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  1. #1
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    making your own carbon fiber seatpost

    since I can't find any seatpost lighter than 160g in 26.8x300, I'm wondering if should get a generic carbon seatpost cut the head of drill a hole and somehow glue the aluminum cylinder for the bolts just like an m2racer.
    what do you think?
    thanks
    Last edited by Limon; 12-14-2004 at 08:18 AM. Reason: I hit the button to early

  2. #2
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    well I've successfully reglued a xtr post together. It had siezed in the TI bike so I had to put a big old pipewrench on it. I cut the damaged section off then glued/epoxy the clamp insert back into place. Its been 6 yrs now.

    If it is as simple as replacing the clamping device and gluing the head insert onto a CF seat post - I'd say go for it. If it involves drilling through the CF, then I'd avoid it.

  3. #3
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    Quote Originally Posted by heatstroke
    well I've successfully reglued a xtr post together. It had siezed in the TI bike so I had to put a big old pipewrench on it. I cut the damaged section off then glued/epoxy the clamp insert back into place. Its been 6 yrs now.

    If it is as simple as replacing the clamping device and gluing the head insert onto a CF seat post - I'd say go for it. If it involves drilling through the CF, then I'd avoid it.
    or maybe just glue the head of a thomson seatpost to a carbon post
    where can I get the glue for this?
    thanks

  4. #4
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    Maybe not?

    Quote Originally Posted by Limon
    or maybe just glue the head of a thomson seatpost to a carbon post
    where can I get the glue for this?
    thanks
    You need to use an epoxy resin and carefully prepare the aluminum surface cleaning carefully with a solvent, slightly sanding with 600 grit, cleaning again with solvent and binding it to the carbon. You also need to prepare the (inner) surface of the carbon tube making sure that all possible residue (e.e. mold wax) is removed. Tolerances between the two parts have to be precise because what is keeping the two parts together is the epoxy which is not strong at all. You might want to consider adding aluminum powder additive to the epoxy, pin the tube to the post before epoxying or possibly add a layer of carbon and vacuum bag it in place (would add almost no weight).

    DO NOT use 5' epoxy that you buy at the hardware store because you want to be able to control the curing time (and fluidity) with more precision than that and get the highest quality resin you can get not some (expensive) crap over the counter. 30'-60' curing is a good ballpark to work with ease: you definetely do not want to run against the clock if something goes wrong. High quality epoxy is http://www.westsystem.com/ can buy at http://www.fiberglasssupply.com/Prod...t_catalog.html

    Of all possible hand-made carbon works joining aluminum to carbon is not exactly the easiest ... and you might consider that MAXM is coming out with a 400mm carbon post supposedely at 175 grams http://titusti.com/gear_components.html
    Attached Images Attached Images
    Last edited by Davide; 12-14-2004 at 10:51 AM.

  5. #5
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    Email Damon Rinard: drinard@yahoo.com

    He's from Sheldon Brown's site and is experienced with DIY carbon fiber.
    I was impressed with his garage built carbon fiber bike frame...


  6. #6
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    I agree using a better epoxy with a slower gel time would be better for the job, along with vacume bagging it. I took in consideration that he did not have access to a vacume pump, or the bagging material. Unfortunatly when you get into vacume bagging and the different type of epoxys out there you will need more money. It sounded to me that he wanted a quick fix and wanted to do with the least amount of money involved, since it was going to be a just for him and not something he wanted to start producing and selling.

  7. #7
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    Quote Originally Posted by skin6061
    I agree using a better epoxy with a slower gel time would be better for the job, along with vacume bagging it. I took in consideration that he did not have access to a vacume pump, or the bagging material. Unfortunatly when you get into vacume bagging and the different type of epoxys out there you will need more money. It sounded to me that he wanted a quick fix and wanted to do with the least amount of money involved, since it was going to be a just for him and not something he wanted to start producing and selling.
    Oh, I know ... to do the job well would cost a a bit, but I am not sure I would trust a quick fix on a seat post

  8. #8
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    yu got me skerd!(urban diccionary.com)

    Quote Originally Posted by Davide
    You need to use an epoxy resin and carefully prepare the aluminum surface cleaning carefully with a solvent, slightly sanding with 600 grit, cleaning again with solvent and binding it to the carbon. You also need to prepare the (inner) surface of the carbon tube making sure that all possible residue (e.e. mold wax) is removed. Tolerances between the two parts have to be precise because what is keeping the two parts together is the epoxy which is not strong at all. You might want to consider adding aluminum powder additive to the epoxy, pin the tube to the post before epoxying or possibly add a layer of carbon and vacuum bag it in place (would add almost no weight).

    DO NOT use 5' epoxy that you buy at the hardware store because you want to be able to control the curing time (and fluidity) with more precision than that and get the highest quality resin you can get not some (expensive) crap over the counter. 30'-60' curing is a good ballpark to work with ease: you definetely do not want to run against the clock if something goes wrong. High quality epoxy is http://www.westsystem.com/ can buy at http://www.fiberglasssupply.com/Prod...t_catalog.html

    Of all possible hand-made carbon works joining aluminum to carbon is not exactly the easiest ... and you might consider that MAXM is coming out with a 400mm carbon post supposedely at 175 grams http://titusti.com/gear_components.html
    this was going to be a spare time project, I think I'll pass on that one for now
    but if I get bored and try it I'll let you know.
    thanks
    la vida sigue.

  9. #9
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    I think the MaxM specs on the Titus site are old

    Quote Originally Posted by Davide
    and you might consider that MAXM is coming out with a 400mm carbon post supposedely at 175 grams http://titusti.com/gear_components.html
    The actual MaxM site lists the same MX-27 post at 225g. Probably old pre-production info on their sister company Titus' site;

    http://www.maxmcomponents.com/pages/seatposts.html
    Nuke the entire site from orbit. It's the only way to be sure.

  10. #10
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    to whoever suggested bonding epoxy to aluminum.... be careful. Becuase of electrolysis properties of the materials, the aluminum will oxidize very quickly if you don't coat it correctly with some stuff before hand. (forget the name of the stuff, but its pretty common)

  11. #11
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    2004 vs 2005

    Quote Originally Posted by Circlip
    The actual MaxM site lists the same MX-27 post at 225g. Probably old pre-production info on their sister company Titus' site;

    http://www.maxmcomponents.com/pages/seatposts.html
    You are looking at the 2004 seatpost, the post at Titus refers to the 2005 with the new seat clamp that supposedely saves around 50 grams, but it is not in producrtion yet, see below for the side view of the new seatpost clamp
    Attached Images Attached Images
    Last edited by Davide; 12-14-2004 at 11:49 AM.

  12. #12
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    yep

    Quote Originally Posted by Limon
    this was going to be a spare time project, I think I'll pass on that one for now
    but if I get bored and try it I'll let you know.
    thanks

    That was the intention but it can be fun to try
    Last edited by Davide; 12-14-2004 at 11:53 AM.

  13. #13
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    I stand corrected

    Quote Originally Posted by Davide
    You are looking at the 2004 seatpost, the post at Titus refers to the 2005 with the new seat clamp that supposedely saves around 50 grams, but it is not in producrtion yet, see below for the side view of the new seatpost clamp
    Thanks.
    Nuke the entire site from orbit. It's the only way to be sure.

  14. #14
    Forging Elite Awesomeness
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    May I ask how you got carbon shards in your thigh?

  15. #15
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    Quote Originally Posted by bhsavery
    to whoever suggested bonding epoxy to aluminum.... be careful. Becuase of electrolysis properties of the materials, the aluminum will oxidize very quickly if you don't coat it correctly with some stuff before hand. (forget the name of the stuff, but its pretty common)
    I was getting ready to post the same thing - AL and CF don't agree galvanically that is. The AL parts should either be primed real good, or the adhesive should be a consistant thickness around the bondline - I woud suggest adding micro ballons to control the thickness of the adhesive between the two parts to prevent the AL and CF from contacting each other.

  16. #16
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    Galvanic

    Quote Originally Posted by Andyman_1970
    I was getting ready to post the same thing - AL and CF don't agree galvanically that is. The AL parts should either be primed real good, or the adhesive should be a consistant thickness around the bondline - I woud suggest adding micro ballons to control the thickness of the adhesive between the two parts to prevent the AL and CF from contacting each other.
    Epoxy is a good conductor unless baked, microspheres will not change much of it properties. Possible solutions: add a layer of (4oz) fiberglass at the joint, and maybe bake the piece in a hoven for at least 12 hours at 250F+ (not hard to do)

    The fiberglass is the easiest solution and regulalry used ...

  17. #17
    Cassoulet forever !
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    Bhslavery and i are (on our respectives sides of the world) trying to make home made carbon mtb frames (and parts).

    Davide and others, you are welcome to give us some advices and opinions in the dedicated thread in the innovation forum:
    Custom Carbon Fiber frames? or whats wrong with the c.f bike industry
    Frenchspeaking 29"ers community site http://VingtNeuf.org

  18. #18
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    Quote Originally Posted by 20.100 FR
    Bhslavery and i are (on our respectives sides of the world) trying to make home made carbon mtb frames (and parts).

    Davide and others, you are welcome to give us some advices and opinions in the dedicated thread in the innovation forum:
    Custom Carbon Fiber frames? or whats wrong with the c.f bike industry
    I am out of my league there: way too hard for a full suspension, maybe a hardtail or a carbon version of the Fango (that I am sure I would build heavier, more fragile and at more expense!).

    I only built windsurfs and aluminum/carbon boom: way "easier" than a bike (I think, maybe I am wrong).

  19. #19
    Cassoulet forever !
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    Well, as you have seen, we plan to use the same process as the one you use for windsurfs : lost foam and vaccum bagging.

    I will start with an hardtail. There is already several people who have done that.

    With a full suspension, the only difference is to take care of how to deal with suspension inserts.

    If you have experience with windsurfs, this should be easy for you !
    Frenchspeaking 29"ers community site http://VingtNeuf.org

  20. #20
    Max
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    i have built some carbon saddles, and i can tell you unless you have a negative-form (sp?) your frame will probably look kinda ugly. the plastic bag will fold and leave a very rough/ugly surface


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