Thanks to all that responded on the repair of my holding tank. I did remove the tank and there is about a 6 inch rip at the base of the outlow. I drilled holes at the end of the tear and then drilled holes a place 6 wire sutures to bring the tear in good apposition. I then used the new abs cement and fiberglass screen to create a pretty nice looking patch. Problem this am is that any residue not at the patch site is quite easily removed from the tank, which leads me to believe the patch also will not hold. I did sand and clean the entire area very thoroughly, any thoughts. Thanks Charlie

89 Barth 38 Regency Cummins/Spartan

This may sound like a "d'uh", but when you're sure everything has cured completely, fill the tank with clean water, check for leaks, even go drive around a little to really put the stress on it. If the patch doesn't hold, at least it will be just water that blows out all over the road. Don't ask me how I happen to know this little tidbit of advice.

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Originally posted by bill h:


Can you cut a shaving off an edge and see if it floats? ABS sinks and all PEs float. Use a trifle of liquid in the water to break the surface tension, as they are both in the specific gravity range near 1-point-zero.

Did you do that?

quote:

Originally posted by Charlie:

Problem this am is that any residue not at the patch site is quite easily removed from the tank, which leads me to believe the patch also will not hold.

Probably not. But sometimes folks get lucky with adhesive patching of PE, if that is what you have.

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I fixed my black tank with JB weld, I cleaned it first, sanded it and then used denatured alcohol as the final cleaning agent. So far it has been holding. The reason for the break was obvious, there was a slight rounding on the bottom to shape toward the drain exit, however the tank was held in place by a piece of flat stock that over time just broke up into the opening of the drain.



After repair I made a relief for this in the flat stock to take any pressure off the drain area.

Got deathly sick for two days during the repair, even thou I used rubber gloves and flushed the tank may times before starting, some bug that my body didn't like was still in there.

If it fail again, I will replace the tank with a larger one and fix the vent pipe that extends 1/2 way down into the tank. After the tank is about 1/2 full, the toilet will bubble back when flushing and odors will start coming into the coach. Someone didn't pay attention to detail when installing the tank.

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Someone didn't pay attention to detail when installing the tank.

Ed's picture illustrates it very well. Most tank problems, black, gray or fresh are the result of concentrated stress. Any stress on something that will bend needs to be distributed evenly to avoid distortion and eventual failure. I had a black tank fail because the full weight was borne by just two metal bars. After repairs, it got better, flatter support and stayed fixed. I have no doubt that my welds would have failed without better support.

Even fresh water tanks. One day, while buying PE sheet to make a new tank, I spoke with a guy who had a fresh water tank split open at one side because it bulged when full. He welded it shut and put it back in with plywood support on the sides.

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Got deathly sick for two days during the repair, even thou I used rubber gloves and flushed the tank may times before starting, some bug that my body didn't like was still in there.

Out of curiousity, Ed, what black tank chemical do you use?

I let mine sit, freshly flushed, with a bleach solution before I do any work. And we use Happy Camper, which contains enzymes and magic stuff. When not being driven, we always let the tank sit with a little water and HC just to keep it inhospitable to bugs.

I am operating on reasonable hunches, here, with no hard evidence. It would be interesting to have a medical or health dept person send in different black tank samples to see if different treatments have different results as far as E. Coli or whatever.

Bill, I talked with several people and they all assured me I had an abs tank. I did take shavings and put them in water with some detergent and sure enough they float. HDPE is what you are telling me.Did you have a suggestion as how to proceed now. ie remove the abs cement if possible and use what? You have my attention and thank you for the info.

Charlie 89 Regency with broken holding tank



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quote:

Originally posted by charlie:
Bill, I talked with several people and they all assured me I had an abs tank.

How did they determine that?

The only way I can know for sure without any testing is what is what is the molded code on the product. It is voluntary, so every maker does not do it. Otherwise, I have to test, as welding or gluing requires the correct material and technique.

An experienced person can also burn a sliver and tell by looking and smelling.

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I did take shavings and put them in water with some detergent and sure enough they float. HDPE is what you are telling me.

well, when you add the floating to the non-sticking of the ABS cement, it is probably HDPE.

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Did you have a suggestion as how to proceed now. ie remove the abs cement if possible and use what?

Yup, remove everything you can. Pry, scrape, scratch, sand, etc. Stop-drilling can help. However, drilling plastic introduces stresses of its own, which may bite you later. I have had better success using a hot rod to make stop holes. The heat allows any stresses to relieve themselves as the plastic heats and cools. As long as the rod is not too hot. It needs to be just hot enough to make the hole. If you do stop drill, be sure to resharpen your drill to about a 60 degree angle, or buy one for plastic to minimize the stress risers you create.

Once it is clean, you have a choice of taking it to a plastic welding guy or trying to weld it yourself. A talented amateur can use rod or scrap material and a heat source. A soldering iron with or without a heat control will work. So will the cheap Harbor Freight welder. At least for a while. My favorite brands of welder are Urethane Supply or Seelye, but they run a little more. I justify the expense by fixing other broke stuff, which seems to abound. Yea, verily, it multiplies.

One other way to go is a new cement made by 3M that is reputed to work on PE. 3M 8005 is reputed to mend PE. I haven't used it yet, but I would expect it to be good, coming from 3M. The tool is overpriced, but you can cobble one up with two dowels, a little metal, and a caulking gun. You don't need the nozzle, either, just mix what squeezes out and apply. I carry some with me now, just in case.

Another thread here covers some of the same ground.

Loctite sells several adhesives touted for PE, but my results with them at work were not consistent. They are particularly deficient at gap filling, and when I inquired, no good answer re: filler was provided.

Thanks Bill for the info. When I boght my barth in 2002 I did become a member of this site with Dave at the helm and since then have been busy doing other things. Anyway I was not aware of your technical expertise and appreciate you sharing with me. My area of expertise is far removed from rv repair albeit I do like to tinker now that I have retired.Thanks again and at this point I am mobile with the tank and will take it to someone with a welder. Happy Trails. Charlie

Bill, I filled the tank with water + 1 gallon of bleach and let it sit for a day before I started to work on it. I probably didn't get all of the areas covered, I probably should have driven it around a bit to slosh the water/bleach around. It was nasty!

Next time I will use a HAZMAT suit HeHe!

quote:

Originally posted by MWrench:
Bill, I filled the tank with water + 1 gallon of bleach and let it sit for a day before I started to work on it. I probably didn't get all of the areas covered, I probably should have driven it around a bit to slosh the water/bleach around. It was nasty!

Next time I will use a HAZMAT suit HeHe!

At least a face mask of some kind. I would've thought that the precautions you took were sufficient.

Did your symptoms suggest E. Coli?

Don't know what E. Coli is like but both ends were going for quite awhile the first day, high fever and then very weak the second day. third day finally felt like human and by the end of the week i was back somewhat to normal. Didn't seek medical attention so have no professional opinion.

I intend to do some extreme sanitizing before I tackle the vent issue or replacing the black tank.