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Use of Composites in Bass Guitar Design.

(WORK IN PROGRESS)

Introduction

The idea for a graphite necked bass guitar was first championed by Geoff Gould a bass player who worked during the day designing communications antennae in satellites for Ford Aerospace. He took the idea to Rick Turner at Alembic and together they registered a patent for the idea in 1978 1).

The basic concept behind the technology involves embedding reinforcement fibres in resin to form a matrix. The reinforcement can be made from free forming graphite fibres, woven graphite fabric sheets or chopped up pieces of graphite fabric coated. The fibres or fabric are coated with polyester resin and layered the inside of a mold or the outside of a form. The resulting combination of resin and fibre is then typically treated under pressure to remove air bubbles and set the resin to form a very light and very rigid composite monocoque structure. Cold pressure methods have also been made available more recently for smaller sized parts.

Alembic and Modulus as Pioneers of Composite Technology

The first through body composite necked Alembic bass was purchased by John McVie 1976 although some prototype necks had been made before then. Geoff Gould set up Modulus Graphite to supply unfinished necks to Alembic. Alembic would then take the necks, apply wooden fingerboards and fit them to the bass bodies. Other companies licensed the technology from Modulus including Musicman and Zon 2).

To quote David Fung (Dfung) from the Alembic forum:

”…thought I'd fact-check a bit with Geoff Gould, who founded Modulus Graphite (now Modulus Guitars, but he's no longer with them). We talked, then I got busy, but here's some answers… …Geoff made some proto necks, but the first instruments you could buy with graphite necks were Alembics. As you may know, the Modulus neck is hand fabricated out of epoxy-impregnated graphite fabric in a mold, then cooked at high temperature and pressure. Alembic built forms that some of these early molds were made from, so they could be joined into what you'd call a Series bass these days. Rick Turner, who was at Alembic at that time worked with Geoff to file the US Patent for the monocoque (hollow) graphite guitar neck. Geoff/Modulus fabricated the graphite neck blanks to Alembic and later other companies as well, but the two companies were always separate. Alembic did the assembly and finishing of the graphite necks in their shop. Most of the other instruments that have used Modulus necks get completed and finished necks directly from Modulus.3).

This is a 1979 Alembic Series 1 made with a graphite neck

According to Dfung, Alembic initially offered separate bolt on necks under the Bassstar brand but also offered through body necks as a custom option.

“A through-body graphite-neck instrument was Geoff's ultimate goal, but they are expensive and only a handful of players would be able to own them. So, Modulus created a line of P-, J-, and Strat replacement necks, which were called BassStar and BlackKnife. They were still tremendously expensive at $600, but much more affordable than a $3500+ Alembic. Because Modulus had an ongoing business relationship with Alembic and because Alembic had a very positive aura around high-end instruments, Modulus licensed the Alembic name for these necks for a number of years, but they were produced and distributed independently from Alembic's channels”4).

Around 50 through body necked Alembic instruments were made according to Mica Wickersham5). Each neck was custom made for its future owner which required the fabrication of a custom mold. This was a very expensive exercise as the mold needed to include the usual custom variations in headstock, neck dimensions and profile. The necks were fabricated by Modulus and sent to Alembic for fitting and finishing.

Graphite necked instruments were made for most of the major bassists using Alembics in the last 70's including Stanley Clarke, Greg Lake, Jimmy Johnson and John Entwistle. Apparently the Spyder basses that John toured with had graphite necks.

In 1998 the patents on the truss-rod free, Modulus composite neck technology expired. Numerous variations and patents have been subsequently submitted by others based on the original idea and these are covered in more detail at the end of this article. Neither Status nor Vigier licensed technology from Modulus. Both Rob Green and Patrice Vigier developed their own lamination techniques separately from Modulus and Steinberger.

Alembic, Modulus and Musicman

While producing necks for Alembic, Modulus developed their molding technology sufficiently to offer finished composite necks to Musicman. Musicman released their Cutlass range of basses in the early 1980's. There is some uncertainty about when the first Cutlass bass was produced. There is reason to believe the range was started in 1980 6). Other evidence is available to suggest that prototype Cutlass II basses were on display at the NAMM Music Convention in 19837). However its generally believed that most Cutlass basses were produced beween 1983 and 1984 with some examples of Cutlass 1 basses perhaps made before then.

Musicman Cutlass I made for Cliff Williams of AC/DC Musicman Cutlass II

1979/84 Musicman Cutlass I (left) made for Cliff Williams of AC/DC, 1984 Musicman Cutlass II (right).

Both Alembic and Musicman stopped offering composite necked instruments in 1984. According to Mica Wickersham there were some quality control issues encountered.

“We were Modulus' first customer, and very excited about the concept of composites. The “farming out” aspect was not something we were uncomfortable with - for the graphite basses and guitars to be made, it was a requirement. As Geoff's only customer, there wasn't anything to compare our relationship to since we were it. It would not have been possible to supply us finished necks - ours were all neck through construction. David is familiar with Modulus' business practices outside of Alembic, so much of what I read was news to me. There are many reasons why we stopped offering graphite necks. The necks {did} move, and the absence of a truss rod was a real disadvantage. Even if the necks were as stable as hoped, fine tuning was not as simple as truss rod adjustment. The earliest necks were of superior quality to ones we received toward the end of our graphite days. I've posted this before, but the ones with a woven fabric appearance are much more likely to be stable. Later necks had graphite chunks of various sizes and not uniformly aligned. Failure rates for necks we received were as high as 2 out of 3 for various manufacturing defects. These were primarily due to inconsistent wall thickness and voids in the decorative section of the peghead. Of course, rejected necks did not make it into finished work. Sure there's a “pita” aspect to a build with graphite, and not to be overlooked is health issues for the good people working with the material. The original molds were made with rather round necks that were not to everyone's liking. Getting new molds made for a custom job as David mentioned is very expensive. With the limitations of the material at the time, and the expense of making custom fabrications, graphite necks became impractical.” 8)

Its been documented that some of the graphite necks produced for the Musicman Cutlass basses had to be recalled because of severe neck bows. These recalled instruments had their frets removed and the fingerboard was replaned to address any neck bow before being released as fretless instruments.

However Modulus were pivotal in introducing composite technology into mainstream manufacturing and the collective consciousness of bass guitarists. Steinberger also had a significant role in making the use of composites acceptable however their cast manufacturing method has generally been eschewed in favour of laminated, monocoque construction by other manufacturers.

Typical Construction of Composite Necks

Another extract from Dfung on the Alembic forum describes the Modulus contruction process:

“This helps make the instruments more produceable as well. In the case of Modulus, the “secret recipe” of the materials and construction is carefully tuned so that the fretboard can be planed to dead level and frets installed dead level under no tension, then will pull into the desired target relief when strung up. Over time as the materials change, they need to adjust the fabrication instructions to compensate, and this slowed down production because transitional instruments needed to have additional fretwork before they could go out the door. Incidentally, the fingerboard on Modulus, Status, and original Steinberger is phenolic, the very first composite material. The graphite is way too hard to be shaped into a playing surface (it will quickly dull regular tools). Geoff considered a wood fingerboard but was concerned that it might not be stable since wood can be very subject to expansion with humidity and heat. He ended up selecting phenolic because it's easy to work (pretty much the same as wood) and aesthetically he wanted the neck not to have any wood in it. The graphite in a Modulus neck is fabricated in two pieces - a main molded U-shaped part that has the shape of the back of a guitar neck and a thick flat plate that it bonded on to the top of the U. Together they form a monocoque tube which structurally is stronger than a solid neck (and saves on expensive materials as well). The phenolic fingerboard is epoxied on top of the flat piece… … The curved main part is cooked in a mold, then the open side of the “U” is milled with a carbide tool to be dead flat and the flat piece is bonded on top of that.”9)

Again some insight is also offered by Dfung on the differences between Modulus and Status methods of construction.

“The Status construction uses pretty much the same materials and process as Modulus, but the necks are a true one-piece construction, where Modulus is two-piece. Modulus lays up the pre-preg fabric in a mold then bonds two pieces together to form a monocoque structure. It looks like the Status stuff is done by creating a foam core and wrapping pre-preg fabric around that core. It's probably easier to tool up a mold to make foam cores than one that directly forms the neck, and another plus of the Status process would be that you should be able to hand cut any shape in the foam buck rather than have to fabricate a mold. I'm pretty sure this is how the German Basslab basses are made, many with really crazy shapes, but I haven't ever had a chance to look inside one of these.”10) Rob Green has stated in a personal communication to Crazykiwi that observations by Dfung on the construction of Status necks are not accurate but declined to comment further on the grounds of commercial sensitivity.

Above(L-R): Modulus 'thousand dancing ladies' finish, the suspended graphite fibres of an early Alembic neck and the graphite weave of a Cutlass neck.

Modulus necks were prone to delamination because the glued surfaces were not substantial enough in later examples.

“The most infamous problem with Modulus necks is that the neck shell thickness varies which means that the width of the bonding surface between the back and the underlayment is variable. The graphite pieces are pretty impervious to damage, but the glued bonding surface isn't. If the glue line splits (technically a “delamination”), you're in a world of hurt, since repair requires the entire neck to be split apart and reglued, fingerboard and frets replaced, etc. If you're talking about a thru body instrument, then it's approaching hopeless (and certainly expensive). If the fabric isn't laid up right or cooked right, then the piece might have a warp that might not surface for years. Of course, these sorts of problems (and their painful solutions) crop up with wood as well. The earliest graphite necks were built up and cooked by Geoff himself. He had a lot of experience working with this stuff when nobody had much experience. In the later years, Geoff was busy running his company and fabrication was done by others - not necessarily “worse” but probably “different”. That might be reflective of why the earlier necks were better.”11)

Other examples of neck bow have been noted in instruments by Status, Vigier and Modulus, most likely because the fingerboards for these instruments were made out of phenolic resin recipe that was not stiff enough to withstand string tension for years without relief. Although these problems have been addressed by all the manufacturers since the mid 90's, the application of composite technology has always proved more demanding than the wooden equivalent.

Adoption of Composite Technology by Manufacturers Since The 1980's

Graphite inserts in bass guitar necks are common place these days and offered by many manufacturers producing mid to high end instruments including Alembic, Spector, Smith, Celinder, Fender, Yamaha amongst others. Most custom luthiers are happy to add it inserts to instruments they have been commissioned to build.

However a number of companies including G. Gould, Vigier and Steinberger (since owned by Music Yo/Gibson) have offered wooden necks with composite structural elements as significant features. For example, Vigier have offered the 90/10 system on their instruments (10% composite, 90% wood) and G Gould offer a t-shaped cross section on their Genesis line of instruments12).

As exponents of the technology in various ways, Steinberger, Status, Basslab, Gus, Miller and Rainsong have all offered instruments made completely from composite technology during the course of their development as companies.

Steinberger introduced the L-2 in 1980. It was a revelation in being both headless and made from composite materials. The instrument was easily taken onboard aircraft as hand luggage and the headless design meant minimal tuning problems while in transit. The bass was constructed from a mold using graphite and fibreglass fibres suspended in polyester resin. Steinberger also experimented with making the distribution of graphite fibres deliberately inconsistent so as to introduce some limited flexibility back into the neck structure where desirable 13).

[insert pic of Steinberger XL-2A]

Later the L-2 was developed with an active preamp circuit and utimately became the XL-2A. The minimal design aesthetic was distinctive and Steinberger admits that perhaps the body shape of the L-2 was too small in some respects 14). The range of instruments was expanded to encompass different body shapes and other features such as a transposing vibrato bridge were also offered. Although fashions come and go, the headless Steinberger L series bass has achieved iconic design status.

Rob Green's company Green Machine Technology (GMT) first introduced their headless range under the Strata15) brand in 1981 but a legal threat from Fender over similarities to their Stratocaster trade mark forced Rob Green to change the name to Status.

[insert pic of strata]

Rob Green initially working out of a small workshop in the back of Soundwave in Romford, Essex16), sharing the space with Barry Moorhouse, who ran a PA Company before setting up the Bass Centre, and Mark Gooday who was one of the founders of Trace Elliot. Later, GMT moved to Chelmsford and expanded thanks to growing demand and a series of high profile endorsements. Status Graphite are now located in Colchester and have employed a variety of construction techniques over the years ranging from laminated construction over MDF and hardwood cores to a hollow, monocoque construction, filled with epoxy foam to tune the acoustic response of the composite construction.

Miller have also used hollow body construction and offer a custom composite instruments as well as a range of other audio related applications17). A similar hollowbody construction has been used by Basslab who market the hollowness of their instruments as a feature18). Gus Guitars was started by Simon Farmer and they make use of lightweight tone wood cores before hand layering laminations of graphite weave fabric and epoxy resin. The resin hardens without the need for an autoclave. A tour of the Gus workshop is available here:

http://www.gusguitars.com/tour.php

Finally, Rainsong are a company specialising in the construction of all composite acoustic instruments and, while no longer offered as part of their range, at one point they offered a composite acoustic bass guitar. At the time of writing this entry, no pictures or clips were available of the bass but links to various models of guitar are easily found:

6 string acoustic http://www.youtube.com/watch?v=QiYiKogKiCM

12 string acoustic http://www.youtube.com/watch?v=QedSjOncLLk

nylon stringed acoustic http://www.youtube.com/watch?v=Njlb6jKOU3k

Jazz guitar http://www.youtube.com/watch?v=iRhsrm3snQE

As far as the future of composite technology is concerned, manufacturers have generally seemed to adopt composites along a sliding scale of implementation depending on where the point of balance between wood and composite was considered most desirable. The original problem of different rates of thermal expansion between wood and composite has been addressed by dramatic improvements in adhesive technology thanks to research by Formula 1 engineers, Aerospace engineers and yacht designers. However there appears to still be room for exploration as technology continues to develop.

Manufacturers using Composite technology

A fuller list of manufacturers and luthiers currently using composite technology as a significant structural component includes:

Basslab http://www.basslab.de

Bogart http://www.merlin-bass.de

GGould http://www.ggould.com/home.html

Gus Guitars http://www.gusguitars.com

Klein http://www.kleinguitars.com/

Miller http://www.miller-instruments.com/

Modulus http://www.modulusguitars.com/

Moses http://www.mosesgraphite.com/

Parker http://www.parkerguitars.com/code/models/models_bass.asp

Rainsong http://www.rainsong.com/

Schack http://www.schack-guitars.de/

Scott Ambush http://www.scottambush.com/

Status http://www.status-graphite.com/status/frames/index_home.html

Steinberger http://www.gibson.com/products/steinberger.html

Steinberger fan site containing history http://www.steinbergerworld.com/ [note, the construction details page has been deleted]

Switch http://www.switchmusic.com/ [this link is dead at the moment]

Vigier http://www.vigierguitars.com

References:

Patents

These are some examples of patents for composite neck technology that have been filed in the US:

http://www.freepatentsonline.com/6774292.html

This is a patent for a neck with a wooden core, outer skin of graphite composite, truss rod and twin graphite reinforcement rods. It needs to be hand manufactured but the wood is used as the main tone shaping characteristic.

http://www.patentstorm.us/patents/4846039/fulltext.html

This patent was submitted by Stephen Mosher of Moses Guitars Inc, for a solid composite neck consisting of layers of longitudinal graphite fibres with resin containing carbon power.

http://www.patentstorm.us/patents/4846038/claims.html

A second patent filed by Rick Turner for a T-bar shaped composite cross section in a wooden neck and frets secured by pins rather than tangs.

http://www.patentstorm.us/patents/6111175/fulltext.html

A T-bar shaped composite cross section integrated into the headstock filed by Richard Lasner of Modulus Guitars, as also featured in instruments by GGould in the Genesis range.

http://www.patentstorm.us/patents/6538183/fulltext.html

This patent describes the use of a non-foam elastomeric layer inside a hollow compsite construction to help dampen certain frequencies.

http://www.patentstorm.us/patents/4681009/fulltext.html

This patent describes the use of a single graphite composite member to reinforce a wooden neck using a substantial graphite reinforcement rod into which the truss rod (or rods) have been embedded.

http://www.patentstorm.us/patents/4290336/fulltext.html

This patent was submitted by Peavey for a fully molded instrument from composite materials in a clam shell construction, filled with epoxy foam to introduce some form of acoustic dampening. This bears some similarities to the construction technique used by Switch Guitars in their Vibracell range.

http://www.freepatentsonline.com/4313362.html

This patent was submitted by Thomas Lieber (maker of Stanley Clarke's Spellbinder range of basses) and

http://www.patentstorm.us/patents/pdfs/patent_id/6657113.html

This patent is for an integrated composite resin based fingerboard with glass bead frets that have the same if not better wear characteristics than conventional steel frets. The fretboard can also be fitted in a non-parallel angle to the neck if desired and to a neck that has already been pretensioned thereby producing the same effect as a fret-dressed fingerboard.

http://www.patentstorm.us/applications/20060174753/fulltext.html

Is a fairly ingenious patent to use electrically conductive elements to improve the consistency in distribution of matrix elements within the resin. It is also possible to introduce a degree of electrical and thermal conductivity.

As can be seen, these patents are mostly focussed on solving the following drawbacks of composite technology:

1) The different rates of thermal expansion between composite and other materials (eg. wood or phenolic resin)

2) Using the graphite technology to improve the structural consistency of wooden necks rather than replace them.

3) Improving the design of a composite neck to make it respond tonally like wood but retain all the benefits of composite construction.

4) Incorporate other technologies into composite neck construction to improve the versatility of the technology.

5) Simplify the manufacturing process

The future application of this technology has still has much potential.

* (still to describe and summarise) http://www.freepatentsonline.com/4950437.html http://www.patentstorm.us/patents/4951542/description.html http://www.wikipatents.com/4846039.html http://www.patentstorm.us/patents/4313362.html *

Youtube clips:

Composite cello construction
Seminar for motorcycle part fabrication
PBS TV programme on the move and expansion of Steinberger from Brooklyn to the Newburgh facility during the height of Steinbergers popularity
 
info/tech/use_of_composites_graphite_necks_in_bass_guitar_design.txt · Last modified: 2009/04/09 22:45 by crazykiwi
 
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