Finish before assembly?

[nautilus]

Hi all!

I'm building a wooden trunk. I added some details, and it has some mouldings, beads, grooves, etc.. I'm almost ready to glue the whole thing up, and I'm wondering what to do with finish. In some other projects, I always end up by having to deal with shellac on akward areas, with complicated access for the brush, etc, and many times, that result in a poor finish.

I'm thinking in just putting the shellac to every single piece, BEFORE assembly, which would be much easier. Then maybe just give one general touch to the whole trunk once assembled, to fill the hairline gaps.

Is that a good idea? Or I'm going to screw up the project? :(

Thanks for any suggestion! Nautilus

[George]

As a turner who applies shellac with a rag on one of the most difficult forms out there, a bowl, I say finish afterward. Be sure to sand, set with water, sand before assembly while things are more accessible. The shellac will stand up whiskers too, so be prepared for one final knockdown after assembly. Then use a mock French polish technique, adding hundreds of thin coats quickly with a rag made slick by a drop or two of oil so it won't drag and stick.

[Andy]

Should be fine. With many finishes, you want to be especially careful to leave the glue surfaces bare (i.e. mask off your joinery). However, I *think* I remember hearing that wood glue sticks fine to dewaxed shellac. If you do try to stay away from glue surfaces just to be safe, it should be no problem to pre-finish your pieces. I've done both (pre- and post-finishing), and the best method depends a lot on the particular project and your preferences. If you finish before assembly, it will probably come out more evenly, and you won't have thick or rough or thin spots on inside corners. However, you then have to worry about any bumps, scratches, dents, etc. while you're clamping and gluing up your project, as you can't just sand them out later. I would think shellac wouldn't be too bad, as you don't have to sand between coats - that was a hassle for me while varnishing the rocking chair I just finished - couldn't reach the inside corners with steel wool while roughing between coats, or rubbing/waxing at the end. Not too noticeable overall, but if you look closely there are some pretty rough spots. Good luck, Andy

[DJ Delorie]

What I do is apply a sealer coat after I've cut all the "showing" faces, but before I cut the "assembly" faces. I.e. I do all the beading and stuff, apply the finish (taping over any surface that will contact other pieces of wood), then cut mortises and tenons. The sealer coat, for me, is ONLY to prevent glue from messing up the final finish.

[James "Cubby" Culbertson]

I finish before assembly a fair amount. A lot of it depends on the piece but I just finished a cradle and decided not to finish before assembly. I sure wished I had! I typically get to about 1-2 coats away from a final finish on the parts then glue together. Then do the 1-2 coats final finish once the glue is cured. Be sure to tape off any joints or areas you want glue to stick. You shouldn't screw up the project as long as you keep finish where it's supposed to be. I typically brush or pad so this advice may not make sense if you are spraying. Cheers, cc