DIY Fridge box - lid ideas required

[Relax]

I have decided over next winter to replace my front opening, inadequately insulated fridge with a top opening, water cooled jobby with better insulation.

I have installed an additional battery (now 3 x 110Ahr) and solar panels (2 x 60W) over last winter to back up the Aerogen4 wind charger and at the moment this appears to keep pace with the existing fridge during the day. Predictably, when switched off at night it does not stay cool for long, hence the need for better insulation.

I have kind of come to the position of making a liner myself from ply, glass and epoxy, rather than getting a Tektanks type thing done at some expense and also tension over 'will it won't it fit' (it will need to be an odd shape - as I suppose most boat fridges are). I planned to do this in two halves with the top/lid seperate and then bolt and Sikaflex them together.

My only real issue is what to do over the lid - are these available anywhere? If making it myself could it also be done with ply and epoxy or might I be better using a Tupperware box as the basis? Seals I assume I could buy from North East Rubber or someone?

Has anyone here done this?

 

[prv]

My boat has a home-made fridge. The top seems to be a piece of foam encapsulated in some sort of outer skin, perhaps a layer of gel coat. It's too light for the stiff outer layer to be more than a very thin skin. The foam has been shaped with a bevel or taper - the bottom surface is about 1 1/2" narrower all round than the top surface. It sits into a matching bevel in the encapsulated foam that lines the box.

Pete

 

[Billjratt]

I made one more or less to your specs!
The locker was near the mast step - deepest part of boat, and almost big enough to take a plastic "swing-lid" bin and basin side by side, the basin being shallower following the curve of the bilge. They were "moulded" to suit the actual space by cutting and resealing with a soldering iron and a hot air gun (paint stripper).
Once they were in, they were completely boxed round with slabs of roof insulation, and then gaps and extra void filled with expanding foam.
I used a waeco compressor and evaporator.
The lid was made from another slab of roof insulation carefully carved to fit the aparture, and lightly glassed over with a fine scrim. It is separate from the hinged locker lid, simply being lifted out and replaced as necessary.

Some pics for what they're worth...

 

[blush2]

If you use slabs of roof insulation, seal any gaps between them with PU expanding foam. We have a fridge made from a transparent plastic crate, when the fridge is used constantly (ie longer than a weekend) condensation develops between the crate and the insulation. Because there is a small gap somewhere in the ply outer box, the rather unpleasant condensation drips into the locker below, but must also be damaging to interior of the ply box. This winter's task is to replace all the slabs with expanding foam.

The lid is made out of plywood with a piece of slab insulation, the top is a piece of the work surface over the fridge. The crate itself is recessed by the depth of the lid. The lid is hinged with those double sort of hinges (not sure of the name) so it opens flat.

The other problem with using a crate is condensation in the fridge which needs regular mopping out. We have a small tray under the cooling coil with a thin sponge in it to soak up the drips.

 

[rogerthebodger]

Have you considered using this expanded PVC board that is used in the UK for window cills. I got a sample from my brother to make my fridge from but could not get it in South Africa so made mine from stainless steel insulated with PU foam including the lid.

 

[Relax]

Thanks for the feedback folks - helpful.

A stainless steel liner as above would be great but short of buying a TIG welder and doing it myself its not practical. The liner will need to be laminated from epoxy onto plywood - thinking about 3 or 4 layers of glass would be adequate? Polyurethane in whatever form appears to give the best U value - I thought to build it up in 25mm layers - 100 on the bottom, 75 on the sides and 50 on the top - no scientific basis for this but sounds about right and has to be better than the 20mm of polystyrene I have at the mo.

I know I need to keep gaps to the minimum but am wary of using pu foam in cans - it expands very forcefully and can cause damage if not allowed a way out of the hole.

Thankfully although the space is a slightly odd shape I can remove the old and build the new beer cooler without destroying any joinery - the top is hinged anyway. I hope to get the compressor and water pump under the fridge.

I hav'nt managed to turn up too many suppliers of equipment on the web as yet - only penguin, can't find any supplier for waeco parts, as opposed to fridges.

 

[vyv_cox]

I'm surprised you need to turn the fridge off at night with the electrical resources you have. I have 125 watts of solar panel, in Greece so they usually keep the batteries well up, but no wind generator. I also have 3 x 110 Ah batteries. Fridge is a 65 litre Waeco, not great on insulation but with a water cooled Danfoss unit. I run it constantly, May to October, and rarely see battery voltages below 12.0. The batteries are 6 and 7 years old now and doing well, so they seem to accept this treatment.

 

[john_morris_uk]

I have just gone through this whole process and am still making and fitting the lid! In the end I have got hold of some resin worktop and have laminated some bits together which I am then machining with a router to make the lip and seal etc. The liner is stainless steel and the inside of the lid will be stainless steel with closed cell foam inside it. I have used Celotex and then filled the gaps with expanding foam.

The fridge parts came from penguin and are water cooled. So far VERY much more efficient and seems to use less amps than the old air cooled one.

 

[Relax]

To be honest I don't think I need to turn the fridge off at night and I suspect I'm being very conservative with the batteries - my batteries are never below 12.4 but they are of unknown age seem to go through loads of water and I was planning to replace them over the winter.

Seems as though no one has an easy fix for the lid?

Where'd you get the resin worktop - the only ones I've found are the corian types at corian type prices - beyond me I'm afraid.

 

[john_morris_uk]

I agree that the resin work-top wasn't cheap - but I got it through another YBW forumite.

 

[Bobobolinsky]

Instructions for manufacture are in "This old boat" by Dan Casey. A water cooled outfit is 20% more efficient than air cooled so batteries should defo be OK.