Thoughts on finishing plywood

Maker Talk
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Hi all!

If you’ve been near the laser room in the past week, you’ve probably seen me cutting out these shutters/privacy screens for the windows in my house-

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Here are the windows in question:

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I’m going to be glueing two of these panels together for each window, giving me a 1/4” panel, and plan on running a grooved frame around the outside edge. I want to finish them to match my cabinets, which are a super dark brown/black color.

What are your favorite stains/finishes to use on plywood in these situations? The one caveat is that the final coat needs to be spray-able, as the detail in these panels doesn’t allow me to sand the char (and therefore burnt smell) away. Because of this, I need to use a spray capable of “sealing” the burnt internal edges.

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I… do not have any relevant advice. Just here to say that those are GORGEOUS and you are going to cause me to undertake a project for sure. :slight_smile:

Spraying is also difficult - to get deep into all those internal corners, you have to spray from all directions. Maybe a low pressure spray gun, with a nozzle to make a fine mist that can just fog up in the cutouts?

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I love the Mudéjar details. Did you generate those yourself?

I used a similar inspiration for a project in my Design class last semester.

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We’ve been using a few coats of Minwax warm satin fast-drying polyurethane from rattle cans to seal the burned edges of laser cuts and tend to spray from all 4 directions to hit all the edges

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Thanks for the suggestion!

@aneel this is a few purchased designs I slapped together to fit the dimensions I needed.

I lived in Jaipur for a while, where this type of window was “common”, but wanted a bit more variation in design than the ones there.

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Spraying is definitely the way to go.

Something with UV protection would be good especially if these will get constant sunlight. Windows may block some of this, but hard to say unless you know the properties of the windows.

In this application, Lacquer will peel overtime, within a year of Texas sunlight.

A 3-4 coats of good polyurethane can work, and if you really want to have something durable in sunlight consider spar urethane.

Spray would be the way to go for application. Nice even strokes from one side to the other, with each coat change your starting edge.

You’ll need a few cans of spray at least for good coverage. With poly, make sure to follow the timing instructions. If you wait too long for additional coats you’ll have to do some light fine grit (like 400-600) hand sanding to allow follow on coats to bond properly

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Current plan of attack is:

  1. Sand everything super lightly (mostly to reduce flash on the rear side of the cuts)
  2. Glue together using roll on contact cement (I was going to buy some of the 3m spray for this but found a bunch of weldwood in my toolbox)
  3. Spray stain seal/pre-stain (reduces blotchiness)
  4. Spray stain
  5. Stain walnut edge banding
  6. Glue edge banding on
  7. Spray 4 coats (starting on a different edge each time to try and hit the most of the interior cut area) of satin water based poly finish.

If anyone sees any glaring issues here please lemme know!

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Looks like a pretty solid plan to me!

If there’s any uncertainty on how those steps will turn out and if you’ve got time, you can run those steps on a test piece.

Otherwise seems pretty well thought out.

On 7, don’t forget to read the timing instructions just to be certain and plan that day out.

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I’m wondering if using some of the brown paper from a paper bag might be enough grit as a sandpaper alternative for you.

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It’s less about how to sand in those areas (I’d probably go with a dremel and flap wheel) and more that I do not want to spend 4 months sanding lol.

For surface prep this plywood will hold up fine to 240grit paper.

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A water based poly will raise the grain. Left unsanded it results in a rough finish IMO.

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yeah, exactly. the first spray will harden with grain and fibers sticking up for a rough surface. i spray poly once, let it harden, knock it down with 320 grit, and spray again to get it smooth. a used 320 sponge is probably about the equivalent of a paper towel or bag.

i can bring a sample to the next laser sig.

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Being that they’ll be in the windows up high, would that matter greatly?

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it depends on who has to dust them, right?

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What is this thing you call dusting? :wink:

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