0

TL;DR: How can I prep a round piece of 12mm plywood 30cm in diameter, so that I can apply wall paint to it and it will look as close to a wall as possible?

Why: I'm making a light fixture. The idea is to get an indirect light by taking a ~20cm diameter 20mm thick central post and put LED strips on the outer edge so that they shine along the wall. Then, I would place the aforementioned 30cm diameter plywood (with chamfered edges) on top of it to achieve a sort-of glowing effect around the fixture.

To achieve a sleek and most invisible effect (in particular when the light is off), I would like it to have as much of a wall-like look as possible. How can I do that with plywood? (Or would another material make a better job? The natural material for wall-like look is drywall/plasterboard, but I don't think I would ever get a precise enough cut to get a neat look, and also fixing that to anything is somewhat trickier.)

Improve this question
5
  • 2
    Sand it smooth and clean. That should do the prep. To match the paint, it might be easier to paint the wall and plywood together, unless the wall paint is very new. Same exact paint, old and new will not match exactly, difference between new and shinely and old and faded.
    – crip659
    Commented Apr 15 at 16:55
  • @crip659 The room has been painted about a year ago and I can't repaint, but that means that even if the new stands out now, new paint shall faint quickly enough that it will become very closely matching pretty soon.
    – yo'
    Commented Apr 15 at 16:57
  • 1
    Make sure to prime both sides of the plywood first or else the moisture in the paint might cause it to curl a bit and not lay flat.
    – Milwrdfan
    Commented Apr 15 at 20:47
  • @Milwrdfan You mean priming with an epoxy-based penetration primer like the one you'd use on the wall itself? Or is something else recommended for the wood?
    – yo'
    Commented Apr 15 at 20:48
  • You could cover the wood in paper, perhaps kraft paper has a texture similar to that used in drywall. Then prime and paint as the surrounding wall. But since the wood will be standing a few cm proud of the wall, not actually blending into it, I don't think this is necessary. It doesn't have to be invisible, it can't be invisible, so just do something nice.
    – jay613
    Commented Apr 15 at 23:46

2 Answers 2

Reset to default
1

Probably doesn't matter too much what the specific primer is. You'll just want something that prevents the wall paint from soaking into the plywood and causing it to warp. I might suggest actually looking at something like MDF which will have a much smoother surface, and for your application, might work better than plywood since it's not going to have any potential internal voids, and is easy to work with.

Improve this answer
2

Plywood isn't the best stuff to use to get that "as much like a wall as possible" smooth look. It will be very hard to make the plies disappear behind the paint: the plies will telegraph through even after sanding, filling, and painting, and always be seen.

A better panel would be MDF, especially if you can get double-refined MDF. It has no plies and looks homogenous after a couple or three coats of primer with decent sanding between.

Prime the edge, let dry, sand with 150 grit. Prime again, sand with 150 grit again. Prime the edge a third time along with the rest of the surface, sand with 220 grit. Then paint.

(Please note the grits may need adjustment; a test run or two may be useful before doing the final piece. I'm no finish wizard: a question on painting MDF might be good on Wood.SE)

Improve this answer
2
  • Yep, I know, but it turned out OK - painting with a roller covers a lot of imperfections :) (I would share the final photos if there was a straightforward way of adding photos to comments...)
    – yo'
    Commented May 22 at 11:14
  • I'm glad you got a good final product! You can edit your question to add an update, then post the final picture of your project. It would be interesting to see what you did!
    – Triplefault
    Commented May 22 at 12:15

Not the answer you're looking for? Browse other questions tagged or ask your own question.