has anyone used expandifoam from home depot to help float the boat incase of hull damage?

Don't use an expandable foam in boats! First of all, it can expand too far and blow the deck off of your hull. This foam will also absorb water and fuel over time increasing the weight of your boat. Use pool noodles or pipe insulation instead. A block of foam or a bag of foam peanuts is better than nothing.

im glad i saw that. i didnt know it absorbs. i knew of the potential over expansion.

i heard that you could empty out a pop bottle and tape in to the inside of your boat and make sure the top is on tight so its water proof and the air will stay in. that should help your boat float if it flips.

Hi guys. I like the pop bottle idea. Is that the best way to go or is it just whatever way we like it.

I've been using pipe insulation in mine. If you have the room, you can use pool noodles and cut them up to fit. Any of these can absorb water and oil over time to it doesn't hurt to put new ones in yearly. Some people use bubble wrap to put in some areas where it will fit. Ifyour boat has a hatch or some kind of cowling, add some sheet foam or whatever else you have in case it comes off in a flip. Double-sided tape will hold that in place.

This flotation is going in the front of the boat, so whatever I put in there can not come out.
any ideas?

Go to home depot and get rigged insulation it’s vary light and you can carve it in to what you need.
normally comes in pink or blue color in 8'x2' I plan on using this for my boat I have used it before it dues not get water logged I have tested it.
You may be able to get it at a construction site for free if you ask they use if for foundations and skirting theirs always leftovers

Pinky d brain, how did you test it, and for how long? Water logging takes time, so if you put it in a bucket of water for an hour, that's not long enough for it to absorb water.

I have used surfboard foam as boyancy.
I shape a piece of surfboard foam to fit inside the cavity, coat it with resin and fix it in place with a small dob of epoxy. The reason I used surfboard foam is the fact that it is easy to work with and the resin won't disolve it like noodles etc.
I found that if you shape it well, you can coat the inside of the cavity with resin and fit the foam shape into the cavity, let it dry. Then sand the top of the shape flush with the deck, then add the deck.
It strengthened the deck and made for a more rigid boat that floats.

Regards Brettos.

Epoxy wont attack polystryene or pool noodles (foamed polyethelene or similar)

Polyester and vinyl ester will attack polystryene foams, but not the expanding or surf board foams.
Surf board foams or similar core materials tend to be heavy compared to stryene or pool noodles.
The best is a sealed container fill with air.
What ever you choose must still be sealed to reduce the absorbtion of water and fuel.

Pop bottles or bubble wrap ... works best and lightweight . The bubble wrap though WILL get "eaten" up from both nitro and gas fuels ....
I use small eye hooks epoxied into the front inside sides of the hull and stretch rubber bands from one to another to hold the pop bottles in place .

find yourself an old boat life preserver cut off the covering and use the guts.this stuff is very workable,you can cut it to fit tight.if you live near a mercedes collision repair shop ask them for the packing that they use for shipping hoods,thats what i used.it comes in 5'x1'x3"

Ridged Insulation:
Testing the ridged insulation we put it in water for like a weak and I have also pulled it out of foundations where it was exposed to water all the time and it was still good. I have used it in full size boats with no problems

Here is a web site of one of the products that stats "it's practically impossible for it to be penetrated by moisture"
http://www.owenscorning.com/around/i...s/foamular.asp

hope this helps