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 Post subject: Expandable Foam
PostPosted: Sun Aug 30, 2009 6:37 am 
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Has anyone used Home Depot grade expandable foam to repair delamination and had it fail? I bought a quart of git rot, used it all, and still have 75% of my repair job to go. At that rate I'll have more invested in Git Rot than the purchase price of the boat itself (yes, I bought the boat in a high state of ignorance!). We won't even get into the added weight issue. I've heard the "it's not a good enough adhesive" and "it's not structural" comments, but neither was the original foam and it still lasted 10 or 20 years(the boat is now 33). I'd love to read your thoughts on this.

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 Post subject: Re: Expandable Foam
PostPosted: Sun Aug 30, 2009 9:36 am 
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Maximus, You might try "Pour foam", it's a 2 part expanding foam which you should be able to get from a good plastics supply company. A word of caution though...This foam will expand with some force behind it. In other words, using it may add to the headache you already have. Try some in an old mixing container first to see what it can do.


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 Post subject: Re: Expandable Foam
PostPosted: Mon Aug 31, 2009 9:19 am 
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Location: Flagler Beach, Fl
I did this 3 years ago, you can probable find old posts on this but you have to use a 2 part polyurethane closed cell foam. I sail strictly in the ocean and my hulls are still rock hard and have had no problems. I used the 4 lb foam. 1gal of foam and 1 gal of hardner filled the front tips in both hulls from the tips back to the front pylons. Added 16 lbs of weight to the cat.

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Coral Reefer
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Flagler Beach, Fl


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 Post subject: Re: Expandable Foam
PostPosted: Mon Aug 31, 2009 1:51 pm 
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Coral Reefer wrote:
I did this 3 years ago, you can probable find old posts on this but you have to use a 2 part polyurethane closed cell foam. I sail strictly in the ocean and my hulls are still rock hard and have had no problems. I used the 4 lb foam. 1gal of foam and 1 gal of hardner filled the front tips in both hulls from the tips back to the front pylons. Added 16 lbs of weight to the cat.


How much does the boat weigh now? That stuff is notorious for soaking up water.

It's also weight where you least want it - in the bow.


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 Post subject: Re: Expandable Foam
PostPosted: Tue Sep 01, 2009 4:18 am 
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I'm not interested in filling the hulls with foam. I just want to fill the void where the old foam used to be... between the fiberglass layers of the deck. The hull I used the Git Rot on had no foam core left in it at all, and the amount of Git rot necessary to fill that space is going to be cost and weight prohibitive. I heard Gorilla glue expands.... I wonder it that would work. I'm going to create a mock-up of my hull situation out of cardboard and see if the expandable foam forces the layers apart too much and to see if the gorilla glue is suitable by any stretch of the imagination.

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 Post subject: Re: Expandable Foam
PostPosted: Tue Sep 01, 2009 8:59 am 
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Location: Flagler Beach, Fl
Like I said it added 16 pounds to the cat. The foam is a marine foam and does not absorb water. Actually it seems to have given more buoyancy to the tips and a lot more structural integrity to the hulls. Same foam used by whaler and other boat builders.

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Coral Reefer
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Flagler Beach, Fl


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 Post subject: Re: Expandable Foam
PostPosted: Tue Sep 01, 2009 9:25 am 
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Okay... how much?

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 Post subject: Re: Expandable Foam
PostPosted: Tue Sep 01, 2009 9:52 am 
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Joined: Fri Jan 30, 2004 2:56 pm
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Location: Flagler Beach, Fl
This is a website that will tell you all about the foam :http://www.uscomposites.com/foam.html

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Coral Reefer
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Flagler Beach, Fl


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 Post subject: Re: Expandable Foam
PostPosted: Tue Sep 01, 2009 5:31 pm 
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Well, I experimented with expandable foam (DAP Tex), and, although it may not be totally dry yet, it seems entirely unsuitable for delam repair. BUT! I also experimented with Gorilla Glue, and I think I may be on to something here. GG expands by a factor of about four, when dry it is very hard, it's adhesive properties are through the roof, it's entirely waterproof, and priced so that even poor people can afford it! I'm going to mess with it a little more and let it sit overnight, In the morning I'll make a decision whether to use it in the hull or not.

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 Post subject: Re: Expandable Foam
PostPosted: Wed Sep 16, 2009 3:33 am 
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Joined: Sun Jun 07, 2009 6:41 pm
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Coral Reefer wrote:
Like I said it added 16 pounds to the cat. The foam is a marine foam and does not absorb water. Actually it seems to have given more buoyancy to the tips and a lot more structural integrity to the hulls. Same foam used by whaler and other boat builders.

How can it ad more Buoyancy to a hull if its on the inside,???? :lol:


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