Originally Posted by FlyJake
I have a 1984 Tiffin Allegro that I got a yr ago and finally got around to working on the gray water tank. There seems to be at least 3 areas with cracks that could be patchable (watched a great YouTube video) for like $30 in materials. A new tank is about $280 and install would be another $200ish.
The question is do I try and patch it or just replace?
Thanks for your thoughts!
If you can get a new tank for only $280 I would jump on it.
On our RV that was not an option. We went with the plastic welding method. We did order the proper LDPE welding rods and stainless steel reinforcement mesh. Canít find the Amazon link right now. Also went with the hot-air welder.
The trick is to grind the plastic down to clean material, drill the crack ends (as you did). Recommend filling the crack first, and grind smooth, as necessary.
Next using the hot-air welder to embed the mesh. Then cover the mesh with more LDPE rods. The last trick is to melt the plastic until it becomes transparent and fads the LDPE filler rod. This takes a lot of patience and some practice so as not too burn the old HDPE tank plastic.
In our case the gray and black tanks were wedged in casing extra stress on the outlets for the dump valves. With some trimming of the tank outlet length, and some slack on the two tanks, we achieved a stress free fit. The last thing we did was to add an extrasupport strap to distribute the water load.