Brian's Guitar from Conception to Birth or How to Build a Guitar in 62 Easy Steps!
53 Rub Out the Finish
Remember to wait a week after spraying the last coat before you touch the guitar. If you did all of your preparation, sanding, and spraying carefully, you should see a pretty smooth surface. But it’s not smooth enough! As they stay in all of the books I’ve read (and it’s clever enough to repeat here), it’s time to finish the finish.
From now on, always rest your guitar on a clean, soft towel when working on it so it doesn’t get scratched. Start off by removing the screws protecting the mounting holes and take all of the tape off the guitar. The lacquer will have built up over the top of the tape and you want to be sure the sanding you’ll be doing will ease the edges of the lacquer to bare wood abutments. Also, even though you used the easy-release painter’s tape, after being on for about a month, it will have begun to stick and leave some residual goo behind. Use an Exacto blade, but do NOT cut with it which might gouge the wood. Instead, scrape backwards with the blade at the corners of the cavities. This will shave the edge of the lacquer off so when you peel off the tape, you don’t peel the lacquer off with it. Use the point of the knife or a dental pick to thoroughly clean off all of the tape which might be hiding in the corners. Inspect for any sticky glue stuff remaining on the bare wood and clean it off with some mineral spirits. They call it rubbing even though it is actually sanding. The high grit sandpapers don’t produce much visible dust, so I guess they thought rubbing was a better term. When rubbing out the finish with these fine grit sandpapers, you need some kind of lubricant. It makes the rubbing a bit easier, it extends the life of your sand papers, and it helps carry off the fine dust. In an old spray bottle, mix up one part mineral spirits with one part paraffin oil (about 8 ounces of each should be enough for the whole job). Use a foam or felt sanding block as much as possible and for all grits which helps keep the surface level and eases hand fatigue. I like to start with 600 grit wet/dry sandpaper before moving into the MicroMesh abrasives. Now don’t go hosing down the piece with the lubricant; you’ll end up with oil all over the place. Just spray once in the middle of the guitar and a little here and there, or when rubbing a smaller area or and edge, spray a small amount directly on the paper. Sand with firm pressure. Start by rubbing the whole surface in small circles, then rub 45 degrees to the grain direction, then rub with the grain direction. Now repeat this to yourself over and over again: “Do not skimp on the sanding.” If you get lazy on only one grit, it won’t become evident until you get to the last grit and it’s not as glossy as it should be. This is why I recommend rubbing in three different fashions, so you’re sure to rub everything thoroughly. With these finer grits, it’s impossible to sand too much. Don’t worry, there is no danger of sanding through 30 coats of lacquer.
The 600 grit is the most important since this will perform the leveling; you will not be able to level the surface with the MicroMesh abrasives. Start with the back of the guitar, spray on some lubricant, and rub thoroughly as noted above. When you’re done with the back, wipe it down with mineral spirits to remove any dust. Now inspect the surface very carefully in a low-angle, grazing light. You’ll first notice that your beautiful shiny guitar is suddenly dull. Everything’s alright, that’s what’s supposed to happen. You’ll get it brilliant looking again after working through all of the grits. What you’re looking for are any shiny spots or any unevenness in the surface. The shiny spots will show the low areas which did not get sanded with the block. If the surface is not dead flat, sand more with the 600 grit until it is. If the surface is really off, you may have to take a step back to 400 grit for a more aggressive attack, then back up to 600 grit again to start smoothing. Take extra time on the first grit until the surface is perfectly level with no dimples. Only then can you continue to the finer MicroMesh abrasives. There are 9 grits of MicroMesh abrasives, and at about 20 minutes per grit, this will take you a while. Find your rhythm and rub all surfaces in the same order so you don’t forget an area. I did the body back first, then the headstock, cavity cover, truss rod cover, body front, then finally the body sides. Add a spritz of lubricant as needed. When you finish an area, wipe it off with mineral spirits and inspect. When you finish a grit, take a short break, then repeat the procedure with the next grit. You can split the rub out over a couple-three days so you don’t get too tired or bored with it.