Plastic water tank leaking

Jul 19, 2015
Beneteau 343 BVI
Has anyone fixed a plastic water tank? I think it has a crack in the bottom net to the edge. We are in Grenada so I may not be able to get a new one anytime to soon.


Mar 16, 2010
Beneteau 411 Oceanis Annapolis
JB Weld and Permatex both make an epoxy putty that is NSF rated for potable use and will set on wet surfaces.
Aug 22, 2017
Hunter 26.5 West Palm Beach
The hot air guns are tough to get a strong weld with. You need to V out the crack well & heat a large area to spread the stress with a large bead. The progress is very slow, but results can be good & later rework is an option with this method.

Some epoxies work better than others, depending on the temperature range you will encounter & the material that the tank is made of. When using the "tank repair" epoxy sticks, I usually putty up both sides of the crack with the stuff after first drilling through the cracks in a few places to allow the putty to have a place to connect from the inside to the outside. I believe that this gives better mechanical strength to the repaired area.

Duct tapes vary in adhesive chemistry & backing composition. Some work much better than others for temporary repairs. Polyethylene backed tapes with solvent based adhesives generally work well for temporary repairs on plastic water tanks, but finding an exotic tape like that in a remote location is like finding a winning lottery ticket.

Cleaning the plastic well before patching is very important regardless of which repair method you try. Use solvents, not soaps for your final cleaning. Read the tech sheet for the adhesive that you plan to use. Alcohol prevents proper curing of some moisture activated adhesives (like 5200).
May 4, 2018
Catalina 25 SV Colorado
Gorilla Glue Tape worked as a temporary fix for looks like black electrical tape but thicker and held in water.
Mar 26, 2011
Corsair F-24 MK I Deale, MD
I was able to get the G/Flex 655 we will see if it works.
West Systems does not post drinking water safety info. Generally epoxies are fine if properly mixed and many are certified for drinking water. You could always overcoat it with something certified (Sika 291 is certified, for example).

I'd lay some finish glass cloth in with the G-flex if I was you. I've done it that way. Also, you will notice that flame treating is very important. BTW, this does not work with most epoxies, at all.

(Last number is bond in PSI--this agrees with my testing.)
Polyethylene (HDPE) 655 80-grit sand 400
Polyethylene (HDPE) 655 80-grit sand, flame treat 1890
Polyethylene (HDPE) 655 Alcohol wipe, flame treat 2312