Quote Originally Posted by martin54 View Post
Yer but that picture has been photoshopped Richard, that's really a steel beam you have made look like wood lol

LOL !

it's not my photo, I googled for an example to show that thin sheets of wood can be made to be 'not bendy'.


Before starting my design, I made a few test torsion boxes with hardboard skins . it's amazing how they work !

for them to bend, they have to curve. now everyone knows, the outside of a curve, is longer than the inside. So the only way for it to bend, is for the skins to stretch !
the further apart you keep the skins , the stronger the end result.


The only problem you have to solve is how to fix parts to each other, so I chose not to use harboard. With MDF, you can use cheap super glue to 'harden' any fixing holes, which greately increases their strength. washers are good for spreading the load too.
Another trick is to use a rot treatment/wood hardener over the whole part. it's basically liquid plastic, and soaks into the MDF stiffening it and waterproofing it.

The use of ply instead of MDF, is also a good option, as it takes screw fixings a lot better.