New Foam - Keeping IT Dry?

Hello.

I am about to replace my foam after installing new stringers. I am assuming you seal everything so no water can get back to the foam. My question is do you provide some means for evaporation to occur or do you just completely seal it?

I would make sure that before you set/seal the hull with the new floor that it has no sweat or moisture. If you have it in doors it should be good as long as you do not see moisture on it. I hope that is what you were asking.
G.

not real sure i understand ,but once you foam it seal it 100% so no water can get to it.........if it is foame right it should expand and fill all the little voids thenn seal up the expansion (pour holes) with cloth and resin.......don't give water a way to get back to it.............

The newer "Pour foam" is "closed cell" where as the older foam was an "open cell". The older foam was able to absorb water but the newer foam does not. If you have any voids in the area that you are foaming, even if you "air tight" seal it, you will get water into the voids due to condensation. What I do on my boats is mix up the foam, pour it into the cavity and before it starts to expand, I cover the area with a piece of plywood that is covered with vinyl sheeting like the painters put down to avoid spills. I then place some weight (cbs block or 2) on top of the plywood for about a half an hour. You have to be careful with the amount of foam that you put into an area, as to much can cause bowing of the structure or even in extreme cases, "BLOW OUTS". With the plywood on top with moderate weight on it, if the amount of foam is to much, the plywood will lift and the foam will overflow versus causing structure defects. If you don't put enough in and the expansion is not enough, you can add more foam. If you have to much, you can cut off the overflow with a wood hand saw. Before you cover the area and seal it, I recommend that you resin coat the foam surface. Be careful with the foam as any area that it gets on, it stays. Tape off the surrounding area and cover with vinyl sheeting. Also wear surgical type gloves and a respirator.

Hope I helped!!!

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RAZOR Jim &raquo;</TD></TR><TR><TD CLASS="quote"> If you have to much, you can cut off the overflow with a wood hand saw. Before you cover the area and seal it, I recommend that you resin coat the foam surface.</TD></TR></TABLE>

Thats an important step.
Even if the new stuff is closed cell, once you grind it, cut it, scuff it, etc, all bets are off.Its only fully waterproof until you trim it.

put it in a bag and then foam it...and coast guard requirments it must be of a closed cell type of foam..