Build a custom icebox

[Delancey]

What draft looks like. Your box is now a pyramid. Easy enough just got more complicated.

Easier to just buy white FRP sheet from a builders supply and laminate to foam or plywood to make the inside of you box. This material is pretty cheap and is NSF certified. Very durable and cleanable surface.

Less waste and effort than making a throw-away mold then having to lay up gel coat and glass, trimming finished part. All for a one-off? Wouldn't recommend that option unless you were making several parts or had lots of time to kill.

[Delancey]

Inside of my cooler. I laminated the FRP sheet to 1/2" plywood so I would have something behind it that would accept screws for shelving to be added later.

Your typical Igloo cooler just has a thin molded plastic liner with insulating foam behind it. You can do the same. Should be able to laminate the FRP directly to foil backed foam with something like 3M Super 77 spray adhesive. Test adhesive first.

Finish inside corner joints with food grade silicone caulk or if you want to get all fancy can make an epoxy fillet like I did. Tint the epoxy white if you are picky about appearance.

[Scaramanga F25]

They already exist. For your size boat I would get at Yeti or an Esky
super cooler...expensive but good seal. Cools for 4 to 6 days. 2 to 2/1.2 inches of insulation. Difficult to build a cooler and get an acceptable seal. Bass Pro Shops.

In my 25 footer I have a small Engle Freezer/refrigerator. Very low current draw.
But I have a small diesel, a wind generator and 3 batteries.

[Celestialsailor]

Originally Posted by Delancey

Easy enough to waste a bunch of time, materials, and effort if you make a mold without incorporating the single most important aspect of mold making for rigid fiberglass parts - draft.

https://en.m.wikipedia.org/wiki/Draft_(engineering)

All the mold release in the world won't do you any good if you have parallel faces or undercuts on your finished part.

I use the particle board with the white on the one side (forget the technical name, sorry). If I do not want draft or have a reverse feature, as i did with my box, you lay it up and merely pull the mold off the part in pieces.

[Delancey]

A very effective seal can be easily made by using two parallel rows of silicone "kerf-in" weatherstripping. Basically presses into a saw kerf. Used sometimes in exterior door manufacturing.

[Delancey]

Originally Posted by Celestialsailor

I use the particle board with the white on the one side (forget the technical name, sorry). If I do not want draft or have a reverse feature, as i did with my box, you lay it up and merely pull the mold off the part in pieces.

True, can be an option where the investment in the time and effort to make a throw away mold and then gel coat plus glass lay up are worth it because there is some special need. For a simple box like the OP is talking about it doesn't make any sense to me when the FRP sheet is so much easier. The white finish on the partical board is called melamine and is a very good surface, bwt.

Besides being readily available and inexpensive, the FRP sheet it is basically a pre-finished material that doesn't require an special skills to work with and can typically be used to produce a finished box in a way way way less time and effort than throw away mold making and laying up gel coat and glass. Basically can make a box from FRP with less effort than can make a mold. About $30 for a 4' x 8' sheet so also probably cheaper than buying all required tools and materials for a custom glass box anyway.

[hamburking]

Start with the cooler you already own and love. Put it in a larger cooler. Fill the gap with expanding spray foam. Now you have an uber-cooler with a double insulated lid and factory smooth finish inside and out.

[svfraidknot]

an old friend fellow cruiser that later swallowed the hook after 12 years on board his boat built in mine for me . he had built his in years before and said he made some mistakes he would not make on mine ,, he owed me 6oo bucks but had over 80 hours involved before he finished ,, i have ten inches of the hard foam insulation in the bottom and 8 inches in each end and 6 in the front and back 6 inch lid that is beveled and fits in snug .. he used the foam insulation that you mix and poor to fill in the voids ,, 2.5 cubic foot freezer ind 3.7 foot refer end with 4 inches divider , he set it up for me to add a cold plate later in the " freezer " end .. i have put a 40 pound block of ice in the freezer end and had plenty of ice 3 weeks later.. part of the improvements i made to her ,, she is for sale listed here in boats for sale section ,, 42 solaris catamaran .. great live aboard ..

[Delancey]

$37 for 4' x 8' x .75" white melamine and $35 for gallon of Bondo polyester resin at Home Depot? Plus cost of gelcoat, fiberglass, mold release, gloves, chip brushes, laminating roller, mixing trays, rags, and some solvent for cleaning up? Don't forget quarter round or pvc pipe for the corners, screws or nails for fasteners to hold the mold together, maybe putty to fill some holes that can't be avoided.

Do yourself a favor and get the FRP sheet and some silicone caulk instead. Spend all the time you saved not messing around with mold making and layup doing something useful.

[viking 1944]

Welcome aboard david,
Two quick thougts for you, For ice chest's in the open you can put a thick quilt over it to insulate from the sun and you can make a "P" trap of tubing so the water drains without loosing the cold and everything stays dry. Happy Holidays
El Condor Pasa

[Terra Nova]

Originally Posted by Celestialsailor

I use the particle board with the white on the one side...

There is no place on a boat for particle board.

[Sailmonkey]

Originally Posted by Terra Nova

There is no place on a boat for particle board.

Particle board makes a nice mold though.....,as was suggested by the particle board post.


Sent from my iPhone using Cruisers Sailing Forum

[Martkimwat]

I built a cheap but very effective cool-box with refrigeration unit a few years ago in my Tradewind 33. I used 1" thick sealed PV panels which give equivalent insulation to 8" of closed cell foam, I had the panels made up by a company in UK who makes them for insulated boxes for transporting critical items that need to be kept cold (human organs etc). I then encapsulated the box with 1" thick closed cell foam inside and out to protect the mylar film from any possibility of being punctured thereby maintaining the vacuum. I glassed the inside of the box and then flow coated it to give a reasonably smooth surface. The top was pre-moulded GRP with angled sides to the lid and matching drop in lid. In all I have 3" of insulation all round equal to 10" of closed cell foam and then a normal Waeco C50 compressor and refrigeration unit plumbed in with the pipes entering through the gap between the top and the sides (you can lightly crush an edge of the PV panels to allow the pipes access and still get the top to fit tightly, just don't use anything remotely sharp!) my panels cost £100 a few years ago when at the time blue sea refrigeration in the US were quoting about $2500 for their version of these panels. the box is about 120 litres. I am still in the process of a major refit on the boat so havn't had a chance to try it out yet but I'm hoping it will be very efficient.

[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

[Terra Nova]

Silicone is good as a sealant, but you want something very low density to fill gaps.