Carbon Fiber Fun

[BentAero]

One more thing: You don't need the $40 thru-bag fitting they sell. http://www.fibreglast.com/product/thru-bag-vacuum-connector-00910/Vacuum_Fittings
Just make a home-made straight spigot type vac port by attaching a small piece of 1/4" npt pipe to the quick-connect coupler. Cut several perpendicular slots in the pipe, (don't rely on the air escaping only the hole in the end of the pipe -resin will plug it.) then tape on a scrap piece of breather material. Leave some 'neck' near the coupler for sealant tape. Wrap a piece of the grey sealant tape http://www.fibreglast.com/product/gray-sealant-tape-00581/Vacuum_Bagging_Films_Peel_Ply_Tapes around the neck of the pipe, then insert it into the bag. Tube bag is easy, but not required. Just make sure the 'tail' of the spigot breather is long enough to lay several inches onto the breather material that covers the carbon fiber. This will allow the air to escape.
Clear as mud, right?

 

[Lief]

Rick! I'm NEVER gonna catch up with all the posts I've missed if ya'll keep making such good, long, interesting, master-craftsman posts of stuff like this!
I was wondering where I'd find out what your "rank" (Carbon Craft Master) came from.
NOW I know.
A gem indeed.

This isn't production ready - it's museum ready.
Artwork.

 

[super slim]

Gary, I did not realize it made it lighter and stronger, I just thought it would be faster to make!!!

Is vacuum bagging faster than wet layups, after the mold has been made?

Rick has produced a stunning well made tail box, especially with the folding lid!!!

 

[LarryOz]

I can't even begin to say how impressed I am with your tailbox layup. Good job Man, It looks fantastic!

What Gary said times a "million"! - You are amazing dude!
You can do this "and" ride a V up and down Californian mountains! Incredulous!

 

[Rick Youngblood]

Thank you Gary for the great info. I've purchased from Fibergast, nice products like the release agents and rollers. I may venture into vacuum bagging in the future, but for the time being will stick with wet layup.

And once again thanks guy for the positive comments.

 

[telephd]

That's astounding craftsmanship Rick!

 

[BentAero]

Gary, I did not realize it made it lighter and stronger, I just thought it would be faster to make!!!

Is vacuum bagging faster than wet layups, after the mold has been made?

Rick has produced a stunning well made tail box, especially with the folding lid!!!

Vacuum bagging makes a product stronger and lighter because it removes excess resin and compacts the layers of fabric while at the same time removing air. Resin is heavy and has no strength.
Vacuum bagging is an additional step that can be done to optimize the composite product vs an air-cure.

Wet layup means you are saturating dry fabric with a wet, liquid resin/hardener goo one layer at a time. Most home fabricators will let the wet layup air-cure on it's own. Just like letting two-part epoxy cure.

The alternative to wet layup is to use thermoset resin pre-impregnated fabric, commonly known as 'pre-preg'. It's much easier to use as its 'no mess', but it requires an oven with fume venting, plus tooling/molds, and vac lines that can handle 350 f. Pre-preg is best cured in an autoclave, but that's a whole different magnitude of cost and complexity.

 

[RojoRacing]

hey rick how hard would it be to make carbon fiber disc wheel covers? I'm already looking into buying some sheet abs to make my own covers but then i thought they could make for some awesome molds to carbon covers. i'm curious as to how many layers you think it would need? the idea would be to be as light as possible and there wouldn't really be much if any stress to the part since it's just taped on. i can't get a strait answer about any pre made covers fitting a front wheel with disc rotor so my best bet for a perfect fit would be to make my own. i'm sure if i can find 0.030 abs sheeting(no luck so far) they would perform well enough for my race but Catalyst claim their carbon covers are half the weight.

this guy made a great DIY tutorial of how to go about it http://forum.slowtwitch.com/forum/S...DIY_disc_wheel_cover_how-to_thread._P3552095/

 

[RojoRacing]

looks like Mcmaster sells nylon in 1/32" thickness, i think at that thickness even nylon should be flexible enough to bend into a slight dome.
http://www.mcmaster.com/#8540k421/=13524ga

 

[Rick Youngblood]

hey rick how hard would it be to make carbon fiber disc wheel covers? I'm already looking into buying some sheet abs to make my own covers but then i thought they could make for some awesome molds to carbon covers. i'm curious as to how many layers you think it would need? the idea would be to be as light as possible and there wouldn't really be much if any stress to the part since it's just taped on. i can't get a strait answer about any pre made covers fitting a front wheel with disc rotor so my best bet for a perfect fit would be to make my own. i'm sure if i can find 0.030 abs sheeting(no luck so far) they would perform well enough for my race but Catalyst claim their carbon covers are half the weight.

this guy made a great DIY tutorial of how to go about it http://forum.slowtwitch.com/forum/S...DIY_disc_wheel_cover_how-to_thread._P3552095/

Hey Jason, hmm...for me to do a project like this may not be cost effective as I would need to do a bunch of r and d to get started with a concept, trial and error, mold, etc.

I would think perhaps it would be less expensive to purchase pre-fab sheets of carbon fiber and build a disc in the same fashion as abs. It can be cut and shaped with the same tools as abs, but instead of abs glue, you would use a two part epoxy mix in the seam. The pre-fab carbon fiber can be purchased off eBay from Chinese venders for a much cheaper price than I could produce it.

In order to get the strength along with lightness vacuum bagging would be necessary as Gary mentioned above. Vacuum bagging in be in the future for me, but currently I'm not setup to do yet.

 

[RojoRacing]

Those were my thoughts exactly but wanted to confirm with you of wether it would worth me trying for a first carbon project. I figured without vacuum bagging there would probably not be any weight advantage over plastic.

 

[RojoRacing]

I looked at some carbon plate I could use instead of abs but damn, they want like $140 per side in the U.S. I can't find anything that's 1/2mm thin and big enough for a wheel 24"x24" on eBay.

I may be stuck with plastic for now unless someone can find thin carbon plate big enough at a reasonable(poor college student level) cost.

 

[Rick Youngblood]

I looked at some carbon plate I could use instead of abs but damn, they want like $140 per side in the U.S. I can't find anything that's 1/2mm thin and big enough for a wheel 24"x24" on eBay.

I may be stuck with plastic for now unless someone can find thin carbon plate big enough at a reasonable(poor college student level) cost.

Checking with China eBay seller for that size.

 

[RojoRacing]

Checking with China eBay seller for that size.

I'm thinking 0.3 mm would be best. In your opinion woul 0.3 mm be 2 or 3 ply carbon?

They say those catalyst carbon covers are paper thin and you can easier chip the edges if you're not careful

 

[RojoRacing]

here's an option at a more reasonable price. i can get 0.25mm 0r 0.5mm at 580x580mm i wish it was 600x600 but i think 580 is just enough for my 55mm deep rims. i'll make some out of plastic first to confirm the minimum size needed before ordering. what do you think, 0.25mm or 0.5mm? 0.25 is basically 10 thousands of an inch which sounds crazy thin and could be prone to buckling if not perfect, especially at the seam. i sure wish i could go down the street and hold each piece in my hand and say "yeah this one feels good"

http://www.easycomposites.co.uk/#!/...re-sheet/Prepreg-Carbon-Fibre-Flat-Sheet.html

 

[MrSteve]

Making your own wheel covers?
Bear in mind that the wheel you plan to cover does not need to be 'aero.'
It helps if your future covered wheel is strong and stable.
It helps if the wheel rim is the strong, old-fashioned boxy type and if the spoke count is not too low...
see this: http://sheldonbrown.com/rinard/wheel_index.html .
The boxy rim will leave you room to custom fit your wheel disks; aero-rims are pretty finicky and leave
you very little room to work with.

For example, I ended up using a Mavic Ksyrium wheel for my disc covered rear wheel: its rim is much less
aero than the stock Cruzbike wheel rim is and is plenty strong and light.

Finally, another advantage of using a wheel dedicated to the disc covers is that you still have your
original uncovered wheel ... for windy days.

Hope this helps,
Steve.

P.S.
Mine are ugly, hacked out of 1/4" polystyrene sheet foam insulation and are lashed to the spokes with waxed artificial sinew.
They're ugly, flashy and both very light and pretty dang fast.

 

[Rick Youngblood]

here's an option at a more reasonable price. i can get 0.25mm 0r 0.5mm at 580x580mm i wish it was 600x600 but i think 580 is just enough for my 55mm deep rims. i'll make some out of plastic first to confirm the minimum size needed before ordering. what do you think, 0.25mm or 0.5mm? 0.25 is basically 10 thousands of an inch which sounds crazy thin and could be prone to buckling if not perfect, especially at the seam. i sure wish i could go down the street and hold each piece in my hand and say "yeah this one feels good"

http://www.easycomposites.co.uk/#!/...re-sheet/Prepreg-Carbon-Fibre-Flat-Sheet.html

Jason, it's beyond my experience as to what thickness to use. But I'm essentially thinking the same thing you are to go as thin as possible and still be rigid enough to hold its shape and not buckle under the forces of air. There are so many different compositions of carbon fiber weave, some are very stiff and others are not so much. Comparing thickness to thickness, CF vs ABS, CF can be much more rigid. Wondering if they can send you a few samples before you invest in a couple of large pieces?

 

[RojoRacing]

What we've learned in the Mtb world these last 5 years is that per weight carbon rims far outclass any form of alloy rim shape. The only shortcoming to the carbon rims is they can fracture from rim strikes on rocks from low PSI, not really an issue for road bikes though. I suspect a quality U shaped 40 mm deep carbon clincher rim these days is just as light as a quality boxy alloy and twice as strong. The new carbon rim look nothing like the narrow stock Cruzbikes rims, they have a big round shape that further increases their structural strength. The rims I used in my new wheels were offered in 4 depths, 25, 33, 55 and 88mm. I chose the 33s over the 25s for my front wheel because the weight was nearly the same but the strength would be a bit stronger. In the rear I chose 55s because it would be easy to fit a manufactured cover onto a 55 vs the 33 with its 22mm of extra surface area. The 88 was out of the question due to the increase in weight and lack of aero benefit with the planned covers.

After noodling half a dozen quality alloy rims on the Mtb I'll never go back to alloy rims again on any of my pedal cycles.

 

[RojoRacing]

Jason, it's beyond my experience as to what thickness to use. But I'm essentially thinking the same thing you are to go as thin as possible and still be rigid enough to hold its shape and not buckle under the forces of air. There are so many different compositions of carbon fiber weave, some are very stiff and others are not so much. Comparing thickness to thickness, CF vs ABS, CF can be much more rigid. Wondering if they can send you a few samples before you invest in a couple of large pieces?

So after many hours of surfing the web with very little progress I stumbled onto a gem this morning while trying to calculate the weight of the covers in each thickness. Apparently I have a carbon supply house down the street that also offers finished sheets in 24x24 sheets. I'm going to head over there later and talk to the sales rep and see about examining some options first hand.

I have question about the glueing process for my seam. Is it as easy as gluing a 1" wide strip to the back with some kind of resin? Will I need some kind of primer?

 

[Rick Youngblood]

So after many hours of surfing the web with very little progress I stumbled onto a gem this morning while trying to calculate the weight of the covers in each thickness. Apparently I have a carbon supply house down the street that also offers finished sheets in 24x24 sheets. I'm going to head over there later and talk to the sales rep and see about examining some options first hand.

I have question about the glueing process for my seam. Is it as easy as gluing a 1" wide strip to the back with some kind of resin? Will I need some kind of primer?

Nice find Jason. The cf shop should have gluing supplies they can recommend that will work with their resin compounds. My cf seat is three pieces I made separately. The bottom and sides I glued together using the same two part resin compound that I used to layup the cf fabric. Talk to the cf shop about joining the two ends together, whether overlapping or butting the ends together and over laying a piece over the butted ends. What procedure would they recommend. The nice thing about cf is once you have joined the two ends together you can sand and finish the seam to become invisible, unlike abs. Also if you are concerned about uv protection, ask whether their resins or finished sheets are protected, you may need a clear coat of uv protection.