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JACKofSPADES

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Discussion starter · #1 ·
Hi all

I have been searching on the internet for a while now and did not finds much information on how people build Carbon Handlebars,

Could you guys please help me. I want to start experimenting and try building a 710 mm Flat Integrated Handlebar and stem out of Carbon Fiber.

I know you can make a mold of the top and the boddem and put them together and then after it dried you put more carbon on and so on.....but isint there a way to do this without having to put pieces together where they can potentially break. Like one Hollow integrated handlebar and stem ..... almost like this

 .

So any help will be appreciated ... thanx

Jack;)
 
#2 ·
CF bars

Be very careful!

In MHO you are treading in deep waters. Think of the results of breaking carbon bars. They have a lot of engineering designed into them to create something strong enough to handle the forces exerted on them. Anyway, I wouldn't attempt them even with the hobby background in carbon I have.

There are lots of reasonably priced bars on the market.
 

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#4 ·
I think what you ought to look into more is CF manufacturing in general.
You're talking about monocoque construction, which uses molds to form complicated shapes into one piece. Unless you have a CNC at your disposal the molds are going to be very, very expensive though. Like many thousands of dollars expensive.
 
#5 ·
Dude, I was a total carbon newb in the not too distant past. Starting with bar-stems as a monocoque structure - it's complicated for a task that is relatively simple in nature.

What you're asking about is called bladder inflation molding.

When you start asking questions like "There has to be someone who ____", yes maybe someone somewhere has, but in my experience they haven't documented it, and more likely, no, someone hasn't in the first place.

If it were me, I'd take an existing stem, and miter to an existing handlebar, and overwrap the joint with carbon fiber, as it would be a relatively simple joint.

Proceed cautiously.

Your concern of putting two pieces together and have them potentially break doesn't have much to do with reality - lots of outfits make carbon bike frames using tube-to-tube and then carbon overwrap on the joints. Appleman Bicycles and Parlee Cycles to name a couple.

Look at Calfee's bar stems:

https://calfeedesign.com/product/components/barstem/
https://www.bikerumor.com/wp-conten...nt/uploads/2012/03/2012-NAHBS-Calfee-SuperClean-di2-bar-stem-battery-post04.jpg

On both images you can see a bulge where the carbon overwrap occurs. The bond surface area is very great.

What adarn says is correct about high precision completely hollow molded parts. I've been developing tools toward that end for more than a year, and I've invested a few grand so far and am only now approaching my first complex hollow monocoque part.

I don't want to kill your interest, I want you to know what you're getting into, I think you're biting off more than you can chew right at the moment. Making carbon stuff can be real fun, sometimes it can really suck. I just want to make sure you cut your teeth in terms of making something simple your first time, rather than... literally cutting your teeth.
 
Discussion starter · #6 ·
Drew Diller said:
Dude, I was a total carbon newb in the not too distant past. Starting with bar-stems as a monocoque structure - it's complicated for a task that is relatively simple in nature.

What you're asking about is called bladder inflation molding.

When you start asking questions like "There has to be someone who ____", yes maybe someone somewhere has, but in my experience they haven't documented it, and more likely, no, someone hasn't in the first place.

If it were me, I'd take an existing stem, and miter to an existing handlebar, and overwrap the joint with carbon fiber, as it would be a relatively simple joint.

Proceed cautiously.

Your concern of putting two pieces together and have them potentially break doesn't have much to do with reality - lots of outfits make carbon bike frames using tube-to-tube and then carbon overwrap on the joints. Appleman Bicycles and Parlee Cycles to name a couple.

Look at Calfee's bar stems:

https://calfeedesign.com/product/components/barstem/
https://www.bikerumor.com/wp-conten...nt/uploads/2012/03/2012-NAHBS-Calfee-SuperClean-di2-bar-stem-battery-post04.jpg

On both images you can see a bulge where the carbon overwrap occurs. The bond surface area is very great.

What adarn says is correct about high precision completely hollow molded parts. I've been developing tools toward that end for more than a year, and I've invested a few grand so far and am only now approaching my first complex hollow monocoque part.

I don't want to kill your interest, I want you to know what you're getting into, I think you're biting off more than you can chew right at the moment. Making carbon stuff can be real fun, sometimes it can really suck. I just want to make sure you cut your teeth in terms of making something simple your first time, rather than... literally cutting your teeth.
Click to expand...
Thanx for the advice, it really IS going to help me . So if u were me. unexperienced in CF and all where would you have started ???
 
#7 ·
I'd start with making tubes. Where I got my initial exposure was with Bamboo Bike Studio, laying up frame joints with overwrap by way of "tow", and I peppered them with questions. It was fun and enlightening, but there were details I didn't like and... one thing after another from there.

The big cost of high tech carbon is really about making the forms/molds that the carbon ends up taking, rather than the carbon itself. That and the potential danger involved with very high air pressure. I've blown a multi-part mold apart at 30 psi, I was in another room on purpose. The piece that broke put a good dent in my garage door.
 
#9 ·
I follow - not very many, honestly. I'd go haunt talkcomposites.com a bit. And Google in general, a lot. One thing I've noticed with the few people who have done composites documentation is communicating the point of a given material clearly. Simply "this is the material you use and in this order" isn't enough for me to learn why, I ended up stumbling on a few of the points through trial and error.

For example with vacuum bag compaction I didn't really understand the reason for the breather cloth aside from acting as a sponge to carry excess epoxy. It's actually to ensure that the vacuum film doesn't create a circumstantial seal, thereby preventing the full removal of all air from the envelope. Few came out and just said it.

Some terms to get you a good start:

Thermal expansion
Epoxy shrinkage
Cathodic corrosion
Bladder inflation molding ... vs Vacuum bagging ... vs "intensifiers"
Autoclave (you probably can't afford one of these, I sure as hell can't)
Thermoset vs Thermoplastic
Exothermic runaway <-- I almost started a fire in my basement over not thoroughly understanding this one
Vacuum resin transfer or vacuum resin infusion ... vs Prepreg ... vs Wet layup
Isotropy vs Anisotropy
Pot life
How to make light weight epoxy "putty"
Woven / twill carbon vs unidirectional carbon, this one is a big "why" that took me a while
Epoxy sensitization (do not neglect this part, if you get epoxy on your skin, you don't need to panic, but you do need a sense of urgency to get it clean because you can develop allergies with exposure)

As composite fabrication is applied to bicycles, look up factory tours of existing companies. Parlee is particularly interesting, I still don't know what specific formula of silicone they're using for lug compression.

Compare composite materials against metals, where they're similar and different. See if you can find any parallels between composites vs wood working. Compare failure modes of metal to failure modes of carbon. This idea in particular is why you are getting advice to be cautious, carbon is extremely strong but doesn't warn you when it is about to break, it just breaks, and sometimes in horrifying fashion.

Read some patents. These can be hard as there is generally a lot of material to sift through to get to the good stuff.

Read about planes and windmills.

There is a pile of information on the net that skips important steps or assumes common knowledge, which is super frustrating when lacking a knowledge base. Take everything with a grain of salt and ask "why" often. A big one I had is "why do composites generate so much waste material?", and the answer is, "not necessarily".

When it comes time to make your first tube-to-tube joint, man, just find the cheapest materials and go ahead and screw it all up once or twice. I know I did!

Just giving you a heads up that if you're getting into composites as a hobby, starting with bikes is like playing a video game on hard mode.
 
#10 ·
I did about 8 months of research prior to starting my 1st carbon bike build. I scoured every Youtube video about carbon, every Instructable, and Tons of blogs and webpages. With each one I picked up a little bit of info.

My focus was on frame building, not handlebars, but the the basic technology and methods are the same.

A few of the ones I have used:
Carbon Fiber Bike
Homemade Carbon Fiber Bike Project
https://www.youtube.com/user/TheProjectJunkie1/videos
How I built a carbon bike frame at home (and a bamboo frame too)
How I Made a Carbon Fiber/Epoxy Composite Bike in my Garage, by Damon Rinard

There are many others out there, have a look. Then get some inexpensive materials and start experimenting.
 
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