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.
![](https://i.imgur.com/vPuE6eOl.jpg)