Sanding oak (or other) plywood

[Patrick Nailon]

Everyone,

I'm working on my third 'big' project, a mission style bookcase, with glass, muntin-style doors.

There are 6 pieces of oak plywood in this project, and following general practices in the past, I've sanded the same kinda plywood three times - with 80 grit, 150, and 220. I'm thinking tho, that since this is hardwood veneer plywood, the faces are pretty darn smooth already, and I'm considering just doing the 220 grit on this to finish them up.

Anyone's thought's on this?

BTW - a recent copy of 'Woodsmith' mag had a user tip for creating a sanding jig usable with a disk/belt sander (table model). This jig puts a wide plywood fence just over the flat belt sander face, at 90 degrees to the belt, allowing you to do beautifully square sanding on edges of anything. I did all the edge sanding for this project, in less than an hour. I highly recommend the jig.

[Prashun Patel]

I'd skip the 60, but I'd start at 150gt. I think it establishes an even, clean base upon which to finish sand.

[Frank Drew]

I agree with Shawn, there's no reason to use a fairly coarse grade like 80 grit on furniture grade plywood. 120 or 150, then 220 and I'd call it done; IMO oak doesn't have a grain that rewards going any finer than that.

[glen box]

I get good results just using 220 on furniture grade plywood. You have to make a few more passes, but you dont have to change paper:D.

[Tom Esh]

Hopefully your oak ply is something better than the BORG stuff. Some of that has such thin veneer it'll barely withstand 220, let alone anything coarser. In any case I usually start backwards with ply. I test an area with 220 to see how it works by itself, and drop to a lower starting grit only if it proves necessary. I also use a sheet sander or even a hand block. I find it way too easy to sand right through a thin layer with the ROS.

[Patrick Nailon]

I've only bought Orange Box oak ply to date. The first I did sand thru, but that was after the aforementioned 80/150/220 drill.

I'll post pictures on this once it's done. Should be a nice addition to our hallway (which I recently redid).

[Ron Williams]

We are currently finishing a large job with Mission style Trim all in Qtr Sawn White oak 180 will properly prep the wood for stain or your sanding sealer. We had the M.L. Campbell rep to come to the job site and help us with the proper technic

[glenn bradley]

This is a "that depends" deal. I have gotten veneer ply that I could hand sand with 150 then 220 and move forward. I have gotten ply that I have had to be very careful with 220 so as not to cut through the veneer. i will start with a finer grit on veneer than I do on solids for a given "feel" of roughness that I'm starting from.

[Howard Acheson]

Hardward veneer plywood is factory sanded to about 180 grit. Unless there is some damage or discoloration, it is not necessary to sand with a more agressive grit. And, as today's veneers are so thin, avoid any sanding with a machine. Just sand with 180 grit on a sanding pad. It's ready for finishing at that point. Apply a thinned coat of your finish and let it fully dry. Then flat sand with 320 paper on a sanding block. This is the step that really produces a surface ready for your final coats.

[Richard M. Wolfe]

I'm with Glenn....it's a "that depends" deal. It depends on what the plywood looks like to start. If it's been hanging around for a while it may have aged and discolored and take more to brighten it. Regardless, I don't start with corser than 120. My usual for plywood is to go from 120 to either 180 or 220,depending on what I think is appropriate.

[Steve Clardy]

I seldom sand cabinet grade ply.

If by chance it feels a tad rough, I'll use a block with 220 and just scrub it lightly.

[Jim Becker]

I sand plywood with 180 grit. Period. I rarely start coarser and pretty much never use 220.

[Doug Shepard]

I do 180 then 220 and NEVER use anything but a hand sanding block. The veneers are usually too thin to get anywhere near it with a power sander.

[Brian Peters]

220 is overkill, even 180, 150 is ideal for stain grade sanding. A random orbital sander works well if you are good and conscious of what you're doing, block sanding is fine but takes a while on larger surfaces. Most decent plywood whether mdf or ply core should come presanded on the face(s), you shouldn't need to go 80, 120 etc, it should be just 150 and that's it. If you really need to do 80 on veneered plywood I suggest you find a better supplier!

[John Eaton]

I'm with Jim - pretty much just use 180. If it's real porous I might spray some sanding sealer after stain then knock it back to touch. The outer skin of plywood is much too thin these days.

-- John

[Patrick Nailon]

Well, I decided, based on the range of answers, to go with one sanding at 220. The ply felt very smooth already, but I wanted to give it a "once over". I have B&D palm sander, which I used. I ended up sanding thru at one edge a little bit, but I think that was more tipping the sander.

The wood came out marvelous. I had 6 pieces to sand both sides, then drill shelf pin holes (I made my own jig for that, which worked great. I'll upload the pictures of it soon).

Thanks to all - I'll be using some of the tips in the future.

[Walt Caza]

Hi Patrick,
Just a quick tip...
to help avoid tipping the sander near edges,
butt up a scrap of the same material, or another part, no clamps or anything,
just lay it there. Now you can sand right to your edges, and onto
the same thickness scrap, without tipping.
Much less chance of tilting and sanding through the thin veneer.

Myself, I sand oak to 150-180. Any more changes the way it takes stain.
By the time I knock down the topcoat between layers, it is quite smooth.

I can often get the surface I like with a piece of worn-out 120 paper.
After it loses it's bite, I performs as a finer grit.
I get tired of reaching for yet another sheet of sandpaper.
I try to milk them for all they are worth, as my patience allows.
Good luck with your project,
Walt

[Patrick Nailon]

Excellent tips, Walt. I was trying to sand two boards next to each other, but didn't think of using scrap to avoid end burn. Luckily, I don't have any problems that can't be hid once the carcase is together. I'll keep all the suggestions in mind - especially not needing 220 grit for a good stain/finish. Always something new to try.

[Greg McCallister]

Would you all then recommend a 220 on a surface NOT stained or is 180 good enought - clear finish?

[Brian Peters]

180 is overkill on paintgrade, and the softer you make it the worse off you are because the paint won't adhere well. I've seen people polish the crap out of woodwork thinking its neccesary with a scuffable primer. For clear I wouldn't go above 150 unless its a soft wood like pine or mahogany and you are sanding something like veneered ply/mdf and you have to be more careful. 150 is fine and you don't need start with anything less, if you do then you are buying bad plywood.