Best Way to Make Carbon Fiber Panels?

Discussion in 'Boatbuilding' started by CatBuilder, May 25, 2012.

  1. CatBuilder

    CatBuilder Previous Member

    We are going to use carbon fiber as a fashion accessory in a few places.

    Can anyone explain or provide a link to a process that can make perfectly smooth, transparent carbon fiber panels like these steps?

    [​IMG]
     

    Attached Files:

  2. waikikin
    Joined: Jan 2006
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    waikikin Senior Member

    This seems to be a good forum for cosmetic carbon parts, Herman posts there & plenty of vehicle related stuff. http://www.compositescentral.net/index.php

    All the best from Jeff.
     
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  3. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    How about just black 'glass and save some money. The weight difference isn't going to be significant enough to screw with anything.
     
  4. CatBuilder

    CatBuilder Previous Member

    Considering I haven't priced out a roll of thin carbon cloth yet, that might be a very good idea! :)

    Even if I used black glass, how would I get that nice, clear panel made where you can see the cloth perfectly?
     
  5. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    It'll have to be done in a perfectly fair mold, bagged preferably under ideal conditions.
     
  6. TeddyDiver
    Joined: Dec 2007
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    TeddyDiver Gollywobbler

    Hand laminating epoxy squeeing with putty knife. You could use Basalt fabrics instead of Carbon.. much more tolerant for impacts (I do)
    BR Teddy
     
  7. groper
    Joined: Jun 2011
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    groper Senior Member

    i used to build kiteboards with a clear carbon cosmetic finish - by vacuum bagging in 1 shot... Ill explain;

    firstly, the panel is built on a smooth table mould (i used polished aluminium for the kite boards as i could curve it to the rocker i wanted).

    The first layer down was a thin veil of 100gsm woven e-glass wetout with clear unwaxed polyester resin (surfboard laminating resin used instead of clear gel coat), once it cured (it stays tacky for chemical linking) i layed over the carbon cloth and wet it out with vinyl ester resin - inhibbit the resin to slow it down if you need more working time.

    Then, applied the shaped core over this which had shallow 2mm grooves scored into the bottom surface (like infusion scoring), then applied the top layers of cloth and peel ply all wet out with the same batch of vinylester resin. I had to cut the scoring so the air could escape out from beneath the bottom of the core to the edge of the panel...

    Now comes the unique part, you dont use a breather layer over this, you place a thick roll of flow media (shade cloth) all around the perimeter of the part, not on the part, with a vacuum line going into this, and bag the plastic film straight over all of it - i used acrylic sealant and a silicone gun instead of tacky tape so it was quicker and less mucking around to apply the bagging film.

    Once you apply the vacuum, get ALL the wrinkles out of the bag whilst the vacuum pressure is only slight, then increase the vacuum upto 26" (keep the pressure below styrene boiling point of 93% absolute). Use a squeegee to scrape over the bag and push all the resin and air bubbles towards the edge of the bag as it wont get there on its own due to no breather over the laminate. The excess resin will go into the perimeter shade cloth/breather material and towards your catch pot. Before you leave it to cure, the part should look perfectly flat and smooth with the plastic stretched tight over the panel - no wrinkles and no pools of resin.

    Once its cured, peel off the peel ply and you will have a nice flat peel ply textured surface with ZERO pinholes, the mold side will be already smooth and finished... this is important, as any pinholes will show up in the next and final step.

    Get your standard spray painting gun, i think mine had a 2.5mm nozzle but cant remember right now.... mix up some "surfboard finishing resin" which is a thin clear waxed polyester. Then thin it some more with styrene monomer so you can spray it nicely and add some wax in styrene - i had to do this as there were places where the resin would stay tacky... i cant remember the ratios, i think i used about 8% wax in styrene and 10% styrene monomer to get things looking nice.

    Catalyse it, and spray it like you would a 2 part PU paint with a wet edge, it should go down perfectly flat filling the peel ply texture and curing to a hard UV protective coating thats as smooth as a brand new surfboard and that clear carbon finish that looks a million bucks... i also used texalium cloths and what not for other effects etc in the same manner.

    You probably wont get it all sorted on your first attempt, but this is how i got everything to work so there was no sanding at all, and a perfect finish on both sides of the kiteboard.

    Never thought id post my trade secret that took me about a year to develop, but here it is and i hope you enjoy :)

    Ha, even found the pics from 10 years ago still on the net... [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
     
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  8. CatBuilder

    CatBuilder Previous Member

    WOW!!! Groper, that is the best detail I have ever received. Thank you.

    Ever more "wow" are the boards! I grew up skateboarding and snowboarding (since the early 1980's), so I have a natural tendency to appreciate a fine board and these boards are AMAZING!

    Beautiful work.

    I have to admit, this sounds like a daunting task for making decorative parts, no matter which method is used.

    I thought there might be a quick way to do it on a flat sheet, bagging to the sheet, then give it a quick sand with very fine/high grit sand paper, then put on some kind of coating like varnish or something. You know... how you build wood up to look the same?
     
  9. groper
    Joined: Jun 2011
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    groper Senior Member

    im sure there are other ways of doing it... i worked out the above method as it allowed me to do it in one continuous layup, with no sanding at all besides cleaning up the edges prior to the final spray job...

    If you get any pinholes or other imperfections in the surface, you must fill them prior to any finish coat or they will show up as tiny craters in the top coat. The carbon cloth has a tendancy to want to pinhole wherever the tows intersect. it was a problem that took me a long time to figure out... with the bag directly on the peel ply, you have a solid resin finish with no pinholes.

    In my first attempts, i had air bubbles trapped under the core, so then i figured the scoring to allow the air out, perforations in the core might work aswell, but i never tried this at the time.

    I wanted to use epoxy, but none of the commonly available resins at the time, had a high enough HDT (and still dont i beleive), so when they were left on the beach in the sun, they get VERY hot because they are black, and the resin softens and could loose their shape - so i moved to a vinylester resin with a high HDT. This also allowed the compatibility with the polyesters and UV protection - another thing epoxy was no good for.

    I never tried infusion resins as a finish coat, these would probably be even better for spraying that final coat.

    If you happy doing a panel in 2 shots, you could hand lay each carbon layer on the table by itself as it stays resin rich and good finish... then bag the core to it, 1 side at a time using the grooves as a means for the air to escape.... you may be able to simply squeegee the pre-cured top skin on, working the air out as you go like tinting a window, but i couldnt try this as my kiteboards had a 3D compound curved top surface... flat panels might work fine...
     
  10. groper
    Joined: Jun 2011
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    groper Senior Member

    If you try the same idea using a straight hand layup, you never end up with a flat finish... there is always resin pooling somewhere and an uneven thickness... As the finish is black and shiny, these variations are easily visible in the reflections and ruin the finish... the vacuum pressure and tight bag helps level everything out.

    I also never tried skipping the peel ply, and just laying the bagging film directly onto the wet laminate and doing the same as i outlined above... this would negate the final spray job - cant remember why i didnt do this back then, but there was probably a reason... i think the cloth still prints thru...
     
    Last edited: May 28, 2012
  11. mydauphin
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    mydauphin Senior Member

    Cat,
    Let me know where you get Carbon fiber. I am looking to buy a couple of yards and every place is giving me some ridiculous prices. The only way to buy cheap I have found is to buy a whole roll.
     
  12. hoytedow
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    hoytedow Wood Butcher

  13. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Epoxy a piece of black 'glass to the bottom of the polycarbonate and call it a day . . .
     
  14. Boston

    Boston Previous Member

    pretty cool stuff Groper

    and Par, that would be cheating ;-)
     

  15. AndrewK
    Joined: Mar 2007
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    AndrewK Senior Member

    If you infuse the carbon/black glass on a sheet of glass you will get a very smooth and glossy surface like in the photos.
    Infuse only a likght weight cloth alone and glue this to a plank with the radiused front edge. Heat along the radius past the laminate HDT to get it around.
     
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