Cutting channels & notches in Foam ?

[GPW]

" which I assume the purpose of the canvas would be” ... Er , If we read that correctly ... Not really ,The outer canvas provides a tension skin spreading the load across the surface , it does protect the surface a good , bit , but taking the compression and tension loads is much more important , and where the foam “sandwich” gets it’s strength .

AH, In the past several years , we‘ve seen products that would be applied ( like paint)_ to the outer foam surfaces , touted as a “finish” for foam , but all of that was used on outdoor statues and things that didn’t “Move “ and were Not subject to the loads and shocks of roads and highways. Like many of these “flash in the pan” products , seems they quickly faded away ( AFAIK) ... Another problem is it was fairly expensive too ... for a camper ... The old canvas covering is hard to beat .... The Old Timers used it long ago on their trailers ... as well as boat and canoe guys, going waaaay back ... Well tested , long ago ... ... and not really expensive ... easy to patch ... etc.

I believe all of this is discussed ( at length) in "the Big thread “ ( Thrifty Alternatives ) ... It’s non fiction , but an informative read... based on true stories ...

[GPW]

Just an idea of what might be an easier and less messy method of supporting the foam .... A while ago big Mike did a CNC cutout of a sheet of plywood , removing most of the wood , but leaving a series of cutouts within the camper profile ... Now say that was 1/4” plywood , or maybe even thinner ? ... if the cutouts are properly engineered , then that could be glued Flat to a sheet of foam , (no channels) , and that, in addition to the simple outer skin should be Extremely strong and provide “hard points” to hang things from ... Pretty easy , but in reality trading sawdust for foam dust ...

[Andrew Herrick]

Thanks for the explanation, GPW. I think I might have misinterpreted the original question. I wasn't thinking of the canvas as a skin; just like a strip of canvas laid between the routed channels and the wooden 1x wooden frame inserts. Hard to explain with text ...

I'm with you on the canvas skin, though. It amazes how long an expedition canvas wall tent can last!