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I am building a loft bed, the post (4x4) will have a notch/lap joint at one end which will have a beam sitting in it. Wood will be pine or white wood. The furniture will be painted white (semi-gloss). I can't figure out the best path forward for painting the lap joint, I think I can:

  1. Paint the beam and post all over then attach the two. This will have two painted surfaces touching anywhere there is contact. On the plus side there will be no exposed bare wood anywhere, on the negative I somehow have to account for the thickness of the paint in cutting the lap or have it not quite smooth across the joint.
  2. paint the beam and post but do my best to not paint the area the beam and post meet. I worry that with this method the "sloop" in the connection between the two (carriage bolt) will make it so it would be pretty hard to be perfectly lined up so some bare wood would be exposed.
  3. Put it all together then paint. Not ideal as I have to paint it in place and if it is ever moved I am back to number 2's issue (or if it shifts a little over time).

I am leaning towards #1, is there a way to account for the thickness of the paint in cutting the lap? Maybe it'll be insignificant, given I am a beginner and the lap will be far from perfect anyways. I am open to other ideas too.

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  • Think a bad lap cut would show more than a bad paint job. Measuring to account for the paint will require testing(painting scrape and measuring)or very good guessing. The only way a beginner gets good is by practice on waste wood, then can do the real job. Paint should not throw off the measurements to much(~1/16), unless quite thick.
    – crip659
    Jul 21, 2022 at 13:22
  • You you intend to be able to take the furniture apart again at some point in the future?
    – brhans
    Jul 21, 2022 at 13:45
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    The woodworking.stackexchange.com site can probably give you better ideas. They are more into joints/painting.
    – crip659
    Jul 21, 2022 at 13:45
  • Remember lumber is rarely perfect, my dad always said it’s not a piano (when it came to frame work like this).
    – Ed Beal
    Jul 21, 2022 at 20:23

1 Answer 1

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I would definitely recommend perusing Woodworking.se for finishing ideas. In the meantime...


I'd go with option #3.

Of course, you'll have to make several test joints to ensure your lap joint is going to line up with the precision you're after. Attempting to then adjust that for the thickness of two layers of paint will be neigh on impossible. Additionally, over time, the two painted surfaces will stick together. When you go to disassemble the bed, you'll rip paint off, not only from inside the lap (meaning your joint won't line up correctly when you reassemble), but it'll probably take visible paint with it (requiring a touch up when you reassemble).

By painting after assembly, you'll end up making your joint nearly invisible. When it comes time to disassemble, you take a sharp utility knife and cut the paint along all the lap joints. This will give you a nice clean and sharp break in the paint at the joint. Remove the bolts and with a few blows with a rubber mallet, you should have the joints apart without any noticeable paint damage. You're now looking at what would have been the result of option #2.


You could, of course, go with option #2. If your lap joints are nice and tight, the wood will hold itself together without the bolts. You would NOT want to leave it this way when someone crawls into bed, but it should stand on its own before being bolted together.

Painting it in this state would require careful masking and/or a very steady hand when painting around the joints. If you do get paint into the joint, wipe it off immediately. You'll likely end up leaving a ghost of color in the joint and that should be OK. You just don't want a layer of paint in the joint.

If there's enough slop in the joint that you're seeing bare wood exposed after painting this way, then you should really consider remaking the joint. Your wood will be bolted together, but the fit & finish won't really be all that great and you'll probably end up with the bed frame wiggling every time someone leans on it, climbs into it, rolls over in their sleep, whatever. Eventually all that movement will wear the wood joint and the bolt holes, potentially leading to enough slop that it could collapse.

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  • I will note that making nice looking, tight half-lap joints is a skill that takes time to develop. My first foray, plowing out the laps with a router (they were at angles across 2x4s) and a template did not leave me with good looking joints. Fortunately, it was a piece of shop furniture and I knew it probably wouldn't look good. It was bad enough and time consuming enough that I adjusted my construction design for the rest of the project to skip the half-laps!
    – FreeMan
    Jul 21, 2022 at 16:01

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