Media blasting for snowflake wheels?

Discussion in 'Airheads' started by headtube, Oct 20, 2012.

  1. headtube

    headtube 6 mesas de invierno!

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    As some of you may know from seeing my posts that I purchased a 79 RS that had been neglected. Stored outside, different numbered carbs, mismatched parts to say the least. I'm not complaining. And I don't mind the challenge having never owned a Beemer before. It gives me something to do over the boring winter months. Many thanks to the inmates for your help and experience.

    I have now turned my attention to the wheels. The rear is gold, front is silver with plenty of discoloration. So I have decided to powder coat them. My local guy uses sand-blasting before powder application. Should I look into something less aggressive? His work is amazing, and he has a strong clientele. Link to his website... http://www.quyscoating.com/?page_id=124 He says the sand-blasting shouldn't be a problem.

    Since you guys have more experience with these wheels I thought I'd throw it out to the forum. Thanks again in advance.
    #1
  2. 100RT

    100RT Long timer

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    I have read different discussion about the heat from powder coating makes the wheels brittle. I do have a friend that powder coated his snowflakes and one indeed did crack. Coincidence, perhaps.

    I did a through cleaning with degreaser then soap and water, scuffed them up with a scotch brite pad then sprayed mine with Duplicolor silver mettalic lacquer then clear lacquer. They look factory fresh and can be touched up anytime.

    Plus it was inexpensive!
    #2
  3. DaveBall

    DaveBall Long timer

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    Personally, I do not like using sand. I use glass beads. Sand is usually quicker to remove everything, but also much more aggressive in removing metal as well. I do my own bead blasting. On a wheel, I will start with course beads first, then go to medium and then fine. That way I get a nice smooth finish. Some guys have liked it so much, they just clear coat them. Others have had them powdered coated all kinds of colours to match up with whatever scheme they are going for.

    Snowflakes are steel wheels. They will take a lot more abuse than most people think. But they can bend.
    Make certain that your front wheel is the warranty replaced one. It will have some webbing between the spokes close to the hub. The warranty replacement is still available.
    #3
  4. RecycledRS

    RecycledRS Along for the ride

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    I don't think you meant steel
    #4
  5. Houseoffubar

    Houseoffubar HoFmetalworks.com

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    Just a little info, powdercoating will not make wheels brittle. Powder cures at 400f this will not effect the heat treat of the wheel. If anything it would make them softer, not brittle.
    Snowflake wheels are cast aluminum, not steel.
    Just FYI
    #5
  6. boxerboy81

    boxerboy81 Stay Horizontal

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    If the bloke that does the job is good and you have good references, I'd go with his expertise. The bearing area needs absolute protection from the sand though he should know that.

    I've had a few wheels powder coated as have many, many others. If you do powder coat, I would advise to not get a clear coat done. It'll lift eventually.
    #6
  7. headtube

    headtube 6 mesas de invierno!

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    I know the Fiche says the wheels are cast iron but this is erroneous. However, as an experiment I placed a strong magnet on the wheel. The magnet did indeed react, but only slightly. My guess is the wheels are a cast alloy with some metal mixed in for strength. If this is the case then the wheels are stronger than just plain aluminum alloy, and could indeed take the aggressiveness of sand-blasting and the heat of powder coat without ill effects.
    #7
  8. pbarmy

    pbarmy Long timer

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    Powder coating makes it harder to mount a tire without damage to the finish,according to my buddy who has a shop.
    #8
  9. DaveBall

    DaveBall Long timer

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    Snowflakes indeed do have Iron in them. They are NOT aluminum. Magents do not stick to aluminum.
    Plus, just go pick one of those snowflakes and you will immediately know that it is not aluminum. They are damn heavy.

    As to sand blasting, do it if you want. The wheels will take it fine, but it will be a rougher finish, which can also be cleaned up with finer and finer sand. Just will take more work to get them nice and smooth. Glass beads will give you a nice smoother surface to paint. Even when using powder coating, the better the prep work and smoother the surface, the better the final finish will be.

    Before blasting, pull the bearings out and insert a rubber bung. You can measure the hole and drop by Home Depot to get a bung of the correct size. Bang it into the hole and it shoule seal things up just fine. But, remember to remove it after you are finished the blasting and have cleaned the rim well. Once the bung is otu, clean everything a few more times, just to make certain that you have all the grit removed.

    Or, you could get creative and just acid dip the whole thing. I have heard of one powder coater that does that. I don't know if it helps or hinders in the process as I have not seen anything done from that guy.
    #9
  10. Houseoffubar

    Houseoffubar HoFmetalworks.com

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    Sorry, snowflakes are aluminum. They may be alloyed with something else, but I doubt it is iron. Iron is almost never alloyed with aluminum.
    If a snowflake was iron, it would weigh over 80lbs. as iron is three times the weight of aluminum. No production mag style rim has been made of iron, or steel.
    Also, just to be fair, I held a magnet to my snowflakes, and it does not stick at all.
    #10
  11. langloisandy

    langloisandy Been here awhile

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    Been there/Done that... they blast nicely with either sand or glass. Go for it! Blast the crud off, it's motivating to see new metal under old finishes!

    One finish I like is the older Mercedes silver wheel paint (ask your local paint mixer-dood, they can look it up) It's a silver, but matches that "alloy wheel" color wonderfully and makes for an easy touch up if you scratch or ding a spot during a tire change.

    Andy
    #11
  12. 100RT

    100RT Long timer

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    #12
  13. DaveBall

    DaveBall Long timer

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    If the snowflake wheels are aluminum, somebody had better inform BMW about that. They list them in their parts microfiche as CAST IRON .
    Front weighs 12.57 pounds and rear weighs 15.65 pounds.


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    I checked this on 3 different sites.
    I just came in from the garage after checking both bikes with magnets. Stuck to all 4 wheels.
    #13