“The Bow Bass”
April 16, 2020
I’m John Larkin, owner and builder here at Flon Klar Guitars. I am currently in the process of designing and building the first Electric Upright Bass (EUB) from Flon Klar Guitars. I thought I might post here a bit about the building of this instrument and include some pictures of the journey. This will be an ongoing blog, so check back every couple of days to see my progress.
Being a bassist with a long-time interest in jazz, I thought it might be interesting to put together an instrument that would be suitable for traditional jazz while being compact enough for easy transportation. Having never played an actual upright double bass, I wanted it to be familiar enough in its composition to be easily adapted to the hands (and mind) of an electric bass guitarist, while keeping some of the features that make a double bass… well, a double bass.
I had a bass guitar design in my files from about 5 years before that had never been built, so I thought I would try to adapt it for my current purpose. The striking feature about this design was that the bass didn’t really have a solid body- the “body” was a series of thin metal cables that would be attached to the solid neck of the instrument in a way that would suggest the shape of a body- which is pretty much exactly what I wanted to do with the EUB. So I reworked the design, began purchasing parts and materials, and got started!
1. Parts and Materials
February 10, 2020
I’ll skip the actual design planning, because the details of that get kind of tedious. One thing I will say, however, is that initially I wanted to draw up the plans in Sketchup, and began doing so, but the design details changed so many times that the Sketchup rendering became unmanageable, and (not being a complete pro with the program) I finally abandoned it. (Those of you who have any experience with CAD programs will probably have an idea of what exactly happened to the Sketchup drawing after 1000 changes!)
Once I had enough of the “plan” on paper, I spent a few weeks selecting, purchasing, and finally assembling all my parts and materials in one place to take a family portrait, before getting started.
2. The Neck
February 17, 2020
Most of my instruments are “neck-through,” meaning that the neck is one continuous piece all the way through from the headstock to the bottom. This bass would be no exception, and as always, this was my starting point. Originally, I had wanted to cut the pieces on the table saw, but because the shape of the neck was a little tricky, I decided to use a saber saw instead.
First, I made a fiberboard template.
Then I traced and cut the maple and walnut pieces.
The mahogany board was pretty thick, so I would have to take a different approach to getting my neck pieces out of it, without wasting too much.
It took awhile, since a lot of it had to be slowly cut with a hand saw, and finally a chisel, but I eventually got something like a 2×4 out of it.
February 20, 2020
To build the laminated neck, I had to get several thin slices out of each chunk of wood. As I began to slice the wood on the band saw, the drive belt on my 15-year-old Craftsman finally decided to have a catastrophic failure!
February 22, 2020
While I waited for a new belt to arrive, I began cutting the glass pieces for the fingerboard inlays.
Stained glasswork was something I had never attempted before, but I’ve always found that the best way to learn something new is to a) read and research as much as possible, and then b) jump in head first!
I had recently purchased a ring saw in anticipation of this project, and I was hoping it would be a lot faster than cutting glass with a diamond jeweler’s saw. I was not disappointed! The FK Spider logo was traced out and cut in just a few minutes!
February 25, 2020
The drive belt for the saw arrived, so I installed it and continued with the neck wood slicing. Once I had all the pieces sliced and planed, they were ready to glue.
I hadn’t built a jig for this neck, so in order to minimize misalignment due to slippage, I glued it in 2 stages. (I normally glue with Titebond III, but I had decided to try Titebond’s relatively new Hide Glue. It’s a little different to work with, and it works alright, but I don’t know if I would use it in the future.)
February 26, 2020
The next day, my neck blank was complete!
March 1, 2020
After planing and squaring the neck blank, I was ready to start shaping it. With my drawknife and a variety of scrapers, chisels, saws, and planes, I started removing wood.
March 9, 2020
After several days of shaping, detailing, and constant refining, I was ready to cut the truss rod channel. Traditional upright basses don’t use truss rods, but because of the length and comparative thinness of my neck, I wanted to make sure I had the ability to make adjustments if needed.
3. The body
March 10, 2020
Putting the neck aside for a while, I started working on the “body” of the bass. The body, as I said before, wouldn’t really be a body, but a system of wire cables stretched between 2 “bow” structures, one at the bottom of the bass and the other about halfway up the neck. I cut and shaped the bottom bow from the same walnut as I used in the neck, drilled the holes for the cable hardware, and then attached it to the bottom end of the neck.
Over the next few days, I busied myself with details and minor adjustments to the shape and overall layout of the bass.
March 16, 2020
I began cutting out the pieces of mango wood for the top, back, and sides. I had never worked with mango before, so I wasn’t sure what to expect. It turned out not to be the easiest wood to work; it seems like it tears easily, and the grain is kind of crazy and changes direction a lot, which made the results of cutting, shaping, and sanding somewhat unpredictable. Again, I had to cut the blank from a bigger slab, so hand saws and chisels.
March 20, 2020
I glued on the back, and while waiting for it to set, I cut, shaped, and drilled the upper bow and cut the mortise that it would fit into.
March 22, 2020
I got the upper bow glued in, as well as the mango pieces for the sides. From there, I was able to start hollowing out the control cavity.
March 26, 2020
While attempting to bend the mango top into an arch, the piece cracked along the crazy grain, so I had to make a new piece, this time with the arch cut into it so I wouldn’t have to bend it.
March 28, 2020
The cable slot came next.
Then I lined the control cavity with copper foil, to help control RF interference.
And finally, the mango top went on. Now it’s starting to look like something!
April 1, 2020
Once the top was set, I cut in the pickup cavity.
April 2, 2020
And from there, I began to install the bridge pieces.
Oops! That spacing isn’t right! Good thing this is a prototype!! As it turned out, even with the arched top, it still wasn’t high enough for the strings to miss hitting the upper part of the body, so I created a little additional arch piece, this time with the correct spacing.
However, once I did that, which changed the angle of the bridge mounting surface, I had to plug the holes in the rear of the bass where one row of fasteners had originally gone through. I intended to make new holes at the proper angles, so I didn’t put any effort into aligning the grain of the plugs with the grain of the back piece. I ended up NOT redrilling those holes, so now the plugs are a bit obvious.
April 6, 2020
After a lot of fine tuning and adjusting, I finally got the bridges in at the right height with the right spacing. I hope.
I thought of different ways to take up the 6″ of thread-wrapping on the ball end of the strings, but none of them seemed particularly attractive to me. At the last minute, I finally decided to make the “tailpiece” integral to the body on the bottom end, out of sight. The ball ends recess nicely into the holes, bringing them almost exactly 6″ away from the bridge saddles
4. The Pegbox
April 7, 2020
I laid out and cut the pegbox from a chunk of walnut burl. As I got it sized and shaped, I realized just how soft that wood was. I’m a little concerned that it won’t hold once it’s under full string tension, but I’ll deal with that if the time comes. I finished drilling for the tuners, then glued the pegbox to the top of the neck.
April 10, 2020
I discovered a minor problem with the jack hole. Since I had centered it on the side of the body, I realized that it competed for the exact same position as the cosmetic “body cables” that will eventually run up the side of the neck, meaning that I wouldn’t be able to plug my amp cable into the jack. So I ended up filling a part of the hole and redrilling it about 1/4″ higher. With the jack installed, it’s barely noticeable. (Again, it’s a prototype!)
April 11, 2020
I wired up the electronics (Krivo pickup, EMG volume and tone controls, Neutrik locking jack), plugged into my testing amp, and got a “thump” out of the pickup. It was a good day.
5. The Fingerboard
April 12, 2020
At this point, I’ve done about all I can do to the bass until the fingerboard is ready. As I mentioned before, I’ll be inlaying the fingerboard with a stained glass design, and this design will require backlighting. (Originally, I had planned on bringing light to the glass with fiber optic cable, but after some preliminary trials, this didn’t seem to be all that effective. I experimented with other methods for a couple of days, and finally settled on (the very inefficient method of) using individual LEDs for each section of glass, combined with paper diffusers and reflective surface space behind the glass. Down the road, I may experiment with some larger fiber optic cable, but the 1mm variety I have on hand just doesn’t do the job.)
I cut out all the glass pieces easily on my ring saw (24, plus the 2 I already cut for the logo inlay) and started cleaning up rough edges with diamond files and sandpaper. After taking 2 hours to finish 4 pieces, I decided I needed a real glass grinder, which I ordered immediately. I was later informed that shipment of the grinder would be delayed by a week, so that brought production to a standstill.
April 14, 2020
I decided to go ahead and do a Danish oil finish on the bass, so I spent a couple of days applying that. It will have plenty of time to dry as I wait for the grinder. ?
April 16, 2020
After building a little mock-up of the proposed lighting system for the stained glass fingerboard inlays, I realized that the fiber optic cables I had planned on using weren’t going to bring enough light to the glass. I began to experiment with other means of getting light behind the glass, but nothing I tried seemed to do what I wanted. It looks like the best way to accomplish my goal is to set a separate LED behind each square inch or so of glass, along with everything I can think of to help reflect and diffuse the light evenly. I’ll be improvising a bit through this process, and I’m not sure how it’s going to turn out!
April 22, 2020
To build the laminated neck, I had to get several thin slices out of each chunk of wood. As I began to slice the wood on the band saw, the drive belt on my 15-year-old Craftsman finally decided to have a catastrophic failure!
April 28, 2020
The grinder finally arrived! Time to get to work finishing up a pile of rough-cut glass!
April 30, 2020
With my inlay pieces all shaped and ready, I began routing pockets for them in the fingerboard. In order to diffuse the light properly, I need to separate the glass from the light source as much as possible, so I’m routing out 3/8″-deep pockets, which will be filled mostly with clear epoxy to help with the diffusion.
May 2, 2020
All the routing is done, and I have epoxied in the glass logo pieces on the “12th fret.” I’ll do all the set-up on this one inlay to make sure it works right, before I start setting the arc inlays.
May 10, 2020
Over the past week, I have completed the lighting, set all the inlays, and glued on the fingerboard. The inlays and lighting look great!
Unfortunately, I was right about the pegbox- I noticed that it had developed a crack, so I removed it and made a new pegbox out of a chunk of bocote. Then I scarf-cut the neck and glued on the pegbox.
May 11, 2020
got the last of the repairs sanded and prepped, then laid down another Danish oil application. I’ll wait a couple of days before starting the lacquer process.
6. The Finish
May 31, 2020
OK, so it’s been more than a couple of days. The prep took a little longer than expected, with some extra sanding followed by more oil application and more wait time. But- today was the first day of the 3-week lacquering process! Over the next week, I’ll be spraying the bass with lacquer several times a day, and after the 6th day, the bass will sit for 2 weeks to allow the finish time to dry. So, in the meantime, there are other projects to get to, including the start of Christmas tree ornament building, which begins on July 1st!
June 4, 2020
Finished spraying the 17th and final coat of lacquer today. I’ll let it dry until the 20th, then start the final sanding and polishing.
In the meantime, I got a jump on Ornament-building season by laying out and cutting out my templates for the individual pieces that make up each ornament. I would post some pix, but that would spoil the surprise!
June 23, 2020
Two days ago, I started the lacquer coat leveling, and by noon yesterday I had the final sanding and polishing done. I noticed a few low spots in the lacquer (not unexpected), so I started spot-filling these indentations and pinholes with lacquer and a tiny brush. I’ll let it set up for a couple days before I continue.
7. The End
July 10, 2020
I apologize for dropping off the face of the earth for a few weeks. But I haven’t been idle! The repairs to the finish took several days, but nothing worth writing about. Then I started on the final step of hardware installation- the “body” cables, electronics, tuners, bridges, nut, and finally, the strings. I then thumped around on it for a few minutes which led me to realize that I had a problem- after about 3rd position, the strings started buzzing out on the raised top edge of the mango top and the pickup. I raised the bridges slightly, and even went as far as to actually use the truss rod to add a little forward bend to the neck. This enabled me to reach a full octave on each string, but I’m going to have to lower that leading edge of the mango by at least 1/8″, probably more to be safe. That will then require a serious repair to the lacquer, which I’m not looking forward to. Maybe next week…..
And then- I built the case! The construction of the case (my first attempt at building one) may or may not be interesting enough to post about, but I didn’t take a lot of pictures; so briefly:
I had already planned out the design and purchased materials. After that, Step 1 was to build the bottom box at 56″ L x 18″ W x 4″ D. I built it out of 11/32″ AC sanded plywood. I’ve never been great at box-building, but this came out pretty clean and square. Step 2 was the top box; same dimensions, but 2″ D. Each box also has corner blocks, and 2 stiffeners (1″ H) dividing the boxes into roughly even thirds.
Step 3: I wrapped the boxes in black Tolex with a snakeskin texture. My second shot at wrapping a box in Tolex; the first one was a speaker cabinet I built in 1985! This one came out much better!
With hindsight, Step 4 should have been the hardware installation. But I decided to apply the foam interiors to the boxes first. Not a huge mistake, but the hardware would have been easier to install without the foam in the way. I used 6 cans of spray foam gap filler, and I could have used one more in the top box. Before spraying the foam, I made rough cardboard forms to block the foam from the shaped insets for the bass, the stand, the bow, and a small accessory compartment. Once the foam was dry, shaped , and trimmed, I removed the cardboard forms and glued in a thin layer (1/2″) of polyethylene foam sheeting to the bottoms of the shaped insets.
I had purchased some really attractive “cranberry” polyester satin fabric to line the case with. I wanted to do each box in a single continuous length of fabric, but with hollowed areas of the lower box, there was no way to smoothly follow the topography of the foam without having to bunch up the fabric at certain points, so I ended up going full crinkle as I worked my way from one side of each box to the other. IMO, it looks cool! Step 5, check!
Step 6: With the interior lining done, I set the top box in place over the bottom box and installed the 4 hinges. Then I took a scrap of the satin lining, cut it into 4 strips, glued 2 strips back-to-back, twice, to create the limit straps to prevent the lid of the case from flopping open too far and damaging the hinges. This a big case, almost a full sheet of plywood, so it’s heavy.
After that, I finished it up with the metal box corners, latches, handle, and little round plastic feet- 4 on the bottom and 4 on the back side (to prevent the case from sitting directly on the hinges). The hinges and corners are black, and I really wanted to go completely black-on-black, but I couldn’t find any black latches, so that was slightly disappointing.
And then- it was done!
(Well, kind of. I still have to modify that mango edge. Once that’s done, I’ll post new pictures and an audio sample on the “Instruments” page of the website.)
I hope you enjoyed following this little adventure. I had a blast creating this instrument, and I’d love to build something like it for you. If you, or a bass player or guitarist you know, would appreciate a custom-built instrument, from our design or yours, please use the “Contact” form to start the conversation with us about building your new instrument from Flon Klar Guitars! Thanks!