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Is it even possible to buy flat plywood?

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Forum topic by 9saws posted 02-02-2015 02:55 PM 1798 views 0 times favorited 26 replies Add to Favorites Watch
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9saws

11 posts in 671 days


02-02-2015 02:55 PM

Topic tags/keywords: flat plywood straighten plywood warped plywood fir plywood

Hello there. I’m new here. Nice to meet you.

Is it even possible to buy flat 1/2” fir plywood nowadays? The last piece I bought came from the local old-line lumberyard, who you would think has reputable stuff. A lot of pieces bowed and twisted. I tried clamping them up with beams and blocks to bend them the other way, and leaving them indoors surrounded by air for weeks. No dice. They were incorrigible.

I’ve seen a few straightening methods in YouTube but after this, I’m not sure I believe them. Anyway, if you wanted a reasonably flat sheet of 1/2” fir plywood, where would you go or what would you do? I want fir for reasons which we can ignore for this discussion.

Thank you kindly.

9

PS I’m in Durham, NC, USA if you have any hot leads.


26 replies so far

View Mainiac Matt 's profile

Mainiac Matt

5989 posts in 1789 days


#1 posted 02-02-2015 03:05 PM

The ability of plywood panels to stay flat is directly dependent on the number of veneer layers.

I’ve never seen Fir plywood made in any other grade than construction sheathing, and 1/2” has 5 layers of veneer. Also, you will have voids in these layers.

By contrast, 1/2” Baltic Birch has 9 layers of veneer and zero voids.

-- Pine is fine, but Oak's no joke!

View RogerM's profile

RogerM

759 posts in 1859 days


#2 posted 02-02-2015 03:25 PM

Not sure why you need perfectly flat 1/2” plywood sheets but you are fighting a loosing battle with 1/2” fir plywood. Have you considered Medium Density Fiber Board (MDF)? Large sheets of wood is never stable so you have to deal with it. As stated by Maniac Matt one of the methods in dealing with it is to laminate it.

-- Roger M, Aiken, SC

View MrRon's profile

MrRon

3926 posts in 2704 days


#3 posted 02-02-2015 04:32 PM

Baltic Birch plywood is reasonably flat, but not perfectly flat. No plywood is perfectly flat, so you have to learn to live with that fact.

View Loren's profile

Loren

8295 posts in 3108 days


#4 posted 02-02-2015 04:53 PM

Look for a plywood dealer. They serve the industry and are
pleasant to deal with. The quality of plywood available
at big box stores is spotty. I see great old 1/2” plywood when
I salvage materials sometimes but the grade of stuff I’ve
seen at Home Depot is a far cry from it.

For 3/4” you can get hardwood ply with 1/8” MDF plies inside,
usually 2 I think. It’s quite satisfactory and flat enough. Of
course it’s a cabinet grade material so while not expensive
it’s not cheap either. I haven’t looked at 1/2” stuff like this

View 9saws's profile

9saws

11 posts in 671 days


#5 posted 02-02-2015 05:23 PM

Thank you for the nice replies!

To batch-respond:

I’ve never seen Fir plywood made in any other grade than construction sheathing…

Oh, sure you have.

Not sure why you need perfectly flat 1/2” plywood sheets

I think I said “reasonably flat” I’m building boxes, not nailing it to studs.

Have you considered Medium Density Fiber Board (MDF)

Actually, that’s what I want to move away from. It’s an acoustic issue that you just have to trust that I know what I’m doing.

Baltic Birch plywood is reasonably flat, but not perfectly flat

Of course that’s a go-to, and I love the stuff, but right now I want to use fir.

Look for a plywood dealer.

Huh. Interesting idea. Thanks.

The quality of plywood available at big box stores is spotty.

“Spotty” is a polite word, but I always appreciate and applaud politeness. The world needs more of it.

Best,

9

View Ghidrah's profile

Ghidrah

667 posts in 682 days


#6 posted 02-02-2015 05:46 PM

Luan 1/2” ply is pretty good, I use it often for shop cabinets and jigs. If ply had been sitting in a curved position at the lumb yd for an extended period, (months and months) it’ll end up taking the shape of the curve.

-- I meant to do that!

View tomsteve's profile

tomsteve

393 posts in 679 days


#7 posted 02-03-2015 01:59 AM

Hiigher quality ply bring higher price and when ya see he price for that higher quality fir ply you just might go to birch, maple, or even oak.
Search the yellow pages for plywood.
Look up custom cabinet builders and ask wher they purchase their plywood.

View Loren's profile

Loren

8295 posts in 3108 days


#8 posted 02-03-2015 02:01 AM

Have you considered 1/2” lauan ply?

I haven’t looked for it lately. It’s pretty stable, flattish
and not pricey. I used to get it at HD but I don’t know
if they still sell it.

View patcollins's profile

patcollins

1420 posts in 2325 days


#9 posted 02-03-2015 02:06 AM

My Lowes sells something called Arauco Ply and it isn’t bad. Its not Baltic Birch by any means but it is a whole lot better than the other stuff they have and the price is reasonable.

View Dan658's profile

Dan658

93 posts in 730 days


#10 posted 02-03-2015 02:09 AM



The quality of plywood available
at big box stores is spotty.

To say the least…. I mentioned it earlier today in another thread, but I found a utility knife blade laminated in a sheet of birch from Rona (a Canadian home Center) by cutting through it with my table saw. Imagine my surprise when sparks started flying out of the sheet as I ran it through. Quality…..

View 9saws's profile

9saws

11 posts in 671 days


#11 posted 02-03-2015 04:02 AM

”...but I found a utility knife blade laminated in a…”

Wow…

View Loren's profile

Loren

8295 posts in 3108 days


#12 posted 02-03-2015 04:19 AM

I say it’s spotty because I have bought a lot of satisfactory
stuff at big stores, though the 1/4” ply is not worth the
name, imo. Just junk now, gotta remember that.

Sometimes I only need a couple of sheets and I don’t
want to deal with treking out to the good sources. I
don’t always regret buying my ply at HD or Lowe’s but
I know I can’t do a bookcase job with 1/4” ply backs
with the junk they’re stocking these days. I’m going
to buy 1/4” veneered MDF in the future from a plywood
dealer.

In terms of the 3/4” cabinetish ply and MDF HD sells,
it’s adequate for many jobs.

Also, in my experiences plywood dealer pricing is often
a pleasant surprise. They have never beat me up for
buying a couple of sheets.

View realcowtown_eric's profile

realcowtown_eric

565 posts in 1397 days


#13 posted 02-03-2015 04:20 AM

A lot of plywood is made offshore, so it comes to NA with various moisuture levels. It’s mpt unusual ot see the top sheets curled up to levels suitable for boat building. Baltic birch, why that’s oventimes out of square.

And fir ply does come in GIS, not just sheathing

Ply from the borgs is often sorted through, starched and damaged, and you’ve got someone elses “leavings”
There is no simple solution

I’ve found bullets in wanut, silica inclusions in teak lumber and various metal inclusions in MCP

Point is u never know what yu fnd.

Eric

-- Real_cowtown_eric

View Garbanzolasvegas's profile

Garbanzolasvegas

356 posts in 687 days


#14 posted 02-03-2015 04:26 AM

Christ even if it’s FLAT they all come with more narrow dimensions. Hell none of the specs are even close anymore. 3/4 of an inch could means “anything”. I made the mistake of buying some 3/8s inch stuff and never measured it and dadoed my stock to fit it!

It made great firewood

-- If you don't Play, you can't win

View 9saws's profile

9saws

11 posts in 671 days


#15 posted 02-03-2015 04:30 AM

Oh yeah, the last box I built had two different versions of 1/2” in it….

showing 1 through 15 of 26 replies

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