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Homemade carbon road frame project.

Can you home fabricate a carbon road frame? I had heard that you could do it with if not minimal craft, at least with minimal means. I asked around but the response from those with experience, riders, engineers, designers etc was that you needed an autoclave  – the capacity to compress and heat the composite in a unified moment.

Since then I’ve come to enjoy a very real and refreshing economy of knowledge one that contradicts the doubters assumptions. I don’t have a composite or engineering background, in fact I work in the arts in a world of opinion and subjectivity, so the distinction of trial and error is both necessary and refreshing. If the experience I collect is sound the frame will hold together, if not,  it’s my neck! I’ve been fabricating frames for over five years now, although mindful not to over complicate things I continue to develope, explore and refine the process.

See below for build story and posts of developments on other projects. Happy to discuss so leave a comment if you wish to be in touch and please do post any of your ‘homemades’! This blog is a gesture of enthusiasm but without the work that others have previously posted I wouldn’t have known where to begin.

If you choose to use any of the information provided, be mindful of the consequences, I believe it takes a fair amount of craft to undertake a build – I’m simply reporting here that it is indeed possible.

Latest completed frame.

 

08/06/15

The moulded saddle came out well. It could be formed to a high gloss smooth finish but I find there’s more traction to stop the rider sliding back like this. Also I’ve always like the fabric look of it.

07/06/15

This is a test attempt for a more significant mould I’ll be making in the coming weeks. The first step is to secure your pattern to a release surface and filet the edges to ensure the mould does not gain a mechanical hold. Next is the release agent, in this case a release wax.

The next layer was a thick resin gel coat and once the gel coat had reached a tacky but not full cured state, several resin soaked 100g strand mat fiberglass. I then laminated several more layers of 300g strand mat to finish off.

By all accounts bike manufacturers use automotive clear coats to finish their frames.So far I haven’t paid much attention to my finish as I’m still too nervous following a build about the ride being sound. Usual I get side tracked on another build and can’t stop riding the new frame long enough to strip it back and invest the extra hours buffing and lacquering the finish.

This time however I thought I’d try this MaxMeyer Acrylic product.

12/10/14

New Saddle. Shaped as always from dense Styrofoam but Vacuum bagged to allow me to achieve the concave areas.

A lower profile than the other saddles I’ve made and at 190g a more competitive weight. I’ve still used the ti rails but this time I bonded the rails directly into the carbon using small sections of the insides of an old Flite saddle. I sprayed the underside black before adding a topcoat of resin.

The saddle upper was vac bagged over some shaped Styrofoam. I made the shape quite deep to start with so that I could play with the final profile.

2014  . a frame build – Aero tubed frame.

Built bike that I rode today. You may notice the omission of the front derailleur! There wasn’t enough space to attach the ‘band on’ derailleur i was using, I’ll have to shape and rivet on a hanger. Pics to follow.

I also mounted the bottle cages using this handy tool a friend let me borrow. It rivets the bosses into the carbon. In addition I glued the rivets in with structural adhesive just in case the process of drilling and compressing the rivet had propagated any splits in the carbon.

Finally following the addition of hardware and the top coat of Herringbone carbon, tomorrow I will tap the BB shell and build the bike up for riding next week.

 

I shaped the area between the tyre and the BB alot closer this time. Hopefully the addition carbon will add to stiffness.

Here’s the ‘Sugru’ rubber mold that I formed around the internal cable bosses. I used one on each boss to compress the carbon around the boss. A lot of the larger companies use a similar method at various points around the frame where high compression is desired.

Frame before the top coat of carbon. You can see in these images the different orientations of carbon around the seat post (to strengthen the area to receive the carbon quill seat clamp) and around the joints.

Final layers.

Vacuum bagging the BB area.

Shaped joints –

Work in progress – shaping the head tube. Once these areas were wrapped like the image depicts, I then orientated uni directional (UD) carbon over the joints.

Work in progress – shaping the TT – Seat Tube. Here I was thinking of different shapes but in the end went as simple as possible and removed as much carbon (weight) as I felt comfortable with.

Third generation frame about to be wrapped.

I’m still using a similar fabrication process and geometry but I’ve included an aero seat tube, internal cable routing and an over sized down tube. I’ve bonded the frame before adding the final layers of carbon, which I can now include in the joint process.

Decisions re the frame began with limiting factors, like what seat clamp to go with. I chose the FSA carbon k-wing ISP.

I bonded the frame with 3M Structural Adhesive. I think bought from Transair –  http://transair.co.uk/.

The joints. I don’t bother filleting the joint like I did on the first frame, instead I’ll wrap the joints with tow, layering on more (lighter) carbon and then I’ll shape accordingly.

The BB Shell. Bought from Ceeway – you need to contact Peter directly and request the carbon parts you’re looking for. He’s really helpful!

Internal cable routing adapters. Also from Ceeway.

Tube off cuts. They vary in wall thickness. The head tube (top left) has a yellow Kevlar base layer. The seat mono stay (top right) has an internal bulkhead. The two tubes mid left are the ISP off cut next to my Deda fork off cut. Mid right is the top tube and down tube and at bottom the chain stays.

I’ll be using this UD carbon Tow to wrap the joints. Bought from East Coast or Easy Composite.

2013 – . a frame build 

The frame rides really nicely but has a totally different geometry from the first frame, the difference in feel was quite shocking.

Road and safety testing a new build, ridden for the first time yesterday. Depending on how it feels/performs I may reinforce the BB area before adding a top coat and bottle bosses. It came in at 936 grams before wrapping and with the ISP weighs around 1350 grams now.

USP’s = 1 1/8 – 1 1/2 Head tube – Carbon BB Shell – Sloping seat stays – 215 gram rear end – Carbon dropouts – Triangular sloping top tube and an ISP.

Bike before the final layer.

built a jig for this build.

Pretty happy with the weight considering the ISP. This seems to be a bench mark weight at this size and using this process.

ISP

Carbon BB shell.

1 1/8 – 1 1/2 Head tube.

Carbon dropouts.

The finishing layer of UD carbon. I was at the bespoke bike fair and a friend who distributes Faggin bikes showed me a frame with a hand stitched leather finish. It got me thinking and this finishing coat is useful for hiding any inevitable pin holes in the finish. Looks beautiful in sun light!

2013 – a. frame build

Been away for a while working on these two.

2012 – a. frame build – Homemade road frame project. Hopefully useful for anyone wishing to get on and build bespoke!

The geometry – because this was my first build, I oriented towards what I understood to be a traditional set up.  I established the geometry with research from three separate sources: my existing frame (riding position), the Cyfac Postural Manual http://www.cyfacblog.com/downloads/ and as many published frame geometries as I could lay my hands on.

I found that making a drawing gave me a better feel for the logic and dynamics of frame geometry. Given that I had no previous experience, any insight was useful. During the build I shortened the wheelbase and altered the seat tube angle. Clearly not all of the drawing is to scale, that BB shell is way too big.

The rear end: Deda – was bought from Ceeway http://www.framebuilding.com/. I bought the rear end with a steel BB shell and aluminum dropouts. in order to complete the frame I also bought all the bosses, head tube cups and an inexpensive Carbon fork.

The tubes – I started with a sheet of foam board from a craft supplier, roughly cut the tubes to size and refined the shape on long lengths of sand paper.

Any blemishes were filled and smoothed out.

I don’t have the clearest images of the next part of the process. The carbon is cut to wrap the tube the required number of layers in one roll. One side of the carbon is painted with resin. The core is wrapped in carbon and a layer of peel ply is added before the tube is compressed. I used electrical tape, applied with the sticky side out and them perforated with a needle which allows excess resin to drain.

Before wrapping the carbon, I inserted a metal stud for rigidity.

Before the structural layers of uni directional carbon were wrapped, the foam core and stud were removed with Acetone.

The cups were compressed and glued onto the head tube. I figured the plates pressing from each side would help align the cups.

The end of each tube was sanded to seat into its respective join. Where ever there are two different materials (the BB steel to carbon) being joined, the area was insulated with glass fiber. Nasa have release some interesting papers on composite uses, including on the causes of galvanic corrosion.

Part before assembly.

The next step was to build a jig. I was working to a 5mm margin of error, I’d read somewhere that this was common in factory frames. Having said that, with the jig I built, I found it pretty easy to be exact.

The dropouts, BB and forks were fixed using M6 and M16 stud into an MDF box.

The angles were achieve with two pre-cut MDF guides.

I used a section of Unistrut, with some metal parts I had lying around, to create a hold for the seat tube.

The parts were aligned and strapped into position ready for the adhesive.

Once I’d spot glued the frame, it was removed and check for alignment.

Now to flox the joints before commencing with the layups. I created the flox using a mixture of Epoxy and shredded carbon fiber. The flox creates a full weld around the join, much the same as a fillet brazed frame (but without the strength).

 

Next – shape the joint in order to receive the layups.

All of the shaping was done using 5mm strips of sand paper, in much the same as a fillet weld would be shaped.

Traditionally each joint should, as I understand it, receive a full schedule of layups. This means uni directional carbon being compressed over the joint at something like 0/33/45/90 degrees. http://www.youtube.com/watch?v=l9x2PjozPus – this Cyfac video demonstrates the process.  I never really found clear advice regarding the repetition of layers required for each joint. Each area might well receive a different number and will return a different feel and stiffness. I used intuition and common sense, the BB requiring more support against lateral movement etc..

After the carbon (and a layer of Kevlar to protect against chips and cracks on the down tube) has been applied, a peel ply is added, both to help draw out the excess resin and also to enable the compression layer to be easily removed. I used electrical tape to compress the joint, it was punctured with a needle in order to allow the excess resin to drain away.

It is advised that all layers of carbon are compressed in one step, this helps avoid any de-lamination etc.  ‘However’, because perfect results are a little difficult to achieve every time, I compromised to allow myself one workable initial multi-directional layer. This layer was shaped and sanded to achieve a smoother bed before adding the final set of layers in one go. I did this in one quick step, trying to complete the full layup before the first layer was fully cured.

It is important to avoid sanding the structural uni-directional carbon, the fibers should remain continuous and unbroken to allow energy to flow and disperse. The multi-directional carbon is more or less decorative and as such it can receive a light sand to smooth the finish.

This image depicts the first and worst joint I made.

At this point I added a few top coats of finishing resin. The resin can be used to fill any minute blemishes and will help protect from UV. Finished joints.

Next, time to fix the bosses.

Running the front mech cable was a head scratch. I couldn’t think what to use to direct the cable and protect the frame. It occurred to me that the only time I’d seen a cable grommet that size was on the back end of a Bic Biro. So why not. I mounted a steel washer at the exit point and they both work well.

Mounting the gear cables to the down tube was pretty simple. I just molded flox around a pair of aluminum tubes and coated them both in carbon.

Same with the rear mech cable.

…and the brake cables.

Bottle bosses.

In a few spills last year, along with my teeth, I wrecked a couple of Flite Titanium saddles and fancied trying to recycle the ti and builds a carbon version. This was the ‘very light’ out come:

 

The Ti bars are loose in their fixing and between the (chain ring) bolts and the saddle are a couple of rubber washes, both of which allow the saddle to flex. I made sure I ran a layer of Kevlar through the carbon layers just in case it tried to bite me!! I’ve done several thousand miles on this seat now and it seems both comfy and strong enough.

A few close ups of the finished article, the first of which depicts the Garmin center mount I also made…

Bottle cage 24g

Finished cage.

I forget exactly but I think the total weight of the frame alone was around  1.4kg. If I become g sensitive I know the areas I over spec’ed.

I’m gearing up to build again with more contemporary geometry, shorten the head tube, lower and curve the top and shorten the wheel base. Try to make it more responsive and a little stiffer.

Suppliers:

Carbon:

East Coast Fiberglass suppliers – http://www.ecfibreglasssupplies.co.uk/

Carbonology – http://www.carbonology.com/

Easy Composites – http://www.easycomposites.co.uk/

Frame build:

Ceeway – http://www.framebuilding.com/

The Project Junkie – http://theprojectjunkie.com/

Carbon Wasp –

Brano Meres – http://www.bmeres.com

Research:

Metal corrosion – corrosion.ksc.nasa.gov/ .

Bio-mechanics – Cefac