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Forum topic by Hopdevil posted 05-17-2013 05:09 PM 1540 views 1 time favorited 14 replies Add to Favorites Watch
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Hopdevil

182 posts in 1739 days


05-17-2013 05:09 PM

Topic tags/keywords: plywood warping

Getting ready to start on the new kitchen cabinets….

We all know that plywood, if given the opportunity, will warp. I will need to buy more than I can use due to the distance I have to go to get the good stuff. Will it warp less if I pre-cut it into size before i am ready to work on it? i.e. if I cut all the sides to 24 by 30.5 are they less likely to warp than if kept in a full sheet? If so, should I stack them flat? or on end? Any hints to keep it from warping?

Any feedback will be appreciated!

-- Buzz ---- Message sent from the End of the Internet.


14 replies so far

View DS's profile

DS

2131 posts in 1073 days


#1 posted 05-17-2013 05:24 PM

We all know that plywood, if given the opportunity, will warp.

Says who?
The entire point of plys is that it stabilizes the material to prevent warping, shrinking, cupping and bowing.
I’ve seen cheaply made imported plywood with high moisture content warp, but a properly made plywood panel is very stable.

If all your plywood is warping, it is time to find a new supplier. (IMHO)

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

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PurpLev

8476 posts in 2301 days


#2 posted 05-17-2013 05:32 PM

pre-cutting will expose new wood to moisture changes and could potentially induce warping as opposed to your conception that it will minimize it.

the smaller/narrower you pre cut the parts, the more chance those moisture changes will warp those parts. I would leave the sheets in full size, or at least as large pieces as possible.

that said- I only had 1/2” plywood warm on me, and thats when I cut it into 2” strips. never had that with 3/4” ply though regardless of how narrow I have the parts cut.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

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Moron

4666 posts in 2546 days


#3 posted 05-17-2013 05:35 PM

says me.

left on bench top with one side exposed and the other not, looks like a corn chip in no time.

I stand them up as straight as possible without falling over, each sheet tight to the next. I would say that if they are pre-cut you would reduce the warping but regardless, once gables, tops, bottoms and backs are attached the warpage is minimal

-- "Good artists borrow, great artists steal”…..Picasso

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DS

2131 posts in 1073 days


#4 posted 05-17-2013 05:36 PM

If you are going for the “good stuff” look into 'Classic Core' plywood. It is my preferred cabinet plywood and it has guaranteed dimensional stability. (3/4” thick is actually 0.750” thick with veneers)

It achieves this stability due to the top and bottom most plys are made of MDF. It takes screws like plywood and is very flat and very stable.

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

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a1Jim

112083 posts in 2230 days


#5 posted 05-17-2013 05:43 PM

I’ve done it both ways with out problems. I think it has to do with what the conditions are in your area and your shop plus how you store your material. Jim Tolpin in his book “Building traditional kitchen cabinets ” suggest pre-cutting your plywood and doing the assembly at the very end to conserve room in your shop.

http://product.half.ebay.com/_W0QQprZ717255

-- http://artisticwoodstudio.com Custom furniture

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DS

2131 posts in 1073 days


#6 posted 05-17-2013 05:45 PM

I’m sorry, I thought we were talking about “the good stuff”.

In any case, an unbalanced panel will always warp due to glue stresses.
A panel with too high moisture content with one side exposed and the other not, will warp as well.

The trick is buying a properly made panel—aka “the good stuff”.

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

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oldnovice

3760 posts in 2021 days


#7 posted 05-17-2013 11:55 PM

I have never had plywood “corn chip” but then I live in a fairly dry California climate.

I have BIG stuff cut at the yard (don’t have a truck), not the big box store as their saw seem to chip the ply badly!

-- "I never met a board I didn't like!"

View Charlie's profile

Charlie

1017 posts in 939 days


#8 posted 05-18-2013 12:17 AM

I live in the northeast (near niagara falls)
When I did my kitchen last year I used a program that optimized a sheet based on the sizes I told it I needed. Made for less waste. It also meant that some pieces hung around for a while… a month maybe? I’m slow. I stacked stuff flat. Took up very little room actually. I made boxes in sets (all of the pantry cabinets, all of the island cabinets, and then the oddball ones) and when a set was built, I made the face frames. While my wife was putting a finish on the cabinets (they’re her cabinets after all) I made another set or I made doors. I’m not a cabinet maker. I used some nice 3/4” 11-ply for the carcases and baltic birch drawer bottoms (they’re almost 3 feet wide and get loaded with dishes) and drawer fronts. She wanted plain flat drawer fronts with no molding. Just the edges rounded over. I can’t remember anything warping but I’m sure any slight bends would have gotten pulled out when I attached face frames and backs.

View Hopdevil's profile

Hopdevil

182 posts in 1739 days


#9 posted 05-18-2013 01:45 AM

Thanks Folks,
I appreciate all the insights! I live in Lancaster County, PA – (South Central PA)
I will be using 3/4 inch Cherry plywood with veneer core from Industrial Plywood in Reading PA. I will be using 1/2 inch Baltic Birch for the drawers. The doors and drawer fronts will be made from 4/4 cherry obtained from a local source.
I will be renting a trailer to go get the wood and bring it home and break it down.

-- Buzz ---- Message sent from the End of the Internet.

View FirehouseWoodworking's profile

FirehouseWoodworking

624 posts in 1926 days


#10 posted 05-18-2013 03:25 AM

Interesting site DS on the “good stuff”. When I clicked on the link and surfed around the site, I clicked on the “retail distributor” tab and guess who comes up – HOME DEPOT!!

To be fair, I happen to be currently building a cabinet for work, so we get the materials from Home Depot (long story, best left for another day.) I’m using 1/2” and 3/4” birch plywood.

It really isn’t too bad at all. I’ve only found one small void in the plies during a cut. The sheets are rather flat and I haven’t seen any warping. Plies are solid. Both faces look good. Edges all the way around are solid. Thickness is right at 23/32”.

And what I found most interesting when I picked it up, this US-produced, birch plywood was a couple bucks cheaper than Ecuadorian-produced “sandply” plywood of the same thickness. And it looks so much better!

Cheers!

-- Dave; Lansing, Kansas

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reedwood

882 posts in 1329 days


#11 posted 05-18-2013 12:32 PM

Hey Buzz, nice name.

I’m finally building my own cherry kitchen cabinets too. Should be done with the final 4th clear coat today.

Here are a couple of ideas that may help, based on my experience with this project:

I built my base cabinets out of pre finished clear maple plywood – 59.00 ea. 1/4” plywood – 39.00 This saved a lot of time finishing and sanding and it’s half the cost of cherry. And it looks fantastic.

Either make the exposed end panel out of cherry or build in a matching door panel, which I did. The money saved will pay for the upgraded cherry raised end panels. The scrap maple ply worked great for the 4” base boxes and 3 – 2” screw rails, all attached with pocket screws.

I use pocket screws for the face frames and carcass. They’re great time savers and very strong.

Upper cabinets were made of hand selected AB cherry plywood, not the most expensive grain cut.
I also have seeded glass doors and cherry bead board backs.

I always avoid using screws inside when installing upper cabinets. Design a 1 1/4” screw rail outside – top and bottom.

I made a jig for the 1” spaced 5 mm shelf holes – stop 8” from the top and bottom for a custom look.

I added a removable panel to recess the under counter puck lights in to and hide the wires. There are puck lights inside the uppers as well – switched by touching the exposed door hinge, low medium, high.

I installed 3 toe kick drawers! very cool. I added Formica to the bottom of the tray sheet base cabinet.

I used biscuits for the face frames – don’t nail them! Avoid any face nailing if possible.

Accuride makes a self closing BB side mount drawer slide that works great. Order online. Don’t buy from Big box store – too expensive!

Cherry plywood will turn dark where ever exposed to light! If you are going to store it, it would be easier to bury all the full sheets together and protect them from light and some moisture until your ready to cut to size.

I hardly ever use a plywood factory edge… it’s just a good habit. So if your going to precut anything, leave it long, the edges always get damaged.

Don’t forget your 1/4” plywood for the backs and drawer bottoms on the list. Consider bumping your drawer dimension to 5/8 or 3/4”. It will double the strength, make the hardware screws work, give meat at the bottom 1/4” dado and a larger end to nail to.

Are you going to staple/ nail these drawers? SS counter sunk screws would look cool. maybe exposed dowels? The last time I made Baltic birch drawers, I added 1/4” x 3/4” solid maple to the top to hide the end grain and then 1/4 rounded the edge 3/16”. Usually, I make all my drawers from 3/4” solid dovetailed maple.

.....see what happens after three cups of coffee? Hope this helped some, I enjoyed sharing it!
Be sure to take lots of pictures and post the project here. Good luck!

-- Mark - I prefer the tumult of liberty to the quiet of servitude.

View huff's profile

huff

2804 posts in 1938 days


#12 posted 05-18-2013 12:40 PM

Buzz,

It really shouldn’t matter if you leave your sheet goods whole or cut to size to store for awhile. It will depend on how much room you have in your shop and how you will be able to store your inventory.

If you stand your full sheets either on end or on the edge, just make sure you have them standing as straight as possible.

If you have some 1/4” sheets, then I woud sandwich them between the 3/4” sheets.

Note of caution; Be very careful if you have your full sheets stored like that. When you go to use a sheet, if it is tight to the others, it will create a suction and when you pull the top sheet towards you, you can actually start the entire stack to tip. I’ve seen guys get hurt really bad when 10 – 15 sheets of 3/4” plywood tip over and trapped them.

Also avoid storing any of your lumber directly on a concrete floor if that is what you have in your shop, flat or on edge. Concrete has a lot of moisture.

Lay down some 2×4’s or something to create a barrier between the floor and your lumber.

Good luck with your new kitchen.

-- John @ http://www.thehuffordfurnituregroup.com

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Hopdevil

182 posts in 1739 days


#13 posted 05-20-2013 11:09 AM

Thanks again to all of your help! This place is great. I have learned so much over the years. Lots of good stuff in there. I am using Blum Full Extension drawer slides and the doors will be european style with full overlay. I will use pocket screws and biscuits where it makes sense to keep things hidden. I plan on making the drawers with the 1/2 inch Baltic Birch. (We only plan on being in this house for a few more years and I’d rather take my learning’s and apply it to another set at our next location (Wherever that may be)

-- Buzz ---- Message sent from the End of the Internet.

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Hopdevil

182 posts in 1739 days


#14 posted 05-30-2013 12:33 AM

Follow up question please.

I got a number of sheets from an industrial plywood company that services the industry and most of them are nice and flat. the 2 pieces of 1/2 inch 5×5 baltic birch plywood I got however are rather warped. (leaning side by side, one corner sticks out about 4 inches). I know once I cut them and build them into the drawers a lot of that will be straightened out, but is that normal? should they always be ‘dead flat’. Should I return them? This place has an amazing selection of plywood, the 3/4 birch finished both sides is great as is 3 of the 4 sheets of 3/4 cherry one side and pre-finished birch on the other.

thoughts?

-- Buzz ---- Message sent from the End of the Internet.

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