When Do I Finish a Project Prior to Assembly?

by Dale on March 24, 2014

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When do I finish a project prior to assembly?

Never, and here is why. For me, it’s simple to glue first. Then I move on to finish, sand and then complete the piece – instead of multi-focusing on many individual parts and pieces. Especially since I usually spray lacquer on everything. Trying to spray each small part (after taping glue surfaces) and keeping them from being blown off the bench or horses, waiting for the individual pieces to dry and then turning them over and repeating the entire process is tedious and ultimately an unnecessary process.

For example, if you want three coats it is unfortunately necessary, for the sake of wasted time and effort, to spray and dry at least six times for each part, and sand between coats. Keeping track of all the parts and which surface has how many coats at any given time and you may have more than a dozen separate parts- then, when you have them all done- you must remove all the tape which covers the glue- not particularly a fun task. When the time comes to glue the final project together, you have to be precisely aware of the clamping process. You must protect not only the surface, but also the finish from the clamps.

If you do get a small dent from the clamps- it’s a quick fix when the wood is unfinished with sand paper or even possible to steam away a major deep dent. Attempting to remove a dent on finished wood is quite a complex and possibly unnecessary task, often resulting in ruined finish which will require you to touch up the finish where the dent was. A banal task which leads to even more time lost.

Gluing prior to finishing eliminates a plethora of potential problems, stress, and headaches. The only part of the process which could possibly justify the method of “finishing first” – “gluing last” would be the ease of cleaning up the glue, as it pops right off finished wood and there could be small chance of a light spot left by dried glue.

In my method I begin the process of gluing the unfinished wood by washing off the glue with water or the right solvent for the glue type- (alcohol for epoxy). After it all dries and cures, I sand the glue joints. If the piece gets stained, I keep a sharp wide chisel and sand paper handy during the entire staining process, so if I find a light spot I can scrape it away with the chisel, sand, and then go over the spot again with the stain. This method works well, even with dye stain, if you work fast. The process is the same, without stain on the first coat of lacquer or sanding sealer but I just let it dry first and spot spray the first coat where the light spot is, after sanding. The next coat blends it all in.  By the 3rd coat the flaw has been erased to a memory- total invisible. (I would do the same, no matter what finish I used – wipe on/off or surface coating like shellac or lacquer.)

So, the next time you are tempted to try “pre finishing” a project like some articles have suggested- and if time doesn’t mean as much to you as it does to me- please, be my guess and try it! However, I prefer the faster, more efficient system I have detailed to you here. Let me know your thoughts, ideas and concerns as I am always looking for ways to effectively create a piece of true quality, while getting the most quality for time spent.

 

{ 4 comments… read them below or add one }

Paul Anwiler April 27, 2014 at 11:02 am

Hi Dale, I have often thought about finishing a project before assembly, and a couple years ago when building a king size bed I finished the panels before glue-up. I was worried about the panels shrinking and then leaving a non-finished non stained line along one or multiple edges. I did only the panels stained and one coat of finish. Then put everything together and still finished the entire piece with multiple coats. It came out beautiful but did take longer. Whats your thoughts on shrinkage in panels. This was quarter sawn white oak 1/2 inch thick panels, and i know it will not shrink much. Take Care look forward to seeing you this summer Paul

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Dale May 2, 2014 at 11:53 am

Hi Paul, I used to prefinish all my panels exactly like you described, but the extra time involved was a real concern. So I quit doing it and decided that the repair on the few panels that required it took lots less time than prefinishing every panel I made. But you are right, it is better to prefinish, when time is not a concern. Thanks, I hadn’t thought about that when I wrote the blog.

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Nick May 10, 2014 at 1:11 pm

I have never pre-finished a job… Even on the custom furniture… I would think this would be harder unless of coarse your using an oil base stain …. But I use an LS1.1000ws lacquer base stain … And a sealer and top coat 2x each … I also think that 6 coats of anything is entirely way to much … You will take it from a fine piece of furniture or what ever it is , to a plastic looking coating on it … Even if it is 6 x 3-5 mil finish per coat

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Dale May 13, 2014 at 12:01 pm

Hi Nick, Thanks for commenting. By six coats I meant 3 on each side, letting it dry before turning it over, referring the time involved. If you were using a wiping varnish six coats would not be too many since the coats are so thin. Also in boats they use up to 12 coats and in fact it does look like plastic, but will hold up to the elements.

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