Any Framebuilders want to make a extra strong carbon frame?

BiGH

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I can't rememmber if i've posted this before, but i was just wondering if anyone would actually consider makign their own ebike carbon fibre frame? you could use massive dropouts allow for extra large tyres, disc brakes, rack mounts everything.

I certainly don't have the skill to do this, but i'd love to hear from others who might!

http://www.bmeres.com/carbonframe1.htm
 
I'd kicked around the idea of welding up a steel frame, but hadn't thought about carbon.
Since weight isn't much of an issue with an Ebike, This might just open up the possibilities of building some more exotic shapes, and having a frame that could hold and hide all the cables, batteries, and controllers.

I've worked with fiberglass and carbon with my RC planes, and its amazing how easy it is to build with. And amazing how messy it is, too. :shock:
 
I was thinking that too.

the hardest thing is to heat it to cure the epoxy, i think - 50ºc for such a large object may be an issue.
 
A guy at work made a Bamboo bike, with carbon joints.

Yes, bamboo.
 
BiGH said:
I was thinking that too.

the hardest thing is to heat it to cure the epoxy, i think - 50ºc for such a large object may be an issue.

Nah. I can get big sheets of styrofoam from...

*shifty eyes*

...places.

You could make a heating box out of plywood and a hairdryer or something. Keeping it at the right temperature would take some attention, but shouldn't be unreasonably hard. How exact does the temperature have to be?
 
Link said:
Nah. I can get big sheets of styrofoam from...

*shifty eyes*

...places.

So that'd be work then?
 
BigH,
have a look at this carbon framed recumbent bike, should give you some ideas!
http://www.rqriley.com/bike.html
 
CF trike;)

now THAT would be cool hehe

thanks for the link!

I wish i was good enough with CF laying.
 
I've seen the bamboo frame... it's awesome... I would rather see someone doing a bamboo frame than a carbon frame..... I have great respect for people doing different things that work using primitive materials.

I rode alongside the bamboo frame for about 3k's..... much admiration from this end.

The only thing that could beat that is a frame (that works()made of paper mache
 
I've no experiance with carbon fiber in compound curves, and I hear its pretty tricky to get it to look right.

So I need some practice.

And after reading this yesterday, then having a few beers, I've come up with an idea. 2 of them, actualy.

The first, I think I'll make an aerodynamic case for my Cycle Analyst. Anything's better than clunky box it came with. Maybe I could add a compas and a slope indicater into the same case, and have better bar mounts as well.

Should be easy enough, and give me an idea if I have the skills for a frame.

Another idea that hit me.. after the 3rd beer, was to build a rear battery rack for a full suspension bike. It could only have come after a 3rd beer as I don't have a full suspension bike. Not yet. But I think the best way to build a rack for one would be CF.
 
getadirtbike said:
Give me 6 weeks... I'll have a purpose built E-bike frame... just wait.. it'll be worth it
....and when you do, please post in the "Frames" thread on the EV Business World page so I can send you some orders.
Don
 
Don,

Will defintiley do that . I've just got to get the first one finished off and tested and the rest will follow.

It'll be Chro Mo with at least 8" of rear suspension. if you're seriously interested send me a PM.
 
Mark_A_W said:
Link said:
Nah. I can get big sheets of styrofoam from...

*shifty eyes*

...places.

So that'd be work then?

Yup.

So, how ya figure we should shape this stuff? My first idea is a solid wax skeleton that could be melted out of the frame. Would probably take care of that compound curve problem. You'd have to be a good sculptor, though. And where would you get all that wax?

Of course, if you wanted to make a solid frame, vacuum bagging would probably be the way to go.

Would be worth it, though. I love the look of nice, glossy carbon fiber...
 
why don't you make it solid? :) if you want to pass wires through it make an internal conduit out of a small tube of some sort
 
Solid like totally solid or like a one piece frame like they use in some racing bikes?

Carbon fiber isn't cheap. And you would need several layers to make it strong enough for a frame. Yeesh.
 
I work with the guy that did the carbon fibre for this bike. He'd be the one to ask, and more importantly probably the right person to build the frame.

http://images.google.com.au/imgres?imgurl=http://www.motorcycle.com/images/content/Review/enginet.jpg&imgrefurl=http://www.motorcycle.com/manufacturer/a-technical-look-inside-the-hunwick-hallam-design-45974.htm&h=151&w=250&sz=19&hl=en&start=7&um=1&tbnid=e-cI5RQQAN5mzM:&tbnh=67&tbnw=111&prev=/images%3Fq%3Dhunwick%2Bhallam%2Bpic%26gbv%3D2%26svnum%3D10%26um%3D1%26hl%3Den%26sa%3DG

Hope you've got deep pockets though.... Carbon fibre is pretty hard to get in decent amounts these days.... Boeing have bought up a lot of the worldwide supplies for the 787 (it's entirely made of composite material).... That's not to say that you can't get it though.
 
I also know some of the guys that built these cars

http://www.fsae.rmit.edu.au/Documents/RMIT%20Racing%20Sponsorship%202007.pdf

They have a carbon fibre monocoque which is very rigid... another expensive exercise though.
 
Link said:
So, how ya figure we should shape this stuff? My first idea is a solid wax skeleton that could be melted out of the frame. Would probably take care of that compound curve problem. You'd have to be a good sculptor, though. And where would you get all that wax?

Of course, if you wanted to make a solid frame, vacuum bagging would probably be the way to go.

Would be worth it, though. I love the look of nice, glossy carbon fiber...

Shaping foam is easy. an electric carving knife like you use to cut a turkey works great for roughing out the shape, and runs about $12, if you can't sneak your Mom's, Wife's, or Girlfriend's out. Once you have a rough shape, then you use sand paper, or an electric sander. I build planes this way, its realy easy.

The foam actualy gives structural support, doubleing the striength of the frame. it would also act like an internal shock absorber, stoping vibrations in the frame.

I've never used vacume bagging on any CF or fiberglass, just wax paper comression. I bet the bagging would be better, but expensive since you would need 10-20 layers of CF, and each would need to be bagged.
 
It would be really easy to take 8 pvc pipes and strap them together in a 4x2 (four up/down verses 2 wide) configuration and glue them together then wrap this with carbon fiber. That would make an extremely strong and lightweight main frame tube that could also double as the battery pack. (you could place the cells inside the tubes) You could load about 80 "C" cells inside a 20" long top tube from the back. (5x2 - 100) This is still going to force to to use NiCads or NiMh though.

The biggest problem I've had using materials like steel is that you simply can't cover enough batteries with steel (no matter how thin or how drilled out) without having the weight rise too much. Even aluminum would not produce a light enough frame for something that held batteries.

So carbon fiber might be the way to make practical the idea of "inside the frame" batteries.

Surface area translates to weight... carbon fiber is just light enough to pull it off... :)
 
I do fiberglass too... it looks like it's about the same process. The difference seems to be that with fiberglass you use a generous amount of resin, but with carbon fiber it looks like you are supposed to squeeze as much of the resin out as you can and end up with mostly the cloth. With fiberglass if you use thicker cloth you get more flexibility, but if you use many thin layers of cloth you get more rigidity.

:arrow: We need a link to carbon fiber construction techniques...
 
whitepaper1.gif
 
FrankG said:
I've muddled through a few fiber glass projects and wondered about Carbon Fiber...

Is it the Vacuum bag or wrapping of the part in tape (as in the 1st link that started this thread) that helps make the frame/part whatever so light??? Or is it a special resin/catalyst along with the CF???

When I read about 6 or more layers of CF I can't help but think that if it was being done with fiber glass it'd be heavy...

Also is there any point making a fibre glass frame as a proof of concept to iron out the bugs before spending a large amount of cash on CF, or are the two prcess very diferent?


CF is a little heavier than Fiberglass, for the same thickness mat, but whats being used to build a frame is a thinner mat than automotive or marine grade fiberglass mat. we're talking stuff as thing as a paper towel, or even thinner. The stuff I've used is only 6 grams for an entire square yard of mat.

The idea with wrapping it, or vacume bagging it is to help compress the mat to the surface below it. CF mat likes to return to its flat form, and will pull away from a curve while it cures. you need something to secure it to the shape while the resin hardens. It also helps squeeze out the extra resin. As Safe points out, the more thin layers you can add, the stiffer it becomes. It also makes it stronger.

As for working with CF and fiberglass, its essentualy the same, except for CF's stiffer, and doesn't like to stay bent while you're working with it. it also needs special shears to cut it. Sisors won't do it, and xacto Blades will get dull in just a few cuts.

Making a full fiberglass frame as a "proof of concept" ain't a bad idea, but you could go as far as a single layer of glass over foam to try it out. then build up the CF over that. having a layer of fiberglass as a base will help keep the CF from being too brittle.
 
Here's a CF bike of interest,
http://delta7sports.com/
 
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