Hardite info?

I would imagine its much the same as any other CH powder (like 'casenit'). Heat item to cherry red and dip. Repeat as often as needed for required 'depth' of hardness. Don't know if stuff like this 'goes off' though - if its very old may not be 100% effective. Is there a chemist in the group? hth Mike

Yes, I think it's equivalent to Casenit. That sounds simple enough.

Thanks Jordan

I've never understood how this can work. Surely the slow cooling in the powder can't give a really hard surface? I've always reheated and quenched. Russell.

History suggests that diamonds which are pure carbon came out of the earth and cooled slowly.In case hardening, you are introducing carbon in higher percentages than in heat treatable carbon steel.

If you follow the art of ancient swordmaking- look up Shotley Bridge in County Durham- you will find that the German finest swords were made by folding carbon into iron rather like making Swiss Rolls.the steel was so good that swords could be coiled into gentlemens' top hats. My father- who incidentally did his blacksmiths apprenticeship in the next village, used parings from horses hooves for case hardening!

Yes?

AFAIK, with Kasenit, you repeat the red hot and dip process as many times as you desire, and pound it into the quench on the last trip through the cycle.

I have some, but have not used it for anything in anger, and that, a while ago.

Cheers Trevor Jones

Unfortunately it is not easy to produce the pressure required to form diamonds in the workshop!

I take your point that the carbon content may be greater than for heat treatable carbon steel but it is still necessary to cool rapidly enough to prevent pearlite being formed instead of martensite. Perhaps air cooling is rapid enough for a thin case?

Regarding the swords, the japanese were using this folding method to make swords from about the 14th century. However they quenched the edge to harden it while protecting the greater part of the blade with clay to keep it tough.

Regards, Russell.

I haven't a clue of what went on in the Geisha World of Japan in the

The word which comes to mind in an old unproven tin of 'jollop' is not what it might do with a chunk of steel but whether it contains cyanide for starters!

Come on- it's raw chemistry not physics!

There are major differences between cyanides and hexacyanoferrates. The former are used in some plating baths, some gaseous and liquid hardening processes and for killing religious nutters. The latter are used in case hardening powders along with barium carbonate and as the anti caking agent in icing sugar.

It's chemistry :-)

Mark Rand RTFM

Oh, dear!

More modern history than either the cementation processes of the Japanese or the exiles from Solingen, the best case hardening compounds or mixtures were banned.

Anyone dying to tell me otherwise?

Is there a safe handling procedure for hardening with cyanide?

Get someone else to do it. Accidents can happen too easily and with cyanide usually only once.

In article , Mark Rand writes

Yes, well, bear in mind that barium salts are about as poisonous as cyanide (albeit quite a lot slower). Barium carbonate is insoluble in water, but unfortunately it will readily dissolve in dilute hydrochloric acid (which is, for this purpose, what the digestive juices in your stomach are). I know some recipes use Ba salts (e.g. the one in Guy Lautard's books) but in view of the fact that they are mostly S1 poisons* I doubt if you would be able to buy mixtures which did contain Ba.

Also, hexacyanoferrates give off lethal HCN when heated with dilute mineral acid - for example sulphuric or hydrochloric, just the kind of things you might use as a pickling bath. I remember doing this over a candle in the garden (in case I passed out) to learn the smell in my mis-spent teens.

I don't think there would be any reason to panic, just take sensible precautions - do it in a well-ventilated space (or outside), don't ingest the stuff, and don't heat it or its remnants in acid.

David

Thanks David and everyone else.

I don't know if I'll ever use the Hardite, but got the message that it's stuff to be handled with caution.

Jordan

David, Hardite contained 20% Barium Chloride. Our correspondent HAS half a tin of which the rest is presumably potassium ferrocyanide. Enough to send an Australian synagogue into some disarray?

Oh, Ravensworth 2674( the real bit) is within a Sabbath's Day journey from the 2nd largest Talmudical College this side of the -------- Jordan.

Shalom

Norman

Barium chloride is £5.30/500g from lpchemicals

LD50 is about 1g for barium chloride. More toxic than paracetamol, but about four times the dose required for HCN.

Good job case hardening isn't done with caster oil seeds :-)

Mark Rand RTFM

Thanks Norman for the additional, err, information?

Jordan

But chemistry is just a branch of physics.

...and physics is just a branch of mathematics, so you're both wrong ;-)

Regards, Tony