question about carbon fiber

spookelele

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Sorry if this is a dumb question.. but I bought a flake (schoenhut chinese fluke flea clone), replaced the strings with martin flourocarbons and it sounded terrible, so I took it apart, to see what could be done with it after seeing the "pimp my schoenhut" thread.

So.. what I'm thinking of is a learning project of replacing the soundboard with a 1.5mm sheet of carbon fiber plate, which I think should be easy, since I don't think I'd need to brace it, and that's the thickness of the original plywood face, so I wouldn't have to alter the plastic body. (200x300x1.5mm carbon plates are like $19). Also I'm thinking of going to a tenor scale neck, using a prefab fretboard, replacing the saddle with a regular rosewood one, adding a nut, and installing some geared tuners.

What Im not sure about, is what a carbon fiber sound board will sound like. Outside of the blackbird, I'm not seen anyone make a soundboard with carbon fiber.

Would I be wasting my time/money doing this? Sure I could just buy a flea, but I like tinkering, and the way the plastic body is made.. makes it really easy for a non-experienced lay-thier to make a body, connect a neck, etc.

What do you guys think? Am I just off base with the idea of a carbon fiber sound board?
 
A friend of mine Rolly Brown became the National Fingerpicking Champion at Winifield KS in the early 80s Playing a plastic carbon fiber guitar . Can't be all that bad.

If you have the money time and tools go for it.

http://www.rainsong.com/deal/
 
Personally I think you are getting into some deep waters here. It isn't so much a question of how the carbon fiber is gonna sound is how you are gonna mate it perfectly to the existing neck/neck block/fingerboard/sides connections. These connections all need to be flush/flat/true/plumb. Otherwise, it doesn't matter what kind of tonewood you put in, it won't get proper intonation no matter what you do. On the other hand, what do you have to lose? At the very least you are gonna learn a lot of lessons and who knows, you just might build the perfect plastic uke. Conclusion: Think how it all fits together before you start thinking about top thicknesses. Then go for it. Send pitchers...
 
Just do it!
 
Carbon fiber is a cool idea. Better test some glues to see what will bond the CF to the plastic body. I had issues even bonding wood to it. I've pimped a half-dozen Schoenhuts so far. They're so cool!

Critical part is setting the neck to accommodate the top thickness. Also, you'll have to sand down the perimeter of the body to be level with the thinner CF, otherwise you'll have a lip. Use the plywood soundboard on a pattern router to duplicate the shape in the CF. That way it will snap right in place on the body.

I did work up a scale drawing for a Tenor sized Pimped Schoenhut. But I haven't built one yet. I made it for a 14th fret join. I did have to move the bridge location down a bit to make it work. The body is too small for a 12th fret join. I can send you a PDF if you want.

ScreenShot2014-12-19at101510AM_zps596bcea9.png
 
http://forum.ukuleleunderground.com/showthread.php?96315-Pimp-My-Schoenhut

he's got good pictures of it dismantled there. The neck is a straight piece of maple plank that's been notched and rounded, and then screwed to a support structure inside the plastic body. Im considering trying to open the gap between the main body and the spaces in the ribs that hold the neck brace, to increase the volume of the body, since as it's built.. that space is dead.

as for glue, my plan is to use a CA gel.
It's whats used in archery to glue plastic fetching to carbon fiber shafts.

RPA_uke: Do you have any advice on a solvent for the crap they used to glue the plywood to the back? I don't want to grind it. Im planning on trying vinegar, but I'm not sure if what they used is like titebond, or if I need something stronger like hcl.
 
Actually the neck join using the two screws is surprisingly secure. (thanks really to the Flea design, the Schoenhut is identical) BTW, Schoenhut loosely translates to "Pretty hat" just sayin.

Be careful opening up those ribs at the neck join as they provide the stiffness to the structure and make the neck so secure. This will be especially critical for the much longer tenor neck. It will be interesting to see how well thick CA works to bond to the plastic body, keep us posted. And as for the crap the factory use to bond the top, well I wish I knew what that crap was, 'cuz it works like an MF. The only way I've found to remove it is with a sharp chisel.
 
Actually the neck join using the two screws is surprisingly secure. (thanks really to the Flea design, the Schoenhut is identical) BTW, Schoenhut loosely translates to "Pretty hat" just sayin.

Be careful opening up those ribs at the neck join as they provide the stiffness to the structure and make the neck so secure..

I was not going to remove them, but cut holes in them. I had considered trying a hole in each rib at alternating ends, and then opening a hole through the plastic body on the side near the neck, which would essentially give me a port tube, but the thing about port tubes is they distort frequency response based on the tuning of the port and I lack the math to figure out what frequencies that would be, so I'm going to stick to holes to try to use that volume.

I've built speakers before, but not an instrument... so I'm going to be a bit conservative for this, and see what I learn. Even if it ends up sucking, I think I'll gain some experience and perspective, or just know if the idea was bad to begin with.
 
The 1.5mm CF sheet will be much too heavy and stiff I suspect. The CF will weigh much more than a piece of plywood the same thickness and it is mass and stiffness that will determine how your instrument sounds .5mm would be more suitable, maybe with a couple of small braces if required. The other thing to consider is how you are going to shape your rectangular sheet . The CF will blunt any saw blade or router bit in seconds and it is a lot to sand away. No-one seems to be quite certain about the long-term heath effects of inhaling CF dust, but it should be avoided.

Just a couple of thoughts

cheers
 
The 1.5mm CF sheet will be much too heavy and stiff I suspect. The CF will weigh much more than a piece of plywood the same thickness and it is mass and stiffness that will determine how your instrument sounds .5mm would be more suitable, maybe with a couple of small braces if required. The other thing to consider is how you are going to shape your rectangular sheet . The CF will blunt any saw blade or router bit in seconds and it is a lot to sand away. No-one seems to be quite certain about the long-term heath effects of inhaling CF dust, but it should be avoided.

Just a couple of thoughts

cheers

Hi, have you worked with CF before?
CF is actually pretty easy to cut. It's nowhere near as hard to cut as formica, which is another material I considered, cuz it's cheap, but I think CF should be more resonant. They make some speaker cones from CF, but never from formica :)

CF fiber is actually very soft and fluffy. It is usually cut with plain scissors because although it's got high tensile strength, it's not got great shear strength. The "hard" part is epoxy, which has a rockwell hardness of roughly 75. For comparison abs plastic is usually 85-95's. (higher number is harder material). There's pretty much no way it's gonna blunt a router bit. There's nothing in the plates that's really all that hard.

As for health, you're right.. sort of. CF is nano-carbon chains. But ground CF is still bound to the epoxy, making it much safer because it's a much larger particle. I still wouldn't suggest eating/breathing it, but I wouldn't suggest breathing anything that isn't air. :)

Anyway, my CF plate should arrive next friday, and my fret board in 2-3 weeks. (slow boat from china, don't hate... cuz thats where most fretboards come from really)
 
I have been using CF tow impregnated with epoxy every now and again for close on 30 years as re-enforcement on soundboard braces and things like that. I was shown how to use it by Greg Smallman, the Australian classical guitar builder who developed carbon-fibre/balsa lattice braced guitars in the early 80s. In the last ten years I have been using CF/epoxy bars for mandolin and ukulele neck re-enforcement and sometimes using CF tube between the neck and tail blocks for extra body rigidity. I found out the hard way that using any kind of toothed saw blade to cut a CF bar to length will blunt it within seconds and to hit it with a router bit does the same to them. I have no idea why the combination of the soft CF and epoxy is so abrasive, it just is. Maybe thin sheet CF/epoxy will be easier to work with, but I would be thinking about having a stock of Dremel cut-off discs on hand as they are the only thing I have found which will cut the stuff.

I can only suggest you think about the weight of a 1.5mm thick CF/epoxy sheet compared to the weight of a similarly dimensioned piece of spruce or mahogany.

Cheers
 
Graham, your short use life on toothed blades used with resin matrix materials may be due to the resin softening -It probably is be coming plastic actually. The resin dust in a plastic state adheres to the gaps between the blades, clogging them, they overheat. yada yada. If this is indeed the case a solution presents itself to me. A blower system, to remove the dust from the cutting area will allow heat rejection from the cutting area on the blade and improve the useful blade life between sharpening.If this seems efficaious the blower air stream should be directed towards your dust removal or storage receptacle. (Or your resin recycling reservoir is that is appropriate to your resin material and shop practice).
 
Okay, I'll bite on this thread.

Issues I see that you may run into, along with some comments on some things you're planning:
1) Redundant to what Graham brought up, but machining the sheet should be a pain at best, especially when bringing them into the sides. Not to mention cutting a soundhole. I think starting with CF sheets and laminating them would be the way to go.
1a) I cut CF rods with a hacksaw. Yes, they make dust, and they dull the hacksaw. When I used to extend the CF rod in my neck past the scarf joint, sanding them was a bitch as well - not sure if the sandpaper was eating the cf, or the other way around.
2) Ca glue, for cf and plastic?
3) Change to tenor scale? Does the body fit the new bridge placement? Is it optimal for the design?
3a) I don't see a new neck coming into play.
3a1) See item #3 above.
4) Change the saddle to rosewood? I don't get this one?
4a) Just curious - using the same bridge, or using a new one? Funny that you'd specifically change the saddle, but mention nothing of scale length, bridge placement and bridge material.
5) Most fretboards from China? I missed that one. All mine come from lumber, either local, Africa or South America.

I think it would be easier to start from scratch. But I don't think this is about easy, or a final product. This is about a process just to say "this is what I did" no matter the outcome.
Unless I'm missing something, this exercise has nothing to do with a series of questions in the Lounge about a musical instrument as much as it has to do with taking apart a musical instrument and Frankensteining it. Eddie Van Halen already did that, but I'd like to think he had a musical, sound and playability related goal to his guitar.

This one, I don't get. BUT, I don't have to - its not in my shop.
 
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Okay, I'll bite on this thread.

Issues I see that you may run into, along with some comments on some things you're planning:
1) Redundant to what Graham brought up, but machining the sheet should be a pain at best, especially when bringing them into the sides. Not to mention cutting a soundhole. I think starting with CF sheets and laminating them would be the way to go.

The body has a lip around the edge. It's built to wrap up the side with the soundboard snapping into the recess. It's not built flush like a real uke. I don't have to trim the plate on the uke. I need to make a top that will fit into the body. I've gotten the original top off in one piece, so I have a perfect template.

1a) I cut CF rods with a hacksaw. Yes, they make dust, and they dull the hacksaw. When I used to extend the CF rod in my neck past the scarf joint, sanding them was a bitch as well - not sure if the sandpaper was eating the cf, or the other way around.

I've only worked with CF rods. Lots and lots of them for arrows.

2) Ca glue, for cf and plastic?

yes. It's what we use in archery to bond plastic fletching to carbon shafts. If you have a better suggestion, I'm all ears.

3) Change to tenor scale? Does the body fit the new bridge placement? Is it optimal for the design?

I plan on making a new neck. The neck they use is pretty much a straight piece of maple notched on one end to fit the body block, and then rounded on the back. Is it optimal for the design? I dunno. But my fingers are used to tenor scale and soprano's feel cramped to me. Im hoping the longer string length improves the tone, but not having built an instrument, I don't really know if that's going to be true. I basing that on piano, and sound of longer strings on grands, vs upright/spinnet or even between grands of different lengths. Again, I could just be completely wrong, since there are some very full sounding concert ukes, and Im constrained to body volume because I'm using an existing shell.

3a) I don't see a new neck coming into play.
3a1) See item #3 above."

I was planning to make a new neck, because I'm assuming that I need 17" between the saddle and the nut, and I don't see a way to do that without a new neck. Is there a way? I'm assuming that the bridge needs to be in the middle of the soundboard somewhere. Again.. I'm a newb, and didn't think you could place the bridge on the butt of the body out side of like... electric solid body or something where you don't need an actual sound. Am I wrong? Im basing alot of this on assumptions, and maybe I'm wrong for doing that?

The way they make the neck join the body I think should make it easy to make a new neck. My plan is for a straight plank of maple. Notch the one end to fit the body, grind the sides of the neck to fit the fretboard, and then round the back. For the head, I'm not going to bend the head back, but make it straight. The slot design of the original head means you get a break angle over the nut without bending the head back. I'm debating not using the slot design, and instead using string trees to pull the string down over the nut, so I can get more traditional shape to the head and still not bend it back, but I'm still thinking on that.

4) Change the saddle to rosewood? I don't get this one?"

The saddle/bridge it comes with is a solid 1 piece molded plastic. There's no way to compensate for tone, or for action height. I am probably going to need to do both, since I'm guessing the fretboard is going to be a different thickness than the original plastic one the 1 piece saddle/nut was made for.

4a) Just curious - using the same bridge, or using a new one? Funny that you'd specifically change the saddle, but mention nothing of scale length, bridge placement and bridge material."

see 4)

5) Most fretboards from China? I missed that one. All mine come from lumber, either local, Africa or South America."

Seeing how the vast majority of mass market ukes are built there.. yes. They produce most of the uke fretboards there. I'm hoping they have the spacing right based on the volume they churn out, and the one I'm getting is coming from the same place kala/makala/mahalo/etc is getting them from for their entry ukes. I'm looking for function here, cuz Im new, and I don't want to tackle making a fretboard yet.

Like I said, I'm a complete newb to lutherie. I'm assuming the chinese fretboard is more accurate than one I would make at this point. I've done my own setup type work. Leveling frets, nut/saddle height/compensating saddle. But I've never built any instruments, which I understand is a completely different thing. Also.. making a fretboard seems like alot of work, and if it ends up sucking in the end I'd hate to have spent alot of time in this part.

I think it would be easier to start from scratch. But I don't think this is about easy, or a final product. This is about a process just to say "this is what I did" no matter the outcome.
Unless I'm missing something, this exercise has nothing to do with a series of questions in the Lounge about a musical instrument as much as it has to do with taking apart a musical instrument and Frankensteining it. Eddie Van Halen already did that, but I'd like to think he had a musical, sound and playability related goal to his guitar.

This one, I don't get. BUT, I don't have to - its not in my shop.

Don't get me wrong. I don't expect the outcome to be mind shattering good, but hoping it's not going to be crap either (which is what I am starting with anyway).

Like I said in the original post, this is a learning exercise first and even if it's bad, I think the experience would be fun. You're looking at it from the position of someone that already knows how to do all this stuff from scratch. I'm looking at it from the other side of getting my feet wet and starting with baby steps by using some pre-made pieces, but not having them all just work by themselves like a grizzly kit.
 
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