Posted by Rick Denney on January 28, 2003 at 00:20:28:
In Reply to: Re: Re: Home-made hard cases posted by curious one on January 27, 2003 at 21:40:27:
In my opinion, no. If sheet metal was heavy enough to provide the same skin strength, it would be far heavier than marine-grade plywood. I've seen the metal cases that are on the market now, but I wonder how well they will survive being battered in regular use. And joining the metal at the edges is no picnic--rivets pull out, welding is too expensive and is too hard to do well on thin sheet metal (unless it's stainless steel, which is too heavy), and epoxy isn't strong enough. You can use aluminum angles at the corners, but the metal sides will eventually get caved in. Wood is marvelously stiff for its weight.
Wood is nature's composite. It works the same way as fiberglass or carbon fiber embedded in epoxy, which depend on high-tensile fibers held in a plastic resin. Wood's fibers are cross-laid in plywood and held in place with waterproof glue. Wood is less dense, though, than plastic, and for a given weight it is nearly as strong.
Rick "who thinks 10-guage aluminum might be durable enough but would be really heavy" Denney