Grand Angus Project, Part 6: Update on some issues

Well I wasn't going to make another post until the guitar was fully cured and I'd started the final sanding and finishing, which (if on schedule) would have only been about a week away. But it's not on schedule, and I wanted to post an update now as to why rather than wait until it's done and do it all retrospectively. Because I'm good like that.

When I last posted I was finishing off the clear coats of lacquer. Or so I thought. I'd done about 7 coats of clear lacquer and went to give it a good old rub down so it would be nice and smooth for the last coat or 2.

I ran some sand paper over the body for 3 or 4 strokes, then looked at the paper, and the dust in the paper was red - the same red as the finish that should be under about 7 coats of clear lacquer. This was me, yeah, "what the f*ck?!" After that many coats, the lacquer definitely should have started to build and the grit coming off the guitar should have been white.

Obviously the lacquer wasn't building as quickly as I expected it to. This meant one of two things; either my expectations were off, or there was something wrong with what I was doing. So I did what any sane person would do; go on the internet and ask strangers for advice.

I hit up the Official Luthiers Forum and asked the question. Advice was fairly unanimous that my 2:1 ratio of lacquer t water was overkill, my lacquer was over thinned and as a result was either all but evaporating or completely soaking in to the wood.

I had to take it back to the beginning for the clear coats. All the coats I had done so far were basically useless. I tried shooting straight lacquer, as someone at OLF suggested, but it wouldn't shoot. Even with the air pressure cranked right up and the spray pattern as narrow and strong as it could be, it barely came out of the gun. Not surprising really, it's winter here and the temperature is not ideal for spraying.

I mixed a new batch, this time at 8:1, a much thicker ratio than before. This time, with a little playing with the settings on my compressor and gun I was able to get a nice spray pattern. My passes had to be a bit slower than before, but no biggie!

I also changed my spray schedule, as per advice at OLF. Instead of spraying 1 coat a day, I sprayed 3-4 coats a day with 1 hour intervals, over a few days. After 7 coats, I took it down and gave it a rough sand. Finally, white residue! That meant the lacquer was finally building. I sprayed another couple of coats, left it a day to dry, and then started sanding. I sanded at 400, 600 and 800 grit. I didn't get it back to perfectly smooth, even after hours of sanding, but it was a lot closer than before I started.

Now I've sprayed 2 more coats, and left them to dry. And that's it! I could probably have given it a couple more coats, but I think it will be fine. I'll give it at least 3 weeks from today before I start wet sanding. I'm hopeful I can go straight to 1000 or 1200 grit with wet sanding, but I think that might end up being ambitious. But we'll see!

That's it for now. See you in about a month!