Truing an aluminum wheel - Page 2
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  1. #21
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    How much heat is enough?

    A friend who knows rather more than I do about straightening aluminium alloys, but is basically a practical technician, smears ordinary hand soap on high-strength aluminium items (which includes ski and tent poles as well as alloy wheels), before heating them until the soap goes chocolate brown.

    I knew heat would help, but I had no reliable way 'in the field' of telling how much.

    I broke enough ski poles before getting to know him, and have straightened enough since, to be inclined to raise an eyebrow when I hear the oft repeated line "no heat put it there"

  2. #22
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    I was under the impression that alu. and it's alloys were typically "hot short" That is, the yield went down with increased temperature. So, Heat to anneal, but bend cold.

    I wonder what a metal spinner would do......? Spin hot?

    Correct where wrong.

    CalG

  3. #23
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    Quote Originally Posted by CalG View Post
    I was under the impression that alu. and it's alloys were typically "hot short" That is, the yield went down with increased temperature. So, Heat to anneal, but bend cold.

    I wonder what a metal spinner would do......? Spin hot?

    Correct where wrong.

    CalG
    Not quite true, AFAIK: yield strength almost always drops with increasing temp, which would make almost all matls hot short, if your definition held up.

    - Hot short means behaving in a brittle way at high temperature, which I take to mean the UTS is depressed, in relation to the yield strength.

    Ductile metals yield well before they snap; brittle ones just before.

    Presumably (IANAM) this means that a hot short alloy's rupture strength (UTS) drops quicker than the yield strength with rising temperature.

    When we're straightening something, we want the biggest amount of wriggle room between those two values: we need it to yield (with sufficiently low force not to overstress the adjacent beam sections), but not to rupture.

    I'm not qualified to give advice on which situations and alloys would respond better to annealing vs hot bending; the main thrust of my comment was to try to counter the suggestion that any form of heat was - axiomatically - unnecessary or undesirable.

    In my fairly limited experience of straightening thin tubing from very strong - and highly work-hardened- alu alloys, hot straightening seems to give a better result than annealing. A wheel rim is also a rather strong alloy, but generally heat treated rather than work hardened, and the proportions are very different - it's a very nuggety beam.

    [I don't disagree at all with the poster who suggested avoiding heat if damage minor - partly to avoid interfering with the OEM heat treatment.]

    OTOH, AFAIK, spinning is typically done by annealing rather than heating. That said, it's usually done with more ductile grades, and it's more of a 'flow-forming' operation, changing the form of a relatively weak section, but nevertheless requiring quite a lot of force, because deformation is happening in three dimensions at once rather than just two.

    Moreover, you don't want the surface skin heating to the point where it's going to try to weld to your tool.

    Rather a diff kettle of fish, I think ...

    I'll stop here before making (more of?) a fool of myself

  4. #24
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    Ryan,

    My dad used to have a Sterling with wheels that looked similar to your picture. I guess his eyesight was getting worse and/or his attention span. He would hit potholes pretty regularly in the winters here in NJ. The tires on the wheels were very low profile and it would ding the rims of the wheel. Often they looked like yours does. Sometimes barely noticeable. With low profile tires the effect on smooth wheel turning of even a small ding was more pronounced than on a tire/wheel with a taller profile.

    I looked at some of the rims that he dinged and while they looked OK on the outside but all of them were cracked quite deeply on the inside. After about four or five times replacing the rims at $500 each he heeded my suggestion to give to my brother in Atlanta, GA (fewer potholes and better driver.)

    Be sure to check the inside of the rim where the dent is and if it is showing some cracking there. The cracks may not go all the way through. If it is cracked I would replace the rim if I were you.

    He now drives a car with higher profile tires and hasn't had a problem since.

    -DU-

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    Default Bend wheel training request

    Hello memofornow.ias I read your message iam wondering if you can provide any bend wheel repair training. As iam interested to get in wheel repair .your respond is really appreciated thank you
    Quote Originally Posted by memofornow View Post
    I have been repairing Alum rims for 5 years now.

    Do you want to learn to do this long distance or would you rather UPS the thing here? Shipping is around $35-$40. That's one way I might add. Minimum cost to do the work is $55. I can give you a better labor cost if you could put a decent pic of the effected area.

    Memo

  6. #26
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    Our local wheel and driveline shop had been in business for more than a hundred years; began repairing horse-drawn wagon wheels. When I took a slightly dinged OEM wheel into them, I noticed the stacks of large diameter wheels awaiting their turn. The old guys there said the very-low-profile tires mounted on aftermarket Chicom "dubs" mounted on 3-ton Escalades and jacked-up pickups, were the best thing ever to happen to the wheel repair business.

    The tires provide no sidewall give, the wheels are made from old beer cans and the drivers have too much money and too little sense to understand there are curbs and potholes under the snow and slush. At the end of winter, they closed for two weeks and went to Hawaii on the rush job profits.

    But yes, since even today's least expensive cars come equipped with aluminum wheels, that is a lucrative niche. We now have two new wheel repair shops who promise same day service; just drop off your car and get it back wheels looking like new.

    jack vines

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  8. #27
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    Quote Originally Posted by [email protected] View Post
    Hello memofornow.ias I read your message iam wondering if you can provide any bend wheel repair training. As iam interested to get in wheel repair .your respond is really appreciated thank you
    Since the original thread is nearly 10 years old, and since memofornow hasn't posted since early 2010 ... I suspect you are unlikely to hear from him.

    I hope what I'm about to say is totally unfair, but ... the fact that your user name is "thewheelwizards" sure makes this look like a spammer drying to dredge up an old thread to call attention to his/her business. Again, I hope this is untrue and unfair, and if so, I apologize!


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