# Weaving a custom carbon fiber frame?



## wmac (Sep 29, 2010)

I searched and didn't see much about The new manufacturing processes for carbon fiber parts. I suspect it won't be long before we are Weaving entire custom carbon fiber frames or able to use 3D Ti printing machines to create dropouts, bottom brackets and head tubes to glue up a frame from stock carbon tubes: Time Bicycles: Carbon Fiber Weaving and Resin Transfer Molding - Core77


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## Drew Diller (Jan 4, 2010)

(Incidentally, there was a thread just the other day about 3D printed titanium bike parts.)

I've been learning a bit about composites over the last year. From what I gather, their process isn't exactly new. A lot of Resin Transfer Molding is done with vacuum bags for large surfaces like boats, which are so large as to be difficult to be compressed by a mold.

What I've also gathered, and why I was curious about but never explored RTM, is that areas with sharp corners or tight radii (as in, everything on a bike except straight frame tubes) can suffer from resin-rich areas and insufficient compaction. With vacuum bagging that is.

That they're using metal molds indicates they're running higher pressure than just ambient air pressure, probably to address that problem.

With that in mind: female molds aren't exactly custom. They're for repeatability and high quality control. Hold this thought for a moment.

I don't want to sound negative. Carbon can be custom. They're just comparably rare to custom frames of other materials given the number of challenges or annoyances, depending on how you see them.

I did talk to an old composites guy at a small local retailer, he laughed at me saying that I am interested in doing probably the hardest thing to do with composites.

I have aim to build some full carbon frames over the winter, assuming my low cost, small work area 3D printer shows up this year. I'm not sure if I want to do female molds or male molds, so I'll try both before I commit to either.

I guess what I'm getting at is that cost of carbon is coming down. The raw material is getting really cheap, competitive with a steel tube set. But the amount of human labor that goes into it is always going to be higher.


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## zebrahum (Jun 29, 2005)

wmac said:


> I searched and didn't see much about The new manufacturing processes for carbon fiber parts. I suspect it won't be long before we are Weaving entire custom carbon fiber frames or able to use 3D Ti printing machines to create dropouts, bottom brackets and head tubes to glue up a frame from stock carbon tubes: Time Bicycles: Carbon Fiber Weaving and Resin Transfer Molding - Core77


Interesting, that's what I do every day. It's very interesting to see parallel technology being used in cycling.


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## wmac (Sep 29, 2010)

I think we're trying to use CFP to build the same way as a traditional frame, which isn't necessarily the best way to do it. This guy built this bike in his garage using cloth, resin, plastic bags, tape and a vacuum. Carbon Fiber Z Frame Bike

He also built a more traditional TT bike with about $165 in materials. Right now we're at the point where we can build a frame using stock tubes and a little hardware like these TI prints, and lots of labor.

We're just designing to what the. Atrial is capable of. These guys have figured it out and I suspect this design will dominate the future of wheels: 2011 Mad Fiber Road Wheels - YouTube

From what I gather, the current method uses bladders and negative molds. Not hard to do with a CNC machine, CAD software, some tubular weave, bladder and resin. Oversimplified I know, but if we could "knit a frame" around a bladder and place it in a negative mold, it wouldn't have the drawbacks we're currently seeing with the traditional frame design.

Zebra: fascinating - would love to hear more about your industry.


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## zebrahum (Jun 29, 2005)

wmac said:


> I think we're trying to use CFP to build the same way as a traditional frame, which isn't necessarily the best way to do it. This guy built this bike in his garage using cloth, resin, plastic bags, tape and a vacuum. Carbon Fiber Z Frame Bike
> 
> He also built a more traditional TT bike with about $165 in materials. Right now we're at the point where we can build a frame using stock tubes and a little hardware like these TI prints, and lots of labor.
> 
> ...


Well we're a defense contractor so it's probably better I don't go blabbing too much, but we do a lot of work with braided carbon composite parts from air frames to full body structures for aerospace applications. It's pretty fascinating to be honest. I've seen a lot of insane carbon stuff but those Madfiber wheels have always struck me as, well, mad.

I'd really like to see more about how they mold frames, I've wondered if they use an internal bladder or how they do it.


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## wmac (Sep 29, 2010)

How It's Made - Carbon Fiber Bicycles (Guru) 1080P - YouTube

Cyfac Carbon | Custom Carbon Fiber Frames - YouTube

Carbon Fiber: Manufacturing - YouTube

And then there's this guy who built a bike frame in his garage - incredible: Chapter 2 Carbon Fiber Bike Build.wmv - YouTube


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## zebrahum (Jun 29, 2005)

wmac said:


> How It's Made - Carbon Fiber Bicycles (Guru) 1080P - YouTube
> 
> Cyfac Carbon | Custom Carbon Fiber Frames - YouTube
> 
> ...


I've followed some of the garage builds in the past and I love that people are doing it at home; how cool is that?

I could watch these videos all day, thanks so much for posting them. I'm really surprised at a few things: there has been few changes in technology since the first carbon bikes where they used aluminum lugs bonded to carbon tubes as if they were standard steel bikes which is in my opinion a really elegant solution to a very difficult problem. I'm also really excited to see some of the bladders and molds used; the Felt process is absolutely what I was hoping to see when I was envisioning how they built carbon frames these days. That's some pretty high tech stuff right there, fascinating.


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## wmac (Sep 29, 2010)

Yeah, I love this stuff too. I played with CF in building RC planes, but nothing compared to full on aerospace!

There are varying build processes, but I think we've barely scratched the surface of what this stuff is capable of in building bikes. Here's a video by Felt that shows just how different construction methods result in different properties: Carbon Fiber: Materials - YouTube


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## wmac (Sep 29, 2010)

Whoops, link fixed


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## playdead (Apr 17, 2009)

I fix, build, and race carbon sail boats. Carbon fiber laminate is great stuff, but can easily fail if not done properly. Building a bike frame will be one of the hardest things to build with carbon laminate. Good on ya though! It'll be a fun/expensive experiment!


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## wmac (Sep 29, 2010)

The UCI shouldull all the stops and allow manufacturers to go crazy with this stuff to see what they come up with.


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## zebrahum (Jun 29, 2005)

wmac said:


> The UCI shouldull all the stops and allow manufacturers to go crazy with this stuff to see what they come up with.


It would be insane, the bikes they came up with for the velodrome hour record were unbelievable and with the technology currently I can't imagine what they would be cranking out.

I'm voting for open class!


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## wmac (Sep 29, 2010)

Let Moser and Lotus design them


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## wmac (Sep 29, 2010)

Here's a company that supplies pre-made tubes: Roll Wrapped Carbon Fiber Tube > Roll Wrapped Twill Finish Tubes

Wouldn't be too difficult to build a traditional frame. Considering building one for my 6 year old.


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## zebrahum (Jun 29, 2005)

wmac said:


> Let Moser and Lotus design them


Now we're talking!



wmac said:


> Here's a company that supplies pre-made tubes: Roll Wrapped Carbon Fiber Tube > Roll Wrapped Twill Finish Tubes
> 
> Wouldn't be too difficult to build a traditional frame. Considering building one for my 6 year old.


I've long wondered what the quality of Dragon Plate's tubes were, I suppose that's as good a way to find out as any. Which makes me wonder if I can make a low cost BB, ST, and HT lug set mold(s). I wonder how I can sneak this into the R&D budget...


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## disease (Nov 27, 2007)

It would be easy to make negative molds for carbon fiber bicycle tubes. You could use cement molds to copy the tube shapes from existing bikes, and then duplicate them using internal bladders. The cement molds will be very strong, and will capture every detail perfectly. They would also be dirt cheap. Just don't make a mistake, or your carbon frame will be locked into a cement block.

This type of mold could easily be produced out of cement instead of steel. It would not be adequate for production, but for home prototypes it would suffice.

https://www.ibiscycles.com/images/uploads/wygwam/740Feb-China-trip-024.jpg


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## zebrahum (Jun 29, 2005)

disease said:


> It would be easy to make negative molds for carbon fiber bicycle tubes. You could use cement molds to copy the tube shapes from existing bikes, and then duplicate them using internal bladders. The cement molds will be very strong, and will capture every detail perfectly. They would also be dirt cheap. Just don't make a mistake, or your carbon frame will be locked into a cement block.
> 
> This type of mold could easily be produced out of cement instead of steel. It would not be adequate for production, but for home prototypes it would suffice.
> 
> https://www.ibiscycles.com/images/uploads/wygwam/740Feb-China-trip-024.jpg


My name is zebrahum and I have a carbon fiber problem. These videos and pictures are fantastic, I don't know why I haven't done any research on this before.


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## Mr.Magura (Aug 11, 2010)

There are a few ways to skin a cat in this regard.

It's naturally a matter of cons and pros, and which cons that are worse.

I have been working with composites for like 25 years by now, and so far the most interesting solution for a bike frame i know of, is to make the tubing, and use stratification to join them.
Half shells is another option worth considering.

The reason for this, is that making tubes is fairly easy to do with perfect layup without voids or distortion of the fiber. 
This is unfortunately relatively new information to me, so I am still on my first frame with this technology. 
I found that perfect composites are hardly seen when complicated shapes are involved. 
Now I use high pressure molds and exclusively UD fiber, unless for surface protection.

Braided tubes or weave (counting out stuff like Textreme) is the straight path to too low fiber percentage, so that stuff I left out a while back. (Textreme is for instance the stuff Madfiber uses).
Braided tubes and cloth also bends the fibers, thus offering less stiffness. 

Now I have results that are pretty consistent, up around 70% fiber, and hardly any voids, using UD, pressure molding, vacuum infusion, and oven curing. 

The next step is to have some of my stuff CT scanned. That ought to reveal any voids of significance. In the end I plan to CT scan the entire frame. 
That at least would make for some nice wall art 

So in short, no, weaving a frame is not the next step towards perfection, but rather an easy low cost manufacturing method, offering a low weight / stiffness ratio, and a low fiber percentage, relatively that is.


Magura


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## shirk (Mar 24, 2004)

It would be interesting to see North Sail's Thin Ply Technology applied to carbon frame manufacturing.

Thin Ply Technology > Home

It's been used in skis by Movement out of Switzerland and has made some incredibly light skis that are strong and have a great feel to them.


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## Mr.Magura (Aug 11, 2010)

shirk said:


> It would be interesting to see North Sail's Thin Ply Technology applied to carbon frame manufacturing.
> 
> Thin Ply Technology > Home
> 
> It's been used in skis by Movement out of Switzerland and has made some incredibly light skis that are strong and have a great feel to them.


Nothing new there.

Essentially it is a fine technology for skis, as they need a very fine taper.
For bikes, it makes no sense to use thin UD layers (which is what they do, and spun a marketing blob around it).

Note the lack of references in their marketing material. It should make a bell ring.

Magura


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## flynfrog (Feb 4, 2011)

zebrahum said:


> Now we're talking!
> 
> I've long wondered what the quality of Dragon Plate's tubes were, I suppose that's as good a way to find out as any. Which makes me wonder if I can make a low cost BB, ST, and HT lug set mold(s). I wonder how I can sneak this into the R&D budget...


From what I have seen they are pretty heavy and full of cheap fiber.



disease said:


> It would be easy to make negative molds for carbon fiber bicycle tubes. You could use cement molds to copy the tube shapes from existing bikes, and then duplicate them using internal bladders. The cement molds will be very strong, and will capture every detail perfectly. They would also be dirt cheap. Just don't make a mistake, or your carbon frame will be locked into a cement block.
> 
> This type of mold could easily be produced out of cement instead of steel. It would not be adequate for production, but for home prototypes it would suffice.
> 
> https://www.ibiscycles.com/images/uploads/wygwam/740Feb-China-trip-024.jpg


Cement molds? For composites? Good luck getting vacuum. More like pulling a wet lay splash off of an existing frame.


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## Mr.Magura (Aug 11, 2010)

disease said:


> It would be easy to make negative molds for carbon fiber bicycle tubes. You could use cement molds to copy the tube shapes from existing bikes, and then duplicate them using internal bladders. The cement molds will be very strong, and will capture every detail perfectly. They would also be dirt cheap. Just don't make a mistake, or your carbon frame will be locked into a cement block.
> 
> This type of mold could easily be produced out of cement instead of steel. It would not be adequate for production, but for home prototypes it would suffice.
> 
> https://www.ibiscycles.com/images/uploads/wygwam/740Feb-China-trip-024.jpg


Actually there are compounds for making molds, so why use cement?

Just the fact that cement shrinks a lot, would be enough to move on to other materials.

If you wanna make a nice mold, filled epoxy backed up with aluminum (for heat transfer and reinforcement) is the ticket. It is pretty easy and quick as well.

Magura


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## Drew Diller (Jan 4, 2010)

Mr.Magura said:


> If you wanna make a nice mold, filled epoxy backed up with aluminum (for heat transfer and reinforcement) is the ticket. It is pretty easy and quick as well.
> 
> Magura


I thought about that, but also thought that using so much epoxy in so small a space would make for thermal runaway. I experienced that once on a small scale and it scared the **** out of me. Didn't think of using metal as a heat sink.

Do I have that about right?


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## disease (Nov 27, 2007)

Mr.Magura said:


> Actually there are compounds for making molds, so why use cement?
> 
> Just the fact that cement shrinks a lot, would be enough to move on to other materials.
> 
> ...


Out of curiosity, what epoxy are you using? I have been experimenting with West System's Pro Set. The reason I use it is the fact that heat is not required to cure. It will room temperature cure. Post curing with heat after will optimize properties, but that can be done later.


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## flynfrog (Feb 4, 2011)

I would look more at aeroxpoy, west system is about the bottom of the pile for hobby epoxies as far as properties go. I also would suggest G10 instead of Al if you plan on doing any heating of the mold AL Thermal expansion is much greater than most composites.


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## Mr.Magura (Aug 11, 2010)

Drew Diller said:


> I thought about that, but also thought that using so much epoxy in so small a space would make for thermal runaway. I experienced that once on a small scale and it scared the **** out of me. Didn't think of using metal as a heat sink.
> 
> Do I have that about right?


Yes partly. The thermal runaway is an issue, if you cure it at more than 20C, and it is a fast curing type of epoxy. 
Filling the epoxy also helps limiting the thermal runaway.

Limiting the layer thickness of the epoxy is also a factor.

Magura


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## patineto (Oct 28, 2005)

Not totally related but check this link for some *Benelli Motorcycle carbon fiber frames*


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## Mr.Magura (Aug 11, 2010)

disease said:


> Out of curiosity, what epoxy are you using? I have been experimenting with West System's Pro Set. The reason I use it is the fact that heat is not required to cure. It will room temperature cure. Post curing with heat after will optimize properties, but that can be done later.


Epoxy system 
R2820 / H8390

I usually fill it with either micro balloons or cellulose fibers.

Magura


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## disease (Nov 27, 2007)

flynfrog said:


> I would look more at aeroxpoy, west system is about the bottom of the pile for hobby epoxies as far as properties go. I also would suggest G10 instead of Al if you plan on doing any heating of the mold AL Thermal expansion is much greater than most composites.


I am using West System's Pro Set, not the standard West System's. The mechanical properties of Pro Set compare favorably to some of the better aircraft grade epoxies.


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## TigWorld (Feb 8, 2010)

flynfrog said:


> I also would suggest G10 instead of Al ...


What's G10?


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## playdead (Apr 17, 2009)

TigWorld said:


> What's G10?


G10 is a special glass epoxy laminate that has extremely high strength


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## disease (Nov 27, 2007)

playdead said:


> G10 is a special glass epoxy laminate that has extremely high strength


You can make nice rocket fins out of it.

https://publicmissiles.com/secure/ComponentsFins.asp


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## flynfrog (Feb 4, 2011)

The fins on this rocket propelled core sampling device were G10










Magura why are you filling your resin? If you get your fiber volume correct the added filler probably isn't going to be helping anything.


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## Mr.Magura (Aug 11, 2010)

flynfrog said:


> Magura why are you filling your resin? If you get your fiber volume correct the added filler probably isn't going to be helping anything.


I don't put much fiber in the molds, just a bit of glass mat usually, hence the filler.

Magura


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## flynfrog (Feb 4, 2011)

Mr.Magura said:


> I don't put much fiber in the molds, just a bit of glass mat usually, hence the filler.
> 
> Magura


So you are making more of a molding paste then? How bad is your shrink with no fiber?


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## Mr.Magura (Aug 11, 2010)

flynfrog said:


> So you are making more of a molding paste then? How bad is your shrink with no fiber?


Nothing serious, due to the filler.

The first layer I usually keep the amount of filler down, and increase the percentage as I work my way backwards. The last layers are pretty close to paste.

Another reason for using cellulose as filler, would be that making taps and threads in the molds, is working rather well. Just don't go below M10 or so.

Magura


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## compositepro (Jun 21, 2007)

towbraids are the emperors new clothes thin shell is standard fibre placement as far as I was concerned when i was building volvo ocean race and americas cup boats

there was a filament winding process which whilst conceptual (torus) was effective at removing joints from moulded objects and meant if you wanted to wind a continuous triangle you could 

A lot of aluminium moulds get made and lots of parts come out of aluminium moulds they often have steam or oil to heat provide a thermal constant?you might find G10 is used in rockets because it doesnt catch fire and those fins are quite close to hot hot hot ,it is also now obsolete ,there are various grades of glass and aramids which exceed carbon fibres in terms of strength unfortunately they are not as stiff but in the same vein there are also special carbon prepregs purely for tooling and the like

we now print moulds and coat them saves on the cement!!!


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## compositepro (Jun 21, 2007)

Drew Diller said:


> (Incidentally, there was a thread just the other day about 3D printed titanium bike parts.)
> 
> I've been learning a bit about composites over the last year. From what I gather, their process isn't exactly new. A lot of Resin Transfer Molding is done with vacuum bags for large surfaces like boats, which are so large as to be difficult to be compressed by a mold.
> 
> ...


Drew your asking the same questions the taiwanese are asking,I can filament wind a carbon tube that exceeds the properties of a 953 tube for 1/2 the cost 100m of Toray carbon t700 6k filament is around £11 maybe $15-16 The machine to wind a tube ,you dont want that cost but you can easily build your own if you have enough experience of composites or designing machines that do these things

The next thing you mention is RTM ,and a guy saying this is hard??? what is hard about it 
nothing in composites is hard once you figure out how to do it!!30 years ago it was try it ....then try again....then try again. If your at the cutting edge this is still true but for building most things the info is already out there

forged carbon is rapidly gaining ground ,you need to think differently, when you are asked how to do something find a way, dont worry about vac bags and pressure intensifiers the more products you discover the more things will slot into place

dont expect to print a mould you will need to figure out another step after this to make it work ,nothing new to see there


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