Plywood -- how to choose different types

[JackOfDiamonds]

I need some plywood for some shelves. I might use them plain, but I will probably coat them with a combo stain+sealant product, because they are near a sink and will get some splashes, so a little bit of water resistance would be nice.

They need to hold a lot of weight but I figure all 1/2" plywood is going to support the same weight, so how do you choose?

Home Depot has the following options, all of them basically the same price:

BCX sanded plywood
PureBond Maple Plywood
Radiata Pine Plywood
PureBond Poplar Plywood
Sande (Brosnium utile) Plywood

 

[bluedog225]

For a lot of weight in a wet environment, I’d go 3/4. Others will know better, but I think the differences are mostly about appearance and less about strength. And I’d seal it with something.

 

[Rc_Guy]

For a lot of weight in a wet environment, I’d go 3/4. Others will know better, but I think the differences are mostly about appearance and less about strength. And I’d seal it with something.

I agree, 5/8” or 3/4”, I usually used 3/4” CDX, even 5/8” seems stiffer than 1/2”

CDX is moisture resistant glue in case it gets wet.

 

[mike93lx]

Purbond have veneers on them to improve cosmetics. Core quality is fine and I've used the for a couple furniture projects.

For shelving, I'd probably buy the best looking sheet of sanded pine on the rack or a piece of BC if they look ok. 3/4 as well

 

[GrayFlattop]

What is “a lot of weight”? What is the span between supports?

 

[larry_g]

Your thickness is determined by the distance the shelf has to span between standards and if it is supported along the back.

lg

 

[BillK]

How big are the shelves going to be ?

 

[JackOfDiamonds]

The shelves are going into a 36" x 18" metal rack, so they will be supported on all 4 sides. The rack itself is rated for 800lb per shelf supposedly. It was the strongest rack I could find. It actually came with 3/8 particle board for the shelves, which I might use for garage sale signs because that's all it's good for, especially if it might get wet. The plywood is to replace the particleboard, and I think 1/2 supported on all 4 sides will be plenty to hold whatever the rack is capable of holding.

 

[alex2929]

I think for “normal” plywood menards has…
Ccx - fuggin junk/not suitable for fjrewood
Bcx - one side sanded
Acx - both sides sanded

If you want or need both sides to look nice, I would get acx…..otherwise bcc is usually pretty decent. Don’t take ccx even if it’s free.

 

[theoldwizard1]

The first 2 letters in a softwood plywood rate each side.

A - Sanded, no knots
B - Sanded, small tight knots
C - Large knots are cut out and pluged
D - Voids, cracks, knots acceptable

The 3rd letter is the glue rating. X = exterior

Inner layers are typicallly D, with knots and voids

"Cabinet/furniture" grade has more,, thinner layers and the inner layers have no voids or knots. $$$

If plywood gets wet, even just sometimes, it will delaminate or warp. Any "sealant" needs to be oil based. Multiple coats. Add boiled linseed oil.

 

[mike93lx]

I think for “normal” plywood menards has…
Ccx - fuggin junk/not suitable for fjrewood
Bcx - one side sanded
Acx - both sides sanded

If you want or need both sides to look nice, I would get acx…..otherwise bcc is usually pretty decent. Don’t take ccx even if it’s free.

The a b and c refer to the quality of each side. Cc is both sides at c grade, BC is one side B and one side C.

 

[cgrutt]

If you have a good lumber yard nearby you might be able to pick up some cabinet grade Baltic birch. It generally has more plys (i believe 1/2" is 9-ply) with fewer voids and is flatter than anything you will get at a big box store. Fewer voids means you can sand the edges and leave them exposed. I'd seal or paint anything that will be exposed to water, including edges. You may also want to laminate the wear surface with Formica (or similar) if it will be used aggressively. Baltic birch is usually available in either standard 4x8 sheets or 5x5. I think the 5x5 uses a different glue that is more suitable for sophisticated milling (cnc, laser, etc) but I've used it for kitchen drawers and it works fine. Usually more expensive than the big box stores but much better plywood.

ETA forgot to mention face and back veneers are also much thicker than the stuff found in the big box stores so sands better and has better wear surface.

 

[Hank11]

Look for some MDO plywood. It is typically used for outdoor signs and concrete forms. The resin coated paper faces are tough and smooth. It is more expensive, but a much nicer product for many uses.

 

[Rc_Guy]

I think for “normal” plywood menards has…
Ccx - fuggin junk/not suitable for fjrewood
Bcx - one side sanded
Acx - both sides sanded

If you want or need both sides to look nice, I would get acx…..otherwise bcc is usually pretty decent. Don’t take ccx even if it’s free.

I have never seen ccx, used plenty of cdx for shelves though, the “C” side looks good enough for shelves. Even my workbench in my old shop was CDX, 2-4X8 sheets cut into 2X8 sheets and double layered for a 16’ long work bench. We sold the house 9 years ago and know the owners of it now, bench still looks great, just like I left it.

 

[Stuart in MN]

This is for utility shelves in the garage? I'd use 3/4" CDX.

 

[Norcal]

This is for utility shelves in the garage? I'd use 3/4" CDX.

if the OP is going to apply a finish on them, CDX is a bit rough, I bought a bunch of microfiche viewers (9, took 3 trips to transport them), most were made of particle board with a dark walnut plastic laminate like Formica®, on them, took them apart taking care to remove all fasteners, ripped them all 24" wide & built shelving with them, and have served well since.

 

[NUTTSGT]

This is for utility shelves in the garage? I'd use 3/4" CDX.

Where is this going would be the first information I would use to answer the question.

House, kitchen ?
Garage, utility sink or shop bathroom ?
Basement utility room or laundry room ?

What is for sale locally ? Price ? Availability or how does the in stock stuff look ?

While a sheet of 3/4" BCX might work but you don't need the whole sheet and can get a discount on a damaged sheet of 3/4" oak plywood for a few dollars more, I know what I would choose depending where it's going.

 

[Jayman17]

You can also stiffen the shelf by adding a hardwood edging across the front edge.

 

[Bert_]

1/2 CDX is probably fine. If you use 3 ply make sure the top and bottom ply runs the short direction since it will be supported everywhere.