Materials: one 4' x 8' sheet of finished plywood 3/4" thick - 35$
around 50 biscuits for biscuit joints - 5$
around 20 drywall screws 2" - 2$
sandpaper, acrylic paint, primer paint, one sheet of 11" x 58" grip tape-12$
Tools: The usual ... Table saw, drills, circular saw with plywood edger, drill bits, sander, biscuit joiner, jigsaw, paint rollers and lots of wood glue and #20 biscuits.
I am an amateur woodworker, this is just a casual hobby to me. People with better skills and equipment have done other plyoboxes and this is one of many different ways to make such an exercise box. The final result is very strong, maybe a bit on the heavy side but that could be seen as a plus..hey it's for exercise..right? My wife was very happy with the final design and uses the box often. My kids like stomping on it too. I too have used the box and feel it is a good workout. So , consider this design if you are contemplating making a plyobox. Good luck!
Step 1: Plywood Cutting
Sides: 14" x 20" 2x
20" x 28.5" 2x
12.5" x 28.5" 2x
Two internal interlocking wall pieces : 28.5" x 12.5" 1x
18.5" x 13" 1x
These two pieces will have a slot cut in the middle so they can be interlocked together. There will be a dado type slot cut into the 28.5" x 20" sides, .25" deep to secure the cross support in place.
The cut pieces need just a little sanding afterward. I used a Diablo 7.25" 60 tooth blade and it worked very well with just a few small side splinters on the cuts.
Step 2: Biscuit Slot Cutting
Step 3: Internal Supports
Next, I decide to put two interlocking support panels inside for extra strength. This box is going to have people close to 90 Kg jumping on it so just to be safe this seemed liked the way to go. I came up with the idea to cut a groove, some carpenters may call it a dado cut I think, so the panels stay in one place until the wood glue drys and the screws are put in.
I used a table saw to cut the groove. I believe it is a 1/4" groove.
UPDATE: OK, I restart this instructable some 10 months after I started writing it. I got involved with tearing out an old build in hot tub and building a deck in it's place..
So, to wrap up this instructable and move on...I think any competent DIYer can figure out how I finished this box.
More glue and screws, sanded down the surface, primer paint, lots of red paint and skate board tape.
Anyway, it's a really heavy duty box, it mostly sits on my patio and doesn't see to much action..I think it is built to last... Sorry for abruptly ending this instructable but life moves on..