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Carbon fibre rod can it be cut down and used?

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bry1975:
Thanks chaps,

Another question will carbon fibre rod scratch 316 SS?

It sounds a useful material and costs about £9.10 for FOUR metres of 2mm rod incl. postage!

TIA

PekkaNF:
Hi. Since you probably will combine many materials, you may want to google "carbon fibre galvanic corrosion". Basics, aluminiums and low alloyed steels get cursory attention here: http://www.boeing.com/commercial/aeromagazine/aero_07/corrosn.html

"will carbon fibre rod scratch 316 SS?" I have build few structures and wanted to but bearing to stainless/aluminium/carbon used teflon and POM. Pom is nicer to work with. I don't remember exact reason why I did avoid contact between carbon/stainless, could have been a word of senior engineer, my consideration to a sea water or over engineering.

Pekka

bry1975:
Thanks for the link Pekka.

The Carbon fibre rods will be used with Hardwood so shouldn't be a problem as long as the material cuts well, has decent stiffness and is aesthetically pleasing.

PekkaNF:

--- Quote from: bry1975 on July 30, 2011, 05:14:49 PM ---The Carbon fibre rods will be used with Hardwood so shouldn't be a problem as long as the material cuts well, has decent stiffness and is aesthetically pleasing.

--- End quote ---

Carbon fibre composites, even extruded rods, have pretty good stiffness. The problem when combined with the wood is that they are way more stiff than any wood. I.E. load sharing is done solely by carbon fibre when they are attached together. Learn that early when I tried to reinforce wing spars with carbon fibre. This is not necessarily problem if the structure is such that it does not bend, like knife handles, other member of the structure takes the forces.

Another consideration is fibre orientation, thin rods have fibres (and good strenght) only on longitudal direction. Twisting/crushing/splitting is not a good idea. Extruded pipes are pretty good on pull, very poor on twisting, because they have very low hoop strenght.

Epoxy works pretty good on freshly prepared carboncomposite/wood bonding. Mechanical fasteners are more of a problem (actually not a problem but need a little consideration) if they carry a load. You drill the hole and cut a bunch of fibres - you put a bolt trough it in the end of structure and load is carried completely by that small iasthmus right next to bolt. It does not work like a metal. Inserts and layers of cloth of different fibre orientation are used. Then again, if the member is more of a decorative than structural, good clean hole trough it would be fine. If trough screw needs to take user induced loads (good car dealership grin when torquing) or it's trough many structural members etc. an "insert" made of metal pipe or such to take up the compression will go long way. When I was a kid I saw one of my relative dive head first on clasfibre composites - apparently it was a steep learning curve for a self taught RR-bike mechanic.

Your projects are always interesting.

Pekka

bry1975:
The idea is to replace the hardened pins below with Carbon fibre pins or a non ferrous metal, carbon fibre is cheaper to buy so will deffo try that.

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