[TheForge] Lye soap

[Mike Spencer]

>> I like to treat the clean steel with phosphoric acid which will
>> protect it for a time from rusting.
>
> .... When you say "for a time," how long?

Varies. There's a knack to getting it right, phase of the moon...

I had one piece of repousse that I treated with phosphoric that sat in
my damp, sea-side, rust-prone shop for several years.  No rust
appeared on it until it finally got some drops of liquid water on it.
Then it rusted a little in those spots.

Other pieces in similar conditions showed some light rusting after
several months.  Pieces left in the rain will rust soon.

Part of the trick is, instead of rinsing with water, to leave the damp
traces of phosphoric acid on the metal to dry, then wiping off any
remaining bloom or crud.  I haven't really learned to control it
well but it's still way less messy than muriatic acid and has
longer-lasting results.

Re. blackening steel: I like Brownell's Oxpho-Blue.  It's changed in
recent years. probably due to regs on toxic stuff, but it still works.
Pickle the steel if it's not already clean, preferably in phosphoric
acid, rinse & dry, wipe on Oxpho-Blue, wipe clean (or rinse with water
if there are pits or crevices), optionally steel wool with 4-ought,
and finish with wax. Makes a bluish-black that deepens to black with
time.

The stuff is toxic enough to be treated with caution. Contains (or
used to contain) nitric acid and selenium.

I found it easier to get uniform coloration than with other commercial
gun blues.

- Mike

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