Carbon thread

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pitbull

by pitbull

I did not find a specific carbon fibre fabrication/tuning/repairing thread so i invite you to show me what you did, want to do, or ask questions and help each other.

I will start this with my tune Kommvor repair i did these days.
Removed the broken piece, pulled fibres through a silicone house, put them in a modular mould,
connected them to the original part with rovings, removed the mould and after some sanding put a top strengthening layer on.
Seems pretty strong until now.
Image
Broken piece removed with dremel. File would work just as well.
I did cut it like you would cut flowers, because you have a bigger contact area and more support like this.
Try putting your hands next to each other, push one down and try to support it with the other one. It wont work.
Now put one Hand on the other and push the upper one down. You will be able to support it with the other hand.
Image
On the top right corner you can see resin, hardener and pva release agent, ready to be mixed up/applied.
On the bottom right corner there are the carbon rovings ready to be impregnated with resin-hardener mix.
I always put them on a plastic surface (e.g. freezer bag). In the middle there is the most important part.
Body protection. Always wear a mask that protects you against the harmful dusts and gases and use nitrile gloves to protect your hands.
Make sure your breathing mask is suited for protecting you against gases !
Above the screwdriver you can see a silicone pipe with a wire loop fed through it. I use this to pull the fibres through the pipe
Image
Image
the assembled mould ready to put the silicone pipe with fibres in it. I use this to give the saddle rails its final shape and make them oval.
I just press a pipe thats bigger than the mould into it and voilà you get 7*9 rails instead of 8*8
Image
here you can see the mould with the silicone pipe (with fibre ) in it.
Image
here you can see the unsanded saddle with the mould removed. You can see how the silicone pipe gives you a nice finish.
The ugly looking part beneath it are the rovings i secured the New rails to the original ones with.
I later did Sand them down and applied one top layer of UD fibre.
Poorly did not find a pic of the finished saddle. Please correct me if i do any mistakes, because english is not my main language.
Greetings from Germany.
Last edited by pitbull on Sun Nov 15, 2015 8:17 pm, edited 13 times in total.

by Weenie


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User avatar
LouisN
Posts: 3508
Joined: Mon Feb 19, 2007 3:44 am
Location: Canada

by LouisN

I had a little crack in my rear seat stay from a RD entering between the wheel and stay last fall.

Since the damage seemed to be superficial, I decided to repair it myself.

Here are a few pics :

The damage :
Image
Image
After the repair, raw finish:
Image
I decided to strip the whole frameset after beginning the sanding process.
Final look:
Image
The bike has behaved flawlessly for the last year, approx. 6000 km.
Oh ! BTW, the frame lost 180g after stripping, base prep and clear coat :D .

Louis :)

pitbull

by pitbull

Nicely done! I would have covered it up with some rovings/ud fibre to fit the looks of the frame but do it how you like. I might have a nice frame with exactly the same damage in a few days :) Folks if you have any questions please ask so we can help each other and get more people to get their hands dirty.

Jmdesignz2
Posts: 272
Joined: Tue Jan 13, 2015 2:27 am

by Jmdesignz2

Perhaps a step by step DIY with materials list and contacts for the materials?

pitbull

by pitbull

If you really want to get started with working on your own projects this is a book to read http://www.r-g.de/w/images/6/69/R%26G_Handbuch.pdf
Dont be confused, up to page 7 it is german but from then there is a translation in the right side.

Marin
Posts: 4035
Joined: Wed Jan 22, 2014 11:48 am
Location: Vienna Austria

by Marin

Cool thread!

Some captions for the saddle repair images would be nice.

pitbull

by pitbull

I added descriptions. If you have any further questions just ask. (Pictures are smaller now as well)
Last edited by pitbull on Wed Nov 18, 2015 7:53 pm, edited 1 time in total.

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Frankie - B
Admin - In the industry
Posts: 6573
Joined: Mon Jun 02, 2003 8:17 am
Location: Drenthe, Holland

by Frankie - B

Pitbull,

great idea, thanks for that.
Could you please post pictures that are a bit smaller? i believe 1027x 768 is the size that can be easily viewed on laptops.
many thanks!
'Tape was made to wrap your GF's gifts, NOT hold a freakin tire on.'
If you want to see 'meh' content of me and my bike you can follow my life in pictures here!

Marin
Posts: 4035
Joined: Wed Jan 22, 2014 11:48 am
Location: Vienna Austria

by Marin

pitbull wrote:I added descriptions. If you have any further questions just ask.



Very interesting!

So basically, once you get the fibers and resin into the mould, you just have to wait and later remove the mould?

pitbull

by pitbull

Marin wrote:Very interesting!

So basically, once you get the fibers and resin into the mould, you just have to wait and later remove the mould?

Thanks !
There are different resins. For some 24h and 20-25° Celsius is enough for others you have to heat the thing up to about 80 °Celsius after that. Usually stronger resins need to be heated. But for my wet laminate normal resins are just enough. Prepreg carbon is another thing. The Name says it is pre impregnated with resin and needs to be stored at a cold temperature to keep the resin from curing. If you want it to cure it needs to be heated to about 180°C. Of course there are different prepreg carbons as well.

pitbull

by pitbull

Frankie - B wrote:Pitbull,

great idea, thanks for that.
Could you please post pictures that are a bit smaller? i believe 1027x 768 is the size that can be easily viewed on laptops.
many thanks!

Thanks :) Ill do it the next time. I thought the Browser automatically resizes them(mine does) or most are viewing this on tapatalk.

addictR1
Posts: 1878
Joined: Sun Jun 10, 2012 1:11 am

by addictR1

woo.. i would love to learn how to repair carbon parts! what' the fastest way to strip off the paint from the carbon? i have a kestral ems pro bar that's cracked by the stem part, i would love to try and fix that up.

pitbull

by pitbull

Fastest way to remove paint is probably a cutter blade. Just rub it perpendicular to the surface.

pitbull

by pitbull

Here are some Cable Guides for my Bergamont Revox.
Image
If you are interested I will show you the moulds and explain how i made them.

addictR1
Posts: 1878
Joined: Sun Jun 10, 2012 1:11 am

by addictR1

pitbull wrote:Fastest way to remove paint is probably a cutter blade. Just rub it perpendicular to the surface.


wouldn't that scratch the carbon fiber underneath?

by Weenie


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