Carbon Building

[CyclesNoir]

Nick,

You opened the door a little bit over in SMOKED OUT, now how about sharing a bit more in pictures and narrative about how you build carbon frames?

[crumpton]

gimme a few days. what i'll try and do is document with words and some pics the next pair of SLs i'm starting tuesday or wednesday.

[CyclesNoir]

Very cool! I'm sure many of us will look forward to that.

[zank]

That will be be fantastic.

[crumpton]

looks like an 8pic max per post so look for updates spread through out the thread.
things i cannot stress enough.

1. DO NOT CLEAN EPOXY FROM YOUR FLESH WITH SOLVENTS.

2. if something is bonded, it is what it is, there is no setting or changing the angle. any anomolies in your fixture will live in your nice carbon frame. make sure your fixture is balls on. you can use heat to pull it apart and redo but this takes some experience.

3. USE SOAP AND WATER TO CLEAN EPOXY FROM YOUR FLESH

4. acetone wipe/abrade/acetone wipe



i'm not gonna deal with any issue that a somewhat experienced frame builder should already know. i'm gonna be as transparent as i can but will not open any cans of worms and will have to keep some things close simply because... that why.

i start day one by bonding up the drops both at the CS and SS as well as creating the BB shell which is essentially a carbon tube and TI shell.

drops back from anodizing(type 2) ready to rip



-->anodizing been stripped from the plugs. on my bench, better peel strength to bare alu. anodizing must close the grain up or something.



-->ends of SS and CS marked for rough cut



best thing ever for cutting carbon tubes.



-->2 sets rough cut. now the hard part.



-->squaring up ends



free handed bore for concentricity. including the nice chamfer at the ends.



-->nice fit and correct off the centerline. this is a must, no setting this later. do it right now or toss in the bin later. when i say nice fit i mean that the stay can actually rattle on those plugs in this state. its gotta be relaxed, just like brazing/welding, if you close up a joint under tension or load, you get bad results and crooked bikes.

[zank]

Yes, sir.

[crumpton]

not gonna crack the epoxy till i have the BB assy's ready.

nice knurled shells to a specific OD to fit my carbon tube and leave a .0025 to .005" bondline(called out in the manufacturers datasheet). same as the drops. see i'm cutting those tubes from stock. the same tube used in the HT of the SL. they are correct for retaining those innards. they are lined in black glass. they are very different than the other tubes in the frame.



nice fit



see that the ID is all slick and probably has release agents on it from Carl at Enve. acetone wipe, abrade, acetone wipe. learn those three steps and do them any time you bond. bond within 30 min. sooner if in a humid icky environment like portland in the winter. haha.



my trick for getting in there



see, now all scuffed and scratchy like your eyes in an austin ragweed festival.



important stuff. acetone and prep wipes. these are special(arrived on the short bus) and leave no residue or lint. btw, if you get epoxy on your skin dont be stupid and clean with acetone or any solvent. use soapy water and live with it.

wipe/abrade/wipe



gloves and un mixed dp-420 blk. dont forget to mix thoroughly



then coating ID of carbon tube.

[crumpton]

now the OD of the TI insert



twist together



lotta goo to clean off the threads. do it now. worry about the ends of the tube later.



now coating the ID of the stay



OD of the drop plug



now all fixtured up and ready to cure. all excess epoxy has been cleaned up now. you can sand it off later if you are into that sort of punishment.



more in a day or two.

[Chauncey Matthews]

Quite possibly the best VS thread ever...thanks guys!
Can't wait till the next update.

[progetto]

Hey Nick,
Neat thread. I use white vinegar for cleaning any epoxy from my hands, seems to work well without adverse effects to the skin. Do you think that a secondary bond as you do between ti insert -carbon shell- pre preg joint laminate is the strongest conection method? I actually bond the ti insert during joint laminate construction using adhesive film between insert and pre preg layers. Haven't had any failures as yet but don't build anywhere near as many as you. Feedback welcome.
Bill

[crumpton]

Bill,

i'm not worried about solvents adverse effects on the skin but rather it thinning and transferring the epoxy into the bloodstream. this is not good. if vinegar is cutting/thinning then i'd still choose soap and water and know that i my work will eliminate whats left in due time. soap and water wont really get it all off but will reduce and keep you from gluing yourself to yourself(a joke) or the next thing you touch. like dirt and lint.

as for carbon co-molded to Ti vs. carbon/Ti secondary bond with carbon co-molded to carbon. i've built plenty of bikes with the joint co-molded to the Ti and have had no issues in the field. i just prefer the latter. and my current method actually adds weigh!

Hey Nick,
Neat thread. I use white vinegar for cleaning any epoxy from my hands, seems to work well without adverse effects to the skin. Do you think that a secondary bond as you do between ti insert -carbon shell- pre preg joint laminate is the strongest conection method? I actually bond the ti insert during joint laminate construction using adhesive film between insert and pre preg layers. Haven't had any failures as yet but don't build anywhere near as many as you. Feedback welcome.
Bill

[vulture]

I was under the impression that bonding carbon to aluminum required a galvanic insulator like fiberglass or anodizing. What protects the stays from eating the dropouts?

[crumpton]

I was under the impression that bonding carbon to aluminum required a galvanic insulator like fiberglass or anodizing. What protects the stays from eating the dropouts?

carbon doesn't "eat". at any rate, the ID of the stays is glass. regardless, the bonding agent has very good dielectric strength and at .005"+ back there, the drops are well insulated.

galvanic corrosion requires 2 things, direct carbon to aluminum contact and i mean direct. coupled with the presence of oxygen. so even if a bit of aluminum does contact carbon, it would need to be in the open.

[Dave Anderson]

Hey Y'all....Nick has this this sh$t covered and has been down all of the roads. His process works. It blows me away with gratitude that he's sharing some of it with us. I, for one, am going to just sit back, relax, and enjoy the show.

Thanks Nick!

Dave

[CyclesNoir]

Very cool! On the edge of my seat for the next installment.

[zank]

Hey Y'all....Nick has this this sh$t covered and has been down all of the roads. His process works. It blows me away with gratitude that he's sharing some of it with us. I, for one, am going to just sit back, relax, and enjoy the show.

Thanks Nick!

Dave

+1000

[crumpton]

i may "have it covered"... but please don't take it for granted, ask questions if you have em.

[ADD]

The one thing I'm really curious about is how you align the hole in the chainstay for the front derailleur cable. I struggled with it and just went the way of steel tubing to avoid drilling a hole. I was thinking trying to make a jig for it, but it wold be rather complex.
Also you vent your tubes or keep them sealed? The one carbon frame I've done so far was sealed, but I'm curious if there is a reason not to.
Really appreciate you post this Nick.

[crumpton]

The one thing I'm really curious about is how you align the hole in the chainstay for the front derailleur cable. I struggled with it and just went the way of steel tubing to avoid drilling a hole. I was thinking trying to make a jig for it, but it wold be rather complex.
Also you vent your tubes or keep them sealed? The one carbon frame I've done so far was sealed, but I'm curious if there is a reason not to.
Really appreciate you post this Nick.

both those questions wil be covered as this progresses. stay tuned.

[VertigoCycles]

Incredible thread Nick. Thanks for sharing. Going to make popcorn now