Thanks Mark
I've been doing some research and have sourced some HDPE. I'm going to have a go plugging the gap and welding it together.
Replacing the tank looks like a long expensive job. I hope to avoid it if I can.
all for a little extra bass!
Why would replacing the tank be so much more difficult and expensive?
Given that you method of repair involves using heat on a vessel that has contained a highly volatile fuel, surely you would remove it first and use steam to remove all traces of fuel, remember it's the fuel vapour that goes bang not the liquid!
Now having gone to all the trouble of removing the tank, you may as well replace it, I doubt that sourcing a new one should be too difficult or expensive, given the number of rusted out cars being dismantled for parts.
Other than the safety risk, by attempting a repair, you risk having to remove it all again if the repair doesn't work!
Stop being a tightarse, and chuck the old tank to the shithouse.It'll cost less in the long run.
Do it right and only do it once. doing thing by halves is guaranteed that you'll be doing it at least twice.
Take it s a learning experience, Don't go boring holes in things until you know whats on the other side, this time it was the fuel tank next time it could be the wiring loom.