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Thread: Smelly metal

  1. #1
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    Default Smelly metal

    Hi Guys,

    I've just come across something weird, at least to me. I've been turning some taper pins from a short length of 1/2" diameter bar that I picked up somewhere, probably the scrap yard. Anyway whilst turning I noticed a really odd smell being given off ! I dismissed it at first but the smell persisted and returned when I started to turn the second piece. Also the surface finish is extremely good, almost as though its been polished, much better than I normally get.

    Anybody any idea what this metal could be. I originally thought mild steel but it seems soft somehow.

    Thanks:
    Best Regards:
    Baron J.

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    I dont know about the smell but from your description of how it turns it might be leaded steel.

    Over the years I have turned various bits of aluminium and I know that sometimes it gives off a distinctive smell.

    regards
    bollie7

  3. #3
    BobL is offline Member: Blue and white apron brigade
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    Can you describe the smell?

    It's most likely you are not smelling the metal at all but your own BO

    see http://www.nature.com/news/2006/0610...s061023-7.html

    In summary
    the source of the "metallic" odor that is generated when a person handles a metal objects results from a metal induced oxidation of skin fats so it is just a type of human BO.

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    Sounds like free machining steel. Last time I used a piece of that stuff it gave off a smell similar to what I would describe as Sulphur.

    Apprarently you cant weld that stuff.

    Simon
    Girl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.

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    Could it be a piece of recycled steel from the sewage works
    Kryn

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    Yep Free machining steel great to machine, not much good to weld, a couple of years ago I was having some turning done, on one of the other lathes they had a 20" diameter length of the stuff being turned the entire workshop smelt like sulfur

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    Quote Originally Posted by BobL View Post
    Can you describe the smell?

    It's most likely you are not smelling the metal at all but your own BO

    see http://www.nature.com/news/2006/0610...s061023-7.html

    In summary
    Hi Bob,

    No, very definitely not my BO Some of the tablets that I have to take cause a very tart BO that is quite distinctive.

    The smell that comes from this metal is only present when machining it. It's a bit like brimstone, when you strike a match that doesn't light first time.
    I also discovered today that it threads very easily and when in tension is nowhere as strong as mild steel. The M4 thread just broke when tightening the nut down.

    Me thinks this bit of rod is heading for the scrap box.
    Best Regards:
    Baron J.

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    Quote Originally Posted by KBs PensNmore View Post
    Could it be a piece of recycled steel from the sewage works
    Kryn
    Hi Kryn,
    I would tend to agree with you but I know it came out of a laser printer ! I also got the motors out as well. Lovely 24 volt DC variable speed controllers built in to them.

    Thanks:
    Best Regards:
    Baron J.

  9. #9
    BobL is offline Member: Blue and white apron brigade
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    Quote Originally Posted by BaronJ View Post
    Hi Bob,

    No, very definitely not my BO Some of the tablets that I have to take cause a very tart BO that is quite distinctive.

    The smell that comes from this metal is only present when machining
    When I said BO I did not mean armpit or other pit type BO.

    As soon as you touch the metal places skin oils from your hands transfers onto the metal - the metal causes the oils to degrade chemically making a metallic smell. This is what causes metals to smell but despite extensive testing, metals have no smell.The the act of turning generates heat which will speed up the rate of decomposition of the oil and increase the intensity of the smell. Apparently our noses are extremely sensitive to body oils decomposed on metal

    Different metals cause different degradation routes for the oils which is why some metals smell a bit different or stronger than others. For example if you have handled a tool it might not smell much be when applied to a different metal it might suddenly smell

    Apparently you don't even have to touch the metal for there to be an effect, there are enough body oils in human breath to cause a small effect Also bear in mind that EVERYTHING in a shed that has been touched is already covered in body oil anyway and it takes very little for it to be transferred from one place to another.

    An accident that demonstrated this happened at uni before I arrived there. A researcher was working in a radioactivity lab and opened a small a small bottle of a radioactive chemical and unbeknownst to him got some on his hands. He then went to the toilet and returned to the experiment. Hours later when the bloke had finished he tested his hands and found them contaminated and so had to be decontaminated. Someone had the sense to ask what the experimenter had done in between handling the material and being detected and of course he said he had been to the toilet.
    Well you can guess what had happened after that. Nearly every single door knob, telephone, photocopier, computer keyboard etc was contaminated. Even the flushing buttons in the women toilets and most of the cups in the staff room were contaminated. Very little of this contamination was "dangerous" and instead shows the sensitivity of the detectors being used.

    Anyway back to the topic - you haven't yet described the smell.

    There are of course many non-metals added to metal and these can smell. One of these is Sulphur which smells, well like S, the other is Selenium which smells like horseradish. Sel is now used in place of lead in brass to improve machinability.

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    Well there you go then.
    Its been caused by the unused volts (from when the motors were running at less than 24V) They have to go somewhere and when they are bouncing around inside the laser printer trying to find a way out, they collide with any leaking laser beams and get vapourised. The resulting smell then soaks into
    the steel. This smell is then released when the steel is cut on the lathe. A by product of this reaction is that the tensiles in the steel are also weakened, or in extreme cases, even destroyed. This explains why it broke when tightening the nut down.

    there you go, problem solved


    aveaniceweekend

    bollie7

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    Very interesting. I always thought that the smell of cutting steel must be caused by lubricating oil or coolant evaporating. I only noticed a smell when dry cutting metals such as some aluminium castings, like engine pistons.

    Different from smell is the "metallic taste" in mouth and nostrils when filing or using emery cloth. Maybe there is a similar explanation for this? Maybe it is an electrolytic reaction (like when chewing Aluminium foil - not that I do that on purpose mind you, but its sometimes attachad to chocolate when not opening the bar carefully...)

    Edit: some people (like me) like using silver cutlery for dinner. I believe it has a different "taste" to stainless cutlery. Is this imagination only, or could there be an explanation??

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    Quote Originally Posted by cba_melbourne View Post
    Very interesting. I always thought that the smell of cutting steel must be caused by lubricating oil or coolant evaporating. I only noticed a smell when dry cutting metals such as some aluminium castings, like engine pistons.

    Different from smell is the "metallic taste" in mouth and nostrils when filing or using emery cloth. Maybe there is a similar explanation for this? Maybe it is an electrolytic reaction (like when chewing Aluminium foil - not that I do that on purpose mind you, but its sometimes attachad to chocolate when not opening the bar carefully...)

    Edit: some people (like me) like using silver cutlery for dinner. I believe it has a different "taste" to stainless cutlery. Is this imagination only, or could there be an explanation??
    Edited by me.
    Girl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.

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    BobL is offline Member: Blue and white apron brigade
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    Quote Originally Posted by cba_melbourne View Post
    Very interesting. I always thought that the smell of cutting steel must be caused by lubricating oil or coolant evaporating. I only noticed a smell when dry cutting metals such as some aluminium castings, like engine pistons.

    Different from smell is the "metallic taste" in mouth and nostrils when filing or using emery cloth. Maybe there is a similar explanation for this? Maybe it is an electrolytic reaction (like when chewing Aluminium foil - not that I do that on purpose mind you, but its sometimes attachad to chocolate when not opening the bar carefully...)

    Edit: some people (like me) like using silver cutlery for dinner. I believe it has a different "taste" to stainless cutlery. Is this imagination only, or could there be an explanation??
    Yep it's an electrochemical effect, different people have slightly different reactions to the metallic powders. For most people Silver is not so good.
    See http://scienceillustrated.com.au/blo...avour-of-food/ for the best metals

    Smell and taste are closely linked. In 2002 I lost my sense of smell for 6 weeks while building a large desk which had an MDF carcase. I remember beer tasting really bad, like sewage, and onions tasting like apples etc. It was awful and it put me off using MDF for a long time until I got decent dust extraction set up in my shed

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    Quote Originally Posted by BobL View Post
    ..............

    Smell and taste are closely linked. In 2002 I lost my sense of smell for 6 weeks while building a large desk which had an MDF carcase. I remember beer tasting really bad, like sewage, and onions tasting like apples etc. It was awful and it put me off using MDF for a long time until I got decent dust extraction set up in my shed
    That must be how you became an expert on smell and taste. My wife had a complete change of taste after chemotherapy. Sadly she passed away two weeks ago.

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    BobL is offline Member: Blue and white apron brigade
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    Quote Originally Posted by cba_melbourne View Post
    That must be how you became an expert on smell and taste. My wife had a complete change of taste after chemotherapy. Sadly she passed away two weeks ago.
    I'm very sorry to hear about that.

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