I had one on my Norton. came of on a bend and cracked it all picked the bike up and the petrol p....ed over the silencer and was steaming luckily it never went up .there not good if u ever have a head on with a car. tank rips off and can go through the car windscreen and incinerate anyone in it if it sets on fire
Going back to this thread. There was a bike in the shop a few weeks ago and the carbs were gobbed solid, cleaned them out and ran it up and they were same again. The ethanol in modern unleaded petrol rots the fibreglass and attacks the resin. This was a Fireblade with a custom seat and tank unit not a vintage tank which would probably be more vulnerable.. It ended up with a filter fitted and told him to put it back to standard as soon as possible.
epoxy is not designed for high build, more as an adhesion coat. if you preferred not to go poly, you could build 3 coats of high build, guide and flat 400 to take out the crazing and re high build for finishing coat.
Years ago i used Petseal on a heavily pinholed Honda tank, It was advertised as an "epoxy carbon fibre sealer" . Was it hell. It was nothing more than ordinary polyester resin with chopped strands of glass in it (Glass being white rather than carbon black). It did not do the job & was a total con.
Look on the bright side, someone i know has a very expensive 56 ft motor yacht that has had its GRP tanks sealed with some kind of tank sealant, The sealant degraded to the point where new fuel filters blocked withing minutes of being fitted. Of course They started the build with the tanks & build the rest of the boat round them including the high class acomadation. The fix is likely to bankrupt the builder.