sledge&wedge
ArboristSite Operative
It's a combination of the pallets I'm getting and the natural moisture content of the soil in my yard. The pallets are what I would call mid-grade. They are stout enough to handle heavy loads when they are brand new, but all of them I can get are well-used. You mention not trusting your old pallets to handle heavy loads... I'd say a 4 foot deep stack of wood that is roughly 6 foot tall is a pretty heavy load.What kind of area do you have your wood in that pallets only last 6 months?!
I used to stack my wood on pallets, they are out back still with other junk on them (car parts, etc). I got them when I moved in my new house in 2009, all still nice and solid.
Heck I cleaned up in the corner of the yard at the shop... junk than had been on pallets since the late 80s/early 90s, lot of those pallets were still decent. Not something I'd trust to put heavy things on and move with the forklift, but they weren't completely garbage either.
EDIT: The angle iron I can get is good heavy wall stuff, and I'm planning to use 3-4 supports per 10 foot span.