Letting Lacquer Cure...Do I Really Have to Wait??

[Pete Andreev]

Hey guys I know this is a question with no definitive answer. I've heard 10-14 days, then I've also heard some say that a week should suffice. I've also heard there are some variables that can affect the time...hot summer days can speed up the process apparently?

It's been almost exactly a week since my last coat. I refinished the neck on my 335. I'm wondering if it's alright to go ahead with the sanding, buff, and polish process...what do you guys think? What exactly happens if you start the final finishing process too early?

[David Farmer]

Very sneaky. You spec a solid plastic body and they use cheep wood as filler to lower the cost.

[Ned Knepp]

I'm sure you all know I like shellac a lot. In my limited work, it's not really much of an issue what I chose to use for finish. When I use lacquer, which I'm not set up to spray in any volume, I like to do a few thin coats then sand back a bit, particularly when I have fills. You all know the drill.

 For those who may not know too much about finishing, my personal approach, when I sand, is to start very lightly so I can feel for any pulling or sticking which I take as an indication that it's not ready yet. The lacquers that I've tried all require at least two weeks before I can do more than light, between coats, sanding without sticky/pulling problems. With fills, I learned the hard way that the only way to handle them it is it fill and sand, fill and sand, etc... then wait. The larger the fill, the longer I have to wait. Trying to hurry things only makes it harder to get it right. ( It's no fun stripping the wax you worked so hard to buff on as protection. Carnauba wax is hard stuff! )  The guitar I mentioned earlier has several long crack repairs that were filled/sanded until they were level... when I put it away. Now every one of them is showing again and will need attention. Thus it goes.

I went to a private school for my highschool years. They split their day into two segments with freshmen/juniors in the morning and sophomores/seniors in the afternoon.  One started early and the other finished late. The reason for this was that it afforded the students time to work a job to help us pay for our relatively expensive education. I spent a couple of those years working for a cabinet company that was actually established in the area to give employment to many of the students.  The lacquer they/we used was heat curried in much the way Peter was talking about. It was an interesting change from the spray finishes I was already acquainted with from working with my father, who also built cabinets.

The finish went on very thick in comparison to what my father and I did. The spray rig was airless which made it VERY easy to create runs and sags on the vertical surfaces. Without the dryers, it would have been impossible to get a clean, run free finish using this material. It was fast.. but it was not as durable nor as fine a finish as could be done using many thin coats and patience. The factory finish was applied in three layers, the first was a thin coat designed to apply the color mixed with a sealer, followed immediately by a heavier coat of clear. This quickly run through a dryer to set the finish, then passed through a handing sanding and finish inspection section of the line. Once the work passed the initial inspection, the cabinet was given a thinner ( but not really thin) coat to "gloss" the finish. This lacquer was a slightly different formula which, if not sprayed too heavily would not sag or run too easily.  There was another inspection of the finish with a final trip through a dryer at the end. The finish produced was ok for a factory finish but nothing like a great finish. The truth is that most people don't really know what a really good finish looks like AND, perhaps more importantly, "quality" in a factory production setting almost always carries a different definition than "quality" in a small shop setting.  

Every finish I know of, that I can actually apply in my work setting, takes time and effort and requires a totally different skill set. I have seen quite a few hand build, well made instruments with terrible finishes.

It's just a completely different skill set that a lot of woodworkers never really develop very well.