fuel tank on my weed-whacker developed a crack and was leaking fuel.

The problem was that it was made out of High Density Polyethylene, (HDPE, or recycle code “2”), and you can’t solvent weld it as it’s impervious to just about everything, (except, maybe, concentrated florine, or Clorine Tri-Floride which burns everything, even concrete!)

The recommended repair is to heat weld it.

I tried before with a crummy soldering gun, but that failed after several uses.

This time I used a small torch


. . . and a strip of HDPE I cut from a laundry detergent bottle.

I placed a section of the strip over the leak and used the torch to fuse the plastic.


That got me thinking. . . .

One of the big problems we have with the acrylic parts of the GoPiGo chassis is that they’re essentially unrepairable if they break.

This got me wondering, can I torch-weld acrylic?  If that’s doable, then we have a way to repair broken chassis parts!

I am going to have to try this. . .


I’ve heard of people who do 3D printing fastening two pieces together by putting a small piece of filament in a rotary tool (like a Dremel) and then working along the seam. The friction of the spinning filament melts it and the surrounding plastic creates a kind of weld.

Hope your weld on the tank holds. I suspect acrylic would be tougher to work with.