stevemid
10-02-2013, 08:11 AM
You may have seen my post on this on my catamaran build thread, but I thought I'd pull this together in one thread for others, especially since I read some good info in my Isotherm manual for the fridge kit I bought.
From Spirited Designs:
Letting all the cold out of a fridge every time you open the door has always been ridiculous to me on a boat. To build a good box is relatively easy. Use as thick a foam as possible. The advantage of making your own box is that you can also make it to suit the shape of the boat and utilize all available space. The foam to use is Urethane foam, this is low density, closed cell-doesn't absorb water and easy to work. Cut with a handsaw (I used a sliding bed table saw to get my box pieces perfectly rectangular) and shape with a sanding board. It is critical to get your joins as close as possible but if you have gaps you can fill them with wedges of the same foam. Glue together with 411 medium density filler and glass internally with a minimum of 400gm’s of glass (double on the bottom). I usually use plainweave to minimize fairing. You can also laminate your pieces of the box separately and glue together after. In most cases a cove of high density glue in the corners is all I have ever done, no taping required. The lid can be tricky but if you can work out a way of cutting this at an angle to avoid jamming this can be quite neat. Here again the aim is to avoid gaps. I usually then glue on the piece of benchtop which becomes your lid. Fit the hinges to this. For this pipes/wires to access the box glue in a piece of conduit to the min size.
The foam (this is the green stuff) can be bought through FGI (Nuplex) in Sydney. A 50mm sheet, 1200 X2400 cost me $140.94
This is from the Isotherm manual which I read after I build my box.
The refrigerator must be well insulated. Use polyurethane or similar foam 30mm thick for 50 litre boxes, 50mm thick for boxes up to 80 litres and 100mm or more for larger boxes.
Battery capacity should be at least 75Ah to enable sufficient power to be stored during engine operation.
Please feel free to add your own bits of knowdedge or advice.
From Spirited Designs:
Letting all the cold out of a fridge every time you open the door has always been ridiculous to me on a boat. To build a good box is relatively easy. Use as thick a foam as possible. The advantage of making your own box is that you can also make it to suit the shape of the boat and utilize all available space. The foam to use is Urethane foam, this is low density, closed cell-doesn't absorb water and easy to work. Cut with a handsaw (I used a sliding bed table saw to get my box pieces perfectly rectangular) and shape with a sanding board. It is critical to get your joins as close as possible but if you have gaps you can fill them with wedges of the same foam. Glue together with 411 medium density filler and glass internally with a minimum of 400gm’s of glass (double on the bottom). I usually use plainweave to minimize fairing. You can also laminate your pieces of the box separately and glue together after. In most cases a cove of high density glue in the corners is all I have ever done, no taping required. The lid can be tricky but if you can work out a way of cutting this at an angle to avoid jamming this can be quite neat. Here again the aim is to avoid gaps. I usually then glue on the piece of benchtop which becomes your lid. Fit the hinges to this. For this pipes/wires to access the box glue in a piece of conduit to the min size.
The foam (this is the green stuff) can be bought through FGI (Nuplex) in Sydney. A 50mm sheet, 1200 X2400 cost me $140.94
This is from the Isotherm manual which I read after I build my box.
The refrigerator must be well insulated. Use polyurethane or similar foam 30mm thick for 50 litre boxes, 50mm thick for boxes up to 80 litres and 100mm or more for larger boxes.
Battery capacity should be at least 75Ah to enable sufficient power to be stored during engine operation.
Please feel free to add your own bits of knowdedge or advice.