is any plywood FLAT these days?!

[Window Guy]

seems like all the plywood at the big box stores are no where near flat.  I'm trying to make a crosscut sled for my tablesaw, and the base is way uneven, and the glue up of the pieces to be the fences are out too... i'm trying to flatten it out, but i wonder if it's just going to get uneven again as summer humidity comes in again...
Any suggestions on how to flatten it?

You got that right my big box store here is HD and what crap as far as any type of plywood or regular pine boards.  Every board I buy there is something wrong with it grrrrrrr. We don't have a good old fashion Lumber yard where I live.

So unless I travel or buy mail order which I am temped to do I have no choice. When HD first came out it wasn't bad but in the last few years they have gone "cheap" and I don't like using that word to often. I would rather use less exspensive but they do not qualify for that.  Grrrrrrrr !


Steve

[RKMBrown©]

They store the stuff outside in the rain half the time. Better off getting mdf if you want flat. But yeah if I get a piece of ply with a bow I just wet it down a bit turn it over and put weights on it over a concrete surface for a couple days.. voila flat.

[mr_skittle]

jteneyck nailed it. While all the talk about plywood is valid, I would say your problem is the wrong type of ply. What you seem to have is construction plywood but what you need is cabinet grade. Gary also has a point about the fence being hardwood, preferably quarter or riftsawn for added stability.

Menard has usually been pretty reliable for quality cabinet grade plywood with a decent selection and price. I can't vouch for other big box stores but with their proliferation and subsequent competition, profit margins are razor thin and it's been a race to the bottom. If you're looking for quality materials, don't let the price point at someplace like HD be a benchmark. You get what you pay for right.