Finish for new workshop walls

[Ken Flesher]

I'm in the last phases of building my new 20' x 24' shop space, not sure what to do about the interior finish. Walls are 2x4 framing, insulated with mineral wool, and the inside is sanded "plytanium" plywood from Lowes, screwed on so I can remove in case I want to change some wiring later. I just finished hanging the last sheet yesterday. Ceiling is also insulated with mineral wool, and the bottom layer is foil-faced polyiso rigid foam, which I will leave as-is.

I originally was planning to just paint the plywood, but now I'd prefer to keep the woodgrain appearance, since it is a woodworking domain. But I don't want to let it just sit bare, would like some sort of finish to protect it. I'm considering using water-based acrylic poly (Minwax or Varathane), since it's easy to apply and dries clear. I do have heat in there now, but I'm concerned about ventilation, it's too cold to open the windows. Would rather avoid oil-based poly. I would give it a quick pass with some 120-grit on a ROS to remove the grade stamps and random pencil marks.

Is there a better choice? What have others done, besides traditional paint?

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[Jim Becker]

The waterborne product is just fine and you don't need to make special ventilation arrangements for it as you wouldn't for waterborne paint, either. If you are going to spray, you absolutely should wear a respirator to insure you don't inhale any particulates, but if you are hand applying, you'll be fine. If you want a warmer color, choose something like the Minwax Oil Modified product or put a drop or two of amber transtint in the regular Minwax or Varathane waterborne product.

Looks like you're going to have a very nice space! Congrats on that.

[Jamie Buxton]

My bet is that if you put waterborne on that plywood, the surface will be too rough to tolerate, so you’ll want to skip -sand it.

[Ken Flesher]

My bet is that if you put waterborne on that plywood, the surface will be too rock gh to tolerate, so you’ll want to skip -sand it.

I'm confused by your reply... Are you saying I should skip sanding it? Not sure how that will make any difference? I'm only planning to remove the grading stamps and other minor marks.

I've used polycrylic on a couple of projects now and didn't think it made the surface unusually "hard".

I also assume it will noisy with all the hard surfaces, one of my first projects will be to make and hang some sound panels to knock it down.

[Jamie Buxton]

I'm confused by your reply... Are you saying I should skip sanding it? Not sure how that will make any difference? I'm only planning to remove the grading stamps and other minor marks.

I've used polycrylic on a couple of projects now and didn't think it made the surface unusually "hard".

I also assume it will noisy with all the hard surfaces, one of my first projects will be to make and hang some sound panels to knock it down.

Sorry.. autocorrect. I'm saying that when I put waterborne finish on plywood -- even well-sanded plywood -- the resulting surface is considerably rougher than the unfinished plywood. I plan on applying a couple of waterborne coats as a sealer coat, then sanding lightly to knock down the nubs, then applying one more coat of finish.

If your sound panels are just to save your ears, you can do that for considerably less with good headphones, or even earplugs.

[Ken Flesher]

Oh, now that makes perfect sense, thank you. I hadn't thought about it, but yes I'm sure the water base will raise the grain. Maybe I'll try some on a piece of scrap to see how bad it is, I was only going to do 2 coats, not crazy about sanding twice though. Good catch, thanks.

[Lloyd McKinlay]

Another possibility is using shellac or even Zinsser Seal Coat. Fast drying, shouldn't raise the grain and the denatured alcohol odor dissipates quickly.

[Bill Dufour]

Wipe the walls down with a water damp rag or paint roller to raise the grain before sanding. Then when the water based finish is applied it will not raise the grain as much.
Bill D

[Bill Howatt]

I think I would consider doing the ceiling white to enhance lighting.

[Ken Flesher]

Thanks for all your replies.

I had some Polycrylic and Shellac on the shelf, so I did a test on a scrap of the plywood. The water-based poly didn't raise the grain as much as I expected, it was a little rougher than the shellac but not that bad, not objectionable. The biggest issue with the shellac is the strong fumes from the alcohol base. I might consider it if this was summer and I could open all the windows & doors and run a couple of fans, but it's just too cold to consider that. I like the idea of pre-wetting the walls prior to sanding, so I'll do that and go with the poly.

Now I'm trying to find the best way to apply. I'm thinking brushing all those walls will take a long time, but rolling is not recommended. I'm wondering about put it on with a roller than quickly back-brushing to get rid of any bubbles? I also have an HVLP gun with a latex paint kit for it, I might give that a try.

The ceiling is already pretty reflective, clean and shiny foil on the rigid foam, and all the joints are taped. I'm actually worried it will be TOO bright.

All the hard surfaces are making it very echo-y in there, lots of noise reflections. I do have a pair of Bluetooth headphones.

[Carl Beckett]

I had shiplap siding on the inside walls of my last shop. Bare wood.

I never did finish them and it gave a nice patina over time as well as the woodworking ambience as you say.

[Jim Becker]

Ken, you can buy a really nice airless from Harbor Freight for about $200, use it to paint your shop very efficiently and then resell it on the Marketplace for nearly what you paid for it. That's how I handled my shop walls. It's the right tool for the job, too.

[Tom M King]

Whatever you put on, it will be a better finish is you sand after the first coat and make it easier to clean any kind of way in the future. It's not as bad as it might seem. You don't have to spend a lot of time like a piece of furniture. Any part just needs one pass with a ROS.

[Ken Flesher]

Ken, you can buy a really nice airless from Harbor Freight for about $200, use it to paint your shop very efficiently and then resell it on the Marketplace for nearly what you paid for it. That's how I handled my shop walls. It's the right tool for the job, too.

Do you mean this one?

https://www.harborfreight.com/airles...yer-57042.html

Looks like there's a 20% coupon out now, which would bring it to $200. Hmmm...

Wonder if this could be used to spray cabinets?

I used one of these types of sprayers years ago, and I was not happy with the amount of paint that got lost in the hose during cleaning. Maybe the newer ones can back drain the hose now? Paint and finishes are too expensive now to waste it, the poly was $70 a gallon!

[Jim Becker]

Yes, that's exactly the unit I purchased and used for my shop walls. It worked flawlessly. I personally would not use a big unit like this for spraying projects like cabinets because it consumes a lot of finish for just to fill up the hoses. I'd invest in a Graco QuickShot for that (about $1200) which Jason Bent has proven it to work not just for paints, but also for clears. The HFT unit is a "whole can" type sprayer (both gallon and 5 gallon...I used the latter for my shop walls and paint)