How can I flatten out a piece of plywood?

Robert: Is the plywood going to be attached to a frame, which would force it flat or is it just being used as it is.

The plywood might be curved because of unequal moisture mitigation from within the panel. If you hold it in your shop/house it might flatten but probably not.

As to correcting it, I’m not sure.

-- Karson Southern Delaware karson_morrison@bigfoot.com

-Karson
The project I am currently considering would not be attached to a frame so it couldn’t be forced flat after the fact.
Thanks,
Robert

This is not really an answer to your question. Instead of looking at Lowes or Home Depot I would suggest going to another store, perhaps one that caters to woodworkers. Localy we don’t have any woodworking stores but we have another lumber chain named Menard’s. I have found that Menard’s has a larger selection of quality plywood, and normally cheaper than the other big chains. I can get 1/4, 1/2 and 3/4 Baltic Birch 4×8 sheets at Menards. A 1/2” thick sheet costs about $40, if memory serves me right.

I have purchased 1/4 sheets of oak plywood from both Lowes and Menards. There was a huge difference in quality between the two. The Lowes had a lesser quality oak veneer and the stain was blotchy. To top it off Lowes was more expensive.

-- Owen Johnson - aka IowaWoodcrafter

Been here before. I swabbed the plywood with a damp rag on both sides, then laid it over a length of 2×4 and weighted the ends. By bending it “over centre” for a few hours the ply came out staight and true. I then stored it between a couple of sheets of ply wood until I needed it. Just think that the lumber store probably had the stock around for a length of time and perhaps other wood leaned against it and slowly bent it out of true. I also have had success wetting the ply, weighting it over a piece of wood and heating it with a hot iron. Same results but was much more time consuming.

-- Jim, Alberta Canada

I think the moisture difference in the two sides causes the bend. Give the concave side a light spray of water, & I bet it will equalize, but that won’t guarantee it’ll stay that way.

-- -** You are never to old to set another goal or to dream a new dream ****************** Dick, & Barb Cain, Hibbing, MN. http://www.woodcarvingillustrated.com/gallery/member.php?uid=3627&protype=1

Maybe you should get Baltic Birch plywood. I think it’s more stable

Check here for a comparison.

-- -** You are never to old to set another goal or to dream a new dream ****************** Dick, & Barb Cain, Hibbing, MN. http://www.woodcarvingillustrated.com/gallery/member.php?uid=3627&protype=1

I’d stay away from most 1/8” ply from the big box stores. I’ve never had much luck with it. I pay a little extra and get the better stuff from Rockler or Woodcraft. The problem with the big boxes are they don’t sell much of it, it stays around, gets roughed up, leans to one side or another, gets out of shape, often has marks you have to sand out, etc. I also, don’t like taking the time to flatten a piece as described above. I’d rather use my time doing my project. I’ve never had a problem with the ply from Rockler or Woodcraft with any of my projects.

Just my 2 cents. Good luck with your project.

-- Betsy - GO BUCKS!

Lee Valley/Veritas also has some better quality thin Finnish Birch ply, including bending ply for formed work. Plus the catalogue is like a Sears wishbook for woodworkers, and Robin Lee and company have been kind sponsors of some of our LJ events.

My name is Douglas Bordner, and I have approved this unpaid partisan announcement.
(Sorry folks, The Iowa Caucas has been running non-stop for several weeks in the neighboring state and the ads have been omnipresent.)

-- "Bordnerizing" perfectly good lumber for over a decade.

Take a look at this.

-- Maplewood, MN

I would bet the main reason its inexpensive is because its imported from China (that was another Forum topic) As a rule, imports from china are not made to the standards as US or European wood products. Also it was probably shipped via the cargo hold slow boat without regards to the humidity experienced on the open ocean. Can you tell I’m not a fan of Big Box stores. You may want to see if you can find any local cabinet shops and ask them where they get their plywood. Some of these places will sell damaged sheets at a discount. you may be able to pull what you need from one of them.

-- Greg - Charles Town, WV

www,cherrytreetoys.com has a wide selection of thin ply.

You might find similar locally at Michael’s or Hobby Lobby if they are near you.

-- No piece is cut too short. It was meant for a smaller project.

Do Google search on Baltic Birch plywood and get a million hits. There possibly could be a very good dealer close to you

I was going to suggest what Dick Cain suggested. If you have to use this particular piece then wet the concave side. I’ve even read in Fine Homebuilding where guys lay the board down on moist grass in the morning on the concave side. The moisture that gets abosrbed expands that side forcing the bow out.

-- Sam