It looks like their site just went down. Here is what they have...
Fiberglass Reinforced Plastic
Of all the materials used to build refrigerator boxes, none is better than strong fiberglass sheeting. Stainless steel looks nice but it is difficult to work with and thermally conductive. Plywood is popular but needs to be fiberglass coated and often ends up with a rough, amateur appearance when you are done. Rparts has the answer - Bright white, pultruded fiberglass sheet.
What is "pultruding"
Pultruding is a high-volume production method of making certain types of fiberglass products. In pultruding, continuous fiberglass strands are run through a resin bath and then fed into heated high-pressure dies. The result is a consistently optimized resin/glass ratio unobtainable by any other method. Anyone familiar with fiberglass knows that an optimized resin/glass ratio means the highest strength attainable - often 3x higher than hand-laid glass.
How do I build a box with it?
The details of box construction are outside the scope of this web site at the present time (we'll be changing that in the future). However, in general, you would use this sheet in pretty much the same way as you would plywood. Use a regular saw and carbon-tip blade to cut individual sheets to size and create the box that you want. Lightly sand the edges then apply a strip of fiberglass cloth and resin (polyester or epoxy) to the outside edges to hold it together. Once it is dry, use thickened and white pigmented resin to create 1" fillets on the inside corners. If you are reasonably careful with the filleting, the result looks like it was just popped off a production mold. Once everything is set, you can paint the inside if you wish but it is not necessary. Even unpainted, the FRP sheet is very bright and stain resistant.
Does it bend?
RParts FRP sheet is available in 1/4" and 1/8" thickness. The 1/4" material is far too stiff to bend much at all The 1/8" material can be comfortably bent to a radius of about 18". Which thickness you should use in constructing your box depends on the size and shape. In most cases the 1/8" material has more than enough strength to rigidly support even the largest vertically hung holdover plate.
PLEASE NOTE: All FRP sheets are subject to a shipping charge adjustment. We will contact you with details shortly before the order ships if this adjustment is applicable.