Blackening mild steel

[Neil WyattModerator @neilwyatt]

Being realistic though – would some one boil this concoction on the stove? Suppose some might with care turning it down as soon as it simmers but I would expect the mix to have a pretty high boiling point and personally I would use a lab type hot plate or similar. Would people take some precautions – gloves etc. I would hope so. Would any one in their right mind melt the solids first and then add water – I'd hope not. Sounds like the nut cases may go to the right place. .

Sadly experience suggests that there are plenty of people who need to be told these things explicitly – they tend to think "after all if you can buy a pot of sodium hydroxide for a quid in the cheap shop it can't be that dangerous". Another proportion of people will simply ignore advice, relying that "providence takes care of children, fools and the United States".

Neil

[Ian S CParticipant @iansc]

Like the warning in a site for paper aeroplanes, warning that scissors are dangerous, and require supervised use, this was for 10/12 year olds, I remember using scissors when I was a Kindergarten, at about 7yrs we used a fret saw on craft day, no close supervision.

Some thing about cotton wool, and being wrapped in it.

Ian S C

[jason udallParticipant @jasonudall57142]

Cotton wool…
Now there’s something to keep away from nitric acid…..

[AjohnwParticipant @ajohnw51620]

The easiest source for dilute HCL is cement cleaner. If the item is greasy a pre treatment with an alkaline even washing soda followed by a wash and dry would probably help. HCL removes rust and leaves metals grey. It rusts pretty quickly then. I tried it on a reamer once. No change in size I could measure and it was still sharp.

yes – "modern" things in the directions outlined are a bit strange. People are inclined to want specific instructions on all sorts of things. This seems to discourage thought and lead to an inability to think for themselves and maybe a lack of confidence as well in some areas.

John

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[Neil WyattModerator @neilwyatt]

I think the problem today is that schools do their 'experiments' with the kids allowed to use nothing more hazardous than lemon juice and a bit of zinc, or worse still just a computer screen.

If you see what happens when concentrated sulphuric acid hits sugar first hand, you are more inclined to believe what the nasties can do, and you handle them with more respect. I still use the back of my hand to wipe my eyes because 'if you use your fingers you're more likely to get something nasty in them'.

On the other hand, if they do use chainsaws or nasty chemicals in their work they are probably much better trained and aware of the risks.

But the long and short of it, is we now have a new generation who, paradoxically, take health and safety precautions more seriously, but haven't the broad knowledge of how to handle anything they haven't been trained to use.

Neil

[Ian S CParticipant @iansc]

From one of my old books: Bluing without heat. Mix finely powdered Prussian Blue with rather thin shellac varnish; gently heat the steel, and apply the varnish.

Ian S C

[AjohnwParticipant @ajohnw51620]

Maybe some one fancies trying another way

**LINK**

John

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[Ian S CParticipant @iansc]

I bought a Bohm hot air engine, and it came with this warning. Caution: The engine must be operated by or under the supervision of persons over 18 years of age.

Flammable objects must be kept from the vicinity of the engine. Do not touch the engine since this could lead to serious burns or injuries. Takegreat care when handling alcoholic spirits. Never leave spirits bottles open. Inappropriate handling of the Stirling Engine may cause fires.

This is not as bad as a bag of tennis balls from China; May cause choking, not suitable for under 36 months. Same label on a Frizby.

Ian S C

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