Finish then assemble or vice versa??

[Bill Rogers]

I am ready to finish a cherry Craftsman Style Coffe Table with BLO and Pratt & Lambert No. 38 varnish.
My question is should I assemble 3 of the 4 main components (the bottom shelf, the long top rails and the leg assemblies) and then finish them all together? Would the varnish end up acting like an adhesive and prevent the bottom shelf expanding and contracting?
It seems like it would be easier to finish all of the pieces and then assemble them but how do I keep the BLO and P&L 38 off of the tenons and out of the mortises and dados? Would masking tape be adequate?
The link below will take you to an American Woodworker magazine and the table can be seen on pages 40 and 41.

Bill

http://books.google.com/books?id=kfYDAAAAMBAJ&pg=PA40#v=onepage&q&f=false

[glenn bradley]

I do a bit of both. The driving reason for me is ease. Some areas of a piece can be awkward to get to once assembled. Also, large flat areas are easier for me to finish if they are laid flat and I can use long continuous movements. Pre-finished or not there is generally some finishing left to do after assembly but the tough parts are already handled. JMHO.

I don't know about the value of the idea that the varnish will act like Tupperware to help with movement. Maybe one of our finishing guru's will chime in on that one.

[David Thompson 27577]

Would the varnish end up acting like an adhesive and prevent the bottom shelf expanding and contracting?

...........how do I keep the BLO and P&L 38 off of the tenons and out of the mortises and dados? Would masking tape be adequate?



Any finish that will look good, will not absolutely prevent wood movement. It might slow it sown a bit. But it can't be stopped.

Yes, tape will keep finish off of the glue surfaces -- go to a paint store (one that sells paint and not much else) and get some "Frog Tape". It is MUCH better than other tapes at preventing the finish from creeping under the edges of the tape.

(I have no affiliation with the makers/sellers of Frog Tape)

[Joe Chritz]

I pre-finish everything possible. Only because it is generally much easier to get a good finish on smaller individual assemblies.

Joe

[Michael MacDonald]

not that you have this situation, but I have heard that frame-and-panel assemblies should be finished before assembly. That way, there is less risk of an unfinished line showing (from where the panel joins with the frame) if the wood shrinks...

otherwise, I have always finished after assembly... takes some foresight to do it before.

[Jerry Olexa]

I generally pre finish....Always on raised panel construction...Easier and safer...

[Thomas Pender]

Certainly with panels, and rails and styles, plus try whatever you can as well. Somehow I always have one bit of glue (or more) that escapes me when I am cleaning out squeeze out. But, if it is finished first it is a lot easier to deal with. BTW - I have even gotten into the habit of fuming pieces before glueup and also stain half blind dovetail fronts before assembling them with glue.

[Brent Ring]

I do a bit of both. The driving reason for me is ease. Some areas of a piece can be awkward to get to once assembled. Also, large flat areas are easier for me to finish if they are laid flat and I can use long continuous movements. Pre-finished or not there is generally some finishing left to do after assembly but the tough parts are already handled. JMHO.

I don't know about the value of the idea that the varnish will act like Tupperware to help with movement. Maybe one of our finishing guru's will chime in on that one.

I am with Glenn, doing a bit of both. Sometimes I pre-finish part of the way, assemble, wipe the glue off nice and easy, and then complete my finishing schedule.

I did not prefinish during some of my earlier learning projects, and erractic stain and finish performance taught me that prefinishing, at least partially, makes a big difference. I will be posting some pics of a dining room set soon and you can judge for yourself. The LOML is pleased, thus I am pleased.:)

[Steve Schoene]

With panels there can be a case, but with rails and stiles. I can't see how that can be done unless you are willing to accept the small differences in level that would be inevitable after the glue up. In my opinion you almost always need to sand or plane the intersections of stiles and rails to bring them precisely to level. But prefinishing prevents that.

[Joe Chritz]

I do a fair amount of 5 piece doors and they all go through the drum sander so they can't be pre-finished. I do stain the profile of the panels before assembly to make sure there is no witness line but finish goes on after they are sanded.

I haven't ever seen an issue with lines showing up on flat panels that are glued in place. Lately I have been doing more solid wood flat panels and those are treated just like raised panels.

Joe