On Jun 2, 10:54*pm, hillpc wrote:
I'm making a home tennis court out of an asphalt paved area. *I've
already bought the net and posts. *The specified concrete footing for
each tennis net post is a 30" square at the bottom, tapering up over a
height of 42" into an 18" diameter circle at the top. A drawing is athttp://sportsbuilders.org/page.php?id=96&from[]=11&from[]=12&from[]=13&..
Could I use 3/4" plywood to make a form strong enough to contain this
much concrete without blowing out or breaking? I think the bigger job
may actually be cutting out a big enough square out of the asphalt
(32"?) so I can then rent a 30" auger to dig 42" deep, cut the corners
out to a square with a shovel, and then drop the empty form in, and
somehow hold it down while pouring the roughly ton of concrete into
each one. *After stripping the form, backfill with dirt and repair the
asphalt. *Any suggestions for me? *I'm thinking readymix concrete for
the little over 1 cubic yard I need to avoid all that mixing, and it's
probably cheaper than buying eighty 80" bags of concrete mix.

You don't need a form if you are digging a hole in the ground. I'd
just auger a 30" hole straight down and then fill it with concrete.
Having a slightly bigger top is not going to be an issue. Just set
the posts a little towards the insides.