You will have to put that bed on a scale when it is complete, that baby is really going to keep the back tires planted. Keep up the good work!

 

I believe I used 10 gauge. I used 2inch square tube to build a frame that bolts to the frame. The raw sheet for the floor was 49 inches wide so I used the entire width. I drilled holes in the floor and plug wielded it to the 2 inch tubing. I am working on a wood floor that will just lay on the metal floor. I used the basic measurements but modified the box to work and look like I wanted. One other tip is to finish the box then mount the running boards and rear fenders before drilling the fender holes. This way the will fit perfectly.

 

Wow! 10 gauge should be plenty strong by itself. One thought though is if you just lay your wood on top of the steel it may rot pretty quickly as water has no place to go. There are some woods that would resist that like cedar but oak or maple would have a problem. Maybe our resident boat builder, GB Sisson, can recommend something better.

 

I built the box to drain and not hold water. The wood will be slightly above the floor and will be very well sealed. Also it is not out in the weather at all.