Check your plywood before you buy.

[Ronn W]

I spent what seemed to be a extraordinary amount of money on some A1, Oak both sides, 1/4" thick, MDF core plywood for a project I am making for a friend (framed panels.)  I had to cut the sheet in half to get it home so there were no returns.  I cut a test dado with my 1/4" router bit  to check the fit and discovered that is was very loose.  The dado mic'd at 1/4" the plywood mic'd at 7/32".  I had previously been told by an emplyee of Youngblood Lumber that their MDF core was a full 1/4".  When I called them up to tell them what happened the guy on the phone was surprised and repeated that it should be  a full 1/4" and he told me what the tolerances were.  7/32" is outside of the tolerances.  Lesson learned.  My calipers go witih me next time.  BTW,  I went to Woodcraft and bought a 7/32 straight bit.  It will be a little tight (sandpaper will deal with that if needed) but at least now the project continues.

I also learned the difference between quartersawn, rift cut, plain cut and flat sawn veneers and the price differences.

[RichardA]

Sometimes, education can get expensive. I hate you had to go through that.  Calipers should solve any future problems.

[Coop]

So you can get qtr. sawn veneer ply? 

[..Kev]

I have always found ply to be undersized.  That's cool if you can get it!  I do have a set of the ply router bits that do help but, they're not perfect either.

[wdwerker]

One benefit to expensive education like that , you know it will never be forgotten !

Besides calipers take a strong LED flashlight. Examine the sheets using a raking light. This will create tiny shadows if there are imperfections in the face. Also keep your eye out for lighter or darker streaks under the face veneer. Any gaps or flaws in the core of the plywood will make the face veneer sag or wrinkle. Some places won't give you much time so practice in the shop so you can confidently give a sheet the once over.

Doesn't hurt to measure the sheet either. While your at it check the diagonal measurements. I usually reserve the highest level of inspection for expensive grades like A1 or even B2 on walnut, cherry, mahogany etc.

The yard I buy from didn't even make me bring a cut up sheet back.  I found a void under the veneer  , took a scrap with the void in it with me just for proof. They replaced the sheet graciously.

 Many years ago the first sheet I cut into was coming delaminated at one end.  I had a whole stack of them. Started inspecting and they all had the same issue in the same layer of each sheet. The owner of the yard told me to cut a 12"square , peel it apart and tell him what color glitter was in the glue. That let the manufacturer track down the bad batch of glue. They replaced the sheets and said I could have the bad stuff or they would come pick it up.  It pays to develop a good relationship with your suppliers. 

[wdwerker]

You can get almost any veneer you want but it may need to be ordered. 3 sheet minimum one time, 10 sheet minimum another time.  There is a mill in South Carolina that does it for them. Maybe a 2 week lead time. 

[..Kev]

5 minutes ago, wdwerker said:

 It pays to develop a good relationship with your suppliers. 

To me, this is one of the most important things!  If you're frustrated because you have to deal with your hardwood dealer, you're a lot less likely to get out in the shop and build.

[Jfitz]

I always expect ply to be slightly undersized.  I'm a little surprised that your hardwood supplier was surprised - but if they spec it at a full 1/4", then I'd take a piece of scrap back and show them.  I'm sure they'd push back on their supplier for not meeting spec or for overcharging for what was actually delivered.

[Chestnut]

Awe that stinks Ron.

11 hours ago, K Cooper said:

So you can get qtr. sawn veneer ply? 

My old yard had some very curly qtr sawn white oak ply it was beautiful, the price he wanted for it was beautiful as well.

[wdwerker]

I just thought of something. You got 2 sided premium grade veneer instead of the regular stuff. Maybe the "A" grade veneer is sliced thinner.  The MDF core has to be undersized to allow for the veneer & glue to bring it up to the full 1/4" after sanding. The back of 1/4" sheets is usually a much lower grade, maybe they usually allow for that thickness. 

[new2woodwrk]

I'm starting to notice something similar more and more at the big box stores - but I think it's more from sloppiness than anything else.

I've stopped to going to HD and now go to L for my lumber. I mostly use ply for my projects as I'm not really ready to use good wood.

I went to pick up some ply the other day, 1/4" birch for a back to a cabinet I'm working on, and noticed the top 3 sheets were not 1/4"

I pulled the 3 out, set them aside and loaded my cart. I found a staffer and told him about it.

If it was the boards (which are also always out of place) I would have put them in the right cubby, but the sheets weren't marked from what I could tell so I let the staffer have at it.

I know it's not the same issue as the OP, but thought it related to being careful when buying lumber at the box stores.

[Cliff]

I have been screwed by this as well. But in my case I was expecting it to be undersized and I used a test piece to do my dado. All was good. Except it turned out all three sheets of ply were different thicknesses and I had tested the dado with the same sheet I had cut the dado in. 

[woodbutcher74]

2 hours ago, Cliff said:

I have been screwed by this as well. But in my case I was expecting it to be undersized and I used a test piece to do my dado. All was good. Except it turned out all three sheets of ply were different thicknesses and I had tested the dado with the same sheet I had cut the dado in. 

Heck, big box plywood varies in thickness along the length of a single sheet. 

[Mark J]

4 hours ago, Cliff said:

I have been screwed by this as well. But in my case I was expecting it to be undersized and I used a test piece to do my dado. All was good. Except it turned out all three sheets of ply were different thicknesses and I had tested the dado with the same sheet I had cut the dado in. 

I purchased a few sheets of baltic birch from my regular hardwood lumber yard.  One was from a different supplier and was slightly thinner than the other two.

If you are trying to do a dado and using a "plywood" dado router bit it's a pain to have a panel that fits a little loose.  

Next time I will consider using epoxy since it has gap filling ability.

[wdwerker]

Yep ! I have found sheets of Baltic from the same manufacturer but different bundles be up to 1/64 different. Remember plywood is sanded after it comes out of the press.  Thankfully Baltic has full thickness veneers on the face. They have to change the sanding belt sooner or later.

[Marmotjr]

On 1/5/2018 at 10:07 PM, K Cooper said:

So you can get qtr. sawn veneer ply? 

All depends on how much you want to pay.  At work we have some foam core sound absorbing sheets with qtr sawn sapele on it.  Each sheet runs about $1500.  Of course, that price is passed directly onto the customer. 

[Coop]

Sounds like the government or corporate America will be the likely customer. 

[wdwerker]

Or an executive conference room where they don't want the staff to overhear them plotting. Yea, or the government....

[Marmotjr]

Nope, it went into a variety of rooms in a residence.  I believe it was top floor in a building across the street from Central Park. 

[Chestnut]

I remembered this post when i grabbed a piece of ply out of the clearance bin at the box store. It was the good American made stuff originally $45 marked down to $10. Only thing wrong with it was a damaged corner.

[wdwerker]

My supplier occasionally sells " shop grade" plywood. It's got flaws but supposed to have at least 80% that's usable . Damaged corners are a common defect. 

A few plywood mills are making sheets that are 48 1/2" x 96 1/2" . This lets you cut 4 rips that are a full 12" wide after allowing for saw kerfs.