Quote:
Originally Posted by RSB333
I tried to glue formica directly to the foam using a cement made for foam projects. it stuck well to the formica, but pulled away from the foam. Also, I may have made a mistake of using the glue in strips, rather than a continuous coating. The Formica curled, allowing moisture to get behind it. I have now removed all the formica panels and am starting from scratch, likely using .09" FRP this time.
The seams at the corners were connected with a 90-degree plastic moulding ordered from Amazon. RSB333
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Formica makes decent countertops, not so good for an
icebox.
First, you need to coat the exposed foam with
epoxy, enough to seal the exposed cell structure, and use thickened
epoxy to fair the foam surface in places where the foam pulled apart/away, a smooth surface is highly desired.
Then you will use thickened epoxy, (~ like mayonnaise,) applied to both the foam surface and the FRP panels.
Use a notched plastic spreader to spread the epoxy, make the applied epoxy on panel and foam at right angles to each other as far as practicable.
Use a slow cure hardener, have some method to hold the panels in place, practice on a couple of pieces of scrap to find the right amount of epoxy to spread and what size of notches
work the best for you.
If it's cold
weather a lightbulb hung in the box will have no trouble in creating enough heat to cure the epoxy.
Take your time, even one panel per session,
cleaning up the drips/squeeze-outs before moving to the next, working as clean as you can pays off big time when doing this kind of
work.
Dry fit each piece, make sure of no fitting problems.
Some gap at the joints is ok, you'll fill them when all is in place.
A small Formica/laminate roller used to go-over the panels will ensure smooth/even contact over the entire surfaces without distortion of FRP or foam.
When all FRP panels are in, best practice is to use well thickened epoxy to create fillets at the corners, the easy
sanding "brown powder" filler with a touch of silica makes for good finish without too much cussing when you sand the fillets.
Use what you got for fillets, something that's glass that can be dipped in acetone, run down a joint and wiped off, can work great, it's a finesse job.
I use various sizes of patternmakers tools, they look like miniature barbells, a different size chromed ball at each end, it makes tri-corner joints without much fussing, whatever you use, keep it clean and dip in acetone before each use.
Then you use
fiberglass tape to cover the joints.
If you lay-out your tape on a sheet of plastic and squeegee it out well, you can then fuss it into place with a minimum of drips/runs/cleanup.
Trying to hold dry tape in place whilst jabbing it with epoxy laden
brushes is sure to lead to expletive/colorful language.
A couple of layers of ~8>10oz cloth, with some stagger works well, you want it to have some physical strength.