Framebuilders - Anybody have tryed a Home Made carbon frame??

what the topic says...

thanks...

ps: the link at sheldon regarding this topic sisnt working..

Since no one has bitten on this thread, I will give it a stab.

I don't see why it can't be done. It would be an easy task for those with high end composite laminating experience & skills. However, I suspect that it is a rare individual who has the requisite skills, knowledge, shop space, material access, time & motivation to undertake the task. Much the same as it is a rare individual who builds his own aluminum, steel or Ti frame. Another example & similar task are those in the Experimental Airplane Owners who build their own carbon planes. There as some, but not many, and most of those are kits.

Perhaps there is a market for kit bikes??? Bob

On edit: Thinking about it, I don’t have any interest in a bike from scratch, but a high end carbon might be intriguing.

Thought about it. The actual build process (laying up) isn't really that hard, but designing the frame (and deciding where to put what type of carbon cloth, and in what direction) and making a foam core or mould are very difficult and time-consuming. Also, you'll have no precident for how strong it will be (whereas a steel builder will now that, as long as his or her brazing is up to scratch, the lugs and tubes will make a good bike), so some form of testing will need to be undertaken (possibly a destructive test, like the guy on Sheldon's site). And bare in mind that it's gonna cost a bit too, for what Sheldon's pal spent you could have a top-spec 'normal' bike (about $2000 I think).

But if you're willing and able to spend a lot of time and money making things like moulds and jigs, that you'll probably only use once or twice and no-one will ever fully appriciate, the possibilities are endless. Just think how many weird and wonderful carbon frames there are out there, from crazy monocoques like the Lotus Sport bike, to bonded tubular ones like the Colnago C50, to the step-through that Sheldon's guy made. Just keep an open mind about design, and you could end up with a bike unlike any other.

Perhaps there is a market for kit bikes??? Bob


there's this one:

http://bikelugs.com/columbus_mecano.pdf

My team won my college's senior-year design competition with a composite hockey stick. A hockey stick is more complex than many might think, but it is immeasurably more simple than a bicycle. It took most of a semester of work for our team to make that thing. We also had access to FEA programs and a shop to build it.

If you want to feel safe on your bike, I think you'd need a good handle on the FEA stuff.

HI again thanks.. about that columbus kit its nice but they dont have a the track option to start with... and well... i dont have 2 grands to spend on it... regarding material it is posible find at ebay carbon cloth in big pieces and cheap ... Oh just like a tip for everybody in here.. thrre is a guy in eastern europe that built a MB frame with Bamboo sticks... looks like a nice proyect.. besides he did his own carbon frame too and looks like easier than work with glass fiber that is a pain in the ass... if u have no clue wtf r u doing heheh (me! hehe)

I wish I could see the sheldon's web page carbon bike proyect, but the link is broken since who knows when...

Doing some research I found out a few things.. well the core is a pain in the ass but using styrofoam RODS our life its a lot simplier, built a low budget frame jig isnt hard. I wish we could share info about it. I found a guy who sells a set of plans for a carbon recumbet (or whatever the spell it is) bike.

Well as far as I see this, the secret is building a nice foam core, if that core is straight the result is an straight frame, depending on the design a frame jig isnt needed at all. SO anybody knows how to use autocad or something? hehehe...

Well I would like to make my own track bike in carbon.. and doesnt look so hard after all, even apply preasure to the fiber to get it really compacted its easy to do using shrinking tape... but well maybe im only dreaming :)

thanks.. anybody wants to share ideas?

Ultra

Fea??????????

Check out this guys web site:
http://homepage.mac.com/w.rentschler/PhotoAlbum71.html

Frames are built with the Dedacciai DCS kit - available from bringheli.com for about $600. Some sort of fixture is highly recommended to hold everything in place while drying.

Enjoy.

Ed

FEA = Finite Element Analysis. It evaluates the strain on any point of the frame after you place all the loads on it. From this, you determine which places need thicker/more layers of carbon, different fiber direction, etc.

Thanks :D

This guy (http://www.bmeres.com/) is my hero. Not only has he made himself a homemade carbon fibre MTB frame, seatpost, saddle, hubs and headset but also a composite CF/bamboo frame as well. Check out his axle-less hub with carbon fibre bits!

http://www.bmeres.com/images/axleless4.jpg

FEA = Finite Element Analysis. It evaluates the strain on any point of the frame after you place all the loads on it. From this, you determine which places need thicker/more layers of carbon, different fiber direction, etc.

Note that if your shapes/mesh is not complex or you're not incredibly picky then you can utilise a standard spreadsheet program such as Excel (I once used Lotus123) as a poor-man's FEA program. I even validated my node model results using ANSYS and everything was close enough... at least within what one would expect of engineering tolerances. Obviously a very large and complex mesh would be a pain to set up in a spreadsheet.

thats the guy i was talking about.. i wrote him but he hasnt asnwer yet...! awesome job...

:)

here's another one:
http://www.fixedgeargallery.com/2005/july/SethDavis.htm

The actual build process (laying up) isn't really that hard, but designing the frame (and deciding where to put what type of carbon cloth, and in what direction) and making a foam core or mould are very difficult and time-consuming. Also, you'll have no precident for how strong it will be (whereas a steel builder will now that, as long as his or her brazing is up to scratch, the lugs and tubes will make a good bike), so some form of testing will need to be undertaken (possibly a destructive test, like the guy on Sheldon's site). And bare in mind that it's gonna cost a bit too, for what Sheldon's pal spent you could have a top-spec 'normal' bike (about $2000 I think).

The trick here is the experience & ability of the laminator. Quality control & technique important. Without it, the laminate part's physically properties can run all over the board. A poor lay-up or resin cure problem will never meet the needed physical properties. But, to the experienced fabricator, these are second nature.

If one goes with traditional straight tube geometry, the molds are easy, assuming that you are willing to go a male plug, wet contact lay-up route. Simply use fluorescent light tubes as the mould. Put your mould release agent on the light surface, do your lay-up, once the part has cured, give the part a sharp tad to break the light tube, & presto, finished hollow part. If desired, one could use this with other curved light tubes if their shape & size fits your needed radius & size.

ON EDIT: As for the fiber orientation, my first instinct w/o any reasearch would be: A triaxial layup of 0, +45, -45 deg. relitive to the frame C/L. (strength along the length & tortionally). I doubt that much hoop strength is needed. For a bi-axial, I think +/-45 deg. I would be worried about not having the 0 deg. layup. I thing I will start looking @ the carbon frames to see what is commonly used.

Thanks for the link on the kit bike. Bob

what the topic says...

thanks...

ps: the link at sheldon regarding this topic sisnt working..

I'm building a homemade carbon framed monotube bent.

John Climaldi (aka Portland John over at Bentrider Online) came up with the idea of using carbon sailboard masts for monotube recumbents and then carbon wrapping at the frame junctures.
http://homepage.mac.com/john4bho/Menu3.html
It looks as if he has removed the construction details of his bike, unfortunate since it was very impressive.

I've acquired a sailboard mast and will saw cut the mast and lug the frame tubes together.
I think lugs are a proven lower tech solution readily facilitating repair, modification, and assembly better for the inexperienced composite worker.

HI thanks :)...

well u can get carbon fiber tubes in the market so far...

Thanks hope we could talk about your proyect since we r in the same area...

Ultra.

here's another one:
http://www.fixedgeargallery.com/2005/july/SethDavis.htm

guy says he works for Parlee and made it in the shop

doesn't sound like "home made carbon" to me ;)

(but cool nonetheless)

Hi again I got an answer from Brano the guy that did the carbon and bamboo frames and he says that both are ok so far today...

...

HI thanks :)...

well u can get carbon fiber tubes in the market so far...

Thanks hope we could talk about your proyect since we r in the same area...

Ultra.

Hey Ultra-where do you buy the tubes?

Thanks,
Jake

I have made several carbon frames since 2000 my first was a pivotless rear suspention mountain bike.
Here's a link to see some of them, I build them for a hobby.
http://www.harnettcycles.com/harnettcycles.html

Brian

I have made several carbon frames since 2000 my first was a pivotless rear suspention mountain bike.
Here's a link to see some of them, I build them for a hobby.
http://www.harnettcycles.com/harnettcycles.html

Brian


Nice bikes! I love the tandem!

I have made several carbon frames since 2000 my first was a pivotless rear suspention mountain bike.
Here's a link to see some of them, I build them for a hobby.
http://www.harnettcycles.com/harnettcycles.html

Brian

Pivotless?

Is this a Moots-like suspension in carbon?

If so, how does the carbon hold up under the flexing?

It is only similar to moots in that it has a flex plate behind the bottom bracket attaching the chainstays.
I made a carbon leaf spring attaching the seat stays to the frame to keep the frame from having any torsional twisting, that works very well and there is a elastomer damper attached to dampen the rebound effect.
The first carbon bike was my mountain bike the suspension is fine after 5 years of riding singletrack.
Carbon has an infinite fatigue life as long as it is designed within its limits.

bharnett,
Interesting design on the rear suspension! Thanks for sharing with us.

If you don't mind, did you use alu or ti for the metal inserts, such as dropouts, bb, and head cups. Also, did you make any special prep to the metal first such as liquid coatings. This would all be in reference to possible galvanic reaction between the carbon and metals, that I have read about elsewhere.

And then if you are really willing to share, how about some info on the main structure. Is your material laid up over a foam core, or have you bonded to shells together.

Thanks again, great stuff.

Kustomz
I make molds for all my bikes that are made out of carbon.
The dropout are 5/16 6063 aluminum, bb shells I get from Quality bicycle products.
The head tube I make out of carbon and machine to size for the headset.
I have a page on my website that gives a desciption and pictures of some of the process.
http://www.harnettcycles.com/moldingfiles/moldinginfo.html

If you don't mind, did you use alu or ti for the metal inserts, such as dropouts, bb, and head cups. Also, did you make any special prep to the metal first such as liquid coatings. This would all be in reference to possible galvanic reaction between the carbon and metals, that I have read about elsewhere.

You need not get too spooked about the galvanic reaction between the carbon (aka: graphite) & other metals. Graphite/carbon is at the noble end of the series. Meaning, it is the protected and noble end of the scale. The metals at the other end are the ones that can be "eaten". Something like a aluminum, galvaived iron/steel, zinc, etc. will give problems when immersed in salt water with carbon/graphite. Really, though, how often are you immersing your bike in salt water? Using a zinc, magnesuim, or steel component in contact with carbon?

The real problem exists with a long term, unmaintained contact between dissimiliar metals; ie. & with bikes, an aluminum seat post in an carbon tube. Easy answer: Use a carbon post (same material) or titanium post (much closer on the scale). Both give the same result: No or negligible reaction. Alternately, create a resin rich layer (resin is almost always non-conductive) on the ID of the seat post where the tube will be in contact. But this adds weight to your frame (You are building of carbon to save weight, right? So go the easy route & use carbon or ti.) If you find that you must use aluminum or other "active" metal in contact with the carbon, coat it in grease, 'never sieze' or similar anti gauling compound; remove the post occasionally & don't store your bike in salt water. Bob

The real problem exists with a long term, unmaintained contact between dissimiliar metals; ie. & with bikes, an aluminum seat post in an carbon tube. Easy answer: Use a carbon post (same material) or titanium post (much closer on the scale). Both give the same result: No or negligible reaction. Alternately, create a resin rich layer (resin is almost always non-conductive) on the ID of the seat post where the tube will be in contact. But this adds weight to your frame (You are building of carbon to save weight, right? So go the easy route & use carbon or ti.)

Note that many bike frames use a steel or aluminum insert in the seat-tube where the seatpost would make contact. Also note that the clearcoat of most carbon seatposts should be enough of a protectant against electron exchange so the coupling is minimised.

Carbon fiber tubes...

http://www.fairing.com/CDData/Frame%20depot%20Content/Frame-depot-content.htm

for sure somebody else sells stuff too.. Oh thanks for the links and the info.. it was great! :)

Oh i forgint something guys... the deal with oxidation and the problem with stell and aluminum parts and tubes inside of carbon... just like the headtube, the seat tube, the BB and the dropouts... well... I super duper friend told me only one thing..,,

"If u dont want to cover the metalic parts with glassfiber,... USE TITANIUMMMMMMMMMMM"...

actually the Ti tubes and parts arent so expensive so it would be one less step, right ? :)

UM.

Hey Ultraman-nice link! Any idea where I can get the prices on some stuff? Is it on the site, and I just cant find it?

Thanks,
Jake

maybe if u call them? heheh :)

oh, yeah, sorry :)

Anyone have inside info on a company offering a carbon tail for MTB with extra long tubes to be used in a 29er application? I have had my front triangle tubes and design for quite some time, but have kinda hit the wall when it comes to the rear.

Let me re-phrase the above. Are the current s-bend carbon tail kits offered for MTB fixed in length, or do they come trim to fit with enough room for a 29er?

No clue, I think they should be a little bit longer... but always u can call to ask... for exaple the guys I mentioned before.

UM

Bob Davis, a retired aerospace engineer, built this is his garage!

There are a lot of ways to crank out home made full suspension carbon MTB frames. For a start have a look at Caron Mikes web page. The first thing you need to do is get hold of Linkages demo software and get your head around the various types of designs that are available. Then get hold of some 3D software (Alibre, Inventor, Solidworks or other). It will take 6 months or so to figure out how to use it but once you have the options are endless. 2D will do but 3D assembly software will allow you to create the various components and assemble and check mechanistic behavior etc. Caron Mike introduces a really straightforward carbon/styrofoam fabrication method. Of course if you want to cut molds and fabricate monocoque parts you require access to CNC routers/machining centers. Just a few ideas.

I built several frames but had troubles with the glassing of the carbon, I made blanks out of foam pieces glued together with brown paper bags and toluene and shaping into a frame, also built a couple out of balsawood but was expensive. They looked great until laying up, came out looking like a porkupine with little pieces of carbon strands poking out.

What about building the way carbon bikes used to be (http://www.bikeforums.net/showthread.php?t=395362), with straight cylindrical tubing & aluminum or titanium lugs?

I'm thinking this might be an easy way to build a bike-- by CNC milling the lugs out of aluminum and gluing (epoxy) the bike together. Without heat distortion and with stops on the lugs, it might be possible to assemble with minimal jigging.

The TerraTrike Edge (http://www.terratrike.com/edge.php) recumbent trike appears to be built this way, but with internal rather than external lugs.

If one had the skills to design the frame in solidworks it'd be pretty straightforward to go from there to a completed frame. One could do basic FEA to figure out the layout and orientation. Following that, ship off the model to have a foam core CNC cut. Vacuum assisted resin-transfer molding won't yield a part as strong as an autoclave cure, but it gets pretty close. VA-RTM can be done as a DIY process which isn't much more complicated than vacuum bagging.