Originally Posted by ctcamper
I have an inch long crack near an edge on my fresh water tank that just developed. I can still fill the tank half full so I can still use it, but I am trying to fix it.
I found a plastic welder at harbor freight and ordered some hdpe welding rods online to be sent to the campground. I figured I would give it a try.
I called the local rv supply/dealer in the area and they said that they have found that glues do not hold due to the flexing of the tank.
Has anyone ever done plastic welding? Does it work?
I did buy a cutting board to practice on before attempting the tank.
Plastic welding, just like regular welding is an "art". When working as a regular fireman for San Diego, I was also tasked with an overtime assignment of outfitting new fire trucks. And, in ordering components, materials etc. for the outfitting, we found out about some plastic boxes that were factory welded and, were 1/2" thick walls that were seriously strong boxes. I mean, we could store chains, heavy rescue material etc. in those and they never broke any of the welds.
So, with that being said, I ordered an industrial plastic welder and, all the related equipment and materials. Then, I attended a short, 1/2 day class on plastic welding. It was presented by a company that does miles and miles of plastic welding, on a daily basis. To say the least, it looks and feels just like regular "oxy-acetylene" welding only, it's not solid or, there's no solid beading like that type of welding presents.
All you see is a clear, molten puddle. But, the adherence is key to all things being just right. One, the "air" used must be almost surgically clean, as in nitrogen type. Regular air, has way too much moisture content, even when ran through a dryer for plastic welding to have a good bond. The second factor is, your "parent" materials, (as in the tank crack) must be also, surgically clean. The heat rate, kind of like regular welding, is ultra critical too. Too hot and, you change the characteristics of the plastic. Too cold, and you don't get a bond at all.
So, if you plan on doing this right, there's just a bit to consider, if you want a really good outcome.
Long story short, I blew a tire on a trip one time. It damaged my fresh water tank. It basically knocked a small hole in it but, that hole, splinter-cracked in multiple directions. I had no idea of plastic welding at the time. But, I found out about it. I contacted a local plastic welder. He did a fantastic job. The hole was filled, then each crack was ground and filled, then, a sizeable patch, was placed on top of that whole broken-repaired area and, welded all the way around. Outstanding work.
Now, you're at a campground you say? Well, to do what, in my opinion, good quality work, at a campground, would be hard to do, based on what's needed for a good outcome. Good luck. Hope it comes out fine. I'd like to see a picture of the damage, before you start.