How do I build a mast out of Carbon Fiber or glass

[Lowcarb]

Hello

I have been searching on how to build a carbon fiber mast. I have located a site on how to build sections out of fiberglass and then assemble them, but, I am sure there are many out there who know how to build a CBF Mast with allot of details/plans. I hope someone would help with this quest and I really don't want to goof it up and get caught out on the ocean with a defective mast. I am sure there will be many who say.."Buy one", ok give me the money and I will, until then help me cut cost and I will build one. I built the last 45' mast out of wood and it still stand today fine after 50knot winds 7.25knott hull speeds. I think if it works for building fiberglass masts then it should work for CBF masts. Any ideas would help and be appreciated so I thank you up front...

Here is what I have found so far: http://www.themultihull.net/st2.htm

[aldo salvato]

I don't know how to build a carbon fiber mast,however,seen that you have built a wooden mast,I would truly appreciate it if you could tell me where I could find printed instructions on how to build one, or repair the one I have.:p ;)

I have not attemped building a mast yet but I have been thinking about it for a couple of years. One thing that I would consider is leaving a rigid foam core in the mast. Carbon fiber takes compressive loads better than glass but still not nearly as well as aluminum. A rigid foam would help resist buckling. The core would also make the mast positively buoyant should you get knocked down. I know that running the halyards externally is a problem but I'm not sure that I would want to cut holes in the mast for the halyards exits anyway.
Another thing to consider is the orientation of the fibers. I would think that about 75% of the fibers should run along the length of the mast. Maybe a unidirectional tape would work good for this and cover each layer of unidirectional tape with a layer of biaxial +45 -45 and finish the outside with a biaxial 0 90.
It would be nice if you could vacuum bag the whole thing but I don't think its feasable even with a very slow hardener on a cool day I think its just too big if your building anything over about 20 ft.
If you do try it, let us know how it goes. I think a lot of people consider building one but I don't know of anyone that has actually done it.
Good luck

[Lowcarb]

Aldo, my list is pretty long since I usually down load the whole webpage and save it. I could zip that up and send it to you. Pop me a PM and leave your email. I will send you the zip.

I am also considering selling 2 beautiful ketch rigged masts with sails and all the riggings if your interested since I am replacing them with carbon fiber masts. I also have photos of the riggings;

[Lowcarb]

More pictures

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More pictures again

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another view

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The original Vicktor Harrasty brochure she was build and rigged as

[Tim B]

Sounds Like you're about to start one damn big project Kelly. I suggest that when you start to mould the mast, that you get a team of people, four or six of you (even numbers divide into neat teams), breif everyone on what you're going to do, then do it.

Steve Tellardin suggests at the end of his article, that you should perhaps seek the advice of a proffessional yacht designer, do seek advice. There's nothing worse that being stuck on the water with a broken mast. What's more, you lose the price advantage. If anything, build it 'too strong', "if it breaks it wasn't strong enough" to quote an old expression. There is no real reason why you couldn't build it as a one peice layup. One thing to note is that if you are using glass fibre tape, overlap the tape at different places in the mast layup, if you have to join several longitudinal strips at different points around the diameter. Another thing is to make it over-length, then shorten the mast. That will ensure that the deck-end is totally consolidated. Personally, I'd use epoxy resin for the layup, three reasons:

1) It's lighter than polyester (and you can get a better glass/resin ratio).
2) It's a lot easier to work.
3) It doesn't dissolve foam when you try to use it.

You may also be able to make a test-model. Once you have made it, rig it, and test it to destruction. Measure the forces on each rigging wire. That will give you an idea of the forces the laminate will withstand. Note also how it breaks.

Cheers, and good luck,

Tim B.

[Lowcarb]

Thanks Tim

Hi

I also for a short time considered laying a mast out of carbon fibre. These were my plans:

the mast should be 16 meters in length (43 ft sloop); building it up just like a boat's hull: moulds in about 1 meter distance; thin stringers along the length of mast, covering it with balsa veneer for giving shape, layering unidirectional carbon fibre lengthwise, in change with bidirectional carbon fibre in +/- 45 deg; working with epoxy; if i'd put as many layers up as an aluminium mast would be, i guess i was on the right side in wall thickness (5 mm). but i gave it up, just as i thought it wasn't worth the risk, better buy an aluminium mast and stick to prooved stuff than having a broken mast in the middle of the atlantic and paddling along to the caribbean... the costs turned out to be almost as high as an aluminium mast, not included work and the risk factor.

[kudu]

Hi Kelly...Checkout sponberg.com or contact Eric Sponberg in the members section, he designs and builds carbon masts...

[kudu]

Correction...sponbergyachtdesign.com

[gonzo]

To build a mast you got to build a mold first. Then you need a vacuum bagging system. Remember that carbon fiber is brittle, so all the calculations for loads and the design for attachment points have to be done in advance. Working with high-tech materials is not easy. I discourage you from starting on a project so big. Start with small parts to learn how to work with the materials. When you do the calculations, remember there are many types of carbon fibers and of resins. Also the ratio of resin to fiber changes the characteristics of the material. Unless you have access to an infusion system, the best would be to buy prepregs.

To build a carbon fibre mast you will need a tapered mandrel (made from steel) you then lay up the carbonfibre as you would any epoxy-resin moulded product. The whole unit would then enter a heated oven and heat treated and cured. The sleel mandrel is then knocked out of the carbonfibre moulded mast. The whole thing would cost a bomb and youwould never retreive you cost /input. Although it is expensive to purchase a finnished product --you would save money in purchasing direct from a source and examining the product befor parting with loyts of cash