building a carbon fiber case

**mandomania7923** · Aug-07-2009, 6:07pm

hello all. i have been thinking of building my own carbon fiber mandolin case. any thoughts, suggestions, or ideas on the shape, structure, material, and process would be greatly appreciated. thanks. also i have found latches similar to the ones on pegasuses and the locks on the bam violin cases. should i do fiberglass for a first time case since it is cheaper?

thanks in advance.

**Rick Turner** · Aug-07-2009, 6:12pm

How much experience do you have in molding fiberglass or other composites?

**Dale Ludewig** · Aug-07-2009, 6:55pm

Rick asks a good question: how much experience do you have with this process?
Then comes the questions: Do you want to make a mold? For how many cases? Figure out all the "little things", like lining, padding, latches, rubbery moulding around the edge, etc. Unless you're really into doing this thing for yourself, I think you'll be way way ahead to just go buy a great case, like a Peg or a Calton. If you're really into doing it yourself, have at it!

**bonny** · Aug-07-2009, 7:02pm

Originally Posted by mandomania7923

should i do fiberglass for a first time case since it is cheaper?

The law of diminishing returns leans towards using fiberglass. A mandolin case is so small that the difference in weight between glass and CF won't be of huge benefit. Certainly not enough benefit to offset the significant cost difference. Chances of getting the first one right should be considered too.

**mandomania7923** · Aug-07-2009, 7:03pm

I'm not very experienced, but you do have to start somewhere. and where better than a mandolin case? I'm looking to only build one the first time but eventually build some more. I have been researching for about six months. I think i'm ready to start. and how would you do it without a mold? of course i would want to make a mold

**Rick Turner** · Aug-07-2009, 8:25pm

First you make a plug; from that you make a mold. The plug can be an external one or an internal one. Depends on how nice a surface you want coming out of the mold.

The real trick is in trimming the top and bottom and then installing the hardware. Then you have to figure out how to line it so it looks as least as good as what's already out there.

Carbon fiber is sexy and pretty marketable in a really high-end way. Just don't think you're going to be able to beat Calton or Mark Leaf or Karura at their own game. You're going to be making cases that will need to cost more than most people spend on their first mandolin.

If you want to see how some good molding is done, check out the Luis and Clark website and also the CA Guitars site. They both have very detailed videos available on how they make carbon fiber instruments vacuum bagging into concave molds.

**mandomania7923** · Aug-07-2009, 9:04pm

rick,

thank you so much for the response. I found it very interesting. What i was wondering about with starting out with fiberglass is i was wondering if it would be good to start out there and then going to carbon fiber because fiberglass is cheaper and i wouldn't want to mess up carbon fiber on the first time.

**mandolinplucker** · Aug-07-2009, 9:50pm

I have done a little fiberglassing on boats and fabricating race car bodies. I would use fiberglass or epoxy reson and glass cloth at least for the first one. cheaper and easy to work with. First make the case out of wood, the size and shape of the case that you want. Glass that and sand it perfectly smooth down to real fine grit paper. Coat this "plug" with gel coat or epoxy paint. Sand this down smooth and coat with mold wax . Make sure that this is what you want because this will be the size and shape of the finished product. Any humps or bumps will be there in the end. Do a few coats of wax and buff it smooth. Spray this down with gel coat and build up fiberglass mat layers till you have a good stiff mold. If you waxed it good you can pull the plug out of the mold. Now you got a mold. To make the case you wax the mold,spray it with colored gel coat and build up a couple of layers of glass and pull the case half out of the mold. Then you have to round up the extruded aluminum, rubber stripping, hinges, locks, handle, padding, velvet material, ect. Hell of a lot easier to go buy a case. I am retired and time ain't money to me, it's just time, but I wouldn't waste it on this project unless you are going into the business of making cases.

**mandomania7923** · Aug-07-2009, 11:12pm

thank you so much for the feedback. this will help alot. i am absolutely going to do it. and the reason is because i will have my mandolin with me every day. Now nothing is going to keep people from stealing it but i will be near a bunch of high schoolers. i don't trust a normal case. i'm paranoid about my headstock scroll breaking in a calton. Pegasuses are nice but 800 dollars and i have multiple instruments and there are things i don't like about them. I will be making more than one case and selling a few probably. thank you so much for the input and hopefully more to come

**mandroid** · Aug-07-2009, 11:48pm

google vacuum bagging, it is a technique to get the air bubbles out.

Though with fiberglass it is pretty common to just chase the air-bubbles out your self by hand ,

a tool that looks like disc harrow is one that you can roll , compress and force trapped air bubbles out

you can use epoxy and fiberglas, epoxy is a bit less noxious smelling than polyester resins

Oh and don't forget to do a good coat of mold release..

1st you get a mold made then you can make your part..

Awhile back someone showed a case they made the first thing after spraying in the gel coat,
in the mold was a nice printed fabric with an interesting pattern on it , no pigment needed
saturated in catalyzed resin..

**man dough nollij** · Aug-08-2009, 1:14am

If you make a nice, smooth mold for fiberglass, shouldn't you also be able to use that for CF later?

**boatman** · Aug-08-2009, 7:32am

For a "one off" project such as you are contemplating, I would think that constructing a cold molded (ie. wood veneers + epoxy resin + vacuum bagging) case would make more sense. This technique is, to this day, utilized for high performance racing multi-hulls (boats) and even aircraft. Objects made via cold-moulding are very strong, stiff and lightweight. As stated above, you've got to make a plug, before you make a mold, before you lay up the fiberglas/carbon fiber object. Let the plug be your case; if you run out of steam before getting to the lay-up, you've still got the structure of your case. Regards

**bonny** · Aug-08-2009, 7:53am

Originally Posted by mandomania7923

i'm paranoid about my headstock scroll breaking in a calton.

Why?
The only breakage I've seen in any Calton has not been the fault of the case.

**jimbob** · Aug-08-2009, 8:32am

I think the price of a Calton and Peg are probably indications of the cost associated with materials and labor....no way to match quality and cost building one case, but it could certainly be done. Be sure to show us some pictures.

**Lefty Luthier** · Aug-08-2009, 9:16am

I occasionally build custom cases for my mandolin customers. It ain't as easy as one might think. For a beginner, I would definitely stay away from carbon fiber since it is very stiff and difficult to form without a male/female mold set. I suggest using either 1/4 x3/4 wood strips with bead/cove edges or 1/8 thick plywood with a single layer of 10 oz glass with epoxy resin. This is how kayaks are built and is very strong.

**mandomania7923** · Aug-08-2009, 11:34am

when you say a single layer of 10 oz glass do you mean for the case or the actual mold. seems a little thin for the case

**Rick Turner** · Aug-08-2009, 12:03pm

You can lay up carbon fiber cloth pretty much the same as fiberglass. Just look at the videos from Luis and Clark and CA Guitars.

I still think the big trick is not making a mold and molding the case, though that is certainly a labor intensive process. The real trick is in getting a waterproof or resistant molding around the lips of the lower and upper portions and doing that neatly, and for that you have to start with properly trimmed edges. That would be best done on a pin router with a carbide saw blade mounted in an arbor. Note that CA does that process on the top of the sides of the guitar bodies, and they do it wet.

Then there's the issue of bending aluminum extrusions or learning how to mold that lip portion of the case. All of this is going to make the molding process look downright easy.

This reminds me of the spike of interest in ferro-cement boat hulls in the 1960s...Wow! A cheap way to build a boat! And hundreds of hulls sat in back yards when the builders finally realized that the hull was the least expensive part of building a boat. The finishing off of the interior and then the rigging, motor, electronics, etc. all made the hull portion look insignificant.

Molding a decent looking case is the easy part. The hard part is finishing it off nicely.

BTW, the only thing wrong with Calton, Mark Leaf, or other fine cases is if you don't use a proper foam wedge to support the peghead. Whiplash damage is very real; it often results in a crack that goes from the nut slot down into the shaft of the neck rather than the usual snapped peghead break that goes with the short grain into and across the peghead. I repaired two very expensive instruments (a D-45 and an RB5) in one month that had been in Mark Leaf cases which had fallen over flat on their bottom sides. The neck support held the neck, and the pegheads kept going... Neither case had peghead support.

**Lefty Luthier** · Aug-08-2009, 1:22pm

Originally Posted by mandomania7923

when you say a single layer of 10 oz glass do you mean for the case or the actual mold. seems a little thin for the case

Fiber glass cloth is designated by the weight per square yard so 10 oz cloth weighs 10 oz for a piece 36 x 36 inches. As I said, you put this over thin wood. Kayaks built from 1/4 inch thick cedar strips covered with a single layer of 10 oz cloth on both sides are extremely rugged. You could jump up and down on a case made this way with no damage to either the case or instrument inside.

**mandomania7923** · Aug-08-2009, 1:43pm

I saw a video where they start with much lighter pieces to get it started and work their way up. would this work as well?

**Lefty Luthier** · Aug-08-2009, 1:47pm

Originally Posted by mandomania7923

I saw a video where they start with much lighter pieces to get it started and work their way up. would this work as well?

Sure but lots of extra work. One other tidbit, use a squeege to spread the epoxy, a paint brush or roller just can't get the tight bond required.

**Rick Turner** · Aug-08-2009, 5:53pm

There is an alternative to hand layup, and that's to use a "chopper gun", but you're talking serious dough and an even more serious commitment to production. That's how the Mark Leaf cases are made...

You can Google for info on chopper guns.

**Big Joe** · Aug-08-2009, 7:14pm

We have been working on the Pegasus USA carbon fiber case for quite awhile. It is not as easy or near as cheap as you may think. The cost involved in building one or a few cases would be greater than buying a decent case to begin with. Our carbon fiber case is almost ready to sell. Yeah, I know. You've heard that before

. It has been a long process with setbacks along the way, but certainly worth the effort. While you may enjoy the experience of building your own case, it is certainly not a task to take lightly.

As for weight/strength advantages for an instrument as small as a mandolin, it is substantially lighter and stronger than fiberglass or anything else on the market. The prototypes we have had were incredible and even with a mandolin in the case it was still so light that most thought it was an empty case and remarked on how light it was compared to other empty cases. Once we showed them the mandolin inside it blew their minds.

I applaud anyone making an effort at something new to them, but please trust me on this, it is not near as simple as it sounds. While there are many similarities with glass, it s not the same and it is far more expensive for materials....far more!!!

**man dough nollij** · Aug-09-2009, 1:51am

I think a good experiment to get familiar with case making (speaking as a noob and non-case-maker) would be to make a really bomber wooden case first. If I were to undertake this project (which I might, when I get back to the real world), I would make a Calton-shaped (teardrop) case out of wood. Bend the rims with a hot pipe like building a mandolin. Glue the rims to a flat plywood back and top.

I'm looking at my Golden Gate case now. It has a top that has the same rim dimensions as the bottom, so that it doesn't over or underlap. There is another strip of plastic that is stitched to the outside of the top, forming an overlap. You could do this easily with a formed wooden case by making the "rims" extra tall, and bandsawing them apart into top and bottom. Then apply an extra layer around the top to overlap. You could make a case that would be bombproof for very little money.

Once you get good at sewing the lining and hiding the stitches, then I'd start thinking about crafting a shell of unobtainium. But that's just me.

**Ivan Kelsall** · Aug-09-2009, 3:21am

In my previous incarnation as an 'employed' person,for the last 8 years,i was an manufacturing /design engineer specialising in glasscloth / glasscloth-kevlar / carbon fibre & carbon-kevlar constructions for Aircraft.
Big Joe is most certainly correct in his advice re.carbon fibre costs.The tools required,just to cut & drill the darned stuff properly,are EXPENSIVE !!.The material itself is expensive & requires proper storgage to prevent moisture ingression - or you can get bubbles in the lay-up. Carbon-fibre is great stuff,providing that your tooling & construction costs can be covered by a LOT of sales. Even then,nobody is going to pay 'big bucks' for a case,especially at the moment,when perfectly adequate cases of other materials are available.
I've gone through this before on other threads on CF case. I don't really understand the big attraction to CF as a case material. A well made CF case DOES look exquisite,but they offer no better protection than a well constructed GLASS-fibre case.
If i were going to make a case 'from scratch',i'd be using what we called 'chopped-strand' glass cloth.This cloth looks ragged off the roll,but when combined with a good epoxy resin,it forms a matrix that's almost bomb-proof & one which can't de-lamninate ,as the layers combine with one another within the resin matrix. My old 'Mark Leaf' Banjo case was made like this & the Mark Leaf cases were possibly the fines (& heaviest) cases ever made IMHO. Not the 'prettiest' of cases -simply the best !.
I could spell out in great detail the tooling & construction principles required to make a good case,(or anything else for that matter),but i'll simply urge caution & a lot of thought prior to starting. One further thought - have you sourced your material(s) yet ?. Some companies only work on what are termed 'minimum batch quantities'. In other words,they'll only deliver a minimum quantity,meaning that unless you order a couple of square miles of material (for instance),they won't deal with you. Think things through very carefully & good luck,
Ivan
PS - A few pic.of my Mark Leaf Case - 'chopped-strand glasscloth with a foamed plastic core between the inner & outer 'shells'.