Waterproofing Insulation for Fridge/Freezer

[Terra Nova]

Can't be cheaper than polyethylene sheeting.

[steamgoat]

I built a new fridge/freezer last winter, used polyiso,all panel edges sealed with aluminum tape,all joints overlapped ,min 4 1/2'' thk,more on hull side. Box made of 1/2''ply,epoxy soaked and interlux perfection painted. Used a Seafrost freezer box unit with a loose foam divider. Compressor on medium,ice box set to 15 F, small 'muffin' fan operating when compressor on. Draws 4 1/2 amps. If undisturbed,runs for 20min then off for 100 min with ambient air mid 80's.Left it on all summer with 2, 135w Keyocera panels. Very happy,permanent cold beer. [my first attempts at Formica work]

[Terra Nova]

Looks good.

[zboss]

Originally Posted by Terra Nova

Can't be cheaper than polyethylene sheeting.

They also make heat shrink poly.

Originally Posted by steamgoat

I built a new fridge/freezer last winter... [my first attempts at Formica work]

How did you build the lid so it fit well?

[gdavids]

Here's a follow-up question. The back wall of the fridge and freezer boxes are against the hull. This starts off as essentially vertical at the top and then toward the bottom is at more of an angle. I am wondering about the best way to keep this all securely in place. The same issue applies to the inside top of the box. Should I glue the plastic sheeting to the hull and then glue the foam sheets to the plastic? Once I build up the desired thickness of insulation I plan to glue or epoxy thin fiberglass paneling material to make the finished inside surface.

Another complication is the inside hull surface seems to stay in a state of dampness - warm air inside and cold water outside. Perhaps run a dehumidifier in the boxes while I am working on this?

Greg

[Nicholson58]

I used to work at DOW. Their expanded Polystyrene foam is about as waterproof as you can get. Also equal or better is UCI pink foam board (Home Depot). Do not use EPS bead foam. This is nearly worthless - the white foam board that looks like tiny beads pressed together.


I also worked for a supplier of refrigeration foam systems using molded in place Urethane foam. This is excellent if the inner box is totally water tight and sealed such as your home fridge. In this system the vacuum molded inner liner is placed in the steel box. All is placed in a strong mold to support the bits and polyol/isocyanate mix is shot in. This rises and due to the dissolved blowing agents, like a shaken bottle of root beer. Cream and cure time is in the seconds to minutes. The key to success is that the foam is sealed in totally both inside and outside so no condensation can occur within the foam. This is critical since all urethane foams are NOT totally water resistant. Exposed over time, they are all permeable.