[TheForge] Hammer heat treating/stainless coloration

[Lynn Emrich]

Ries, I hope that you write the book with lots of
pictures and drawings.

As the polishing of stainless, I beg to disagree. It
seems to me that there is usually more than one right
answer to most questions.

I have put a (almost) mirror polish on 316 C stainless
steel. My method is just to sand using progressively
finer sandpaper, then scotch brite pads, then buff. I
use an angle grinder with a 5 or 6" sanding disk,
usually the hook and loop kind, when I can find them.
It has less of a tendency to dig in and leave big
gouges that are a pain to fix. My local supplier only
has the finer grits, above 220, in the paper used for
polishing marble but it works for me. I just wish
someone made a 5" grinder with variable speeds.

The scotch brite pads are easy enough to find in the
courser grits but not available locally in the finer.
I have to order on line to find all 4 grits. I usually
order from J&L Industrial Supply out of Pittsburgh.

If the work is too big or awkward to take to the
buffer I put wheels on my grinder and take it to the
work. I usually start with black and don't have to go
above the green to be satisfied. You could keep going
but I think the 316 has a problem that any finer makes
look worse.

Just what I do,
Lynn


--- ries <ries at riesniemi.com> wrote:


> Anyway, as mentioned, a powered wire brush will do a
> lot- I use 4"  
> flat wire brushes on my 4 1/2" angle grinders, and I
> use a 12" X 2"  
> stainless wire brush on a 2hp bench grinder- but if
> the piece is  
> heavily forged, where it is dark grey to almost
> black, I find wire  
> brush alone will usually only take it back to a
> medium gray.  
> Sometimes I will sandblast then wire brush- but that
> doesnt give you  
> shiny. Scotchbrite pads on the 4 1/2" grinders will
> sometimes do it  
> too, or scotchbrite belts on the 1 1/2" x 21" makita
> belt sander- but  
> if you want a piece of heavily forged stainless to
> get shiny again,  
> electropolishing is the only way to go.
> I send mine out to a commercial place- it costs
> about the same as  
> powdercoating, they use a 4'x4'x8' bathtub of 120
> degree mystery  
> acid, mostly phosphoric, and a 1000 amp power
> supply, hooked up  
> backwards from a plating setup. And still, heavy
> forged stuff might  
> take 20 to 40 minutes to get shiny.
> Small stuff, you could use a rubbermaid tub full of
> dilute phosphoric  
> (maybe Ospho from the auto parts store?) and a
> battery charger- it  
> will take longer, maybe even overnight, but it
> should work.
> Or find a plater that also does electropolishing.
> This is the best for really twisty turny, lots of
> nooks and crannies  
> type work.
> 
> ries


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