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Laminating G10 to XPS foam


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Need to make up a some dividers for a freezer section in the fridge box.  
Any experience with laminating  G10 (1/32”) to pink or blue foam board?
I am thinking the G10 will give a smooth hard surface, without having to fair or gel coat a fibreglass cloth wrap. 
Scratch up the mating surfaces for some tooth, and layup with epoxy. Would edge the panels first, then face both sides. Lay in a fillet of caulk or thickened epoxy to inside corners. 

Any other ideas or pointers? Expansion/contraction issues?

 

Bill

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It's a good idea. I've built a freezer box just by laminating a few thin layers of 9 oz cloth on the inside of my XPS box. After a bit of sanding it was smooth enough.

However the oil based paint kept peeling off because it was an icebox and was constantly immersed in water at the bottom. Maybe also because it was hard to gently lower a 30 lb block of ice into the cooler without banging up the surface.

Doubt expansion or contraction would be an issue. 

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I think your plan will be a winner.

I haven't done it with G10, only with thin teak ply on 1/2" pink foam for shelving.

It worked every bit as well as I hoped - as stiff as 3/4" ply and less that 1 Lb per square foot.

 

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Yes to abrading the XPS surface. I’ve had epoxy/glass bubble in the sun. A quick spray with rattle can works too.

 I cut XPS with a razor sharp filet knife and straight edge but it’s harder than expected to get a good finish. I’m guessing a table saw might work but haven’t tried it. I cut a little oversized and do a final trim if critical. A 45 degree bevel really helps glass wrap corners, especially stiffer fibers like S glass    

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XPS machines OK on table saw  or bandsaw.  Router pilot bearings compress it and yield imprecise cuts.

You might also consider smooth FRP panel at your local big box.  About a tenth the cost of G10.

Urethan or ISO foam would have better insulation properties.

 

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Yeah, the iso foams have better insulation properties when new - but they really lose insulation properties when they absorb moisture. So you have to make sure your inner box is perfectly watertight and the outer layer of foam is pretty tight too; otherwise you'll get condensation and it soaks into the foam. XPS is more forgiving of fabrication imperfection

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  • 2 weeks later...

I built and ice chest out of xps foam and plywood with a fiberglass layer on the exposed surfaces to water proof. Kind of stitch and glue plywood box within another box and foam in-between.  It works great, pretty good insulation too. I used white pigmented epoxy(west systems white pigment) to coat the inside. 2 years old now and has held up great. I like your G-10 idea. 

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Plenty of experience with XPS. It cuts easily with a sharp knife or through a bandsaw. The higher grades (40 and 60psi) are a bit easier to work with. Hotwire cutting is how the pros do it, but not necessary for an ice box. It’s good to sand the G10 with 80 grit, use 120-220grit and a soft touch on the foam or risk tearing.

DO NOT spray 3m77 or rattle can paint directly on XPS, it will melt.

I’d carefully brush Gelcoat when done.

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On 2/24/2021 at 10:27 AM, wick said:

Need to make up a some dividers for a freezer section in the fridge box.  
Any experience with laminating  G10 (1/32”) to pink or blue foam board?
I am thinking the G10 will give a smooth hard surface, without having to fair or gel coat a fibreglass cloth wrap. 
Scratch up the mating surfaces for some tooth, and layup with epoxy. Would edge the panels first, then face both sides. Lay in a fillet of caulk or thickened epoxy to inside corners. 

Any other ideas or pointers? Expansion/contraction issues?

 

Bill

been using this white fiberglass panel instead of expensive and ugly color G10, works very well for many boat projects.  Mc master Carr  Chemical resistance FRP

2194K27. for an Ice box you could also use FRP wall panel from building supply about 30 bucks for 4x8 panel 

 

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