The actual use of 2# foam questions

[coostv]

Hey all.

Part of the restoration of my boat is looking like I will need to cut out the foam and replace all stringers which will be detailed in my other thread as I progress. I have questions about the actual use of expanding foam that I could not find answers to when I searched.

Working time, I see you have about 45 seconds or so before some of them start to expand. I am guessing that you need to move pretty fast to mix it and get it poured into your holes. How big an area should I expect to fill at a time? I am getting ahead of myself here, but I am just trying to get an idea of what I am in for before I get there.

Holes in the deck. The how many question I suppose will be answered by how large an area will be covered per pour, but what would be the best size to cut? I was thinking about doing 3" holes using a hole saw so I could put the piece back in before covering the deck with glass and epoxy. The original deck was done with 1" holes which leads me to believe they must have had a machine to inject the foam.

Thank you for any input into this!

Chris

1989 Barretta 185 Open Bow

 

[heiliges]

Re: The actual use of 2# foam questions

It appears most people do it before they even put the deck down. Supposedly the stuff can pop off decking. Thats the process I am going with but then again I am thinking of useing foam panels from the hardware store. Supposedly there is a brand that will not hold water.

 

[osborn159]

Re: The actual use of 2# foam questions

i will be using it under my deck as well, i will secure all deck panels with pl adhesive and a few screws, fillet the deck to the gunnels,seal all deck seams, then pour foam, my guess is those have had deck pop did not have enough holes for the air to escape, the way this stuff expands its a chemical air compressor if air gets trapped

 

[Bondo]

Re: The actual use of 2# foam questions

the way this stuff expands its a chemical air compressor if air gets trapped

Ayuh,... It Ain't the Air, it's the Foam itself that does the Damage....

 

[PiratePast40]

Re: The actual use of 2# foam questions

You might want to experiment with a batch first. I put a plastic bag in a 4 gallon bucket and poured an 8oz mix into it. It filled the bucket and also gave an additional 6" 'mushroom" on the top. That'll give you a good idea of how much expansion you'll get.

I did mine in sections and didn't have all the deck attached when I started. The bow is the deepest so I used cardboard dams to get the foam to set up in sections to make sure each area was filled before moving to the next.

I used 2" holes about 18" apart for pouring and expansion. With the bow down, I poured in the most forward hole until it was full. The pour hole as well as the hole behind it act as a relief ports.

Read the directions that come with the foam and watch the temps. I used a heat gun to warm the hull and section before pouring - just put the shout in the hole for 5 or 10 minutes to warm up that section.

It's not rocket science, just think about what you're doing and plan it out before you start.

 

[coostv]

Re: The actual use of 2# foam questions

Thanks for the responses guys. I am just hoping I do not end up pushing the deck up off the stringers.

I thank you guys for the clarification.

Chris

 

[BobsGlasstream]

Re: The actual use of 2# foam questions

Before you pour the foam tape plastic around the holes. it will make cleanup a lot faster. I would also suggest that when the foam starts coming out of the hole don't try to stop it. Let it blow, unless you have another hole to releave the pressure.
Bob

 

[Bob_VT]

Re: The actual use of 2# foam questions

Now that everyone has added advice....... we have a tread that explains it all and the use of SEARCH would have shown it

http://forums.iboats.com/showthread.php?t=288451