3 questions before the deck goes on.

[builderbob1]

1-I've replaced stringers, redid old repairs and cleaned up the loose glass. Some of the original glass mat seems a bit resin starved and porous. Would it be good to paint those areas with epoxy resin to help stop water penetration. I see some people use gluvit. 2-Will PL 5200 stick to epoxy resined fiberglass. If so would that work to fill area between deck edge and hull before glassing the top of the deck. How about between the deck and stringer? 3-2# foam for buoyancy 4# foam for structural. The instructions on the 2# foam says the lower the temp. below 70 degrees the less it will expand. Do you think pouring it in say 55-60 degrees would be equivalent to using a denser more structural foam? The more I read this forum the more I learn and the more questions I have.

 

[RICHARD5]

Re: 3 questions before the deck goes on.

You got me.

I hate foam in the application you're talking about.

Hull integrity is crucial, water absorbtion is secondary to that, so you have to decide. By "some" of the glass being resin poor, we don't know the extent or where in the boat...need more info.

Generally I try not to mix materials when it comes to adhesives. However, 5200 would work for your application. For the final word, consult the mfg.

EDIT: now that I think about it, I believe 5200 was developed for exactly that purpose (joining hull and deck)

 

[Knightgang]

Re: 3 questions before the deck goes on.

If you have areas that are resin poor, then I will bet the glass has already hardened or at the very least has become really brittle. Painting over it with more resin may seal it, but not add any structural benefit. To be on the safe side, I would grind these areas out and reglass them with fresh clost and resin. That way you are sure o fthe bond and material. Less chance of premature failure...

THe 5200 question was answered, so on to the foam question. By not expanding to its full potential in colder weather, I do not think you gain the density of 4# foam, but you also do not gain the full benefit of 2# foam. One of the purposes of foam is to displace water which could sink the boat. By not allowing water in (at 8lbs per gallon) and adding floatation to offset the weight of the boat, you increase the amount of time the swamped boat can float and increase the rescue time.

By the 2# foam not expaning to full potential, you leave access for water, therefore negaing the foam. You also are not gaining the structure of 4# foam, expecially since you cannot predict how much it will fail to rise.

If you want the structure of 4#, use 4#. You want floatation of 2#, use it, and use both in the conditions recommended for optimum results...

 

[RICHARD5]

Re: 3 questions before the deck goes on.

I agree with Knightgang, don't encapsulate the resin poor glass...remove it and add integrity with new material.

That was so obvious to me that I didn't say it.

 

[BobsGlasstream]

Re: 3 questions before the deck goes on.

Builderbob1
I would not want too try and pour the foam below 60 degrees. the amber colored material is the Iso, Most Iso materials start to freeze below 60 and will start to crystalize. I would also not store it any temperature below 65 either, for the same reason.
If the foam does not rise as much the density will be higher but the does not always equal more strength.
The other post answered your other questions. The same as I would have.
Hope this helps.
Have a great day.
Bob