[TheForge] Re: Kitchen Utensil Finish?

[Mike Spencer]

> Hot bluing with various nitrate mixtures  (sodium nitrate, pottassium 
> nitrate).  The cold bluing has a rotten egg smell, so I am guessing some 
> sort of sulphuric acid?

We may be mixing up very different surface treatments.

    There's hot blueing in molten sodium and potassion nitrate.

    There's more than one hot blue method with water solutions of [stuff]
    and steam.

    There's more than one cold blue formula.

Oxpho-Blue (my favorite cold blue) used to contain dilute nitric acid
and selenium (nitrate?).  I believe they changed the formula
(presumably under pressure from some kind of health/safety regs) but
weren't very forthcoming with me about what's in it.

I surely wouldn't want to put it in my coffee but how much selenium
will remain on a piece of treated and washed steel?  Still, I use raw
linseed or peanut oil and toasty-to-very-toasty heat for black
finishes on kitchenware.

FWIW, "boiled" linseed oil isn't boiled these days.  It has dryer in it.
Cobalt dryer?  You don't want to load up on cobalt either so I make a
point of using raw linseed.

- Mike

-- 
Michael Spencer                  Nova Scotia, Canada       .~. 
                                                           /V\ 
mspencer at tallships.ca                                     /( )\
http://home.tallships.ca/mspencer/                        ^^-^^

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