The guitar I call Stella started as an idea that was hatched in '05. I wanted to create a unique sounding metal-body acoustic guitar. The reasons for this deviation from the norm are manifold: a) metals are isotropic (strain is measured evenly in all directions; b) as opposed to wood which is hygroscopic (already alluding to instability - think swelling) but most importantly is an anisotropic material (not having the same physical properties in all direction); c) recyclability; d) availability and sustainability (even Honduran mahogany is becoming scarce now); e) malleability etc. This guitar was originally commissioned by a guy who liked my description (aluminum body resonator guitar with exposed welds) of this idea so well he tried to throw money at the project. I declined the up-front money as I didn't get into lutherie to do production work, it's a labor of love, and besides I was out of the country for an extended period of time and miles away from my shop. I've been carrying around the blueprint for this one in my head for so long that I actually made it without a print, although the neck joint warrants a detailed mechanical drawing and a US patent which I'm applying for. Having years of experience working with various metals, I wasn't too challenged by the scope of the project. I was literally in my ..er.. element.
A little history of this style of guitar. Resonator guitars were originally designed to increase the volume of sound of the acoustic guitar before the invention of the electric guitar. Typical acoustic guitars were not loud enough to be heard over the brass and reed instruments common in the orchestra's of the day. The iconic John Dopyera and others filled that need by forming the National Stringed Instrument Corporation in 1926 to make resonator instruments. A few years later due to company infighting, John and his brothers left National to form the Dobro Manufacturing Company. Side note - DOpyera BROthers...DOBRO means 'good' in their native Czech too! Then again several years later with the instigators of the original conflict ousted from National, Dobro merged with National to be known as the National-Dobro Company. The rest is history, a storied one at that with even more changes, mergers and acquisitions throughout the years...National and Dobro are separate companies once again.
Factory Dobro (left) Leppert Guitars Resonator (right)
Now back to the 'Stella' guitar project. I decided to use 5052-0 aluminum as the material, as it has excellent workability and strength. Dobro had made guitars out of aluminum in the past. They weren't the most popular models though, lack of bass response being the primary reason. The idea of improving upon this design intrigued me. I believed that by increasing the overall body size and making some other changes, I could change that. So off I was to test this premise.
The first step/challenge was to fabricate the soundwell. Knowing that the transducer (resonator cone) must rest dead flat in the soundwell in order to transfer string vibration into the maximum amount of sound. I made an aluminum heat-sink to minimize any distortion caused by welding.
And from there cut, formed and Gas Tungsten Arc Welded this part to great satisfaction.
Next up was to cut the sheet aluminum and form the top and back.
I used an English Wheel to raise the flat sheets into smooth compound curves in order to increase their rigidity, as the top and back have no internal bracing.
Next, I formed the sweeping curves of the sides against a wooden buck.Then came the assembly time, tacking all of the parts together measuring, calculating and disassembling for the insertion of the neck joint cassette.
The biggest challenge was getting the neck to align on all three axes in free space with the bridge. The next guitar will be much easier as I'll have a jig to positively locate these variables.
Next came the fun part, welding the body together. Gas Tungsten Arc Welding (TIG or Heli-Arc) being the preferred method.
I carved the neck out of Peruvian walnut. I have mixed feelings about using this wood again as it tends to split when carved.
The fretboard was made out of Gabon ebony and has aluminum position dots.
This neck has a double action truss-rod, the adjustment screw accessible through a slot in the body. It also bolts on to the body in a way that is a radical departure from the norm. Since this guitar is so non-traditional, I decided that the very traditional French polish method was an appropriate finish for the wooden parts. The peghead face is high-flamed koa with an aluminum 'WHL' inlay.
Now, the only aluminum part that I didn't make was the resonator cone, instead using a Quarterman cone fitted with a Brasilian rosewood biscuit bridge and an aluminum saddle.
The soundhole screens and the tailpiece are off the shelf Dobro parts. My initial idea was a string-through design which would eliminate the tailpiece altogether and F-holes which would eliminate the soundscreens as well. I was anxious to hear this guitar, so I cheated and used these Dobro parts . . . after all this is a prototype. I wheeled the coverplate for the resonator cone after cutting the soundhole patterns. And left the bridge exposed so that a player can palm-mute the strings while playing.
Stella has a unique voice very percussive (banjo-like), focused and loud. I was able to compare Stella to a '31 steel body National Duolian, a newer bell brass National Tricone, a '77 bell brass Dobro DM33 and a '29 wood body Dobro (with a spider bridge). Here's the run down: My favorite was the Tricone ( yes I have a bias...always loved 'em) a full, warm, harmonically rich sound great for blues, bluegrass or Hawaiian music. Second to me was harder to qualify, so I'd say a tie between the '77 Dobro and Stella. With a slight edge going to the Dobro. Bell brass is what they make...uhhh ...bells out of, so this Dobro definitely rings and has more sustain than Stella. Stella is a bit brighter in sound with great clarity and a lot louder, more conducive to finger picking. The wood body Dobro is actually an unfair comparison as it's made of wood and that 'spider bridge' changes things too...this puppy IS the voice of bluegrass. It also is the only raised-nut guitar out of the bunch. I thought the '31 Duolian needed new strings as the sound was muted compared to the others. The guitar store owner informed me that the strings were recently changed. It just didn't seem to project like the others and had a lack of treble response to me. This guitar is in great condition and has an undeniable coolness factor. So, I had to play it longer to help cleanse the (ear) palate. After a while I realized what a nice blues voice it had, which shows just how subjective tone can be. It's overall volume was about half of what Stella put out, so it had somewhat of a disadvantage in grabbing one's attention...it was the quiet one...then again my favorite Beatle was the quiet one. The videos I've posted are recorded dry (without any effects using its built in mic) on a 'plain vanilla' digital camera. I'm hoping to fully utilize my recording studio and get some better quality recordings together to better showcase this subjective concept of tone so that you can decide on what sounds good to you.
Cheers!
William Henry Leppert IV
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