On Thu, 02 Oct 2008 10:47:38 -0400, "T. McQuinn"
wrote:

I'm building an Allan Block retaining wall and I'm trying to follow the
manufacturers directions as closely as I can. It's going to replace a
30 year old railroad tie wall that was secured by rebar driven 6 feet
into the ground. I have removed the old wall and have the block and
gravel on site. But I have never used a plate compactor. I had dug the
old wall back just enough to allow me to backfill with 12 inches of
gravel and then compact it. I see now that any plate compactor I can
rent will need more than 12 inches to operate. I'm leaning towards
digging back a few more inches, renting a reversible plate compactor,
and seeing how that goes. But it has also been suggested that I might
get away with using a jumping jack for compaction - much lighter to move
up on each 8 inch course and also narrower. But the description of how
the thing jumps around is putting me off. Any thoughts from anyone who
has used either device would be appreciated!

With the PC it's easier to get a smooth and level surface. The JJ
tends to leave dents the size of its head. But given the extra heavy
work required to use the PC, I'd probably give the JJ a go. It will be
a lot easier to maneuver on the upper courses. After you've got
everything solid, spread a little extra sharp sand on top and screed
it with a long 2by to fill in any low spots. Regardless of which way
you go, wet down the material before you compact it. Provides a
little lubricant so the material compacts better.

HTH,

Paul F.