I came across a "Vinyl Glue" called HH-66. Anyone tried it? Supposedly it will securely bond PVC-coated polyester. I also saw a video where it was used to seal sewn seams from the outside (fills in the needle holes) but even if it did keep out water I doubt it would hold air in a fully-inflated BC without a good bead along the seams from the inside. The glue seems like it would be easier than using heat, but whatever works the best is, of course, most important.
Also, I'm only finding 300 x 600 denier fabric. Is there such a thing as 600 x 600 or whatever? I don't know what the thread count (if that's what the numbers mean) is on my snorkel vest bc but I'm thinking thicker might be better. I have an old ScubaPro wing from around the 60s or 70s and it's pretty thick. So far I have been unsuccessful in repairing the seams where they let go. I suppose any BC could become punctured if someone was careless but I'd be more comfortable with thicker.
For a back-mount tank I found what looks like the perfect plastic backpack. It's an old Dacor. I removed the U-bolts and cut some slots so I can use a 2" webbing type of tank strap. It is thinner than my other plastic backpacks so the tank with lay closer to my back. I'm planning on filling it with about eight pounds of lead shot for better trim and to reduce the weight on my belt.
