Welding polyurethane round belt

I use round polyurethane belt instead of rubber V-belts on my desktop mini lathe. Now I welds the belt of a given length, and i solved the problem with the search for the rare V-belts in small sizes. It is very convenient to buy a couple of meters, and i can make a spare belt at all times. To weld at home i using a soldering iron for polypropylene pipes. These straps are very convenient for some homemade, pulleys and tensioners for round belt is easier to do, and do not need to calculate the distance between the shafts by any standard belts.