This is how I repaired my tank. this was 2 years and many miles ago and still holding. The kit comes with ABS screen for a patch and burns itself into the old to become one.
Black tank repair
Last trip out I noticed a smell under trailer. Looking under I seen a drip drip. I dumped and flushed good at end of stay. Upon arriving home I found a surprise. The PO had hit the bottom of black tank and cracked it then patched with fiberglass and metal window screen and painted black. I was so busy checking roof seams and frame for rot I missed the tank patch. I cleaned fiberglass off and prepped area for Plasti-Mend patch , hope it works.
Cleaned and prepped area
Patched area 1st. coat and screen patch
Will add more later
Added 3rd and 4th coat
+ added additional strap
Now let it cure for a few days.
Jim and DW
2001 T-2553 Sunline Solaris
2006 GMC Sierra Duramax 2500HD 4X4
Firestone Transforce AT tires
Reese Dual Cam Sway Control