Masking & finishing before gluing

[Mindy]

I've come across several articles lately that include a technique I don't understand. When making a piece that has to be glued together, like intarsia or something with a decoration on it, the instructions will say to mask off the glue area, finish the pieces separately and let dry, and then glue them together.

I know that we mask the glue area because glue doesn't stick well to finish--that isn't the question.

What I'm wondering is, why not simply glue everything together first, and then finish it? The masking adds a degree of difficulty and effort that seems unnecessary to me, but I know the artists wouldn't be doing it without a good reason. So, what's the reason? They're using the same finish on both pieces, and detailing the finish out of the crevises on both pieces...what's the advantage of doing them separately and then gluing them?

Thanks!
Mindy

[Mick Walker]

Mindy, if you glue before finishing any glue that is squeezed out and then you try to remove it by wiping it off will most likely affect the wood and the finish will not look the same wherever the glue is.

[Mindy]

Ah hah, that makes sense. Thanks, Mick!

[lucky788scroller]

Hi Mindy,
Mick there hit the nail on the head for ya (hes from Wisconsin too, of course he is smart! ) One other reason one might do that is for sanding the finish. It is so much easier to sand the coats of finish on flat parts as opposed to a fully assembled project, like the big clocks for example.Its hard to sand into all those tight corners, but needs to be done to have a nice smooth finish.

[handibunny]

Mindy,

Sometimes you can compromise by applying just a sealer coat of shellac that will protect against squeeze-out, but still allow you to do the final finishing after assembly. I do that with my ring boxes, which are easier to finish once assembled, where the shellac allows for clean-up of any of the epoxy I use for the hinges. I usually put in too much, and it oozes out a bit.

Also, you can spot-sand any places where you need to attach something after the piece is finished, like the decorative ornaments on my "furniture boxes". It's a matter of applying the principles selectively to get the effect that you want with the least amount of trouble.

[Ron Standley]

I started doing this because of mentioned glue squeeze out, and I was never able to keep the finish from puddling up in 90 degree corners. Of course I am new at this which may account for some of my problems.

[Mindy]

Thanks for the additional tips and explanations--this makes perfect sense now.

Thank you!
~Mindy