It was somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Howard Rose saying something like:
Read the OP's message - I think the words "seeping slightly at the seam" are the important ones. No mention of it falling apart or generally being decrepit with age. Tanks with seam leakage are *exactly* the ones I've seen treated with this method and they go on for years after that. This method was adopted because of the dangers of welding fuel tanks.
It needs to be done carefully and with attention to detail; in fact, anyone with any fibreglassing experience could do a passable job.
Bodge, my arse. It's a permanent repair, and a bloody good one.