Got an old vhull aluminum jon with a leaky keel strip.  Any one know of a small can product of spray foam with an applicator tube that I might be able to use to fill the gap space in the strip and prevent water from seeping in. The leak is very small.

Just an idea.  I bet someone has done it or tried it.

I would sooner try JB weld or something of the sort before i would use spray foam. They make these epoxys for aluminum that is almost like play doh that you could use as well.

Not sure if it would work in your case but on mine I put the boat up on saw horses and put a few inches of water in the boat.  Then when/if you see water dripping onto the floor I reach under with a Sharpie and circle the rivets or wherever its leak is.  Drain the boat, flip it over and I've found nothing that works better than JB Weld.  Cost less than $5 and there is enough in one package to do a lot of rivets.

I once tried a product called Quicksteel to actually lay down in the keel strip and would never buy it again.  It was messy, did not adhere well to the aluminum and never actually set up like "steel".  It was actually quite brittle.

IF YOU USE A SPRAY FOAM, MAKE SURE IT IS A 'CLOSED CELL' FOAM WHICH IS OF COURSE MORE EXPENSIVE AND WOULD PROBABLY HAVE TO BE ORDERED FROM A MARINE SUPPLY STORE.  THE STUFF YOU GET A HARDWARE STORE IN A SPRAY CAN IS AN OPEN CELL FOAM THAT WILL SOAK UP WATER LIKE A SPONGE AND HOLD IT CAUSING ADDED WEIGHT AND WOOD ROT IF YOU HAVE A WOOD DECK, STRINGERS, ETC.  

ROLL TIDE

A product designed for this situation is Marine Tex.

This looks promising.

http://www.wholesalemarine.com/p/F-E-654/Marine%20&%20Automotive%20Urethane%20Spray%20Sealant%20Foam.html

Only drawback is that the can and the applicator might be single use, you have to use all of it at once. No partial use of contents.

Anyone here use this product??

try wandering over to the iboats forums.  There will be a ton of info there and plenty of advice from many people who have done the same thing.  I will warn you that pictures would definitely be helpful and they will probably ask for them.

i would also recommend jb weld.  works great, dries relatiely quickly, and is d**n strong.

There is a marine sealant called 5200 it is sold at walmart that might also work for you hope this helps.