Now we come to the final stage… Finishing!
I’ve probably said this before but finishing can take up to a third of the time in a build. This is the first thing one notices after the initial shape. You’ve spent all this time with the wood. Don’t short change yourself with the finish.
I start with 100 grit and work my way to 220. There is no need to go any further as the scratches from the 220 will not show under a finish. As I’ve said before finish follows but does not fill. So now is the time for all the holes and flaws to be dealt with.
I don’t drill holes for mounting rings etc. as they will allow water to get into the hole when you’re wet sanding and pucker the finish.
Next, I use marine grade epoxy with a fast cure to fill the pores of the mahogany. The stuff I use is available from http://www.tapplastics.com/product/fiberglass/epoxy_resins/tap_marine_grade_epoxy_system/27 . Most any epoxy will work but I find this one with the fast hardener allows me more than one coat a day.
I cut the first coat of epoxy 25% with denatured alcohol to allow it to get into the pores and make sure my finish sticks to the body. Two more coats full strength, poured on, then squeegeed off with a piece of plastic against the grain. Don’t worry about the lines of epoxy build up. They’ll be scraped even when dry. One more coat and the mahogany is usually filled. If I’ve scraped through to the wood I go back to padding the area with epoxy cut 25%. I do not sand the epoxy because the white dust created can get into the open pores and it’s very hard to extract.
This is when I color coat. I almost never color the wood itself. I use toner coats in the finish. I do this for two reasons. First, if the color goes horribly wrong, I can sand back without the worry of discoloration on the wood. The second reason is that wood has summer and winter growth patterns. The summer wood being softer will take the stain deeper than the winter. Now if that is the effect you want, go for it. In fact PRS has a finish that they call “Cat’s Eye” where they stain black the figured maple cap and when dry, sand it off. The harder parts of the figure will look like the maple had never been colored while the softer parts will still be black. Now they spray a color, say amber, and you’ve got figure that really pops.
On this guitar however, I’ll be doing a classic tobacco sunburst. I start by spraying the entire top amber followed by a teardrop shaped burst adding reddish brown to the mix. The final color is a dark brown and used very sparingly close to the edge of the body. I still want to see the figure of the maple grain in even the darkest parts.
Sometimes I get little flecks of darker color in the lighter field. When this happens let the finish dry and using a steady hand, flick the intruder off with a sharp xacto knife.
When this is done I color the back in the same way, only with a cherry stain. Of course while this is going on the top is masked off to avoid ruining the sunburst. This means taping any control cavities so that finish doesn’t run through.
When I’m satisfied with everything, I mask the fret board and shoot the finish. Make sure you use enough coats so that you don’t go through to the stain. Unless it’s the darkest color it will be almost impossible to fix.
All in all this was great fun and I think the ultimate challenge for this is all the thought that went into creating the jigs and fixtures.