The tank construction is polyethylene and there are not very many epoxies on the market that are available for this application, that will hold. I've been doing quite a bit of reading and that is the common denominator, it being polyethylene and food grade perse.
I came across a company that sells a beginner kit for these types of repairs. The kit comes with the spin weld tool and a few bungs. My plan is to remove the old and patch it (included) and re-drill/relocate the new 1/2 FNPT not to far from the original placement.
Very simple 3-4 second procedure if you have the right tools.
This is the company I contacted in Adelanto Ca and the product they offer. Good deal considering one pro install tool is over 100.00 each. This allows for multiple sizes.
https://www.toyhaulertanks.com/produ...-spinweld-tool
I know epoxy might work and hold, but the last thing I want is for it to decide to let go in the middle of a trip or in the desert and I am completely screwed. There is no coming back from a fresh water supply leak or loss of all your water.
Trip officially over.