Wednesday, June 30, 2010

Refinishing, Book 1, epilogue

It's been another week or two since I last mentioned the guitar. In that time I completed the color coat and applied the clearcoat, buffed it to a shine and admired it... Then sanded off the clearcoat and reapplied the color coat, reapplied about half the clearcoat but then ran out, got more clearcoat, sanded off and reapplied the clearcoat, patched color, and reapplied clearcoat again.

Today I sat down in the garden with the offending instrument and checked it over properly. After about an hour of staring at it in the evening sunshine I concluded that it was back to the drawing board time. This post isn't really an update on the progress, more a post-mortem. That doesn't mean I've given up, far from it, but I want to make sure that I've catalogued and understood all the ways that I cocked my first attempt before I have another go. My pride compels me to add that the following pictures make the guitar look a fair bit worse than it actually does.

When I started I wasn't really sure what I wanted to do with the guitar. I didn't know what it looked like under the paint, and I was curious to find out. Looking back, I don't regret that—it might have looked awesome under that black paint—but I do regret sanding such a large area of paint away completely. The section that was stripped completely (which can be seen in the original post) covered most of the bottom half of the guitar. More specifically it covered the rough, open end of the grain where the wood was cut. This surface proved extremely difficult to cover with primer, and there were still traces of the rough texture of the underlying wood visible even after the colorcoat had been applied. This would have been ok, but it wasn't consistent, even after the clearcoat was put on the front, it was still possible, in the right light, to see the boundaries of the area that was stripped completely.
   In future I will assume that wood covered by opaque paint is not worth seeing unless I have good reason to think otherwise. If I really have to check, then I'll sand away a small area of the guitar, preferably on the belly-cut at the back. Sanding the wood away here would let me see a cross section of the guitar's construction—whether it has laminates on the front and back, that sort of thing—without leaving an area of completely unfinished wood somewhere important.

Firstly, I didn't make any attempt to fill the dings and dents in the guitar's body before I started. This wasn't particularly to do with laziness or inexperience, I just completely forgot about it.
   The problems I encountered at this stage were the result of a combination of bad materials and bad technique. The first can of spray lacquer I used was frankly rubbish, and was completely emptied long before the guitar was ready for the color coat. Lesson learned. I'll make sure to get decent stuff next time I do that, stuff that is specifically intended for priming wood.
   As regards the technique problems, these were rather inevitable when you consider that I'd never so much as held a can of spray paint before I started this project. I've since learned the very real importance of those "thin, even coats" people talk so much about.

This image shows more problems that I'd like to admit; visible primer, cracked clearcoat, bleugh.

Color Coat
This stage actually went largely without a hitch, so I'll instead take the opportunity to talk about the more general causes of shittyness in this project. The first was that, at least at first, I had no idea how long spray paint takes to dry. The stuff I'm using is typically tacky-dry after a few minutes and completely dry to the touch after an hour or two. What I didn't realize though, was that it takes much, much longer than that to harden properly.

If you look closely at this picture you can see the indentations left when the guitar was left leaning against some fabric for a few hours, a day or two after the finish was applied.

   As the guitar has a set-neck I didn't really have anywhere I could hold the guitar that didn't involve touching the paintwork. On days when I'd been working on the neck this inevitably meant fingerprints from carrying it up to the attic at the end of the day. On the first day or two of work, I left the guitar resting on a tabletop, not realizing that this would leave all sorts of strange imprints on the finish. I figured out a precarious arrangement after a few days that left the guitar propped up using blocks resting on the fretboard and inside of the pickout rout. This allowed it to dry properly, but required a great deal of manhandling to get it in place (usually resulting in yet more fingerprints) and was quite worryingly unstable.
   Towards the end of the project I made a hook from a bent coathanger that allowed me to hold the guitar without touching it and hang it up to dry. If I'd had this from the start, I'm pretty sure things would have gone a lot better.
The second big issue was that of masking. I did the masking right at the beginning of the project and, to be quite frank, ballsed it up something horrific.

 You hear that sound? Yes, that's baby jesus crying.

   I used regular (and very old) masking tape, which didn't mask as well as I might have hoped. It didn't give a clean edge, and paint seeped through in places, forcing me to sand the paint off those areas. Worse than the failings of the masking tape, however, was the cack-handed way I put it on. Rather than a sharp, clean edge, it was a sort of meandering, rough line that veered from the edge of the frets to about a centimeter off the fretboard. I uncovered this horror after the first round of clear coating. As an experiment in desperate damage management, I tried painting over the edge of the neck completely, to hide the monstrous join, but this looked just as dumb.

 Oh, the Humanity!


At first, I thought that the clearcoat went on fairly easily. The truth, however, was in the drying. Coats that looked fine when they first went on, started to look progressively more shit as each day went by. The finish on the front cracked like a playing field on a hot summer and the finish on the back developed strange deep grooves, which were probably the result of cracks forming in the layer below. Kristen suggested that these problems were caused by the coat underneath not being fully dry, which sounds right to me, given what can remember of the order in which the coats when on.

 Eeeew. Gross.

Wobbly, Wobbly.

Another big mistake was not putting enough clearcoat on. It's a simple thing, but I didn't realise that you need to put on far more than you think the instrument could possibly need. Extra care should be taken to build up the coats on the edges and on cutaways with really thin layers. Where the viscious, semi-dry paint is likely to flow away from the edge.
   If the paint is put on too thick then the hardened top layer will crack when the lower, gooey layer shifts away from the edge.

Tectonic Paint Movements

This post may sound gloomy, but I'm actually in a good mood about all this. Once I'd got over the initial frustration of having cocked it up, I've become excited about the chance to try it again, better. If this was an instrument I had a burning need to play right now, then I'd be really annoyed by this setback, but as I'm an apathetic guitarist at the best of times, so I'm not in any real rush.