Review on Poly Welder Polyethylene Welding Strips by Paul Dobson

Poly Welder Pro Sweatbands - 5ft (Black) I purchased black LDPE strips, not green or white. I have an old RV with black low density polyethylene storage tanks for black and gray water. The key to successfully welding the plastic of any of these tanks is to figure out what they are made of. In most cases, the recycle symbol on the tank, usually a triangle with a number, indicates what it's made of. To successfully weld plastic, you must use a filler wire that is the same density as the tank or a filler wire that is less dense than the tank. In my case, LDPE worked great. Both tanks had stress cracks in several places from the metal rods and bolts that attached the tanks to the RV floor. I did not remove the tanks. Both tanks were completely dry when I did the welding. I tried this first with a very small triangular iron, but it didn't get hot enough to melt the plastic into a flowable state. At this point, I simply took my propane torch, set it to a flame of about 0.5" or less, and brought it to the tank and bar at the same time. You can see the plastic on both surfaces melt and they actually become one solid piece of plastic. Take a flat welding rod a few inches above its end and bend it to try to press it against the surface of the tank. Place the flame right where the two surfaces meet and it will be apparent that they melt together. Be light with the flame. If you hold it in that range for too long, you may melt more than you need. This also becomes a matter of course. You'll get better at this style of welding. The results were phenomenal. There are no leaks at all. Tested by filling both tanks with water while the RV was on our concrete driveway. The extra material I added to the tanks seems to have increased the tank's strength by making it thicker in that area. I don't think I'll ever have to do that again. It definitely worked like a charm.