I'd recommend heading over to compositescentral.com and checking out the threads on this subject there, it seems to have been discussed in more detail than on this forum. Perhaps even message the user morepower, as I've seen he is quite happy to divulge some of his secrets (he's on here to, so he might be lurking...). He uses a phenol novolac to seal his tanks, so you could ask him where he is sourcing it etc. Alchemie is the company that springs to mind, but it's been awhile since I read his thread so I may be wrong.