what grade of aluminum to use for DIY ?- Mtbr.com
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  1. #1
    I like bloody ankles
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    what grade of aluminum to use for DIY ?

    I'm going to a local metal shop tomorrow to pick up some material for mounts, clamps, etc. The tools I have are a bandsaw, disc/belt sander, drill press, Dremel, and assorted files.

    What grade of aluminum should I look to buy that will be easy to work and hopefully not have any real downsides ? 6061 and 7075 seem to be the most readily available.

    thanks

  2. #2
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    I use 6082 grade for my housings. 7075 is good but it is a bit tougher to machine.

  3. #3
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    For nice polish, welding capability, nice anodisation : 6061, 6062, 5754, 5086.
    For a bit more strenght : 2017, 2024... no welding, anodisation need special care. good machining . Elastic limit is about the same as standard steel (235 Mpa) . I thing that we don't need hight elastic limit, then 7075 is too much expensive for nothing, and it need special care to get this strenght, and oxygen is not a friend for it.
    (when I said no welding, it should be understood as : welding is a pro job....)
    ASk for "data sheets" about the available aluminiums, and relative prices.

  4. #4
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    Deesta is right too. Wish you a good job.

  5. #5
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    Quote Originally Posted by deesta
    I use 6082 grade for my housings. 7075 is good but it is a bit tougher to machine.
    out of curiosity, why 6082 over, say, 6061? does it handle heat better? harder? I can't seem to find that particular alloy in any of my usual places (mcmaster, online metals)

    normally, I'd say just get 6061. cheap, strong enough, easily machined, ano's fine.

    if you want stronger, and don't mind the extra coin, then 7075 would be fine.

  6. #6
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    Seems to me that 6061 is good enough and it's cheaper. I was looking at the higher strength alternatives, but didn't see any reason to pay 3 times as much.

    I did a lot of fatigue testing with 6061 to test out my methods for later use with 7075 and 2024. It does a good job in fatigue.

  7. #7
    I like bloody ankles
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    Thanks for the quick responses, sounds like 6061 will be the right choice.

  8. #8
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    I don't think that many light are pushing the strength limits. 6061 or 6063 are a lot easier to work with than 7075.

  9. #9
    Rolling
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    What in the world are you folks building that you worry about strength details in Al for a bike light housing?

    Buy the cheapest aluminum you can and design your heat sinking correct--good thermal contact to the aluminum using paste or thermal epoxy.

  10. #10
    I like bloody ankles
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    my concerns were not with strength, but rather easy to machine and less suseptible to weathering since I won't be anodizing.

    Seems that 6061 is the most common available and meets both criteria, and it's cheap.

  11. #11
    Rolling
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    Quote Originally Posted by dsjc
    my concerns were not with strength, but rather easy to machine and less suseptible to weathering since I won't be anodizing.

    Seems that 6061 is the most common available and meets both criteria, and it's cheap.
    6061 is great.

    AL has the nice property that it forms an oxide layer that seals if from more oxidation. Sure it has the ugly grey but it's resistant to more oxidation, unlike steel that just keeps on rusting till it's dust.

    The only problem would be that bolts that assemble them can seize.



    ..

  12. #12
    I like bloody ankles
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    So, extending the question now, if I were to create a front stem bracket that were to accomodate a light mount system, similar to what Troutie and others have done, will 6061 still be sufficient ? It's now gone from bike light only, to bike light + integral control and safety structure......

  13. #13
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    Quote Originally Posted by dsjc
    So, extending the question now, if I were to create a front stem bracket that were to accomodate a light mount system, similar to what Troutie and others have done, will 6061 still be sufficient ? It's now gone from bike light only, to bike light + integral control and safety structure......

    6061 will be fine for your light and mounts just dont go really thin anywhere as it is softer than the higher grades . also if you cut threads in it they wont stand over tightening .

    another thing I have learnt is dont waste too much time polishing as then you wont be upset when it gets scratched

  14. #14
    I like bloody ankles
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    Thanks Troutie. My plan has me going no less than 10mm in any structural point on the mount.

    Now I just need to take this 1-1/4" slab of aluminum down to a local metal shop and get the first cuts done. My little 9" bandsaw has proven to be far less than up to the job

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