Plastic Welding

[blybrook]

For all those that want a cheaper alternative to commercially plastic welders, here is a couple of things that can be done to make your own.

Most people already have just about everything you need if you have a propane torch or a 80W soldering iron to weld plastic.

With an 80W soldering Iron, place a carriage bolt where the tip was and melt away, use the same type of plastic as you started with to provide the bond. I do this on canoes all the time and it has worked flawlessly.

With a propane torch, get a 4" piece of 3/8" tubing, a 3/8 pipe to 1/4" flared fitting, small hose clamp (1/2" diameter clamping range) and 4" of 1/4" brake line from any auto supplier. Take the 3/8" pipe and grind or cut a notch on each side (opposite each other) for a length of 2-1/2" to 3", then assemble the brake line to the steel pipe (after cooling). Place notched end over the torch tip (before lighting) and clamp into place.

Weld away! Both work as well as commercially available units and can be made for much less.

HTH Will follow up with photos of the propane unit later this weekend.

[markopolo50]

Can you show a picture of the torch setup? I can't quite follow the "assembly". Thanks. We have used a propane torch to repair windshield washer bottles after freezing/splitting. Torch flame was "feathered" as butter dish plastic was added. Worked for us and of course nothing under pressure.

[Trapper_Rich]

Would love to see a photo of that myself.

[blybrook]

Pictures

Sorry about the delay. I wanted to get these up over the weekend, but was called to work in a bush village. Just got back last night and didn't have my camera with me while I was out there.

Here's a couple pictures of the assembly, hope they help clarify what I was describing above.

[blybrook]

Pictures part Duex

A couple more pics.

[markopolo50]

Torch pics

A couple more pics.

I can see it now, clearly, thanks blybrook. The torch heats up the whole pipe assembly, nice. Mark

[blybrook]

I can see it now, clearly, thanks blybrook. The torch heats up the whole pipe assembly, nice. Mark

Yes, the whole pipe assembly heats up. The notches that are ground in, permit it to fit over the torch nozzle and to dissipate the heat so it doesn't get too hot. It also creates a heated air stream like the harbor freight models that require an air compressor.

It does get hot, so it'll need a while to cool down, but I've used it on two different projects so far and does a better job than the harbor freight unit. Less noise too.

[mannythehunter]

Plastic welding!

Here's another gun set-up...I use a heat gun with a reducer and a few other attachments. One is for speed welding and the other spreads the heat out.. here's some of my projects.. I'll see if I can find a picture of my heat gun..

[mannythehunter]

more pictures

Finished product

[mannythehunter]

Gun boot

I wanted a smaller gun boot to mout on my bike rack.

[mannythehunter]

Plastic welding!

Boot on the bike... can't find a picture of the heat gun, I'll take one tonight..

[JOAT]

Interesting work. What's your experience with the longevity of these repairs? Do you tend to get recurrence at the site of the original break? Or does the recurrence occur next to the original break?

[Paul H]

It depends on if the break is due to an impact to a part that exceeds the design for the part, or if the part is incorrectly designed, also if the core plastic is still good.

What I mean is, if the part is poorly designed and fails due to stresses occuring where the part fails, it will likely fail at the same spot. But, the folks I got my plastic welder from include some stainless steel screen that you can melt into place in a repair that strengthens the joint.

If the plastic is shot from UV exposure (one fender on my boat trailer) then it's just going to keep failing after welding as the plastic is hardened and filled with mini cracks.

In general you can get alot more life out of plastic fenders at al by welding them back together, and the repairs are pretty much limited by you finding all the pieces, and how much frankensteining you want to do by sticthing them together with safety wire before welding.

[mannythehunter]

Plastic welding!

Here's a picture of my gun with attachments.. I spent about $100 on it.. I spent most of it on the gun because I wanted one with good temperature controls..

[mannythehunter]

Plastic welding test

Here is a test... I welded 4 brackets on a box last spring to use as a 4-wheeler box. This winter while 4 wheeling I broke the box and decided I didn’t need it anymore. I took a screwdriver and jammed it between the bracket and the box and pried on it try to make it break through the weld.. Both brackets I tested broke and the weld stayed..