Re-sealing the tanks
Both tanks have finally been internally re-sealed, after cleaning out all of the old failed sealant, which I really never want to do again. I applied polysulfide CS3204 B2 to all of the internal seams in the tank. The final step this week will be to re-install the rear baffles.
The re-sealing process that I followed was to force new sealant into all of the internal seams in the tanks. This was a little different to initial assembly, since the faying surfaces were already riveted. I trialled several tools for applying the sealant and the most effective was a length of bent rod, similar to what my old dentist used when making amalgum fillings. That 's a spin-off benefit from seeing the dentist! The small jewellers scale is graduated in 0.1g increments, which makes it easy to mix small batches when working slowly.
The smell of polysulfide sealant is unique and I'd forgotten all about it, however the memory came back instantly after 20 years.
I also fitted the Vans anti-rotation bracket on the fuel pickup tubes, this was actually the reason for opening the tanks several months ago, which then led to the whole unexpected repair job detour.
Scott McDaniels fuel tank construction videos on Youtube have been very helpful indeed.