yeah dawgie, you are correct, it is some nasty stuff and it will keep on expandind so don't fill the handle up all of the way or it will expand out, i learned it won't come out of one of my nice chamois browning shirts.
Been doing that for a few years... Had several go overboard... They float, thats for sure... I have found the largest advantage to a foam filled gaff is that you get the distinct pleasure of watching them float away! Seems like every time we loose a gaff overboard, we are too busy with a multiple or big fish to ever go around and pick it up... I did recover one floater once... Wan't mine though... Just found it floating around in a weed line... I'm sure glad the previous owner filled it with foam!
gofish put some foam on other arm of shirt and start a trend dude. easy a pie i use to weld over head in my learnin years and had a flap of matches catch far in my right shirt pocket it was blazen so bad my gote was a smolderin. the dude i was workin with came over and smacked me in the chops to put it out i all most had to send his kids my paycheck until i found out what was on far. that shirt was a conversation peice for a long time
here is another good tip, i learned the hard way. never, i mean never ever, never ever ever ever tig, mig, or stick weld with flip flops on, when you have one of those spatter balls get between your toes you can dance like michael jackson except quicker and wilder.