How to repair a leak in the fresh water tank.

[DonDiego]

Our fresh water tank has a crack directly below the water inlet stub. It is about 3 inches below the stub on the flat surface. The crack is only about an inch long. I can use it by not filling completely. However, I would like to repair it if that is possible. Has anyone ever patched a fresh water tank?
Thanks in advance.

[Inland RV Center, In]

Originally Posted by Diego2

Our fresh water tank has a crack directly below the water inlet stub. It is about 3 inches below the stub on the flat surface. The crack is only about an inch long. I can use it by not filling completely. However, I would like to repair it if that is possible. Has anyone ever patched a fresh water tank?
Thanks in advance.

There are 2 ways to try and repair it.

You can use "hot glue" or a "plastic heat gun", that would allow you to fuse the cracked plastic back together.

That may or may not cure the problem.

Do not try to use a hair drier.

The safest way, for a fix, is to replace the tank.

Andy

[TG Twinkie]

Can you tell what caused the crack? Does it look new? Is the filler tube well supported? I found this caulk called LEXELL at the local lumber store that looks kinda like silicone. I don't think it is though, it's really sticky and stays very flexible. You might give it a try before replacing the tank.

[Ganglin]

Some methods and instructions:

repairing rv water tank - Google Search=

[DonDiego]

I do not know what caused the crack. Possibly fatigue. The crack run vertical. It does not look new.
In researching, I see many people try different fillers, epoxies, glues, etc. There is also talk of heating the area to a melting point and refusing the plastic. Does anyone know what type of plastic these tanks are made of. To help, the tank is a pale green color.

[tkasten]

I have seen several tanks repaired with Eternabond sealing tape. Roof Leak Repair Products & Sealing Tape | EternaBond

This stuff is used for sealing rv roofs but has worked very well on tanks especially if repair is up high on the tank. Not too much water pressure up high. One of the rv tanks I am aware of has had the Eternabond tape repair on the tank for 3 years and no leaks.....Tim

[Bex]

Is Eternabond another name for Butyl Tape?
I have tried to find and buy Butyl Tape but cannot find it. I believe Butyl tape could be used successfully to fix this split problem.
Bex

[masseyfarm]

I agree with the Eternabond suggestion. It is a great product, but the repair area must be clean to start with.
See the web site for Eternabond for all the RV hints.
Dave

[Hendrick2488]

I'm going to chime in on Eternabond. It works great and you can get it at WalMart. The problem I had was when I patched one hole the pressure created made the water seep out another hole. So watch for that.

In the end I bought a new tank and therefore agree with Andy from Inland RV that replacing the tank is the quickest, most cost effective, safest way. They have a great selection of tanks but Andy, I have to confess, you are a little pricey on them.

P.S., I still love you guys though and I can't take my money with me.

[DonDiego]

Thanks for all the replies. I am still researching. I will post some of the possible solutions after I fell I am about ready to make a decision.

[dljosephson]

I had this exact problem in my 71 Tradewind and tried the suggested remedies. My advice is to skip it, call up Inca Plastics and get a replacement, unless your time is worth less than $5 an hour. The tanks are made of polyethylene, to which nothing sticks. The crack is caused by flexing the tank wall as you move the filler tube time and time again, the right-angle fitting is like a lever with the arm of the tube attached to it. Any repairs are stressed by the same thing the next time the tube is moved.

Eternabond worked for a few days. Getting that stuff off to try a real repair took forever. It is a gooey mastic material coated on one side of a vinyl sheet and works wonders for all sorts of things, but it did not keep the water inside the tank once we got going down the road. Eternabond works best on really smooth surfaces and the tank surface is rough.

Hot melt glue does not stick to polyethylene. If the crack is not repeatedly stressed and the tank is not too brittle from age, the remelt method works. Practice first on scrap pieces! Grind out the crack to a V shape almost all the way through the material, to provide an area for the new plastic to fuse to. There are several varieties of special tools made that heat up the edges of the groove that you have made in the plastic and simultaneously melt some new polyethylene to fuse into it. The local RV shop sawed up an old tank into rods about 1/4" square and a couple of feet long that they use like brazing rod to fill in the groove, people who make the special tools also sell specially formed plastic "wire" that feeds through the tool. Milk bottle plastic also works but is a little softer than the original. I made this repair using a huge modified old soldering iron (telephone company style, 200 watt or so, the copper tip about 3/8" diameter). It worked fine ... until next time, when the plastic near the crack broke because it too was brittle. Polyethylene melts at 250-260 degees F so this requires the soldering iron to be run at significantly lower voltage than normal (that's why you have a Variac in your shop, right?)

It was a pleasant surprise, taking the frame loose from the bottom of the trailer to replace the tank. Dropping the tank and the piece of 1-1/4" plywood that supports it was a lot easier than I thought it would be (and you will replace the plywood, because with all the leaks over the years it will be pretty spongy). Inca Plastics is not too happy about selling directly to end-users but they will do it if you have all the measurements of your tank first, including all the electrodes you want replaced for the level gauge.

[adore]

Originally Posted by Diego2

Our fresh water tank has a crack directly below the water inlet stub. It is about 3 inches below the stub on the flat surface. The crack is only about an inch long. I can use it by not filling completely. However, I would like to repair it if that is possible. Has anyone ever patched a fresh water tank?
Thanks in advance.

I have the exact same problem, with the same trailer (Argosy Minuet 1977). I found the same temporary solution by not filling it completely. When you find a permanent solution, please tell me, OK?
André D.

[Harry W]

Our '78 Land yacht had leaks in the polyethylene fresh water tank both on the top and bottom. The worst was around the drain plug on the bottom of the tank. The tank was made by Inca and is rotational molded and I was aware of polyethylene's resistance to adhesion, but a new tank was out of the question in view of the trailer's other needs. But, long ago in a land far,far away, I saw a process where poly bottles were dropped through a gas flame to make the surface accept printing, so I cleaned the surface with laquer thinner and lightly dusted the surface with the flame from a butane torch. The multiple cracks were then coated with J-B Weld and the tank was reinstalled after the epoxy hardened. Success! No leaks.

That was over three years ago. I removed the tank today to get the axles aligned (looooong story, new replacement axles misaligned from the factory), and the epoxy patches are still tight.

If laquer thinner attacks the surface of your tank, it is not polyethylene.

[DonDiego]

Harry, there are several versions of JB Weld. Which one did you use? I am leaning toward the J-B Weld 8272 Marine Weld.... Amazon.com: J-B Weld 8272 Marine Weld: Automotive

[boo_n_sue]

Eternabond is expensive but it's a really good product. I have about 45 ft that I'm not using. I'll be happy to send you a snippet big enough to cover the crack in the tank. Send me a private message if you're interested. Good luck!

[Inland RV Center, In]

There are a number of products that can be used that sometimes have success in repairing a cracked water tank.

Depending onh the cracks, and the material used, a fix could be short lived or even last a long time.

The big concern, is to "NOT" used any material that could contaminated the water.

Andy

[Argosy Heir]

You might try this stuff. TAP Poly-Weld Adhesive: TAP Plastics& It say it bonds to poly tanks after they have been flame treated and may be worth a try. Let us know if you have any luck !!!

[TouringDan]

Diego

An old repaired crack in the bottom of my water tank came loose on a recent camping trip and soaked my floor. I tried some JB Weld for plastic but it did not hold. I think any repair will be temporary unless you plastic weld it and then that even may not work. I decided to replace my tank and use the old one to replenish my water supply with when we are boondocking. I carry it empty in the back of my truck and then fill it when I need to replace the water in the trailer. I elevate the tank a little and just gravity feed the water into my trailer tank. I bought my tank for $70 from RV Surplus. However as we all know, new solutions have new problems. The fill connection is smaller than stock and not in the same location and the same angle so I had to jury rig some plumbing fittings to get it to work. It now takes much longer to fill using gravity feed. If I had it to do over again, I might pay more and get the stock tank from Andy.

Dan

[lewster]

Allow me to chime on with a little real world experience from the 'field'. While EternaBond is great stuff, it will NOT seal a polyethylene tank permanently....and by that I mean that it will NEVER leak at the repair point again. Been there....done that!

There only 2 absolutely fool-proof methods that WILL work to your 'eternal' satisfaction.

1. REPLACE THE TANK WITH A NEW ONE

2. Find someone who is accomplished at plastic welding and has experience working on poly tanks. They can use the hot air method (BEST)or the direct heat contact method (still good). If done properly with the correct welding rod (same material as the tank) it will last forever. Not saying that the tank won't split somewhere else though, which is what makes Andy's solution #1!!!!

[Inland RV Center, In]

Originally Posted by TouringDan

Diego

An old repaired crack in the bottom of my water tank came loose on a recent camping trip and soaked my floor. I tried some JB Weld for plastic but it did not hold. I think any repair will be temporary unless you plastic weld it and then that even may not work. I decided to replace my tank and use the old one to replenish my water supply with when we are boondocking. I carry it empty in the back of my truck and then fill it when I need to replace the water in the trailer. I elevate the tank a little and just gravity feed the water into my trailer tank. I bought my tank for $70 from RV Surplus. However as we all know, new solutions have new problems. The fill connection is smaller than stock and not in the same location and the same angle so I had to jury rig some plumbing fittings to get it to work. It now takes much longer to fill using gravity feed. If I had it to do over again, I might pay more and get the stock tank from Andy.

Dan

Sometimes, the savings made by not replacing a problem, can result in spending lots of money fixing new problem/problems caused by the original issue.

Ruined batteries, rotted wood, damaged drapes, fatigue cracks in the frame and shell, are just a few of the unpleasant results.

Andy