With the body done and sanded, and the neck done and sanded, I was faced with the options of grain filling again. My last Les Paul (the blue one) was not filled properly, but after the first few color coats, it was going to be a colossal job to remove he lacquer and complete the grain fill, so I just shot several extra coats of lacquer. I have not polished this guitar out yet, but I'm confident that I have enough buildup to prevent sanding through. I used the Stew Mac grain filler product for that LP, and for some reason, it just didn't work the same as the previous few times. Maybe I rushed it or just didn't pay close enough attention to what I was doing. I'm not blaming that product, but I still really dislike using that product, nothing like coating your perfectly sanded guitar with drywall mud. (that's essentially what this stuff is). The clarity is non existant, and matching the color to the wood is not so great without adding dyes. Adding dye to this product has it's own set of pitfalls which I wont get into here.
I remember reading about pumice grain filling somewhere and decided to revisit that idea. I found this great guide on french polishing published by the Milburns on the Guitars International website. It was a bit of a revelation. (Note: you can also do a google search for this article and download it in a file with all the pictures) I found the article really well written and was able to understand the what and whys of how it's done. The first few sections on sealing and grain filling really laid out the purpose of the shellac, alcohol, and pumice and how they work together to fill the grain.
In preparation to try this method, I needed to find some supplies. I had bought shellac flakes from Lee Valley previously, but found them to be very dark (for 'blond') and full of bug parts, certainly not very high quality. I'm not even sure if this is dewaxed shellac, although I don't remember seeing wax in the dissolved solution when I first used it. A couple hours of searching around and I found a local shop that carries all flavors of shellac as well as a large selection of other finishing products. Wood Essence. The guy seemed friendly enough and I was a bit surprised when he retrieved my 1/2lb bag of shellac from an old fridge behind the counter! I doubt Lee Valley has their shellac flakes in a fridge in the back. I also replenished my entire supply of sheet sandpaper in all grits, bought a set of ColorFX dyes (not that I need more dyes), and some other odds and ends.
To dissolve the flakes of the seeming premium shellac, I used regular methyl hydrate from the hardware store and measured out the flakes and alcohol carefully and combined in a clean pickle jar. It took a full 24 hours for the lump of yellow gum to dissolve, but it did, and the new shellac was crystal clear. I passed on the suggestion to strain the new mixture.
I tried the Milburns method as set out in the guide on a few test pieces of east Indian rosewood. It seemed to work very well, and quite quickly. Armed with this info and a positive attitude, I moved onto the real workpiece.
Step 1 - Seal the light colored binding and purflings with shellac. Check
Step 2 - Apply a couple coats of shellac to the rest of the body. Check. I decided to cut corners here and rather than apply the shellac with folded up pieces of cotton cloth, I used a high quality foam brush. I was able to get the shellac on the back of the guitar very evenly with the brush. This turned out to be a big mistake. The foam brush allows the thin shellac solution to flow out very quickly; there is no control to how fast and thick the shellac comes out.
Step 3 - Prepare the muneca. Check. I did this with nice little pieces of white t-shirt material cut into 4x4 squares and 4 cotton balls in the center. You would be surprised how many 4x4 squares of cloth you can get from a single t-shirt!
Step 4 - Put some alcohol in a squeeze bottle and spread out some 4F pumice. Check.
Step 5 - Wet the muneca with alcohol alone. Check.
Step 6 - Dab some of the pumice and add more alcohol to make the pumice clear. Done.
Step 7 - Rub against the guitar and watch the grain fill. Yeah, kind of.
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| The guitar back with way too much shellac for proper grain filling technique |
At this point things seemed to be going OK, but what did I know? It wasn't till an hour later when I realized that this was not going well. I had small ridges of pumice/EIR dust/ shellac building up, and because the shellac dries so fast, it was nearly impossible to move these piles of 'filler' to where they were needed. I though that if I could have a longer working time I might be able to smooth it all out, so against the guide rules, I added a dab of oil to the muneca along with alcohol and tried to smooth it out. Wrong! Adding the oil had the oppisite effect of grain filling, rather it started to polish the shellace, very nicely I might add. At this point I knew I was screwed. I had made a real mess of the back of the guitar, and although I hate leaving messes overnight, I decided I better reflect on what happened before I made any more mistakes.
The next morning I was making toast with peanut butter when it hit me, the mistake I made with the grain filling the day before. I love peanut butter, but when I spread a thick coat of it on the hot toast, not all of it melts into creamy goodness. Bingo! Too much shellac on the wood makes it impossible for the small amount of alcohol and pumice to work effectively. basically a small amount of the shellac is reactivated, the pumice gets wrapped up in this gummy layer and is unable to effectively get to the wood and enter the grain. The result is ridges of dried slurry on the surface, non uniform in texture and color. When adding the wash coat of shellac to the bare wood, use just enough to coat the wood! (Its too late to change my ways with peanut butter.) It would be easier to add more shellac, but removing it is not so easy.
I thought the work day would never end. I though about it all day and finally when I got back into the shop at 5pm, I was ready to rectify the problem. I started to sand off the mess I made the day before, but after 15 mins of this and a couple pieces of loaded up paper, I decided to try to wipe the mess off with an alcohol soaked rag. This worked well. It takes quite a bit of alcohol and clean wipes to remove the shellac, but within 10 mins, the back of the guitar was a clean slate. Because there was already shellac in the pores (the grain was somewhat filled, it was not a complete failure) I put a very thin coat of shellac on the back. I thinned out my mixture of shellac to probably around a 1lb cut, and carefully wiped it on with a fresh muneca. The back was barely shiny when done. I though less is better. I could always add more shellac if this was not enough. Back to the rubbing with pumice and alcohol. After about 30 mins, I had successfully filled the pores. I worked with a bright light to watch the pores being filled so I didn't have to guess. I also found that if you are working an area and you just can't seem to fill up those last few pores, move on to another area an let it set up. When you come back to it, they will easily fill.
So after I was done, I sat back and had a cold malted beverage to admire the success, I noticed there were still some dark ridges of slurry on the surface, nothing like the day before, but it just didn't look right. I decided to gamble and try wiping the entire surface with an alcohol soaked rag to remove the excess hoping it wouldn't take the fill out of the pores. My gamble paid off, and the back was completely clean and clear after a few minutes of careful wiping. All that was left was raw wood and grain filled pores. Perfect, and glassy smooth. I now added the final smooth seal coats of shellac, applied again with the fresh, shellac only muneca. Strait overlapping stroked from tail to heal until completely covered. Did this 3 times within 30 mins and the back had a nice sheen.
I did the sides of the guitar the same way as the back, minus the first failure and repair cycle. One thin coat of shellac applied and then onto the pumice / alcohol treatment. 30 mins and the sides were done correctly, the first time. Again, I wiped the sides down with an alcohol soaked rag to remove any residue left by the grain filling, then seal coated with 3 thin coats of shellac applied with a muneca. Perfection.
So that's my first adventure with pumice/shellac grain filling. It was definitely a learning process. Just goes to show, you can read all you want, but until you actually 'do', you know nothing. I will someday go though the entire process of french polishing, but for this guitar, lacquer will be the next finishing step, something that I have already learned the hard way with and have nailed down a process that works for me.
I have a new appreciation and a further understanding of shellac. I find it to be a nice finish to work with. The immediate drying time coupled with depth of clarity and ease of cleanup will make it my goto in the future for grain filling and sealing.
