Building a fridge - any advice

Amulet

Amulet

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Building fridge under fwd bunk. Think I've got the guts sorted

Waeco CU54 & VD07 Cooling Kit

seems to do what I want. Compressor in the head.

Struggling for the building of the box itself. Surely I can buy expanded polystyrene somewhere. Aiming for panels 30mm thick in small quantity. Any advice on any aspect of the task appreciated. Trying to work out whether it's worth making an internal mould for the box so I can lay up a shiny GRP box. Could just bodge a plywood thing together and try to epoxy it all shiny inside.

Yes I know 30mm isn't much insulation. I don't have much space in my tiny boat and more insulation would make it too small. Provided I can prevent my wife putting food in it, I may just have enough space for a sensible amount of cold beer.
 
My advice is don't use expanded polysterene, instead use the more modern (and much more expensive !) insulation board sold in builders merchants in various thicknesses. Cellotex is one trade name I think. It cute easily with a knife and has very much better insulating properties than polysterene.
As I say it is expensive, but perhaps like me you could get some offcuts from a building site - do we still have such things anymore !
Any parts you can't easily reach you can use a can of spray foam.

Doesn't your boat have an insulated coolbox, if it does yurn it into a fridge.

Regards
 
Try for a closed cell foam, cut and tape to the required size and shape. start by filling all the corners with good size fillet, use a small jar to smooth it out, this will not only make it stronger but cooler and easy to clean.

Next lay up with 2 or 3 layers or 250 gram CSM and finish with a coat of resin with micro balloons mixed in, brushable consistency,

Sand after curing and add another coat of resin with white oxide mixed in to make a flow-coat.

Tip:
make the top the entry point, this reduce the cold air loss when opening. If possible make a lid that covers the whole top and put a smaller opening in that, this will reduce cold air loss even further but still be aesy to clean when the full lid is lifted off.

Avago and anagoodweekend......
 
if you are really keen, there was an article in PBO some years ago, as to how to make one out of fibreglass...back issue maybe?
 
asj1's advice on getting a quality insultation is absolutely spot on and very important. It will make a dramatic difference and well worth the extra cost. Like you I did not have sufficient room for the right thickness of insulation and used polystyrene sheet. Having Celetex here at home I can testify to the enormous difference in performance.
 
I had the interior liner made by a fibreglass moulding company, about £40 if I remember rightly. Google 'fibreglass mouldings' and pick a small company. They usually make signs and various architectural mouldings, but the company I went to were happy to make a one off box. It was open at the top, with a 15mm flange so it could be screwed up to a plywood top - actually the galley counter. All nice and shiny on the inside, drain in one corner. I then insulated it with a high efficiency insulating board such as others have described. The more insulating the better, particularly if you are contemplating cruising in hot regions.
 
...Aiming for panels 30mm thick...

If you're sticking to weekend sailing on the East Coast or regularly plugging into shore power, this will work. However, if you head to points south, you will at best struggle to provide the necessary amps to keep this cool. Ours works well - certainly better than most we've met here in the Med. it has similar equipment, cooling a box of slightly over 1 cubic foot, but it has an average of 90mm of Celotex insulation around it.
 
Mine is across the boat at the mast step,(in an existing locker) so it effectively had to have a sloping bottom. I used a cheap plastic kitchen set: the waste bin at the deep bit, the basin at the side, Hot air gun to mould where required, and the whole thing surrounded by slabs of loft insulation foam (cut from one board) With a skoosh of builders foam in any voids.
The lid is another piece of the foam, close-fitting, and scrimmed over with resin for wear and tear.
The original locker lid and cusion then covers it all.
The condenser plate sits at the back across the top of both boxes and the compressor chassis is under the floor, circulating the air nicely.
Try to keep compressor cables short and clear of other wiring, as it will cause RF interference.
 
Do we mean Celotex here?

Is this the best, or are there other suggestions for high insulation 'board' type product that could be used to add extra insulation to an existing fridge/freezer?
 
I am doing this at present with the same Waeco kit except the smaller evaporator plate. My boat is in Spain so insulation is very much the issue and sourcing materials is more difficult.
Polyurethane foam which is what Celtex is I think, has about twice the insulating properties of expanded polystyrene so I am using 50mm PU foam sheet from a builders supply co. and filling all the space left using a aerosol can of PU foam.

A pre built GRP box would have been the prefered choice for the inside but not so easy to do at such distance from home so I bought 3mm thick ABS sheets ( 500x600mm) and used clear silicon round the joints which has made a nice easy- to-clean surface. Clearly not as strong as a GRP box and it relies on the PU sheet for support so you couldnt use just the injected foam as I think it would deform the box as it expanded.

I will report back on how successfull the insulation has been but it will be the spring/summer before I realy find out !
 
[ QUOTE ]
Do we mean Celotex here?

Is this the best, or are there other suggestions for high insulation 'board' type product that could be used to add extra insulation to an existing fridge/freezer?

[/ QUOTE ]

That's the stuff. There are other brand names for the same type of polyurethane insulation - Kingspan Thermawall for instance which is available from builder's merchants. Robust and easy to work.

(very) Slightly better are the phenolic insulation boards such as Kingspan's Kooltherm. Never used these, but I presume they're dearer.

I sold the surplus boards from our extension very readily on ebay, and there seemed to be a steady turnover of this sort of thing there.

May be worth a call to Seconds who deal in damaged boards, etc. to see what's available although I've never used them myself.

(No connection to any co. mentioned).

Andy
 
I have done exactly what you have done but ina slightly different way. I measured the space that the fridge was to fit - on my Benny it was originally a "coolbox" I could not find a new 12 volt fridge to fit the dimensions.
I visited an old caravan spares place in Gosport and bought an old ammonia powered fridge in excellent condition for £5. Removed the old cooling plate, fitted the new plate and installed it with the compressor sited above the fridge itself. It works very well, and required very little of planning having established it fitted the enclosure, the rest was very easy to execute. It works very well and spends very little time actually running once the contents have got down to temperature. We have found that if we switch off when the contents are at 4 degree Centigrade, at 11pm, the temperature rise over night is only 3 degrees at 8.00 am the following morning when the ambient air is about 18 degrees. So no serious heat losses, and a chance for the domestic battery bank to recover
 
I replaced a front opener with one I made from a Storage box and insulated it with high thermal cavity wall insulation.

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