Black tank repair?

Thanks for the update Jim.
Jim

Back from my Columbus Day Weekend trip. We had full hookups but as per usual I let it fill up before dumping. No leaks! Winter is coming with some extreme changes in temperature. I guess time will tell if it holds up. What didn't hold up was the GM HEI ignition coil. I moved the rig forward to get a better angle on the sewer hookup, dumped, and then it wouldn't restart. A quick check revealed no spark to the plugs on the 454. I got a ride to the auto parts store, got a new coil (which I also happen to have in my garage at home) and it was good as new.

Nice to hear it. I expect the repair to last as long as you have the MH.

Update:

I put 2 coats of the resin higher up on the tank on Friday. I put another 2 on it yesterday. I'm now officially out of Plasti-Mend.

I filled the tank (to the brim) earlier today and let it sit for a few hours. No leaks!

So I guess now the question is how long will it last? My next trip out is Columbus Day Weekend. We'll see how it goes after some miles on it.

Okay! I filled the black tank halfway up and....

...it still leaks.

But it's not the repair - the repair is awesome. I didn't get the resin up high enough on the side of the tank. It's really tough to get in there. I might have to grind out some metal in order to get up in there to clean and apply the resin (I have enough left to patch it). Ironically, that's not where it was leaking but in the process of preparing the area for the patch, I ground out the old patch. So now it leaks where it didn't before.

So I'm going to let it dry out for a couple of days and hit it again over the weekend. It's a tiny leak - like a drip every few seconds. But any sort of black tank leak is a bad leak.

My next trip out is in a couple of weeks, but I'll have full hookups. Worst case is I won't let the tank fill up past 1/4 (where the leak is).

time2roll wrote:
By the look of the crack I would have recommended some sheet ABS to add support. Although getting the sheet on just right with the Plasti-Mend goop also adds complications.

Looks like good work to me.

Thanks I ordered some ABS but like you said getting it just right looked difficult so I rolled the dice with the mesh.

And I will definitely let everyone know how it goes - good or bad. This is a learning experience for me.

Jim, please do let us know how it turns out, good or bad. All prior fix kits has not worked for such repairs. Could be some new recruits for this process.

Jim

By the look of the crack I would have recommended some sheet ABS to add support. Although getting the sheet on just right with the Plasti-Mend goop also adds complications.

Looks like good work to me.

I put the 5th coat of resin on it this morning. The kit says not to do more than 2 a day, and that a minimum of 3 is required. Since I have some resin left I'm going to put a 6th coat on it this afternoon and then call it done. The instructions say that it will remain flexible for a few days, so I'm thinking I'm going to wait until the weekend to fill the tank.

What's most interesting about it (to me anyway) is that it does appear to be melting into the tank like the instructions say. It's very thick and you glob it on as thick as you can without running or dripping. But after sitting overnight the repair is flat and smooth. This is what it looks like this morning (it's not actually 2 different colors, it's the sun hitting one part of it but not the other):



The true test is going to be if it has really bonded to the tank or is that giant patch just going to break off under a load. I prepared the surface per the instructions so fingers crossed....

The instructions say the stuff can be used for cracks, holes, refastening valve assemblies that have been torn from tanks, altering tanks or custom-fabricating tanks. The repair is stronger than the original tank. The instruction sheet goes on to say it was invented in 1983 by an RV Tech that had a need for a quick fix for holding tanks. After leaving the business he forgot about the stuff until he bought an RV with a broken holding tank. Being retired, and needing cash, he started to market the stuff. It has a money back guarantee, too.

I haven't called Tiffin about the tank yet.

Whatever repair they used before held for at least a decade. I don't know what it was - it was a hard plastic that filled the crack and bonded to the tank. I had a helluva time getting it off, and had to leave a lot of it there. This Plasti-Mend stuff appears to be bonding to the ABS. They say not to coat it more than twice in a day because it will deform thinner tanks as it melts into it.

The gray in the circle was the first coat. It dries pretty much the same color as the original tank. I'm going to put 2 more coats on it tomorrow, then fill the tank to see what happens.