Solvent welding polycarbonate sheets to make a hollow flatblade?

Has anyone done something like this before?

The idea I have in mind looks something like this:
flatblade example

A “sandwich” of polycarbonate sheets would be made, and the middle layer (or several layers depending on the thickness of the individual sheets) would have channels cut out in the middle to make space for neopixels or other lighting to be inserted. And then the layers would all be solvent welded together into one solid piece, and then the edges could be rounded, and the tang machined into a cylinder, etc.

The question though is would solvent welds be strong enough for this sort of thing? And more importantly, would solvent weaken the polycarbonate?

If this idea does actually work, I could see another perk of it being that solvent would (in theory) etch the surface of the polycarbonate and give it a frosty appearance which would help with light diffusion.

Going out and buying some polycarbonate sheets to experiment with and possibly destroy is unfortunately not really something I can currently afford to do without being absolutely sure it will work though. So has anyone else ever tried this before? Would it actually work?

Interesting idea. We can’t even get Mek solvent out here.

The short answer is yes.
A well made solvent weld is very nearly indistinguishable from the original material. However, I’m not sure how easy/practical it is to make solvent welds with large surface areas…

Polycarbonate is also a tricky material, because it has pores in it. If these pores are filled up, it becomes glass-like and brittle. I think this would happen if you use too much solvent and/or pressure when joining the pieces together. Many machinists have discovered that if you turn on the cooling fluid tap while drilling/machining polycarbonate, it cracks very easily. Polycarbonate should be machined dry. This is also why superglue doesn’t work on polycarbonate btw, it fills up the pores and makes it super-brittle.


I’d use glue. Solvent welding is not something I’ve seen done much with polycarbonate. Plenty of cyanoacrylate or uv cure adhesives available though. Check out Permabond.

I use this to put blade tips on FWIW:

I think that’s the stuff that Sublight Drive uses to build his spaceship models!

Not sure how weld-3 does on large flat surfaces but +1 for blade tips.

I never had any luck with weld on 3. Having done a lot of pvc solvent welds (for plumbing) and solder welds I thought it would be easy. My guess is there are small changes in depth at the weld point. Or I’m not getting a good schmear on the interior. Tried it on 3 blades with no luck. Tips?

Wound up going with E6000, which I heard about here on the Crucible. Clear choice for me.