Thank you! You video is the only one I could find that mentioned the correct temperature for melting PU. I got out my soldering iron for electronics, set it to 280 C, melted the two ends simultaneously then carefully pushed them together with my hands. It works perfectly for my rock polisher. Going on two months with no breakage.
Thanks for your comment. I was very confused about this issue, when I did the welding first time, and therefore I made this video. When you look at my text to video, you find sources of information recommending both higher and lower temperatures, than the 270 C i use, but it is in the range 250 to 300 C. If you have no control of temperature, you can easily do welding outside this range. Be aware of the material properties as well, as I mention in the text.
I wonder how stiff this PU is compared with a similar outside diameter automotive vacuum tubing? I am currently using some of the auto vacuum tube for running a pulley, but it is fairly stiff and resistant to bending around the small motor pulley. (This is currently turning a 6" wooden pulley on a double pulley speed reduction set-up) I will give the PU a try if it promises to bend easier than the vacuum tubing. Also, I would try to glue the PU with a cyanacrylate glue instead of heat bonding. Any thoughts?
Sorry, I am not that familiar with automotive vacuum tubing, so I am able to compare. I got no experience in using cyanacrylate glue on PU material. In general, I know that a black V-belts (the raw edge types are best) will cause less transmission loss on a sewing machine. I made another video to compare belts and pulleys.
You've over complicated this process by about 100!... I used a simple lighter to melt each end.. Made an unbreakable joint after the 30 minute curing time...
Thanks for the comment. My video show one cheep DIY example of how to do it based on the recommendations for welding by professionals in the market. They warn against weaknesses caused by excess temperatures. I do know the method you describe using flames or indirect to heat up heat other metal surfaces to be used. But I have not seen trials test data from measurements regarding strength and durability. Your method will be easier, and may work in most cases, but I cannot recommend something that do not have some scientific or professional reference.
