Learned a Lesson in Sanding Plywood Today

[George Bokros]

I was sanding my birch plywood that is the counter top for my shop base cabinets. Two of the pieces were not flush on top and I thought I could sand them flush. Well the top veneer on the birch play is whisker thin and I sanded through it. Ruined the look of my counter top. I do not want to buy another whole sheet of birch ply (~$50 at Lowes) so I am going to shorten the top three inches and move one section of the base cabinets over 3" making the knee hole area 34" wide. At least I can recover without spending more money for an additional sheet of birch ply. A no cost but labor intensive recovery.

Lesson learned do no aggressively sand veneered plywood. I had no idea the top veneer was that thin. It is so thin you cannot distinguish it from the first base layer.


George

[johnny means]

Wrong lesson. The real lesson here is to leave that garbage at the Borg. When veneers are that thin they present and meriad of other problems. IMO, its impossible to make that junk look good, unless your just slathering it with paint.

[Bruce Page]

I learned that lesson the hard way refinishing a large salt water aquarium years ago. :(

[Brian Holcombe]

Wrong lesson. The real lesson here is to leave that garbage at the Borg. When veneers are that thin they present and meriad of other problems. IMO, its impossible to make that junk look good, unless your just slathering it with paint.

The top layer is usually .020", not nearly enough to correct anything other than that which barely grabs a fingernail. However, that doesn't necessarily make it bad, in fact I prefer a large number of laminations for plywood over a small number.

[Rich Engelhardt]

There was a thread about the thin veneer on cabinet grade plywood a couple/three years ago, IIRC.
I recall someone mentioning that the stuff comes pre-sanded to 180 grit & nothing coarser than 220 should be used & that only for very, very, very minor sanding.

I never sand that stuff except by hand with a sanding block.

[John TenEyck]

Yep, the veneer is whisker thin on that stuff. I measured some at 0.012". Basically, you can't sand it at all. But at $50 a sheet what do you really expect? I just paid $145 a sheet, tax not included, for some Columbia MPX A-1 cherry plywood. It hasn't arrived yet, but I am expecting near perfection.

John

[Rich Riddle]

I am considering a project using this birch plywood for the shop. Are the inner layers in the birch plywood any higher quality than traditional b/c plywood or even cdx grade?

[Leo Graywacz]

Wrong lesson. The real lesson here is to leave that garbage at the Borg. When veneers are that thin they present and meriad of other problems. IMO, its impossible to make that junk look good, unless your just slathering it with paint.

I don't know about you but I buy most of my plywood at my plywood supplier. It's still think as a whisker. .017 is the average thickness of the veneers. If you want old fashion plywood you'll have to get it laid up custom.

Otherwise, please enlighten me.

[Leo Graywacz]

Yep, the veneer is whisker thin on that stuff. I measured some at 0.012". Basically, you can't sand it at all. But at $50 a sheet what do you really expect? I just paid $145 a sheet, tax not included, for some Columbia MPX A-1 cherry plywood. It hasn't arrived yet, but I am expecting near perfection.

John

I wish you all the luck. I pay about $108 a sheet and as far as I'm concerned it's crap. Nothing like it was 10 yrs ago.

[Rich Engelhardt]

I am considering a project using this birch plywood for the shop. Are the inner layers in the birch plywood any higher quality than traditional b/c plywood or even cdx grade?
Depends.....
Home Depot in my area carries Columbia Forest Products.
It's really decent stuff.
http://columbiaforestproducts.com/Products/HardwoodPlywood


The local Lowes carries some garbage made in China.
The plys are all wavy - like looking at the Earth's strata on a canyon wall. The also vary in thickness - as can the actual ply itself.....on the same sheet!!
Needless to say, Lowes doesn't sell much of that stuff.
I don't believe they've sold any 3/4" Birch or 3/4" Oak plywood at my local Lowes in three or four years.
They moved it all to an upper spot on the rack that you need to have a worker get a lift and pull it for you. You have to take what they give you - which is the wavy potato chip on top (actually the top three pieces).

Menards carries a few different types.
This one is what I use:
http://www.menards.com/main/building-materials/panel-products/specialty-panels/hardwood-plywood/3-4-x-4-x-8-b2-birch-plywood-wood-veneer-core/p-1714173-c-13334.htm
It's decent inner plys and at a price that won't break the bank.
Menards also sells a ton of that stuff so the stock is always fresh.

[John TenEyck]

I wish you all the luck. I pay about $108 a sheet and as far as I'm concerned it's crap. Nothing like it was 10 yrs ago.

Uh oh. I had high hopes it was worth the money. I couldn't source Jaycore or Kaycore; this was the best I could get. I'll know if it was worth it in few days.

John

[Leo Graywacz]

It's the luck of the draw. Hopefully you'll get the good straw. Mostly the veneers are OK. It's the core that's usually the problem. Flatness is the issue that I always struggle with. I get the jaycore I believe, but it could be kaycore. It's what they have as cabinet grade. The definition of the "1" side seems to be moving in the "2" direction. I get small knots filled with putty on the "1" side to often.

[Chris Fournier]

I have sanded baltic birch plenty and I haven't sanded through. I start with 180 sometimes but usually 220. I like to use a 6" ROS. I am not sanding in preparation for finishing or colour, it would likely be the inside of a utility grade piece. I imagine that the quality of BB ply can vary a lot, I buy mine from a sheetgoods wholesaler and can request a couple of grades. The grades pretty much refer to the presence of patches. When it is used in finer work I lay up my own veneer on a BB ply core.

BB ply is a great product but I don't consider it appropriate for show surfaces, the sliced veneer really isn't up to it in most of the projects that I would undertake.

[Dave Cullen]

I am considering a project using this birch plywood for the shop. Are the inner layers in the birch plywood any higher quality than traditional b/c plywood or even cdx grade?

Traditionally, there are fewer voids in the inner layers of "cabinet grade" birch ply than construction grade stuff. There are also more plys, usually 13 as compared to 7 for the lesser grades. The last time I used birch ply for furniture was for a pair of book cases and the edges cut void-free. I was able to sand them for a stain finish without any trouble. That was 15 years ago though and what I find on the borg shelves now isn't the same.

I still use the 13 ply stuff for subwoofer boxes and shop utility items but I don't expect it to be flawless as it was years ago.

[Kevin Jenness]

Most veneer these days is sliced at 1/42", around .023", and by the time it is sanded it is usually down to .018" maximum. When used as a face on plywood, the veneer is typically laid up on an uncalibrated core, that is, the core has not been sanded to a uniform thickness, and often is not very flat, so it should not be surprising that the face veneer may be very thin in places, especially at the edges. Some mills supply a calibrated core product like "Classic Core" with a thin layer of mdf over inner veneer core, which leads to a more uniformly thick face veneer and better flatness. Registration of face surfaces when mating sheetstock can be best controlled with a tightly fitted spline or closely spaced dominoes. Biscuits really don't fit tight enough to ensure alignment within the typical veneer thickness.

[Ethan Melad]

totally agree - i just got a number of Columbia 3/4 classic core rift white oak sheets and, while not too bad, they're not all that great either. a few visible voids at the edges, and what is passing for A-side rift sawn is not even remotely as straight grained as i would have expected. Leo, do you have a plywood source that would recommend? or an alternative to coulmbia for NAUF stuff?

[Howard Acheson]

Here's the rules for sanding plywood. Plywood is factory sanded to 180 grit. Therefore, it's best to not sand plywood except with 180 grit and sand by hand. Get the first coat of finish on and then sand with 320. That way you are sanding the finish, not the wood. This avoids sanding through today's very thin surface veneer.

[David Hawkins]

I agree. As soon as it gets wet, (and all work surfaces get wet at some point, at least mine do) it will bubble and start peeling. You will need to finish it well and a couple coats of wax would be a good idea to top it off.

[Brian Holcombe]

I find high quality baltic birch without issue, but I always shop local lumber yards over the big box places, since they generally source higher quality. Also, i've always veneered over them with veneers that are approx .020". Thicker veneers are appealing, but they do risk creeping more than thinner veneers.

[Leo Graywacz]

totally agree - i just got a number of Columbia 3/4 classic core rift white oak sheets and, while not too bad, they're not all that great either. a few visible voids at the edges, and what is passing for A-side rift sawn is not even remotely as straight grained as i would have expected. Leo, do you have a plywood source that would recommend? or an alternative to coulmbia for NAUF stuff?

I have no alternate place to get it. Plywood has doubled in price and gone down that much in quality. It's mostly the same no matter where you get it. As for rift plywood everytime I buy it my salesman reminds me that the ends of the ply will have curved grain on them more than likely. And in most cases he's correct.

As far as I can see all the good trees have been used and they just use whatever they get now.

[johnny means]

I prefer veneered MDF for anything that needs to look pretty. It typically has a thicker veneer and no telegraphing.

[Ole Anderson]

I must have gotten lucky. Did my kitchen boxes with 3/4" Hickory ply, both sides looked flat sawn. The "B" side had some pin knots and more of the mix of dark and light hickory which I liked, the "A" side had no pin knots and was more uniform in light color. No repaired knots on either side whatsoever on 10 sheets. I think they were just under $100 per sheet after he gave me the 10% builder's discount as I also bought all of my hinges and Blum slides from him too. Sourced from in stock material at a local cabinet supplier that sold retail. Seven ply, I believe. I edge banded the front of my shelves (28 of them) with 3/4" solid, then flush trimmed them on the router and finish sanded with 180. Only once did I sand through the veneer, and then it was my fault.

[Brian Elfert]

Depends.....

Menards carries a few different types.
This one is what I use:
http://www.menards.com/main/building-materials/panel-products/specialty-panels/hardwood-plywood/3-4-x-4-x-8-b2-birch-plywood-wood-veneer-core/p-1714173-c-13334.htm
It's decent inner plys and at a price that won't break the bank.
Menards also sells a ton of that stuff so the stock is always fresh.

Menards tries to do a good job on storing their "good" plywood stock. The problem is they have a metal grid as shelving for the plywood. The metal grid at the front of the shelving is often bent upward in one or more spots. Menards employees set the plywood on top of the bent metal and then the plywood is warped in that spot and often telegraphs up through the entire stock so a lot of expensive plywood is basically ruined.

Not that Home Depot is usually any better. They put their 3/4" Oak plywood on only three supports and often the supports are bent so they don't line up and again the plywood gets warped. Even when the supports are lined up properly the stack tends to sag between the supports.

[John TenEyck]

I prefer veneered MDF for anything that needs to look pretty. It typically has a thicker veneer and no telegraphing.

So do I Johnny, but not for structural applications.

John

[Scott Austin]

Ole, where did you get your hickory ply ? Drayton plywood

[Ole Anderson]

Ole, where did you get your hickory ply ? Drayton plywoodYes. I don't buy a lot of stuff there, but I probably have been in the store a couple of times a year over the last 20 years.