Cycles Noir

[datas_brother]

+1 for bonding the h2o bosses inside the tube. I've had to fix a few of those because it wasn't done on big box frames.

[CyclesNoir]

Carbon Update....

The various fittings are all fitted to the tubes with the exception of a alu reinforcing sleeve in the seat tube. This isn't really necessary, except to provide a base for a screw to mount the 'braze-on' front derailer mount. Anyhow, I was curious about weight at this point, prior to bonding, faring, and wrapping the joints.


My original prediction was for a 1.25 Kg frame, I'm still looking for that, although it will depend on how well I manage the epoxy to carbon ratio of the finished joints. We'll see.

Mind you, this is intended to 1) be a lifetime frame; 2) ride right, not light; 3) provide a stiff front triangle (38mm down tube, 35mm seat and top tubes).

[datas_brother]

Carbon Update....
Mind you, this is intended to 1) be a lifetime frame; 2) ride right, not light; 3) provide a stiff front triangle (38mm down tube, 35mm seat and top tubes).

+1! no such thing as stiff and durable and super light. Two (first 2) out of three is the goal.

[CyclesNoir]

Joints glued and curing in the jig.

[e-RICHIE]

Joints glued and curing in the jig.

that's hot atmo.
how do you reconcile alignment on a CF frame?
is the fixture also the align-er?
does it all dry into alignment?

and - what checks do you make to ensure what you want is where you want it?

[CyclesNoir]

I can't bend or heat a tube to move things around.

On the other hand, keeping the frame in the jig through the curing of the glue gets me a straight starting point. Therefore, the initial checks are that the tubes are straight in the jig, and centered equal-distant from the baseline of the jig.

This is confirmed once the glue is dried using a Bringheli beam-style alignment table. If all is good, step next (at least for me) is building up a fairing to the joints, so that the CF doesn't have to bend sharply. While this probably adds some stability to the joints. I don't trust them hold while wrapping and vacuum-bagging joints. At this point, it's back to the alignment table for one more check, then I bond some knit (not woven) CF. This stuff drapes like anything. In fact, I can push it around a joint dry, lift it off, and it holds the shape of the joint. This gets compressed with tape, and allowed to cure.

At this point, it's check the alignment one more time, and then move on to wrapping and bagging the joints.

More details about these steps will be over on the blog in sometime next week: www.handmadebikes.blogspot.com

[CyclesNoir]

Details on the blog

[datas_brother]

Hi Rick,

That masking would look good as paint. Clear spiral showing the fibers with a light color in between.

Thanks for the ref. on your blog. I'll be returning the favor as soon as I get mine up and running. Does anybody know when that bill in congress will get passed which changes the day to 36 hours?

[CyclesNoir]

Description on the blog

[Craig Ryan]

Rick, way cool to see how this is done. Keep it going for us!

[CyclesNoir]

It was a short day today, but made a little progress as documented in the blog.

[WadePatton]

Hey Rick,

Kudos for mixing the old and the new. Thanks for being the slowest. I've only been learning for five years yo, but my count is crazy low. Things are a changing!

WP

[CyclesNoir]

Road down to the city today. Saw this at the turn-around:

Couldn't argue with it.

[WadePatton]

Road down to the city today. Saw this at the turn-around:

Couldn't argue with it.

that's a hoot-gotta get a copy.

[CyclesNoir]

Ya, thanks for the bump! By the way, do a google on it, you can buy the poster, mug, etc.

[soupless]

Road down to the city today. Saw this at the turn-around:

Couldn't argue with it.

Where'd you see that?

[CyclesNoir]

Where'd you see that?

Near Devon & Caldwell - on the West side of Central between Devon and Caldwell. There's a nasty gas-station on the corner of Caldwell & Central, with a cloud of cigarette smoke inside. It's convenient, however, to pick up a Gatorade before turning back north on the trail. Just to the North of it is a little coffee shop w/ said poster.

[CyclesNoir]

Some updated build pictures and description are on HandmadeBikes.blogspot.com. These include pictures of a frame in the vacuum bag.

[crumpton]

cool, enjoyed cruising the blog. question, why breather only on one side of the headtube? typically would cover the entire laminate being consolidated for full compaction?

[CyclesNoir]

Nick,

Thanks, that's an interesting question - your feedback is very welcome here.

My research indicates that compaction comes from the vacuum (or more properly the exterior air pressure). The breather serves to: a) provide a path for air to escape; b) soaks up excess epoxy.

As you know, when vacuum bagging against a mold, breather is on only one side of the CF layup. And it does a fine job of escaping air and soaking up epoxy. Similarly, some release layers are impermeable, preventing epoxy from escaping.

Over at Soller Composites, they have a demo video creating a CF tube by vacuum molding over a piece of PVC pipe. In the video, the breather is only used as a path between the inlet spigot and a tube that enters the PVC pipe. The air is evacuated from the bag into the PVC pipe, into the tube, through the breather and out the tubing to the pump. And yeah, they aren't doing things by the book and probably won't ever get their tube off that pipe.

In my experience, I can pull my vacuum and evacuate around the tubes without circling them with breather. Having a clear side allows me to better see how the sandwich is doing, and where I many need to adjust the release layer, or bag. And, it lets me see if any air is trapped - leading me to fiddle the bag until I have it out.

As you saw, the side without breather is up, and gravity helps to migrate excess epoxy from the top to the breather. If the fabric was too saturated with epoxy, it might overwhelm the quantity of breather that I use. But, I spend a lot of time working the epoxy in to the fabric, working air and excess epoxy out, prior to applying the fabric to the joint. So after a good bit of practice, experimentation, mistakes, and what not, there is plenty of epoxy in the fabric, but not too much for the breather.

Feedback?

Cheers,