I had a crack 2/3 around the outlet pipe plus one in the middle rib of my gray tank. I used this plastic weld epoxy (bought from Home Depot but can’t find it on their site now), it worked mint. The whole saga about prep & repair is on the TrailManor Fans page over on Facebook, link below. Also I’m working on a support for the gray tank similar to what the Factory now puts on the new units (won’t fit the older units as they use a different tank these days). You’d be amazed how much the belly of that tank swells when full of water. A bit of support has to help there.
https://www.jbtools.com/permatex-841...yABEgIw6_D_BwE
https://www.facebook.com/groups/1694...6144045316882/