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Build your own Carbon/Kevlar DH Hardtail

Nately27

Monkey
Jul 29, 2003
121
0
Hey guys, Ive been workin on this project for a couple months and wanted to share the process so anyone whose been wanting to make thier own frame can see one route to go about it. I made this one in my bedroom for the most part. The dropouts, headtube, and bb tube are all made of steel and bonded to the carbon skin. The geometry is based on a Evil Imp. or .243. Here's a shot of the jig i made out of MDF board. The axles, bb, seattube and headtube are all adjustable.

I decided to make a male mold for the carbon, and then use it as the core material for the frame. Here's a shot of the preliminary foam core.

And after many hours sanding and shaping here's the finished core:

Heres the first layer of carbon on there: the carbon is H8 weave, 17mils thick. It builds up real fast. It came from sollercomposites.com as did the epoxy and the kevlar. It comes as a dry fabric, which i wet out on a piece of plastic, and then transfer to the core. It is then covered in peel ply, and put in a vacuum bag for 4-5 hours to cure. The vacuum setup came from avt-composites.com and was one of the more expensive pieces of equipment for this project.

and more carbon on:

The finished frame with a layer of filler to smooth out the surface. This is the main downside to a male mold, the surface finish can be less then stellar. So unfortunately you wont be able to see the weave on this frame. mayby the next one though...

and heres the painted frame built up:

It rides like a dream, its really stiff and the geometry feels perfect. Im planning to have a website up with a more detailed description of the process and all the supplies soon. anyways, enjoy!
 

Superdeft

Monkey
Dec 4, 2003
863
0
East Coast
Wow, cool. Carbon often seems like a foreign and difficult material to handle, but it looks like it's possible for the individual to do so. Any weight for the frame?
 

mobius

Turbo Monkey
Jan 25, 2003
2,158
0
Around DC
Derek you got to much time on your hands at VT. Nice frame man mr castle showed me pics a few days ago and i was amazed.
 

Nately27

Monkey
Jul 29, 2003
121
0
the frame weight came out to 7.2 lbs, which is right were i wanted. its in there with other burly hardtails. I guess ill find out how burly mine really is though soon ;) I made the dropouts myself out of quarter inch plate steel. I had to buy a drill press, from harbour freight, but the rest of the work was done with a saber saw and an angle grinder. next time itll be quarter inch aluminum and a table saw as the saber saw is a handful sometimes. The other parts came from henryjames.com, but bikeman.com has got some good items too. even disk dropouts i believe. Oh, and the seatube is carbon, i simply made it around the seatpost i was going to use. I wouldnt recomend this though as removing the post from the tube is difficult, and the carbon tube does not want to hold the post in there, i think theres just not enough friction between the two. Id use a metal tube next time. it would save a lot of trouble.
 

Nately27

Monkey
Jul 29, 2003
121
0
mobius said:
Derek you got to much time on your hands at VT. Nice frame man mr castle showed me pics a few days ago and i was amazed.
Thanks man! as for free time, this was basically my life outside of school and my girlfreind ;)
 

Nately27

Monkey
Jul 29, 2003
121
0
Mattoid said:
Looks great Darek! Looks like ya really have a good process going there, thanks for showin us how it went together. Riding pics?

What a great post.
right now im in the process of modifying the frame:

because i didnt design in enough room for the chain in most gears, but im thinking on being back on the bike early next week. Ive got some carbon curing on it right now as a matter of fact.

Im a chimp too now! hurray!
 

Castle

Turbo Monkey
Jun 10, 2002
1,446
0
VA
Derek can't wait to take it for a spin! good fun!

edit: I think the frame weight was around 7.2lbs (I believe this was due to it's thickness) if my memory serves me right from the convo we had, he can tell you far more than I can....
 
Mar 10, 2005
479
0
Santa Cruz/Sacramento, Ca
That's cool max. Like mindless, I'm really wondering how you can get the BB shell to stay in there. Otherwise, I'd find it very difficult to trust a frame in that color.

I highly suggest you give it a flame job. It'll make it go faster, anywho.
 

Nately27

Monkey
Jul 29, 2003
121
0
the bottom bracket is bonded to the "inner skin" with flox and epoxy. so there are two or three layers of carbon above the bb. you can see the cutout for it covered in carbon iin the pictures Then there I layed up 6 layers of carbon and two of kevlar underneath it to really secure it to the rest of the carbon skin.
 

Nately27

Monkey
Jul 29, 2003
121
0
oh, and for cost. if i had to make it again, it'd cost me bout 350 bucks i think. with the equipment, and all the supplies (i bought more than i needed) i ended up spendin 1200 dollars.
 

Nately27

Monkey
Jul 29, 2003
121
0
i thought about sellin em. I think id have to move the operation out of my apartment if i did. they're awfully labor intensive to build right now too, so they'd be pricey. i'd like to build one in a female mold, so it'd have that carbon finish and be less labor intensive... :D
 

jsun

Chimp
Dec 17, 2004
12
0
Redondo Beach, CA
And I thought I was cool because I wrench on my own bike.
I must give you 'Ultimate Proper Props with the Seal of Approval'. ;)
Nobody ever gets that, you ought'a be proud.
 

Matt D

Monkey
Mar 19, 2002
996
0
charlottesville, va
That's very cool man! Mad props for getting that done at home with limited tools!

Working with the CF is similar to fiberglass right (apply the resin to a mat)? Just curious b/c I've done some 'glassing for car stereo stuff.
 

Nately27

Monkey
Jul 29, 2003
121
0
layin carbon is exactly like doin fiberglass. except that its more common to vaccuum bag carbon then fiberglass, usually only because if you're using carbon in the first place, you're probably concerned with weight. Im still tryin to figure out all the details to a female mold myself. I would def need at least three though, one for either side of the bike and one or two for the inside of the stays. And then yeah, they'd get bonded togethor. I've been tryin to find the best way to do that, but cant seem to find much. There's gotta be a good way to do it, with the amount of carbon stuctures out there. Ideally you'd have some lip to bond togethor, or someway to layup carbon on the seam for strength. Thanks for all the positive feedback guys!
 

$tinkle

Expert on blowing
Feb 12, 2003
14,591
6
once you refine this process, do you think you (or anyone else who did this) would be inclined to publish a detailed "recipe" the unwashed masses could follow?

also, if i can rebuild a mopar slant 6 & bake creme brule, would this qualify me as able bodied?
 

Repack

Turbo Monkey
Nov 29, 2001
1,889
0
Boston Area
Thats rad!

I've thought of doind the same thing. Here are my female mold ideas:

I would use my M1 frame to start. Its high surface area would hopefully make the cf version strong.
Make a clam-shell box that will fit the frame. Fill each 1/2 with something like clay. I am sure that there is something better than clay, but I don't know what. Cover each half with plastic, put the frame betweent the sheets, then seal it all up. Even if the frame isn't 100% centered betweent the 2 halves, the void will still be a good shape. You/I/someone else could then sand down any imperfections in the clay to get the mold surface as smooth as possible.

Or you could make your own frame out of that foam. That would be more fun, especially since a multi-pivot bike would be such a pain.

I had thought that my ideas werew crazy until I saw what you had done!
 

COmtbiker12

Turbo Monkey
Dec 17, 2003
2,577
0
Colorado Springs
That's so cool dude! Did you design it on the computer in drafting programs? Or did you make the jig, get the materials needed and pretty much just do that? Seems like a kickass frame for not a ton of money. Do you think it'd hold up for someone who's like 210#? :p :) :thumb:
 

ÆX

Turbo Monkey
Sep 8, 2001
4,920
17
NM
Nately27 said:
layin carbon is exactly like doin fiberglass. except that its more common to vaccuum bag carbon then fiberglass, usually only because if you're using carbon in the first place, you're probably concerned with weight. Im still tryin to figure out all the details to a female mold myself. I would def need at least three though, one for either side of the bike and one or two for the inside of the stays. And then yeah, they'd get bonded togethor. I've been tryin to find the best way to do that, but cant seem to find much. There's gotta be a good way to do it, with the amount of carbon stuctures out there. Ideally you'd have some lip to bond togethor, or someway to layup carbon on the seam for strength. Thanks for all the positive feedback guys!

nice job.

now you have some good tools you will be able to do a lot.

get some mathacrylate glue. hysoll? sp ? it is THE best stuff for gluing bb or headtubes. aske for a sample and they generally give you enought to last a long time for free.

if you make soem more set tubes use PVA poly vynal acohol sp? it will act
as a release film and make it easyer to de-mold.

if you use a fem mold use a blater or a expanding foam. you will come out with a much better part than gluing halfs together. use the strength of the fibers not the glue to make a strong light frame.
 

Nately27

Monkey
Jul 29, 2003
121
0
$tinkle said:
once you refine this process, do you think you (or anyone else who did this) would be inclined to publish a detailed "recipe" the unwashed masses could follow?

also, if i can rebuild a mopar slant 6 & bake creme brule, would this qualify me as able bodied?
you'd definately be able to do this then. id say patience and motivation are the most important things. and i cant even say i can make a creme brule...
try www.sheldonbrown.com/rinard for a decent "recipe." Im gonna get a website up soon that will have all the gritty details, like a step by step process of the construction. even if its not a perfect process right now, it'd be a start.
 

Nately27

Monkey
Jul 29, 2003
121
0
bcd said:
O, love the seat clamp
haha, i was wondering when someone would notice that ;) 99cent at the hardware store!

so when you are using a bladder or expanding foam, where does the excess epoxy go when its in the mold? do you use porous release film and bleeder fabric at all? or are you using prepreg carbon? and im assuming you put the mold halves togethor for the cure so you get no seams. is that right?

I designed the geometry and profile of the frame in 2D in Autocad. So i was able to check clearances (some) and print off layouts for the jig. ill be using NX3 for the next one so i can have a full solid model.

Most of the materials can be found at lowes, walmart or the fabric store, with exception of course of the carbon fiber and epoxy. www.sollercomposites.com is an excellent source for epoxy and fabric, and I got the vacuum pump from www.acp-composites.com.
 

peter6061

Turbo Monkey
Nov 19, 2001
1,575
0
Kenmore, WA
Just got to chime in with a 'Nice job!'

Been thinking about doing that for some time. Can't wait to see your web site to see even more of your details of the construction.