Turning Cast Iron question – Health & Cleaning Up

[Fowlers FuryParticipant @fowlersfury]

'have posted on this before, as have others.
When washing hands after machining CI, the tiny particles of iron get into the minute surface cracks of the sink whether it's stainless, ceramic or acrylic. Next morning SWMBO has a fit seeing all the rust "stains". Usual domestic cleansers have no effect but if you paint a rust remover e.g. Jenolite over the "stains" they will disappear and domestic harmony is restored. However, such harmony can be quickly disrupted by black marks on pillows from carbon particles which even face washing afore bed will not remove. Answer here is to get one of her make-up removal pads and solution. Wipe face, neck etc after washing and see the amount deposited on pad from skin pores.
Wearing a cap/hat whilst machining stops it getting into hair – if you still have any.

Meehanite is great stuff to machine but the after-effects can be a trial.

 

Edited By Fowlers Fury on 07/05/2019 00:03:57

[David Standing 1Participant @davidstanding1]

Posted by Neil Wyatt on 06/05/2019 22:33:23:

stop me producing black snot for two days.

N.

Waaaaaaay too much information Neil

[Blue HeelerParticipant @blueheeler]

I was very happy with how well the magnet in the plastic bag trick worked at the beginning of the clean up.

[Martin KyteParticipant @martinkyte99762]

Making pastry will clean your hands.

:0)

Martin

[robjon44Participant @robjon44]

Hi all, in the distant past when cast iron was always machined dry there was a recognized medical condition called Turners Lung caused by inhaling CI dust & thence coughing up rust, I only ever met one person who had this condition but that is one to many in my opinion. Therefore in modern times it is machined wet on CNC machines & all the crud is despatched into the swarf bin by the conveyer, however this is not the case in a home workshop, all is not lost however when one extracts the offending material using a vacuum cleaner (pause for dramatic effect), no not directly into such a machine with a whopping electric motor involved, but with a plenum chamber of the type used to clean up ashes from wood burning fires & stoves, an empty canister with inlet & outlet & of course a filter, I have used mine for this purpose, also machine clean up during machining, not to mention extracting wood chip & dust from routers, sanders, planers etc which generally have a fitting for the purpose, maintenance has consisted of giving the outside of the filter a quick flick with a soft hand brush & a wipe round the inside with a damp cloth & lets not forget the crud that finds its way into the footwells of the car!

Cheers Bob.

[Mike PooleParticipant @mikepoole82104]

The sink in our workshop was a custom made boilerplate affair, it didn’t suffer from rust spots but the boraxo deposits did need a scrape off now and again, probably not a first choice for the domestic environment though.

Mike

[Mick B1Participant @mickb1]

Some small proportion of the ultrafines will get past the bag and filter – but realistically, how much would you have to vacuum up to risk shorting the motor? Whatever does arrive in there will probably never go away, or at least the iron content won't, but wouldn't such fines be mostly graphite anyway? I've used my workshop vacuum to clear CI swarf on a few occasions without problems.

I spent about 6 months in my mid-20s machining graphite welding moulds for linking cables on railway lines, modifying them on a Bridgeport from a US rail profile fit to UK. There was some sort of supposed dust extraction system using the airlines, but it was useless and I ended up ignoring it. This was in Notts, and when I came home each evening the locals thought I'd bin wokkin' on coalface down pit. But I don't think I suffered from any health issues – maybe the Park Drive I was smoking at that distant time drove them off – or masked them…

Edited By Mick B1 on 07/05/2019 10:52:54

[Howard LewisParticipant @howardlewis46836]

I once worked out, by extrapolating from a 1 foot square greased plate, that there was a 8.8 litre V8 cylinder block floating around the atmosphere of the machine shop. In summer, looking in the mirror after getting home would show a rusty head! Never though about what I was probably inhaling!

Howard

[Neil WyattModerator @neilwyatt]

Posted by Martin Kyte on 07/05/2019 09:27:32:

Making pastry will clean your hands.

:0)

Martin

Hairwashing is just as good and less anti-social

[Robert Atkinson 2Participant @robertatkinson2]

Posted by Neil Wyatt on 07/05/2019 18:35:29:

Posted by Martin Kyte on 07/05/2019 09:27:32:

Making pastry will clean your hands.

:0)

Martin

Hairwashing is just as good and less anti-social

SWMBO would not thank me for washing her hair with dirty hands and I don't have enough hair to make a difference.

[jimmy bParticipant @jimmyb]

In my younger days, I spent a few years grinding cast iron. In those days you got a pint a milk to help with the dust!

Even now, I hate working with the stuff!

Jim

[John ReeseParticipant @johnreese12848]

Posted by Brian Oldford on 06/05/2019 10:36:23:

If you have a lathe without a screw-on chuck try using an inverted tool and run the machine backwards. Or if it has a screw-on chuck use the tool in a rear tool post. The chips tend to be directed downwards and far less carbon/iron dust gets into the air.

Think about what the upward force on the tool does to the cross slide and compound. It lifts those components creating clearance between the flat surface of the slide and the saddle. Similarly there will be clearance under the compound. Fine CI dust enters that clearance and acts as an abrasive when later you are turning with the tool facing up. Why cause premature wear on your machine just to escape a spray of swarf. Slamp a piece of sheet metal onto the tool to act as a chip deflector.

[Paul KempParticipant @paulkemp46892]

Can someone please explain to me why cast iron 'dust' is considered to be such an abrasive substance? Yes I can see that the outer skin of a casting will likely contain sand and chilled iron particles will be hard but once under the skin generally the iron we deal with is soft and the free graphite even softer and graphite is used as a lubricant. Yes it's messy, gets in to your skin, in your hair and up your nose but does it really lap away at your machine slides if you get rid of the first cut swarf that has sand etc embedded? All sounds a bit hysterical to me and if it's true then the slides on my mill should be completely wrecked after all the cast I have machined on it over the last year!

Paul.

[HopperParticipant @hopper]

I think its the small size and sharp gritty shape of the swarf particles combined with the material being harder than steel or brass etc.

[Paul KempParticipant @paulkemp46892]

Posted by Hopper on 07/05/2019 23:44:29:

I think its the small size and sharp gritty shape of the swarf particles combined with the material being harder than steel or brass etc.

You may have something there in terms of the shape and size of the swarf (particles) but I am not fully convinced by the harness argument. From my long ago involvement with metallurgy the HB of bog standard mild steel is in the region of 130. Pure ferrite (soft iron) is in the region of 100 – 120. Ferrite / pearlite mix around 120 – 200. Most of the castings for models will be grey iron or SG iron so a max of 200 probably. Machine slides on cast beds will have had chills in the mould on the slide surfaces to ensure they are hard or harder than the main casting (say 200 or more). Even steel bed machines will not be mild steel and often steel beds are induction hardened anyway in which case way above 200 HB.

Granted the particles may be sharp when they come off but the edges will soon get knocked off if they are grey iron unlike say carborundum which will be sharp and harder for longer. So I remain unconvinced in the grades of iron model engineers usually encounter (excluding duff castings which are not grey iron but closer to white due to poor foundry practice) will really do much damage to a decent machine. In fact I have bags of nice short curly iron chips that came from my traction engine castings that evidence they are to the softer end of the cast iron spectrum and as iron is crap in tension and not really great in shear, the properties we want are not to the hard end of the spectrum anyway. A glass hard cast iron gear for example is going to be vulnerable to shedding teeth, which is not what we are looking for!

Having a grinder close to a machine is likely to be far more detrimental from the perspective of carborundum dust than machining grey iron I would think.

Paul.

[I.M. OUTAHEREParticipant @i-m-outahere]

I can attest that CI dust or chips are abrasive as hell ! I used to work for a company that made industrial roller shutters and inside these are cast iron cores that have to be turned to size and the centre drilled out for the axle , we had an old Cincinnati lathe that was only used for this pretty much every day and for about fifteen years . The ways were so flogged out on the section near the chuck and a section about a 6 inches long back towards the tailstock that if i layed the edge of a 12 inch rule along the way i could slide another rule laying flat in the gap ! This wear area coincided exactly with the carriage movement and on the other end of carriage the ways showed little wear over the same distance of travel . Before that job i used to operate a lathe that was being used as a linishing machine and even though it had been used like this for over twenty years it didn’t have a tenth of the wear of the Cincinnati ! I started using a mask when using the linisher as the dust would really rip into my throat and I carried this over to the next job machining cast iron , we had a guy who spray painted the rollers or drum for the roller shutters – no respirator , no eye protection and the boss was happy with this as long as the overspray didn’t get on his car !

I like to think that Model Engineering is supposed to be enjoyable not life threatening ! PPE is cheap compared to the consequences of not wearing it ! Last night i was watching some YouTube – A channel called two stroke stuffing where the host is modifying two stroke engines and in one video he is explaining how he does some modifications to the cylinder head , His lathe consisted of a power drill clamped in a vise and to mount the head to the drill he simply screwed the spark plug into the head and stuck the ceramic insulator in the drill chuck . I thought this was dangerous enough but when he turned the drill on and started hacking into the combustion chamber with a carbide burr in a die grinder i started to grimace ! Then i noticed he wasn’t wearing any eye protection and you could clearly see the shards of aluminium flying all over the place ! The only thing standing between him and blindness was luck !

Ian.

[SillyOldDufferModerator @sillyoldduffer]

Posted by Paul Kemp on 07/05/2019 23:31:41:

Can someone please explain to me why cast iron 'dust' is considered to be such an abrasive substance? Yes I can see that the outer skin of a casting will likely contain sand and chilled iron particles will be hard but once under the skin generally the iron we deal with is soft and the free graphite even softer and graphite is used as a lubricant. …

Practical experience shows it to be abrasive. In addition to sand and chilled iron there's also the possibility of carbides in in the mix. Mostly soft iron surrounded by soft graphite plus a small proportion of much harder carbide and perhaps silicon granules. The other factor is that the cuttings come off as a fine powder rather than sizeable chips or ribbons of swarf.

Tiny hard particles carried by a lubricant sounds suspiciously like a grinding paste recipe. And because the mix is slippery, it penetrates under slides and stays there, possible jamming grit into the ways and slides.

I wouldn't recommend cast-iron shavings as a home-made grinding paste because the action is generally mild and unpredictable, but it's bad enough to be worth cleaning off machines. The wear was far more obvious when factories did nothing but machine cast-iron as fast as they could. Occasionally turning cast-iron at home is much less likely to damage a machine, but why risk it?

I always cover as much of the machine's delicate parts as I can with sheets of paper (not cloth!) , and doing so also makes it easier to clean up.

I'm not aware of any health risks particularly due to machining cast-iron. It's not Uranium!

Dave

[Nick HulmeParticipant @nickhulme30114]

Machine it dry and use vacuum extraction, HEPA vacuum or exhaust outside the workshop.

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