[TheForge] Re: Phosphate? (Ping Bruce the chemist)

[Mike Spencer]

Thanks Bruce & parkej7.

The reason I feel confused is that there's an awful *lot* of the gray
grit.  I can't figure out how, with the amout of pickling I can
recall doing, there could have been enough iron in solution to make a
maybe four measuring cups or more of iron (anything) phosphate
crystals.  Where did all that "extra" mass come from?

> Why not try it on two identical bars?  Heat both to red, set one
> aside (as a control), and treat the other with the gunk.  Set them
> out in the weather and keep an eye on them.

Good idea.  We'll see what happens.

> ...may have value as a fertilizer.

I was hoping.  My source of fish scrap dried up long ago and the guy
who was giving me a couple of loads of cattle manure a year (and
loading it  for me as well!) had to give up his cattle for health
reasons.  So some extra phosphorus would be good.

Ob smithing: If you get phosphoric acid at just the right dilution
and. after pickling clean, simply wipe the workpiece down with paper
towels to dry it -- no water rinse or abrasives -- you can get a gray
finish that is resistant to rust in high humidity environments.  Not
resistant if it gets actually wet, though.  I have a demo piece that I
made in the early 80s finished that way that showed no rust after
sitting around in my (former) unheated seaside shop for 20 years.
Other demo pieces stored in the same place were red & furry with rust.
Now there are a few little rust spots where it got spattered with
water.

I haven't had occasion to experiment and try to control the process
but I'm guessing the finish would take paint well.  Not sure.

Tnx,
- Mike

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