We celebrated Independence Day with some bucket
hauler sparks.
I used 16 heavy duty exterior wood screws for a second attempt at plywood
attachment.
They ended up protruding through the plywood side and needed to be
grinded off to achieve a smooth surface. I also used 4 bolts with
washers and nuts to be on the safe side. The nut side sticks out a bit,
but I located each hole so it fits in a gap between buckets.