Plastic Water Tank Cracked! How do I fix it?

[flyingfin]

Originally Posted by gonesail

replace the tank. once they start cracking they are brittle and it only gets worse.

Plastic only has a limited life cycle. Bite the bullet, remove and replace, do it right or it will fail when you least expect

[peghall]

If it's transluscent seamless plastic, it's polyethylene. There are those who'll insist the crack can be heat welded, but it won't be nearly strong enough to support the 8.333 lbs/gal that water weighs. So I hate to break it to you, but it's time for a new water tank.

Ronco Plastics Ronco Plastics Home Page is is your best source for a tank. They make TOP quality thick-walled water and waste tanks for a very reasonable price and have more than 400 shapes and sizes, over 100 of which are non-rectangular, and they install fittings in the sizes and locations specified by the customer when they make the tank. There are retailers who sell Ronco tanks, but Ronco sells direct for a much lower price...and they're great to work with.

When looking at drawings it's important to know that there is no top or bottom until the fittings go in, and YOU decide where they go. So rotate, flip in any orientation to find the tank that fit your space.

--Peggie

[mikebikeboy]

Originally Posted by peghall

If it's transluscent seamless plastic, it's polyethylene. There are those who'll insist the crack can be heat welded, but it won't be nearly strong enough to support the 8.333 lbs/gal that water weighs. So I hate to break it to you, but it's time for a new water tank.

Ronco Plastics Ronco Plastics Home Page is is your best source for a tank. They make TOP quality thick-walled water and waste tanks for a very reasonable price and have more than 400 shapes and sizes, over 100 of which are non-rectangular, and they install fittings in the sizes and locations specified by the customer when they make the tank. There are retailers who sell Ronco tanks, but Ronco sells direct for a much lower price...and they're great to work with.

When looking at drawings it's important to know that there is no top or bottom until the fittings go in, and YOU decide where they go. So rotate, flip in any orientation to find the tank that fit your space.

--Peggie

I was just about to ask where to begin looking for new tanks. Thanks a lot, this is great!

[geoff3nebel]

I would attempt a repair, but nevertheless back it up by inserting a bladder as LeeV advises

[kish]

Any repair of a potable water tank should use food grade adhesives.. That is a difficult search , as reading the data sheet of such commonly available potential repair material will warn of health risks on skin contact and injestion of leached out carcinogens from a repair is hazardous, if used.
Replacement of the tank is the healthiest option.😒😒

[abarrow]

I had a similar problem with my 60 gal forward tank. PTFE and cracked on the bottom near the bow.

I used this https://www.westsystem.com/plastic-boat-repair-kit/.

It's been about 5 years since the repair, and the boat has been kicked around quite a bit going up the Mexican coast. I can imagine there was considerable hydraulic pressure from the pounding. So far, no leaks in that tank.

Just be sure to follow the directions. It helps if you can get inside the tank and patch there as well. In my case, that wasn't possible, but it still seems to have worked.

[David Mathis]

Since the crack is on the top, if you just want to get through the season, a hot glue gun will likely be adequate but for a long term fix, replace the tank.

[abarrow]

Originally Posted by David Mathis

Since the crack is on the top, if you just want to get through the season, a hot glue gun will likely be adequate but for a long term fix, replace the tank.

I'm wondering if hot glue would actually stick to polyethylene. That stuff is like wax!

[Rohan]

Originally Posted by kish

Any repair of a potable water tank should use food grade adhesives.. That is a difficult search , as reading the data sheet of such commonly available potential repair material will warn of health risks on skin contact and injestion of leached out carcinogens from a repair is hazardous, if used.

Wouldn't that be only if you are repairing it from the inside?


In this situation, I would try some FlexTape first before the more drastic options and see how well that works.

[timb7734]

I “temporarily” fixed a leaking pressure tank on a vac-u-flush with Shoe Goo. Kept the boat several more years but never replaced it.

[peghall]

Originally Posted by abarrow

I'm wondering if hot glue would actually stick to polyethylene. That stuff is like wax!

Nothing bonds permanently to polyethylene. Heat welding that blends both new and old PE into a single mass is the only thing that works and knowing how much of each to use in a particular application requires some skill.


Btw...PTFE is a very unusual choice of tank material...in fact, yours is the only tank made using it that I've ever heard of.



--Peggie

[abarrow]

Originally Posted by peghall

Btw...PTFE is a very unusual choice of tank material...in fact, yours is the only tank made using it that I've ever heard of.

It's quite possible I didn't state the material correctly. Let's use the scientific term: "waxy injection molded plastic tank". Whatever that is...

[dreuge]

About 6 years ago I fixed a long cracked 35g water tank. I first tried to repair it using G/Flex and/or 5200 which failed. I then fixed the tank using a plastic welder and some 316SS wire mesh. After 5+ years of some good abuse, the plastic welded tank is still leak free. I wrote up a post on my blog describing the process including obtaining the LDPE plastic welding rods and wire mesh. I knew nothing of plastic welding, but found it easy to learn. The key was using a good hot air welder (not the little soldering iron type). If one is careful, plastic welding can be done with a propane torch in a pinch.

Here is the link to my blog write up. Skip by the G/Flex/5200 attempt to go down to the section on "Water Tank Repair Using a Plastic Welder"

https://svjohannarose.blogspot.com/s...aterTankRepair
Water Tank Repair Using a Plastic Welder

[Nicholson58]

Repair of polyethylene cannot be reliably done using glue and fillers. Nothing sticks to PE. Take the tank to A qualified plastic welder to have the crack filled and a reinforced patch welded over it. We dealt with a company called Total Plastics Inc. There are others. Possible you might get a tank maker such as Ronco to repair it. Ronco might be able to replace it outright.

[Rickdowe2]

I have a Morgan 382. The starboard tank cracked. I purchased a plastic welder from Harbor Freight and a foot to fit it online, it made it a lot easier by drawing the rod through it. I tried HDPE because I was told that is what it was but it would spring a leak when I filled it up. I called the manufacturer of the tank and it was determined it was LDPE. I Bought the rod from Grainger. I also bought a wire sieve,make sure it is stainless, from the local grocery store. After a little practice I was able to make the required repairs and reinforced it by melting the wire into the plastic. I did look at some videos online. It's not that daunting of a task and the cost was minimal. You can do it!