Community Forums

Piker · 07-10-2017, 08:09 PM

I got started on the tank repair tonight. The first pic is of the materials used - ABS pellets used for injection molding, and acetone.

The second pic is after I've mixed them up. I had an extra oil sample bottle from Blackstone - it said HDPE right on the bottom (high density polyethylene). This material does not dissolve in acetone, so it was a perfect mixing vessel with a lid. I filled it a little less than half full with pellets and the rest of the way with acetone. I used a spade type drill bit in a cordless drill to mix. Took about 20 minutes of mixing to get it smooth like pancake batter.

I tested the paste on the side of that tank to see how it adhered. I was kind of amazed. It skins over on the outside fairly quickly, and in a few hours it's dry underneath. The acetone penetrates MUCH further into the existing tank than I had imagined, for a ridiculously strong bond. It really is like the paste becomes part of the tank. You will destroy the tank trying to remove this stuff.

-more to come

Piker · 07-10-2017, 08:11 PM

I've got 2 coats of the ABS paste on the crack. I did not drill the ends of the crack, because I couldn't really tell where the crack(s) begin and end. I prepped the surface by cleaning it with acetone. There was an old repair that the previous owner made with some epoxy type stuff... I removed that repair because I think it was starting to leak too. The crack was right around the outside of the original weld - first pic... I think it goes about 2/3's of the way around the fitting.

I used fiberglass mesh tape to reinforce the repair... the stuff that is used for taping drywall joints. It's handy because it's got a little adhesive on it, and you can place it right where you want it before putting on the ABS paste. (I used this mesh tape with Amazing GOOP 5 years ago to repair a crack in the fresh water tank, which is polyethylene material - still holding today) I made a template to cut a circular patch of the fiberglass mesh and affixed it to the tank - second pic.

And then I gooped it up with the home-brew ABS paste - third pic. And then added some more mesh on a second layer - 4th pic. And then gooped it up again. - 5th pic.

That's all I got done this evening. The goal is to work the corner where the fitting is cracked into a nice big radius all the way around for strength. I think this is going to work, and for the cost of some Acetone and free ABS pellets. Time will tell. I'll post another pic once it's all finished. Probably be a couple days...

-cheers

mkohler30 · 07-10-2017, 08:25 PM

Looks great piker

Mk

wingshot · 07-10-2017, 08:44 PM

Impressive and useful knowledge. Looks great.

WILDEBILL308 · 07-10-2017, 09:06 PM

Great job.
Bill

10Boomer · 07-10-2017, 10:11 PM

Repair looks good!

Franka548 · 07-11-2017, 04:35 AM

Looks like you have it better than new Piker, good job.
Frank

Gordon Dewald · 07-11-2017, 11:19 AM

Everything the guys above said. Learning all kinds of interesting things from various threads on the forum. Have this thread ear marked.

Piker · 07-11-2017, 06:16 PM

Quote:

Originally Posted by Gordon Dewald

Everything the guys above said. Learning all kinds of interesting things from various threads on the forum. Have this thread ear marked.

Well... here's a chance to learn from my mistakes. This turned out to be an epic fail. One reason is that unbeknownst to me, there is condensation inside the tank that leaked out through the crack after I gooped it. Not good. It made a path way behind and through the patch.

The other reason is that I think I may have put it on too thick. It never dried fully. After seeing condensation leeching out from it, I tried to remove it, and the tank was so soft underneath the abs paste from the acetone working on it that you could poke right thru it.

Walking away from this one... needs a new tank and I'm not up to it.

Cheers

sam-3 · 07-11-2017, 06:52 PM

Do a search on the internet for RV holding tank repairs. Several years I put the 2x4 down too soon as DH was backing into our storage spot. It ripped the black tank and "sh...t was pouring on the ground. We just bought some kind of spray at our RV place and a fiberglass mending kit. Look at the glues at Walmart.

Wroughtnharv · 07-11-2017, 08:16 PM

Our Cedar Creek fiver had an issue fresh water tank. The outlet was on the side and since gravity had done her thing for awhile (bottom sag) the holding tank was only good for about half of her capacity. It was kind of a bummer to carry the weight and not have access to but half of the water.

I pulled the tank, easy job on the fiver, cut in a new hole in the bottom of the tank and used a good expoxy to install it. It was still working good when we sold is a couple of years later. I think your idea was viable but might have worked better if the tank was out of the coach and in a place where you could work on it without a time constraint. I really like the idea.

Piker · 07-12-2017, 05:45 AM

... maybe I try to grind off this repair and start over - with very thin coats of a thinner ABS paste that fully cure before applying additional coats... and of course make sure there is no water leaking.

The areas of this repair that are thin cannot be removed. The thick areas actually have air pockets behind them, I think maybe because it shrinks a bit when it sets up.

I'd like to just opt for a new tank, but I have yet to find one that will fit. This tank is L-shaped.

-cheers

Franka548 · 07-12-2017, 05:54 AM

Piker,
You might want to check with one of the manufacturers of the tanks, they may be able to help you, might even have the correct size tank in stock.
Frank

Gordon Dewald · 07-12-2017, 09:29 AM

Quote:

Originally Posted by Piker

Well... here's a chance to learn from my mistakes. This turned out to be an epic fail. One reason is that unbeknownst to me, there is condensation inside the tank that leaked out through the crack after I gooped it. Not good. It made a path way behind and through the patch.

The other reason is that I think I may have put it on too thick. It never dried fully. After seeing condensation leeching out from it, I tried to remove it, and the tank was so soft underneath the abs paste from the acetone working on it that you could poke right thru it.

Walking away from this one... needs a new tank and I'm not up to it.

Cheers

Thanks for the lesson. I would have to argue that while it failed it was not epic. Lesson learned so there was value. Has to be totally frustrating as the idea was sound and practical. Bit of slip in method. Try not to do that again!

The tank appears to be quite smooth without ridges etc. Is it possible to build a plate to cover the bottom of the tank with sufficient glue, etc to bond it to the tank. Perhaps a couple bands to help. Then one could build a new drain and fasten to the tank. Maybe more work than replacing the tank?? Could one build something out of fiberglass and affix it? If the plate is impermeable and sufficient glue should form a seal that will work.

Brainstorming - any ideas?