Polyethylene Water Tank Repair – Crack

This post cover Polyethylene Water Tank Repair – Crack. We show you how to repair a crack in a Polyethylene Water Tank, but the same method can be used for anything made of polyethylene, including canoes, kayaks, or anything else.
The Tank
I bought two 1550-gallon polyethylene tanks that I found on Craig’s list. I bought both for $450, which is about half of what one tank costs. Both tanks needed a little repair, but it was still a good deal. This post covers how to repair a crack. I’ll do another post in the future on how to repair a hole or gouge.
The Crack
The crack that I’m working on looks like it happened by an object hitting the tank and creating the crack with one half of the cracked piece knocked inward.
Clean
The first step was to clean the tank. I did this with a brush, water, and mild dish soap. I washed the outside of the tank just like I would a car. This prevents dirt and debris from getting into the repaired area. On the inside, the tank had some sand in it. I took my shop vac in and vacuumed up all of the dirt on the inside and wiped down the repair area with a wet rag.
Level the Crack
The next step is to level the crack. The two pieces on either side of the crack do not line up, so I stuck a screwdriver in the crack and pried the inner piece out to line up with the outer piece.
The Welder
They make a kit for welding polyethylene. I bought my kit from Amazon and it cost just over $100. I’ll include a link to that below. The welding kit is like a big hot soldering iron with sticks of polyethylene that you use to fill in gaps.