Punctured water tank?

[75thRanger]

Originally Posted by Ron in BC

It's effectively both. Leaking hot water tank? Turn valve 90*. That stops the pressurized cold water from entering the tank. Keep hot water faucets closed and no cold water can flow backwards to the hot water tank.

I just did it on my trailer to confirm that's the case.

Ron

I can confirm that also. My old Holiday Rambler hot water tank developed a leak last month and I did exactly as you described to shut water off to it.

Still trying to decide if replacing the tank is worth it.

[steve dunham]

Something doesn’t jive in my mind based on the description of the problem and the photos & videos

1) The heating pad has a built in thermostat limiting the temperature but it may have failed ?

BUT ! - According to the internet
1) The plastic used for the fresh water tank has a melting temperature of over 220 deg F
2 ) The foam has a melting temperature of approx 180 deg F
3 ) A difference of over 40 deg F
Thus my question .
How did the heating mat get hot enough to melt the tank yet not hot enough to melt the foam insulation ?

I am probably over looking something but we have the heat pads on our tanks and it makes me wonder if they’re safe to use ?

[padlin]

Everything is just speculation till Medora, or an RV shop, remove some of the foam and get eyeballs on the issue. If you are going to go in and take a look yourself, I found a plastic putty knife works pretty good to cut it. If you take it off as fairly small pieces it's fairly easy.

[alanmalk]

Originally Posted by Thane

...
I installed the rinse system with silicone
...

If silicone is your adhesive of choice then perhaps you should consider "aquarium safe" silicone. This will avoid introducing mildew killers and other unwanted chemicals into your drinking water. DAP made this product at one time, but it has been a number of years since I was in the market.
--
Alan

[Steven M]

Originally Posted by Ron in BC

Edit: the more I look at it the more I wonder about it. My tank is sealed so changing the valve prevents more water going into the tank. If my tank was perforated then I'm wondering if the cold water wouldn't just go vertically and in the outlet? Seems like it would require a second valve at the top junction of the red and blue hoses to be a complete by-pass.



Ron

Ron, check and make sure that the hot side shut off isn't facing the water heater. On mine both the hot and cold shut off are effectively backwards facing the water heater instead of me. Makes shutting off and turning on interesting.

[medora]

Thane, your post was incredibly helpful - thank you! It turns out that this blog entry is pretty much dead on to our sitch. The “donut hole” he describes is exactly what failed on our tank. We popped out the damaged bits and sanded the edges so that we now have a roughly 2” hole. Our plan tomorrow is to take Water Weld and try to patch the hole using a silicone potholder that we cut and adhere INSIDE the tank. The Water Weld will be on the outside, filling the hole. And then I got a small piece of Lexan which we will adhere over the whole thing using the same company’s Plastic Bonding product. And the over THAT we plan to seal the lexan edges using Gorilla Waterproof Seal tape.

We will see if this works! If any of you have better thoughts let me know. We know we can forgo the luxuries and just camp with bottled water, but we will be out a LOT in coming weeks and want to figure this out it possible.

[medora]

And Steve, that’s a very good question - I had no idea the heating pads could EVER get hot enough to cause something like this, but once we got in there and saw the burnt hole and melted stuff around it, it seems that’s really the only explanation. Definitely worth checking with Escape about. We will ask Dustin and post the response here.

[Thane]

Thanks for the tip on aquarium safe silicone.

Sounds like a great repair idea, happy camping.

[hotfishtacos]

Medora, I had a few holes I accidentally made in my water tank and learned that nothing bonds well to PE. Bonding polyethylene is considered very difficult and as a result it is often used as packaging for adhesive materials – as the glue won't stick to it! I had to shave material from the tank corners with a hand plane and melt the plastic pieces to the base material with a special soldering iron tip. This is a common solution for fixing leaks in these tanks. There may be a high tech solution but I couldn't find one. I also removed the tank to do the repair but it wasn't coated with insulation. Your hole is pretty big so you may need to melt a large PE plug into that hole, once you trim it. Good luck.

[Thane]

You may want to add a few screws to your repair. A couple flush screws to hold the inner patch in place before you install the outer patch then 4 or more screws through the whole stack to hold everything in place. The Water Bond will form a good gasket even if doesn’t stick well.
You can hold the inner patch in place with screw, like a handle, as you install it, the Water Bond and outer patch will cover the screw hole after you remove the screw.
You can also use a thick inner patch bigger than the hole by cutting it in two and sliding each half inside. The Water Bond and outer patch will take care of the seam between the two inner patches.
Install the screws in pilot holes for a tight fit and put a dab of sealant on them to seal under the head.
This split type of patch worked well to fix F/A-18 aircraft wing fuel tanks except we used a metal disc between the patches to fill in the hole in the wing skin.
As noted by Alan, aquarium silicone wouldn’t affect the water as much as Water Bond or normal silicone. The screws hold everything in place, the silicone is the gasket.
You may be able to get a full-life repair out of this, it worked on the fighter at Mach 1.8 and 9 Gs.

[tdf-texas]

The only way to permanently repair a poly tank is with a plastic welder. No adhesive is going to stick to this stuff - you are just wasting your time if you try.

https://www.amazon.com/Jounjip-Plast...8534392&sr=8-5

Use PP welding rods to do the repair.

https://www.amazon.com/Polypropylene.../dp/B07TZC2395

[Ian and Sue]

Originally Posted by Thane

You may want to add a few screws to your repair. A couple flush screws to hold the inner patch in place before you install the outer patch then 4 or more screws through the whole stack to hold everything in place. The Water Bond will form a good gasket even if doesn’t stick well.
You can hold the inner patch in place with screw, like a handle, as you install it, the Water Bond and outer patch will cover the screw hole after you remove the screw.
You can also use a thick inner patch bigger than the hole by cutting it in two and sliding each half inside. The Water Bond and outer patch will take care of the seam between the two inner patches.
Install the screws in pilot holes for a tight fit and put a dab of sealant on them to seal under the head.
This split type of patch worked well to fix F/A-18 aircraft wing fuel tanks except we used a metal disc between the patches to fill in the hole in the wing skin.
As noted by Alan, aquarium silicone wouldn’t affect the water as much as Water Bond or normal silicone. The screws hold everything in place, the silicone is the gasket.
You may be able to get a full-life repair out of this, it worked on the fighter at Mach 1.8 and 9 Gs.

I agree the key to your type of problem is to do a sandwich type of patch. They sell bulkhead fittings for this type of tank to install inlet/outlets. They basically work by having rigid pieces inside and outside the tank. The pieces are screwed or bolted together to squeeze gaskets that are between both rigid pieces and the tank to make a seal. Rubber is a better sealer in this case than other items like silicone. You could do the same type of thing but instead of installing a fitting just use a blank or circle of rigid material on the outside between the gasket and the rigid piece. Good luck! and don't worry, go camping!

[steve dunham]

Originally Posted by medora

And Steve, that’s a very good question - I had no idea the heating pads could EVER get hot enough to cause something like this, but once we got in there and saw the burnt hole and melted stuff around it, it seems that’s really the only explanation. Definitely worth checking with Escape about. We will ask Dustin and post the response here.

I wonder if the heating cable did not fail at that specific point and create an arcing fault
I’ve worked on industrial heat mats where the heat cable failed and burnt a small hole in the outer covering of the Mat / blanket but those heat blankets / mats were operating at AC line voltage and the damage caused was not that extensive
I realize your goal right now is to get your tank fixed and hit the road but for Escape and Escape owners with the heat pads it would be helpful to know the cause , and the hazards presented by the failure .

[h2owmn]

I agree with Donna and Iowa Dave. Go camping! I use my water tank about 10% of the time I'm camping. I don't have a bathroom or a hot water heater, and don't want to haul heavy water around. Plus I'm rarely in one place for more than a few nights. And there's usually just me. I have a 5 gallon jug that i carry partly full in the car just in case of a water access problem in camp. It'll be different than the amenities you're used to, but it sure beats staying home. Good luck!

[medora]

Using a bulkhead (perhaps welded in for security) is a great suggestion but - how do we get the internal piece inside the tank? It’ll be too big to fit, unless I am missing something?

[Ian and Sue]

Originally Posted by medora

Using a bulkhead (perhaps welded in for security) is a great suggestion but - how do we get the internal piece inside the tank? It’ll be too big to fit, unless I am missing something?

Hmmm good point...I am used to having a top hatch to do it from! If you had a ring of something rigid and good gaskets with bolts you could cut the ring in half so you had two c shaped pieces which you could fit in with bolts already glued in it and fold the gasket to get it in. bolt it through the outside gasket and your plate, tighten it down and that should work pretty well. Remember this is not a pressure vessel so it does not take much to get a good watertight fit.

[Thane]

I respectfully disagree about wasting time to repair. The patches would be mechanically fastened and not rely on the adhesive or sealant. I agree that adhesive alone is questionable.

I put the equivalent of a screwed on patch on my freshwater tank and there have been no leaks for 4 years. It was screwed on the outside with no inner patch. It is on the side, not the bottom, so the water pressure load is less and I was not too concerned about having only a one sided patch assembly. I considered a two sided patch configuration and decided it was not required. I was concerned about slosh loads so at first I didn’t travel with a partially filled tank. I must admit, it was nice to see it didn’t leak! These thick walled tanks can hold a screw well. If it ever does develop a leak, I will remove it, rotate a few degrees and reinstall with an inner patch doubler.

The 2 piece patch we put on a supersonic fighter fuel tank with no adhesive, only a liquid rubber sealant and fasteners worked fine. That repair was more complicated, we needed smaller holes in the titanium patches and bigger holes in the carbon epoxy skin for load transfer.

Since all the holes were predrilled, we used wires in adjacent holes to hold everything together and practiced the installation process before final install to make sure we got the choreography correct, we didn’t waste time once the rubber was mixed. We didn’t use adhesive so it could be removed and the carbon epoxy skin checked for delaminations during future Depot level maintenance checks. The same repair concept is used with metal aircraft wing tanks but those are easier as everything is aluminum and they don’t have to be removed for future inspections.

I like the idea of an off the shelf bulkhead fitting, you could then completely drain the tank when you are done for the season.

[Thane]

Originally Posted by medora

Using a bulkhead (perhaps welded in for security) is a great suggestion but - how do we get the internal piece inside the tank? It’ll be too big to fit, unless I am missing something?

Good question.

The inner piece could be cut in two, put through the hole then glued back together. The bond line doesn’t have to be super strong, the assembled bulkhead fitting should be adequate to keep everything together. The hole should be a little bigger than the fitting to give some wriggle room. Flush screws could hold the inner piece together and in place as the outer piece is installed.

Anything put into the tank should have a string attached so it can be fished out if it gets out of reach.

[medora]

Ian and Sue - and Thane - I’m so grateful for both of your thoughts. I could run over to the marine store near us and try to get a PE bulkhead — and use the cut in half trick to install, then plastic weld around the external edges to seal entirely. Would a plug screwed into the bulkhead then hold, you think? Alternatively, I could go with the original idea (interior patch screwed in, then exterior Lexan panel screwed in, or maybe instead a PE panel screwed AND welded in? )

Flummoxed as to which way to go?!?

And if I am screwing in - what if anything am I using to seal the screw holes and or exterior patch edges? What sealant would adhere to the PE?

[steve dunham]

I realize you live in a rural area but there are businesses that repair the plastic tanks used in agricultural applications ( Water tanks , tanks for spraying herbicides and insecticides)
Sometimes it’s cheaper in the long run to have it professionally repaired then risk failure down the road .