Welding Polyurethane Belt?

We are using 2" wide flat polyurethane belting from McMaster this year and we are having issues welding it. We tried the heat gun and 2x1 aluminum method but the welds keep failing after a bit of use. I noticed that the belt just gets warm, it never really melts. Do we just need more heat?

You want to wait until the belt is pretty much liquidy goo


It sure sounds like you need more heat. If they aren’t staying together after they cool that’s pretty indicative of not enough heat.


Thanks guys, we will try this soon. Hopefully our heat gun is powerful enough - maybe we just need to wait longer.

First Updates Now / FIRST Capital Ri3D produced a helpful example for welding this type of belt earlier this year.

And +1 to the more heat suggestion.

and with the aluminum, I presume you’re using it as a clamp or substrate. Use as short a run as you can manage, because aluminum will carry heat away rather efficiently.

We did it very recently using a small cast iron pan on a stove top and it worked like a charm if you can’t get the heat gun method working.

Although I can’t vouch for the usability of the pan for food afterwards…

We use a blowtorch:) once both sides light on fire, we blow them out, and press them down into a piece of angle alum. to help with line up and clamp there. Watch out for drips, they are super hot and really attach to your skin! We had trouble before with this because we would melt them and not give it enough time to cool…maybe this is your problem? We found a min. of 15 minutes of cool down time was needed before they would not break apart.

I’d avoid openly lighting urethane belts on fire- the smoke can be toxic. Just a general rule of thumb to not breath any unknown vapors in. A few people on my team started to feel lightheaded/nauseous because of it.

True, how many belts did they do???

This works really well for us welding round cords and belts: https://www.amazon.com/gp/product/B07HR6NYRS/ref=ppx_yo_dt_b_asin_title_o08_s00?ie=UTF8&psc=1

Not a ton, it was the testing what worked best for welding them that caused it.

I’ve welded a lot of belts over the years and spent dozens of hours researching every device that gets hot that could be used for this, including the very expensive professional belt joining kits. Hands down, this $20 hot knife from Harbor Freight is the best tool for the job. It works very well, and when the day comes it doesn’t throw it away and buy another. https://www.harborfreight.com/130-watt-heavy-duty-hot-knife-60313.html