last-a-foam: Has anyone used it?

[sandusk]

Last-a-foam is distributed and manufactured by General Plastics inc. It comes in densities from 3lb to maybe 30lb. They have got a warehouse near my locale, so was thinking of using it for my hatches.

What I am doing:

Right now, my 40ft fiberglass commercial fishing boat has got one single hold of approx 25k lb capacity. I would like to use 2in glass laminated foam boards to divide the hold up into 8ea smaller 4ft x 4ft x 5ft depth holds.

I can get last-a-foam for about $200 for a 2in thick 4x8 sheet. I have read mixed reviews about last-a-foam. a few people have said that it sometimes does not bond well to polyester resin, or delaminates easily with repeated impact. I have also read quite a few good reviews.

Have any of you guys got any experience with last-a-foam?

[Fanie]

I do not know last-a-foam's foam, but get a spec sheet from them.

What to look for is it must be a marine foam, closed cell and almost zero water absorbtion. Have a look at the XPS range from Sondor industries in SA, it is a polyethilene foam, UV resist, doesn't emmit poisenous gas when burnt, flexible so it doesn't crack or break when flexed but when laminated become a big rubber-like shock absorber, temperature insulator, noise suppressor, mildew/algea resistant, you name it. Only drawback is the bloody price !

The problem with most foams is once water finds it's way in, it doesn't come out, results in a very heavy boat with poor handling after a while, so if you are going to do it, use the right foam - it's a once off or do it over time. You can always make the 'furniture' and stuff from it and make the foam parts features. If the boat ever gets holed you mustn't even notice

[sandusk]

Fanie,

According to their website, the last a foam is closed cell, does not absorb water, etc. My worry was more along the lines of how well the resin bonds to this type of foam as compared to other brands. The website does mention a surface treatment for the foam that helps the resin make a stronger bond to last a foam.

Does anyone have any experience using last a foam?

[GrandTraverseMI]

I've used it in aircraft construction. I've used the 1/4 inch low density sheets to build bulkhead in a Glastar fuselage. If a light wind catches it, it will snap into pieces but when bonded on both sides with two layers of fiberglass cloth it is tougher than nails (almost).

I was at a gas station a couple years ago. A lady locked her keys in the car and a couple guys where trying to unlock it by prying the door open enough to get a coat hanger in to unlock it. I had a 6 or 8 inch wide piece of the laminated 1/4 inch thick last-a-foam which I donated to use as a pry bar. Two guys reefed on it without it bending or snapping.

The Glastar kit manufacturer's instructions have you 1st lay down a thicken slurry of resin and filler (milled fiberglass). last-a-foam, in the light densities, is quite coarse which provides plenty of voids on the surface that allows the fiberglass to bond well. The resin slurry is allowed to setup partially before the two layers of fiberglass cloth are added.

I tried using the same technique on 3/4 inch blue board insulation foam hoping that I could use it as a solution for a boat floor. The resulting bond was not adiquate to use it as a structural panel.

I'm probably going to build a boat floor out of last-a-foam for my 16 foot aluminum boat. I use it in Grand Traverse bays in L. Michigan. I need to avoid adding any excess weight because, even though the bays are protected a wind out of the north can result in some serious waves.

I would recommend getting a small amount of last-a-foam and building some sample structural panels. Then run some tests to see if they will provide the strength needed for your application. For my application I will have to add some beam support under the floor to reduce the span distance. I'm thinking of using the last-a-foam for the 'I' beams and set them on top of foam blocks that rest on the bottom of the aluminum boat.

I would be interested to hear from anyone that has build up a fiberglass foam panel flooring for a traditional bench seat aluminum fishing boat.