Carbon Protection

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  • 11-29-2012
    red5jedi
    1 Attachment(s)
    Carbon Protection
    Check out this little 40g protector for the down tube. It was making me nerves when big rocks were slamming into my frame. I think it will do a better job than some of the thin film protectors out there. It's held on my Velcro so I can pull it off when cleaning the frame or doing a race. Two layers of carbon and it sits off the frame around 1/8 due to the Velcro but I like the idea of that gap.
  • 11-29-2012
    ginsu2k
    Nice, good design. Velcro probably helps with a little shock absorptions on impacts. You could probably sell those if you wanted to.
  • 11-29-2012
    PMK
    Similar but different on out tandem.

    http://forums.mtbr.com/tandem-mounta...ed-759595.html

    I wanted 6-4 ti but wasn't able to locate it in surplus. I thought white sparks would be cool going over rocks.

    PK
  • 11-30-2012
    red5jedi
    Quote:

    Originally Posted by ginsu2k View Post
    Nice, good design. Velcro probably helps with a little shock absorptions on impacts. You could probably sell those if you wanted to.

    Next on my list is one for my Tallboy. I might make a couple extra and see if they sell on FleBay.

    PMK: Nice, where did you find carbon tube or did you make that?
  • 11-30-2012
    car bone
    Quote:

    Originally Posted by red5jedi View Post
    Check out this little 40g protector for the down tube. It was making me nerves when big rocks were slamming into my frame. I think it will do a better job than some of the thin film protectors out there. It's held on my Velcro so I can pull it off when cleaning the frame or doing a race. Two layers of carbon and it sits off the frame around 1/8 due to the Velcro but I like the idea of that gap.


    Its probably much better than polycarbonate tape gued rigth on the surface.

    Most stuff that goes into space have dual walls, just a slight gap between them, so if anything hits the first one it will be either dispersed as powder when it hits the second one or at least the energy will be reduced substantially. Just building a thicker (much thicker) wall is not very effective at all, it would have to be like 5-10 times as thick to take the same punishment as a dual thin airspaced (or i guess vacuumspaced) walls. Nasa knows their shizzle!
  • 11-30-2012
    car bone
    Quote:

    Originally Posted by PMK View Post
    Similar but different on out tandem.

    http://forums.mtbr.com/tandem-mounta...ed-759595.html

    I wanted 6-4 ti but wasn't able to locate it in surplus. I thought white sparks would be cool going over rocks.

    PK

    www.titaniumjoe.com
    cheap too.

    car bone delivers!
  • 11-30-2012
    PMK
    Quote:

    Originally Posted by car bone View Post
    www.titaniumjoe.com
    cheap too.

    car bone delivers!


    Sorry Car Bone, you cased the big jump and crashed. I had several phone calls with Titanium Joe and unfortunately he never had the diameters I required.

    As for cheap too, well that is relative, getting a sample of enough carbon fibre and then some to build the glide plate worked out well cost wise.

    Please though tell me more about the NASA stuff, my curiosity is intrigued. This dual walls stuff or construction you speak about do you mean honeycomb type panels?

    PK
  • 11-30-2012
    PMK
    Quote:

    Originally Posted by red5jedi View Post
    Next on my list is one for my Tallboy. I might make a couple extra and see if they sell on FleBay.

    PMK: Nice, where did you find carbon tube or did you make that?

    Made it. I kind of cheated as I used braided tube material and molded it with thermosetting matrix on an aluminum mold.

    PK
  • 12-01-2012
    car bone
    Quote:

    Originally Posted by PMK View Post
    Sorry Car Bone, you cased the big jump and crashed. I had several phone calls with Titanium Joe and unfortunately he never had the diameters I required.

    As for cheap too, well that is relative, getting a sample of enough carbon fibre and then some to build the glide plate worked out well cost wise.

    Please though tell me more about the NASA stuff, my curiosity is intrigued. This dual walls stuff or construction you speak about do you mean honeycomb type panels?

    PK

    I would have gotten sheet, and heated and either hammered it out or made the part in a hydraulic press or even a vice if its hot enough, ti starts to oxidize (gets ruined) at about 400c. 300c would be safe and at that temp its much more bendable.

    They use many layers in the spacecrafts. I found a somewhat related video. Thats a light gas gun or hepervelocity gun Light gas gun - Wikipedia, the free encyclopedia
    <iframe width="420" height="315" src="http://www.youtube.com/embed/Y3iqE2GRHeU" frameborder="0" allowfullscreen></iframe>
  • 12-02-2012
    red5jedi
    Well this weekend I tested the protector with a direct hit. The rock that was kicked up was decent size and it left a dime size scratch on the carbon. The sound from the impact was just a dull thud instead of a higher pitch that I would hear with no protector or just protector tape. There are lots of loose rock out here in NM due to the drought.
  • 12-02-2012
    PMK
    Quote:

    Originally Posted by car bone View Post
    I would have gotten sheet, and heated and either hammered it out or made the part in a hydraulic press or even a vice if its hot enough, ti starts to oxidize (gets ruined) at about 400c. 300c would be safe and at that temp its much more bendable.

    They use many layers in the spacecrafts. I found a somewhat related video. Thats a light gas gun or hepervelocity gun Light gas gun - Wikipedia, the free encyclopedia
    <iframe width="420" height="315" src="http://www.youtube.com/embed/Y3iqE2GRHeU" frameborder="0" allowfullscreen></iframe>

    You must be one heck of a fabricator to hand hammer a heated and annealed titanium sheet that's over 2mm thick into a long semi tube shape on a vise. I have made many aircraft primary structural items and can not say I ever hand hammered heated titanium sheet into shape. Interesting though.

    I asked about the space vehicle comments you made as it sounds like something you are familiar with. A co worker of mine has done contract work for NASA on space vehicles and never mentioned the type construction you described.

    PK
  • 12-06-2012
    car bone
    Hehe no i'm not that good a fabricator, but yeah i was working as a handyman for like 10 years and also machinist, I know how to weld all types of machines and such. 2mm ti is kinda hard to bend to be honest. It usually just flexes back or shatters when trying (ti is tough up to a point then it behaves like hardened steel basically). but 0.5mm would be fairly workable imo, but it needs elevated heat no matter what. you could easily do 2 bends and get half a hexagon shape with any type of sheet bender and propane. And thats close enough in my book.

    I have bent quite a lot of 6-4, 2.something (inch based stock) mm thick ti but i always used the propane and a bending machine (manual). Coldworking it is futile and you just ruin the material. Ti "should" really be heated in an inert atmosphere and forged (its the cheapest way to fabricate anything made out of 6-4), but i have not noticed any failures with my highly unproffessional heating and bending methods. If it chasnged color its oxidized, easy as that, first color is blue/purple (actually straw, but its hard to achieve when using heat on purpose to soften it)
    , and that is passable in some industries. And this is a downtube protector. Its not going into space anytime soon.

    I'm not at all familiar with space vehicles but I have seen a few documentaries and a few pdfs that relate to these double layer hulls, and even triple and quad layers, there is much to read for free about this. Sure its micrometiorites going like 1+km/s and such but still I feel it has some relevance.

    Just look at the thick pieces in the vid, those are at least 6-10mm thick. Didn't really matter there. 2 layers are better imo even if just spaced 0.5mm. I might have to eat that later but for now its seems like a quite good idea. IMO.