Getting Close!

Yes, I am really getting close to finishing but there are still a few more parts to make before I can put strings on it. The nut and the saddle need to be sized and shaped, the bridge needs to be glued on and the tuning machines need to be installed on the peg head. All of these are critical but the bridge is the most daunting. It must be secure because of the tremendous amount of stress created from the string tension. It also must be perfectly positioned to insure the guitar will play in tune. Before I started spraying finish on the guitar I carefully measured and marked the position for the bridge on the top. I had previously cut, shaped and finished the bridge from rosewood. Many luthiers finish the bridge by polishing it with a buffing wheel. Since I do not have a buffing wheel, I hand sanded to 320 grit and then hand rubbed it with 0000 steel wool. This is the same method I used on the finger board giving both a nice luster finish. I put a final finish on both the finger board and the bridge with Behlen's Fingerboard Oil. This oil finish darkened the wood and enhanced the grain and tone. There are a couple of different methods of gluing the bridge in place. The traditional and most widely used method uses glue and special clamps that have a deep throat and are fitted through the sound hole to clamp the bridge in position. These clamps are expensive and it takes at least two and preferably three to firmly attach the bridge. As you might expect three clamps of any size going through the sound hole at the same time would be a tight fit and great care would need to be taken to not damage the hole or the finish of the guitar. The second method uses a special vacuum frame rather than the cumbersome clamps to put pressure on the bridge while the glue dries. I decided that I would try to make a vacuum clamp while the lacquer finish was drying. I already had a vacuum pump, the most expensive part of the clamp system, so I started building wood prototypes. My first attempts were based on a vacuum clamp that I had seen in an LMI catalog. I think this fixture is made from aluminum. My design was made from wood, much more brittle than aluminum. It cracked and broke as soon as pressure was applied by the vacuum. I re-made it strengthening the design with thicker wood and paying more attention to the direction of the grain. This version seemed more stable but I still had problems with finding a suitable rubber gasket material and rubber membrane material. Ultimately I had to order these from LMI. They were not expensive and they worked great. Basically the frame was a simple rectangle made from 3/4" oak (maple would probably work better because of the tighter grain) with a rubber membrane attached to one side. I had a little trouble attaching this rubber. I ended up gluing it with J-B Weld epoxy. On the other side of the frame I attached the solid rubber gasket material. A hole was drilled in the frame to allow the vacuum hose to be attached. The frame fits over the glued bridge on the guitar top with gasket down. The vacuum pump is turned on, sucking all the air out of the frame. This causes the rubber membrane to suck down and put pressure on the bridge, clamping it in place. It worked great and it shortened the drying time because of the vacuum.

Gasket side of vacuum frame.

Rubber membrane side of frame.

Frame in position over bridge.

Bridge glued and taped in position.

After taping holes were drilled and two bridge pins were inserted.

Vacuum frame under pressure.

Frame, pump and hose - entire vacuum system.

Detail of frame under pressure.

Detail of vacuum gauge showing 24 pounds of pressure.

After successfully attaching the bridge I decided to work on the nut. I had purchased a bone nut blank and a bone saddle blank from Stewart MacDonald earlier in the process. When I attached the fingerboard to the neck I left a space or slot for the nut. It seemed logical to leave the space rather than removing it later with a chisel. The nut blank was over sized so it need to be trimmed to length and shaped before attaching it to the neck. This was a simple task. I inserted the nut and marked the appropriate length with a pencil, then used my fret saw and miter box to cut off the excess. The nut blank also was to tall and needed to be shaped. I inserted it in the slot again and used a half pencil (a pencil that I sanded off one side to make a flat side) laying flat on the frets to mark the height and radius of the neck. I then sanded down the nut using the pencil mark as a guide for radius and height. I left the nut proud by about 1/16" so the strings would be above the frets. The top of the nut was rounded over on both sides and ends then polished with extra fine steel wool. After sizing and shaping I applied wood glue and clamped the nut in place on the neck.

Marking the nut with the flat pencil.

Flat pencil transfers the fret height and radius.

Marked nut blank.

Trimmed and shaped nut.

Glued and clamped.

The next step was to do the same thing with the saddle blank. It was carefully measured and cut to length. Then it was marked for height and radius by placing it at the end of the finger board and using the flat pencil to mark it. It was sanded and filed down much like the nut. The saddle is not glued in the slot on the bridge, it is held in place by a tight fit and eventually by the strings. It needs to be removeable to adjust the action of the strings.

I then installed the tuning machines in the head of the guitar. I marked and drilled holes in the head when I finished shaping the head. The holes needed to be reamed out for a perfect fit for the tuners. This was done carefully and slowly with a 5 degree reamer until I got a tight snug fit. The tuners are designed with a threaded retaining ring that attaches from the top and holds each tuner in position. There are small finishing screws on the bottom that keep the tuners from twisting.

Tuning machines ready for installation.

Reaming holes for perfect fit.

Blue painters tape applied to reamer for depth guide.

Finished tuner installation.

Back installation.

 The bridge pin holes now had to be drilled and reamed for a tight fit for each pin. The pins that I had purchased were a 5 degree taper so the same reamer I used to fit the tuners would work for the pins. I had previously drilled two of the holes for position of the bridge on the top. Now, I needed to drill the other four remaining holes and carefully ream them for a perfect fit.

Reaming the pin holes.

Reaming the pin holes.

 At the same time that I purchased the bridge pins, I also purchased a strap pin. It matched the bridge pins but is slightly larger and is inserted into the bottom of the body. Attaching this was simple but was a little frightening because a hole must be drilled through the body. Yes, the same body that I have been laboring over for a year now has to get a hole drilled through it. What if the hole isn't centered or what if the drill bit slips, or what if the hole chips out, or what if, what if, what if. . . Can't stop now, suck it up and just do it.

Reaming for final fit.

Reaming.

Testing strap pin for fit.

The last thing before putting the strings on is cutting slots for the strings on the nut. Again a pretty difficult and important part. The strings must be perfectly spaced for playability. They must be the right size allowing each string to slide through but not to big to allow movement. Man!!! this precision makes my head hurt. All of my books basically say that I need to purchase a set of sized nut files. I agree but this will cost another $80.00 plus shipping and remember I have already spent enough for two new Martins. I know, I keep telling my self that's not the point but when will it all stop? Well, I decided that it's stopping now, so I'm going to figure a way to cut or file these slots with the tools I have! The first important step is to determine the spacing. Some of the books just say to divide the space evenly for the six strings but others say that you need to allow more space for the base strings and less space for the treble strings. This later statement seems to make sense to me but how much more or less? Through out this project, for over a year, I have been faced with problems and things that I had no reference or knowledge to figure out a solution. Most of the time I was able to go to the Internet for answers. What a great resource, you can always find an answer on the Internet. Usually you find several answers and a how to video as well. The problem is, you don't always know if they are the correct answers. This time I found a web site that had a program formula that you could enter in the specific size of the neck and the size of strings and it would automatically calculate the exact spacing between each string. I took this information and drew a template in Adobe Illustrator with the exact string size and spacing. I attached the template onto the nut with spray adhesive and started cutting and filing. I bought an inexpensive Xacto craft saw that the blade was the approximate width of the thinnest E string. I used this to cut the slots for the thinnest two strings. For the wider strings I used my fret saw and started rolling it side to side to widen the cuts. I finished off the widest slots with fine jewelers files that already had. It seemed to work without having to buy an expensive set of files. I was now ready to string the guitar! HALLELUJAH!!!!!

The string spacing template attached. Mat board attached in front and back to protect the fingerboard and head stock.

After over a year I finally finished! The guitar looks great and more importantly it sounds great. No one was more surprised than me. When I was cutting the slots for the frets in the finger board I made the comment that if this guitar played in tune it would truly be a miracle from God! Well, miracles still exist, this guitar is proof. The only problem. . . it didn't make me any better. I have always heard that it was not the violin that made the master but the master that made the violin. I guess that holds true for guitars as well. Oh well, I'll look better while I am attempting to play. I think that is what's important anyway.

It has been about a month since I finished and the guitar sounds better everyday. Even my untrained ear can tell a difference as it mellows and ages. I did take the strings off and pulled the bridge to sand down the back to reduce the string height. The string action was acceptable but a little high. I think it is better now.

Just finished stringing. It didn't fall apart and it played in tune. Amazing!

Finished Hefner 001OM guitar!

Back

Front with pick guard.

Studio shot

Neck detail

Head detail

Side detail

Let's Finish This Thing

The last post was in July and I had just finished spraying about 12 coats of lacquer on the guitar. Everything I had read about finishing said to wait about 30 days to allow the lacquer to dry thoroughly. This seemed like an excessive amount of time. I was used to finishing furniture much more quickly but I never polished out furniture to a mirror finish. So, I put the guitar away and began my wait. I was busy with other things and the time went by more quickly than I thought it would. August came around and I was ready to continue. I had been reading as much as I could find online about guitar finishing. It seemed very similar to auto body finishing. I have a neighbor who owns an auto body shop so I asked him about what he recommended for finishing compounds. He said sense I was hand polishing that I should hand sand to at least 2400 - 3000 grit wet dry paper and stay away from compound. With this information I took a trip to an auto paint and body store. After telling the owner of the store what I was doing he basically agreed. So, I purchased some sand paper in a variety of grits starting with 1500 and going up to 3000. He also recommended a couple of foam blocks to use with the paper.

The wet dry sand paper and foam sanding blocks.

I got a small bowl to put the water in and put a few drops of Ivory liquid detergent in it to act as a lubricant. I began with the 1500 grit and started with the top. I tried to work with the grain as much as possible and worked in small sections. Trying to be consistent from section to section I worked my way around the top and then to the back and finished with the sides and neck. I worked my way around the guitar two times and then switched to the next finer grit. I was trying to get all the tiny shiny pits worked out to a consistent dull finish. I think I stopped a little to soon. I am pleased with the finish but I think it could be a little better. After working through all the grits I was ready to start polishing. The owner of the auto body paint store recommended a "3 in 1" compound, polish and swirl remover. It was expensive but as he pointed out it was cheaper than buying three different polishes. The other problem was that none of these finishing products came in small containers, so I now have a lifetime supply.

Polishing compound and wax.

 

I was expecting this to be a hard messy process. I was pleasantly surprised that it was pretty easy to apply and worked well. Just pour a small amount on a clean rag and apply then rub it off. The harder you rub in the application process the more it cuts the finish. If you rub on a light coat, let dry then rub off it acts like a wax. Easy Peasy! It really brought out the shine.

Front of guitar after polish,

Back of guitar after polish.

Detail of shine.

The Finish

After completing the bridge and before attaching it to the guitar body, the next step is applying the finish to the guitar. The bridge location is critical to the sound and pitch of the guitar and must be established and marked very carefully. As I have stated several times in this blog I have used numerous sources, plans and information from several books in the building of this guitar. I have also stated that sometimes this has been my biggest problem, trying to decide which information or plan to go with. One choice early in the process doesn't agree with future choices made down the line from different sources. This is becoming more of the norm the closer I get to finishing the guitar. This was definitely the case with the bridge placement. All of my books and online sources agreed that placement was critical but they were all slightly different in their method of figuring the placement. At first all my research indicated a simple mathematical solution. The bridge placement is double the length from the nut to the twelfth fret. On further research I found that there was an additional amount added to compensate for the different string thicknesses. This is the part that seems to vary greatly. I finally decided to go with 1/16th of an inch compensation and I hope that works. We will find out when the guitar is finished and strung. If it plays in tune I guess I got lucky. All of this makes my head hurt. . . so I'm going to move on and mark the bridge position on the guitar body and mask it off. This is necessary so there will be no lacquer finish on the body when I finally glue the bridge in position. The other area of the guitar that needs to be masked is the finger board and frets. The sound hole also needs to be masked so no finish gets inside the body.

Masked bridge location.

Masked finger board.

Masked nut slot.

Masked sound hole

Guitar ready for finish.

Once all the necessary areas were masked I was ready to start spraying the finish. I decided to go with a traditional sprayed nitrocellulose lacquer finish. I had some experience with this on other furniture projects and was more comfortable with it rather than trying a completely new process like french polish, a shellac process or the newer waterbased lacquer products. I decided to go with Behlen Stringed Instrument Lacquer because it was available in quart containers rather than gallon containers and I only needed about one quart, making it more economical and it was specifically made for instruments. I ordered it and the necessary Behlen Vinyl Sealer online and received it in 2 days. I later found that I could have purchased it locally at Woodcraft. I called them to see if they had it and was told they did not, only to find it myself when I was in the store later, oh well next time. I started by spraying two light coats of vinyl sealer sanding lightly between coats. After the sealer dried overnight I sanded again with 320 grit wet dry paper and a little water. I was surprised at how hard the sealer was. I have found most sealers are very soft and easy to sand, this was not the case with this product. I found it necessary to use water to keep the paper from clogging up. I then moved on to the final finish lacquer. The Behlen company recommends using this product without thinning but I felt it was a little thick straight from the can so I thinned it with 1/3 standard lacquer thinner. This seemed to spray well and flatten out nicely for me. I sprayed  two coats a day then sanded the next day and started all over again. I worked from 320 grit on the first day then moved to 400 for the next three days and finally 800 for the last two days. In all a little over 10 coats with light sanding between coats. During this process there were a few specs that needed more attention. I used straight lacquer from the can and a tiny art spotting brush to apply extra lacquer to these spots. I allowed them to thoroughly dry and sanded and scraped them smooth. The thicker lacquer acted like a filler and worked nicely. Overall because of the tight grain of the maple I did not have to use any filler on the body. As mentioned in an earlier post I did use a thick CA glue as a grain filler on the head inlay.

First coat of finish makes a big difference in the tone and grain.

First coat on the back.

Spraying finish.

Spraying.

More spraying.

Top after two coats, 8 more to go!

Wow, flamed sides look great!

After approximately 12 coats, I decided to stop. The finish now must thoroughly dry before polishing it to a mirror finish. I am going to let it set for at least 20 days before I start the polishing process. I am extremely pleased with the way it looks now! I am getting really close to finishing but there are still some critical steps remaining. I have to attach the bridge and make the saddle and the nut before I can string it up but my dream is in sight and I couldn't be more excited.