I was trying to get my dive shop to order some Cotol 240 (an accelerator for Aqua-Seal; basically toluene, I think); they farted around for a couple of months before telling me that shipping was prohibitive due to the flammability (in truth, this was due to one employee rather than the shop as a whole - should have talked to the owner.)
Went on-line, ordered from NRS, and had the stuff in my hands two days later. Good people.
I like 303's performance, but it doesn't seem to last in a marine environment. Have to reapply fairly often. You can also order direct from the 303 company (a web search for "303 Aerospace" will bring them up.)