This is very much product-dependent. Most of the time, I try to do as much assembly as I can before I pull out a finish. This lets me sand off any glue squeeze-out and sand flush any joints or surfaces that should be smooth, in case something got off during assembly. For example, where a rail and stile come together to create a door frame, those joints can sometimes be just a tiny bit off after assembly. So I’ll handplane or sand those joints smooth after assembly but before finishing. In this situation, the end result looks much better if you assemble, sand, then finish.
However, there are situations where I do pre-finish the parts before glue-up. Take a frame and panel door, for example, where the panel is going to be installed into a dado or groove inside the frame. The panel expands and contracts with changes in humidity. If it’s finished on a humid day after assembly, then the panel shrinks on a less humid day; bare wood will be exposed and look bad. So I always prefinish the panel, assemble it inside the frame, then mask off the panel to finish the frame. That order of operations gives me the best results.
Another place where I pre-finish before assembly is areas that will be hard to get to after glue-up, such as a cabinet with a lot of small cubbies that would be hard to reach inside afterward. I’ll prefinish at least all the inside faces I won’t be able to get to once it’s assembled, then finish the outside of the case after assembly. This way, I can sand off any clamp scuff marks before the finish goes on.
Another situation where I’ll finish before glue-up is drawers. Yes, I can reach inside a drawer easily enough to finish it, but I often spray my finish, and when spraying inside a drawer, there’s no place for the overspray and air pressure to go except back at me. That creates a dangerous situation, with overspray getting blown back at you. It also creates a less desirable finish inside the drawer box, since the finish doesn’t lay down smoothly with all that back pressure from the air.
So I take my order of operations for assembly and finishing on a case-by-case basis, depending on what the project calls for.
I’m the owner of Benham Design Concepts, a mixed media art studio where I design and build custom furniture and other works of art using wood, glass, stone, and various metals.
In this blog, I talk about the art I create, my journey, and the things I learn along the way.