Build a custom icebox

[Delancey]

The FRP panel uses a tinted resin throughout so gouges will not scratch through a gel coat and reveal untinted resin behind it. It is commonly used to line walk-in restaurant coolers, meat lockers, truck stop bathrooms so pretty rugged. Cannot be thermoformed, has minimum bending radius per thickness.

FRP suitable for exterior of cooler if laid up on plywood and cover outside corner joints with aluminum angle. Maybe 1/2" or 3/4" angle, must be wide enough to cover cut edges of plywood. Might try find a plastic angle instead, maybe friendlier to cockpit than aluminum.

FRP can be bonded to plywood with contact cement or yellow wood glue, epoxy works but is messy toxic overkill. Find a cabinet shop with a vacuum bag for 4' x 8' sheets to lay up with yellow wood glue for you, best bet.

As far as seal goes, five sided box with the six side as lid. If four or five inches thick walls then have four or five inch wide surface at lip of five sided box for lid to rest on, do seal between this surface and lid. Lid is foam slab covered on all six sides with FRP panel.

Install stripping into bottom of lid, not box so wide edge can be easy to clean and does not trap dirt. Can cut grooves for stripping with table saw into board then cut four pieces with miter joints like a picture frame, screw to bottom of lid.

Any hinge on back edge will work, leave 1/8" gap at hinge for thickness of seal. Weight of lid will hold it down but could add hasp if desired. Best of luck, post some pictures when finished!

[Dougtiff]

I took a cooler and disassembled the box and lid, removed the foam, such as it was and put in VACUME panels, 1" = about 6" of closed cell foam, holds ice for ever, Got the vacume panels from RPARTS.COM, they had a bunch of panels of different sizes CHEAP, where I could'nt fit a panel I used spray in foam, quick and cheap.

[Terra Nova]

One of the trickiest parts of building a yacht quality reefer/freezer box is building a proper fitting lid, whose shape should be trapezoidal in cross-section.

[Delancey]

Originally Posted by Terra Nova

One of the trickiest parts of building a yacht quality reefer/freezer box is building a proper fitting lid, whose shape should be trapezoidal in cross-section.

Yes, indeed. Fortunately the OP just wants a custom ice box to sit in his cockpit, not built into a counter top in a galley. The lid you are describing is overly complicated and completely irrelevant to his situation.

He can make his lid as I have described which very simple and easy to make and totally effective, looks like this -

[Terra Nova]

Not irrelevant in terms of efficiency; that's why they're built that way. Just measure the surface area of what you are suggesting, compared to the let-in trapezoid. And factor in the labyrinth. But trickier construction.

[Delancey]

I don't have the time right now but will do a scale drawing comparison just for fun. You will see the err in your reasoning. At let-in trapezoidal lid isn't any better in this situation, just a lot more complicated to make without offering any benefit.

[Terra Nova]

You just don't see the benefit obvious to most builders. When you compare those surface areas you might begin to get the idea.

[Ahoogha 3 times]

Originally Posted by Flint

Hi everybody, Happy Holidays. This may be my first post to CF.

Has anybody on the site ever built their own custom icebox? I’ve been using a Coleman cooler on my PaceShip PY23, about 1.25cuft with block ice for the last couple years. Good for up to 4 days away, but I’d like to build a custom unit that would sit at the back of the cockpit and maybe last longer. Perhaps even include a cold plate for when shore power is available.

Foil covered Polyisocyan boards boast R7 or greater per inch sound good. A tight interference fitting lid on the top. Drain hole with plug. Some sort of waterproof liner inside (unsure what), and a durable exterior cover – maybe fibreglass, unsure.

What am I missing? Are there any pitfalls? Best assembly? I’m thinking 2 inches of insulation in the sides and top, and 3 inches in the bottom.

Any advice in planning this project would be appreciated – thanks
David

THERE ARE THINGS THAT CAN BE USED THAT ARE CONSTRUCTED THAT MAY MAKE CONSTRUCTION EASIER. HAMILTON MARINE HAS COMPOSITE "Fish Totes" that are 28x16x11 inches USED FOR TRANSPORTING FISH LOBSTER ETC or storage bins from building home centers. If the fish totes are to be used two could be bolted together and sealed with an access hole cut in one. FOAM GASKET/SEAL MATERIAL COMES IN A VARIETY OF SHAPES AND SIZES AVALIBLE FROM Mc Masters Carr.com. You can find foam with a higher R-Rateing as well. You may think about using hatch latches and hindges to secure the lid. I have used Dry Ice many times, you have to wrap it in news paper as it may freeze anything it comes in contact with. One thing I like about it is that it does not turn to water when it melts, it just evaporates. If you are going to use ice think about a "Trap" like a sink "Trap" so it will still drain excess water out but still form a barrier to warm air. Spray foam used to seal wildow could also be used in place of foam panels. Motor Home/Camper supply houses may have ice boxes that would fit your needs at a fraction of what a "Marine Ice Box" would cost. Good Luck I try not to re-invent the wheel if I don't have to!

[Delancey]

Okay, I await enlightenment. Please explain to me how Cooler B is more efficient at keeping things inside of it cool than Cooler A.

I am interested to know because when I look at the table it looks like Cooler A has more foam insulation while Cooler B has more wood, as well as a slightly greater contained volume because of the way the gasket seals on the let-in lid bring the contained volume 1.5" closer to the exterior.

For reference both coolers have the same interior and exterior dimensions, .125" FRP sheet inside and out, .25" plywood exterior substrate, and 4" of foam insulation. Be advised the purpose of the angled faces on the let-in lid are to allow for clearance when the lid hinges open, not to create a "labyrinth" as may have been suggested.

[Terra Nova]

De--your example showcases that you are hopelessly baffled by this simple design exercise. And that you are more focused on your own agenda than in learning a simple lesson. So, unless you have something practical to demonstrate, I have no reason to continue to try to help you understand.

[SV THIRD DAY]

Originally Posted by Flint

Wow, thank you everybody who has contributed to this thread. There is huge amounts of good information here. I must decide which materials and which assembly process. The limitations of space on my boat eliminate the “Cooler-within-a-Cooler” option. The same must be said for the Yeti and other high-end consumer products. The chest needs to maximize insulation while fitting within the space available.

Which brings up the next important point(s)

Uncivil: You’re absolutely right. Leaving the ice chest out in the sun is clearly sub optimal.

Viking: Thank you for the suggestion about padding. Perhaps a cushion like the cockpit benches. I am also having a small Bimini built this winter to provide some shade. Last year at anchor I used a fly-apron (sc) off the back of the Dodger that extends as far as the back stay.

Rich (3rd Day): The R-Max product looks perfect for the insulation. I’ll take the truck for pick up Question: Is silicon compatible as an adhesive when assembling the R-Max joints? This would seal them as well as adding a measure of structural integrity

Delancey: I like a lot of what you say. The ‘FRP’ product sounds like it would make a perfect interior liner. White silicon over the joints – done! The kerf-in seals look good too. I imagine the lid having the rigid foam extending back into the icebox interference-fit style. Is FRP durable enough to be used as the external cladding? Perhaps it would need plywood backing. Could I mold a single piece around the sides with a heat gun and have only a single seam at the back?

Seems like the design is starting to gel

To sandwich the layers of R-max together I like the 3M contact spray adhesive 77.

Did I mention that Home Depot also sells FRP board with a nice shiny clean looking surface on one side? It's a winner baby for a nice looking DIY refrigerator box project. Just use the 3M contact adhesive to attach it to the R-Max. For the seams, I like to use quick dry 4200. Makes a nice water tight seal in the corners. For areas where you have two FRP panels butting together in a straight seam. They do sell seam channel, but what I like better is toncut a 1" strip of the FRP board on the table saw and apply some 4200 to the back....boom...apply it over the seam and you are clean and done.

Making a 90% great box isn't rocket science.
But getting that last 10% does ratchet up the skills and techniques needed....but you know what....90% good enough is better than the vast majority of cruising boats I have been on that were actually cruising boats and not dock show boats. So be happy with a 90% solution and get off the dock!

[marlin driver]

Originally Posted by Terra Nova

De--your example showcases that you are hopelessly baffled by this simple design exercise. And that you are more focused on your own agenda than in learning a simple lesson. So, unless you have something practical to demonstrate, I have no reason to continue to try to help you understand.

In other words, he is right and you don't want to admit it.

[Terra Nova]

De--thought of one more thing that might help you more easily visualize the differences, in case figuring the surface area is too difficult to grasp. Simply compare the linear distance around the periphery of the entire exterior to the linear distance around the interior liner. The vast difference between those two distances might be easier for you to visualize than the surface area differences.

[Delancey]

Originally Posted by Terra Nova

unless you have something practical to demonstrate

I suppose if Cooler A is sitting out in the cockpit as the OP intends, you won't have to worry so much about saltwater spray or rainwater leaking into it compared to the less thermally efficient let-in lid you advocate for.

Is that what you mean by practical? Because that little gap around the top of your lid is going to fill up with water whenever it's wet outside.

Or are you talking about how Cooler A is exceedingly more simple to build? Because I would expect the complexity of your let-in lid should be obvious to anybody.

[Delancey]

Originally Posted by Terra Nova

De--thought of one more thing that might help you more easily visualize the differences, in case figuring the surface area is too difficult to grasp. Simply compare the linear distance around the periphery of the entire exterior to the linear distance around the interior liner. The vast difference between those two distances might be easier for you to visualize than the surface area differences.

I'm not sure you understand how insulation works. It's all about depth.

Six inches of insulation is more effective than two. Does that make sense to you? The little gaps in your let-in lid reduce the depth of insulation.

Also wood is not as effective an insulator as foam.

Ever heard of the term "thermal break"? The frame around your let-in lid is the opposite of that because it bridges the interior and exterior surfaces and acts a conductor of heat from the outside to the inside.

Hope that helps.