Gluing a foam block

Ralphiechipper

New Member
I need to reinforce a foam block inside the hull...4 feet on port side..saw this expanding foam called "pond and stone"..it comes in a aerosol can...it's totally waterproof and does not absorb water...the company states their yellow expanding foam absorbs water but not this....anyone ever use this ??any feedback would be greatly appreciated.
 
Is the stuff black? If so I just used some to repair a hole in a shed roof. The stuff is crazy-sticky. It would probably be good for the foam blocks. Just wear gloves and a shirt you don’t care about. Once that stuff gets on you you can’t get it off!!
 
We've been discussing alternatives to 2-part foam here since 2010. :confused:

Since we do have successful applications using 2-part foam, yours would be an experiment. Before proceeding, ensure that the block is firmly jammed against hull and deck. (I wish a good outcome, and good luck). :)

As our member, the late Wayne, stated eight years ago, "pond foam" doesn't need to be a lightweight foam, nor does it matter if it gets soaked-through when used in a pond:
Fixing foam block | Page 2 | SailingForums.com
 
So why would yellow expanding foam in a can not work. It's just a more recent
development since the 2 part foam instructions were written. I've used in under
the cockpit to keep the hull from oil-canning. As for soaking up water the
original foam used by the manufacture has the water resistance of a sponge.
 
So why would yellow expanding foam in a can not work. It's just a more recent
development since the 2 part foam instructions were written. I've used in under
the cockpit to keep the hull from oil-canning
. As for soaking up water the
original foam used by the manufacture has the water resistance of a sponge.
What a great idea! :cool:

What brand, and how did the foam get inserted there? :confused:
 
It was something I picked up at Ace Hardware. The tub had holes in it
but you can easily reach it from the inspection port. The hull under the
tub is only supported on the outside edges. If you hear a "Brattttttttt. . ."
with the boat is planing out that's usually the cause. Push on the hull
under the tub and see if it flexes. I think this is what racers call a hull
that has gone soft. We need some videos from the "Ultimate Inspection
Port" mod posted to see all the flexing and bending in action. It will sort
of look like you are sailing a canvas boat.
 
Video coming up in about a month! :)

I know about sailing a canvas boat. ;)
P8130087-005.JPG
 
I would use the Gorilla brand polyurethane glue that looks like pancake syrup. It sticks well to plastics and fiberglass, foams slightly when curing to fill gaps and is slightly flexible after curing. the foamed parts have a thin water proof skin when dry, as long as you don't cut into it.
 
Is the stuff black? If so I just used some to repair a hole in a shed roof. The stuff is crazy-sticky. It would probably be good for the foam blocks. Just wear gloves and a shirt you don’t care about. Once that stuff gets on you you can’t get it off!!
Yes....it is black...it's a type of polyurethane expanding foam.they attach items underwater sometimes inside a aquarium with this stuff......the yellow foam absorbs water so can't be used
 
We've been discussing alternatives to 2-part foam here since 2010. :confused:

Since we do have successful applications using 2-part foam, yours would be an experiment. Before proceeding, ensure that the block is firmly jammed against hull and deck. (I wish a good outcome, and good luck). :)

As our member, the late Wayne, stated eight years ago, "pond foam" doesn't need to be a lightweight foam, nor does it matter if it gets soaked-through when used in a pond:
Fixing foam block | Page 2 | SailingForums.com
Please help me with this....do I put the foam along the sides where the blocks meet the hull of do I try to get it along the base of the foam block,the underneath side???thanks
 
Looking at an old thread it seems they were trying to match the 2 lbs density foam
used by the manufacture. One person used a hacksaw to put a gap between the top and
bottom of the foam then sprayed in medium density foam, not "Great Stuff." There is discussion
over whether the expanding foam can distort the curve of the hull but no evidence by members
that it has happened. I have seen people pop the bow deck, do repairs and then put expanding
foam on the top of the block and and clamp the deck back down. My take-away is that
the factory put the foam on the top and bottom of the blocks then clamped everything
together. The closer you can get to the 2 lbs density foam they used the better. Since there
are no bulkheads the foam blocks are the only think keeping the hull from becoming
a flexible flyer.
 
You put it where the blocks meet the hull—nobody said it would be easy. ;) The factory put less foam on the top, but some hulls show a huge amount oozing-out from along the base of the blocks. (The very worst place for absorbing water—and adding weight !)

I've still got a loose block to starboard :(, but expect to shop for a really long carriage bolt, and run it right through the middle of that block! :mad:

I would use the Gorilla brand polyurethane glue that looks like pancake syrup. It sticks well to plastics and fiberglass, foams slightly when curing to fill gaps and is slightly flexible after curing. the foamed parts have a thin water proof skin when dry, as long as you don't cut into it.
I've got some $5 Gorilla glue, but it's clear, so it looks like Karo syrup. :oops: It's in a relatively small container, and doesn't expand all that much. To use it along the top and bottom of a four-foot-long block could be prohibitively expensive! :confused:
 
The brown Gorilla glue expands and cures with moisture. The normal moisture in a sunfish hull is more than enough to make it foam before curing,
The nice thing about it is that you wipe it on thin and it can be positioned for a few minutes before it foams and cures. some of the clear gorilla glues are just a CA base, so old fashioned super glue. Too brittle to flex with the hull and in some cases it will eat holes through EPS foam.
 
How are you accessing the block?

There needs to be foam along the top and bottom of the block, it will ooze under a little if the boat is on its side or you apply from the outer edge of the block.

And you will probably be okay tacking the block in place with a foam like that as long as you never let water sit inside the hull.
 

Back
Top