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jlpicard
Advanced Member
Username: jlpicard

Post Number: 251
Registered: 7-2002
Posted on Thursday, November 17, 2005 - 9:12 pm:   Edit Post

I had the strangest experience on a gig a couple of weeks ago. I was playing for a grand reopening of a small ski resort in the mountains of Ogden, Utah, about 40 miles north of Salt Lake City. It was outdoors on top of a couple of flatbed trailers, no covering, stage pointing south directly at the sun all afternoon. I got quite a sunburn on my left arm, ( I'm a lefty )as it crosses the body of the bass and I still had to squint all afternoon, even with dark sunglasses. This gives you an idea of how intense the sun was up at that altitude.
Anyway, I set my bass in its stand about twenty minutes of so before the start of the gig, a hang by the headstock model Hercules stand. I played the first set, everything normal, took a 15 minute break, picked up the bass and noticed the neck was a bit warm,(defintely warmer than the light colored Maple body. I went to play a note and
ffllitt, buzzflitt... nothing! All four strings had totaly bottomed out against the lower four, maybe five frets! PANICTIME!! Now granted, I keep my action very low on this bass. Also, it does not have an adjustable nut and I had no tools to adjust the bridge with me. I did the only think I could think of. Using the lightest touch that I could I played up higher on the neck sometimes having to resort to taking a few notes up an octave here and there. As the set progressed I would go down below the fourth fret to check things out and found that it gradually became better the more I played. At the next break I kept the bass totaly out of the sun and the bass was fine for the rest of the gig. I have not had any further problems with this. Could the sun exposure have caused this in such a short period of time? Anyone else ever experience anything like this with their graphite neck? Mica, Val? care to offer an explaination. I'd always though graphite necks were tougher than that. Mike
keavin
Senior Member
Username: keavin

Post Number: 556
Registered: 12-2002
Posted on Friday, November 18, 2005 - 12:26 pm:   Edit Post

Graphite appears not to be all it's cracked up to be,not only is it not supposed to move,but you pay a hell of a lot more money for it than a wooden neck, & being that it's a man made material it's not perfect either,are you sure it's not made in mexico!.
mica
Moderator
Username: mica

Post Number: 2815
Registered: 6-2000
Posted on Friday, November 18, 2005 - 4:14 pm:   Edit Post

Graphite does in fact move. This is one of the reasons we no longer offer it. You may also be experiencing expansion of the phenolic fingerboard that I believe your bass has. When anything gets warm it expands. If you imagine your fingerboard suddenly growing an longer but still being glued to the neck, the result would be a backbow.

It seems that the earliest necks we got were more stable. These are the ones that look like woven cloth. Some of these move too, but they seem more stable than the ones with large chunks of graphite in the mold.

Glad you were able to limp through the gig, and hopefully the one thing you'll take away from the experience is to keep a small set of keys with your bass at all times so you can make emergency adjustments if needed.
kungfusheriff
Senior Member
Username: kungfusheriff

Post Number: 418
Registered: 8-2003
Posted on Friday, November 18, 2005 - 11:08 pm:   Edit Post

Mike,
Graphite necks are great, but if yours is anything like mine, it's nearly jet-black and no other color absorbs as much heat.
Simple physics...that's why us shoeless hillbilly children walked on the white line at the shoulder of the road, because it was always cooler.
The good news is, should you ever decide to move north, your neck will hardly ever move. I tune my bass every tenth of never.
jlpicard
Advanced Member
Username: jlpicard

Post Number: 254
Registered: 7-2002
Posted on Saturday, November 19, 2005 - 2:02 am:   Edit Post

Actually, the bass is usually pretty stable, tuning wise. Mica, I get your point. Stable or not,If that phenolic fingerboard expands, It is going to want to go somewhere so push against the neck it does! I imagine that if this were to occur too often the fingerboard would probably start to separate from the neck. Now I see why most manufacturers do not use Phenolic boards.I think however, that this was a freak circumstance where the bass was exposed to a more harsh environment than I realised. As I stated earlier, the Sun was rather intense that day. Also , being at about 5500 ft. altitude probably didn't help either. Now that I know I will make it a point place the bass in it's case on breaks when playing outdoors. Thanks for the info Mike
dfung60
Intermediate Member
Username: dfung60

Post Number: 112
Registered: 5-2002
Posted on Sunday, November 20, 2005 - 2:30 am:   Edit Post

I've got a lot of Modulus basses (Modulus built the graphite neck on your Alembic) and I've probably experienced most of the problems that these necks have. I would agree that the problem you had is dominated by by the phenolic fingerboard.

The graphite neck is made in 3 pieces. There's a molded section that has the shape of the back of the neck, headstock, and continues into the body up to the bridge. It has a U-shaped cross section (the neck is hollow). There's a thick flat piece (Modulus calls this the "underlayment")that is bonded on top of the U-shaped neck section and is under the fingerboard. Finally, there's a phenolic fingerboard bonded onto the underlayment. You can see all these pieces if you look at the edge of the neck.

The main neck piece and the underlayment are really, really structurally strong. They are largely impervious to temperature, humidity, and other environmental factors. The phenolic fingerboard material is a special kind of paper that's been saturated with a resin. It's actually fairly sensitive to humidity and temperature, I think more so than a traditional fingerboard wood like ebony.

The main piece and underlayment are bonded together using epoxy and this forms a hollow tube (or monocoque) which is an extremely strong structure. Even then, it will still flex under string tension or even from the tension of the fingerboard. Under extreme temperature conditions that you had by accident, you were probably seeing the force that the fingerboard can exert against the graphite neck structure.

The big difference in thermal expansion between the neck and fingerboard is actually a pretty deal and it exacerbated by the way the neck is fabricated. The problem here is that the graphite neck components are really strong, but the epoxy that's holding it together is much less so. In a perfect world, the epoxy has perfect mating surfaces and is equally strong as the epoxy in the neck pieces, but mixtures can be wrong, the chemicals can vary, as does the prep and conditions during assembly. Modulus builds the neck out of many sheets of graphite fabric which are hand laid into a mold and cooked at high temperature and pressure. The underlayment is a regular plate so it's always flat, but the neck piece has to be milled when it comes out of the mold so that it has a dead flat surface. In most cases, this all works out fine, but if there is any bow in the main neck piece, forward or back, then you have two very strong pieces trying to separate each other and only the glue holding them together.

With the sun exposure you had, the fingerboard is stressing the underlayment. This is particularly bad because the bonding area between the main neck piece and the underlayment is two thin lines at the sides of the neck (remember, it's U-shaped). The fingerboard is bonded across the entire surface of the underlayment so it actually has an enormous amount of strength to pull on the weaker joint. The most serious problem that you can have with a Modulus neck is a separation of the main piece and underlayment (they call it a "delamination") which is potentially fatal.

All these necks are built up by hand and there weren't a lot of Alembic necks at all (I think it's around 50 but only Alembic would know for sure). In regular production at Modulus, the fabricators have a recipe of how much material needs to be placed in the neck and where, but for special stuff like the Alembics, it's a little more chancey, so the Modulus folks often overbuilt these necks to make sure that they were solid and stable, but this might affect the relief in the completed neck which is an extra hassle for setup at Alembic (no truss rod here, so relief needs to be manually cut into the fingerboard and frets).

I think you actually want to be pretty careful about heat and temperature with these necks (which really means treat them like a wood neck). High and low heat can affect the glue joint as would impact if you drop the instrument.

I have had 3 delaminated necks, two of which I've had repaired. One was due to a significant bow in the main piece and too narrow of a gluing area. The other was a failure from a drop (sadly, this was a BassStar through-body). I have the original fingerboard+underlayment from that one which had to be completely disassembled, remilled, and reassembled. It has a concave bow of nearly 1.5" (the phenolic is the short side here). It's physically quite hard to bend, even though the underlayment is only about 1/8" so you can imagine the amount of tension that the glue joint and main neck piece was bearing.

Finally, there has been some evolution of the neck materials over the years. The earliest necks have a finish that looks like tiny crystals, then there was a wavy-patterned fabric, then checkerboard, then the large polygons/chunks that you see today. These finishes are actually all cosmetic material that's placed in the mold for appearances and past that cosmetic layer, the construction is pretty similiar. But I would definitely agree that there are differences in stiffness, stability and tone between the different generations. The oldest ones sound best to me and feel the stiffest, as Mica mentions. However, it's been my experience that the older ones are a lot more likely to have fabrication problems than the polygon necks that comprise most of the ones out there. By the time Modulus was doing the polygon necks, they had much better equipment and had refined the build techniques significantly. All three of my failed necks are old ones - two checkerboards and one wavy.

In case you're wondering, I'm close friends with Geoff Gould who founded and ran Modulus for many years and, in addition to owning a lot of Modulus basses (and a 1987 Series II graphite neck), we've spend countless hours talking about how this stuff was put together.

David Fung
jlpicard
Advanced Member
Username: jlpicard

Post Number: 256
Registered: 7-2002
Posted on Sunday, November 20, 2005 - 8:37 pm:   Edit Post

My neck has the tiny crystals. It appears to be fine along the fingerboard, however, around the top and one side of the headstock, you can see a fracture line between the crystaline part of the head and the solid looking underlayment that appears to have been repaired at one time.

Another thought has occured to me, Why not replace the fingerboard with Ebony then if it is more stable than phenolic? Or, why not build a graphite fingerboard? Or are there other insurmountable issues with trying to install and keep frets in the graphite? Also, hasn't Adhesive science advanced sufficiently since my bass was built ( 80' ) to minimize the delaminating issue somewhat?
dfung60
Intermediate Member
Username: dfung60

Post Number: 113
Registered: 5-2002
Posted on Monday, November 21, 2005 - 12:42 am:   Edit Post

Yes, this sounds like the standard symptoms of delamination, but when it's up in the headstock, it's not as big a problem as when it's in the neck area. When the monocoque is compromised along the neck, you may find that you can't keep the neck straight anymore, but up at the headstock, it's not as serious a problem.

If the parts don't have a natural warp pulling them apart, then I think this sort of problem is fixed by injecting the break with super glue. If they do have tension pulling the joint apart, then it's a much bigger problem. The proper fix requires you to split the neck back into the pieces and mill the warp out. That's major surgery, and generally Modulus doesn't even do this sort of repair work anymore. But, as I said, when it's up in the headstock, I don't think this will be as big a problem.

When Geoff first started making the graphite necks, he's told me that he was concerned about the differential expansion between wood and graphite to use a wood fingerboard and decided to go with phenolic which was the original composite material. Later, Modulus did do some instruments with wood fingerboards (cocabola and chechen I think) but most are still with phenolic. So, I think you may still have the same sort of problem with ebony and you have the problem here of having to remove the existing phenolic board to install a wood one. That's not trivial, especially on a through-body instrument like your Alembic.

A graphite fingerboard would avoid the problems of differential expansion but the problem there is that the material is very difficult to work with relative to wood. You have to cut the fingerboard radius into the surface and install frets. Doing so on a production basis would require using expensive carbide-tipped tools. Phenolic works similarly to wood and they use totally conventional guitar tools to do the fretwork.

There are actually a couple of instruments out here with graphite fingerboards. Probably the most common is the Parker Fly. I don't know exactly how they do it there - it's either a CNC milled fingerboard or they build the graphite layer on top of a shaped form. Moses Graphite necks are one-piece with the fingerboard radius machined in. The Moses necks are a different kind of construction that have a relatively low graphite content (they don't use the graphite pre-preg fabric). Modulus' fabrication technique makes it hard for them to produce two complex shaped parts and mate them; their designs are all one complex piece mated with one flat one. The glue the underlament to the main neck piece, then trim the underlayment to match. It sounds pretty haphazard, but this yields better results than having to have very complex (and expensive) multi-part molds. Although graphite bike frames are sold as being very high-tech, I believe they're all largely hand-made and hand-fitted rather than being assembled my automation.

Glues are definitely more advanced than in the 70's and 80's but it doesn't help much as you're totally dependent on the glue that that's there. The "problem" that makes the older necks less reliable (in my opinion) has to do with the hand-built nature of the necks. Since the thickness that the u-shaped part is built to can vary and the amount of milling it will require will also vary, there's a danger that the width of the bonding surface is too narrow and that's where the delaminations occur. On that failed neck I have, the epoxy bond goes all the way across the width of the neck at the first fret, but is only about 1/8" wide at the section where the joint failed. When they reconstructed this neck they built up the inside of the neck to increase the glued area.

The old-timers who worked on a lot of these instruments have mentioned that necks in the checkerboard fabric period were sometimes built too thin and have the narrow bonding area problem. I believe that most of the crystal necks were fabricated by Geoff himself and were overbuilt as they were figuring out the process. By they polygon finish necks, Modulus had a very good understanding of what they needed the construction to look like and were building at a much higher volume so everybody involved had more expertise.

If the main bond along the sides of the neck is strong, then there's really nothing to worry about. Even with all these hassles, I still love the sound and feel of graphite necks. Wood necks can suffer many of these same problems - warps, delamination, glue problems, design issues although it's quite a bit easier to deal with these problems on a wood neck.

David Fung
jlpicard
Advanced Member
Username: jlpicard

Post Number: 258
Registered: 7-2002
Posted on Monday, November 21, 2005 - 3:37 pm:   Edit Post

I'm beginning to wonder if Geoff Goulds latest designs are the way to go. Have the graphite in the center of a wood neck to take the tension and reduce the dead spots and then let the rest of the the neck do what it does best.
dfung60
Intermediate Member
Username: dfung60

Post Number: 114
Registered: 5-2002
Posted on Monday, November 21, 2005 - 7:50 pm:   Edit Post

Actually, most of the latest GGould basses are back to a Modulus-like all-graphite neck (they do have a truss rod now).
ed_r
Member
Username: ed_r

Post Number: 68
Registered: 10-2005
Posted on Monday, November 28, 2005 - 1:01 pm:   Edit Post

What ski resort? Powder Mountain? Nordic Valley? Snow Basin? Been 25 years but I used to live there! )
jlpicard
Advanced Member
Username: jlpicard

Post Number: 261
Registered: 7-2002
Posted on Wednesday, November 30, 2005 - 6:55 am:   Edit Post

Nordic Valley.

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