From: claytonc@pogo.wv.tek.com (Clayton Carpenter)
Subject: Re: What finish should I get?
Organization: Tektronix, Inc., Wilsonville,  OR.

In article <45126@mimsy.umd.edu> n9020351@henson.cc.wwu.edu (James Douglas Del Vecchio) writes:
#hollombe@soldev.tti.com (The Polymath) writes:
#
##stainless) this Friday.  My SIG P-226 (K-coat, night sights) will be
##...GP-100 will eventually get it's own night sights and black finish.
#
#
#Question:
#
#I've got two polished blued pistols that I am very happy with,
#but I want to give them a finish that will last forever (or a
#long time).
#
#I've ordered info from several chroming places.  Prices are not
#important, as they all seem to be the same, but quality is.  I
#can't tell much about the results from the B&W photos I've been
#sent.  Armoloy looks a dull grey, but it's hard to tell w/o a
#real live look.  They stick in my mind because they are the only
#ones that hard-chrome the inside of the barrel as well.  Metaloy
#is another maybe good one, they do all the work for Wilson custom
#gunsmithing.
#
#This K-coat sounds intersting.  I prefer chrome only because it
#is more durable than blue.  If there was some kind of shiny black
#finish that is as lasting as chrome (and doesn't show scratches,
#even the Glock-finish shows scratches), I would prefer that.  Is
#it possible?  I've heard that hard-chrome is as hard and durable
#as a finish gets.
#
#How does electroless nickel compare to hard chrome?  Is it purely
#a matter of preference, or is there some difference between the
#two, in looks or function?  Many of the finihing places have e-
#nickel as a same-price option.   I know it is softer, does that
#make it wear faster, show scratches more, or look different?
#
#Jim Del Vecchio
#
#PS, I am not real fond of dull "silver paint" style grey.  The color
#I like is more shiny, like stainless along the sides at least.
#What do the finishes from different companies turn out like?

Maybe this will help.
The k-coat is an electroless Nickel plate with PTFE (teflon)
distributed throughout the Ni matrix.  A solution with PTFE
is added to the agitated Ni bath and as the base material is
plated PTFE molecules are traped in the coating with some of
them being exposed to the surface.  As the coating wears more
teflon is constantly being exposed.  The resulting surface is
Extremely corrosive resistant, Extremely abrasive resistant,
has a very low coefficient of friction, and one of the lowest
surface energies available ( ie stuff has a Very hard time
sticking to it ).  The e-Ni/ptfe surfaces I have experience
with look "Stealthy" ie. sort of grey-black.
I just bought a SIG P-226 with k-coat.  My rational follows.
e-Ni is about 10 - 20 times more corrosive resistant than
chrome plate.  The surface of chrome plate is a network of
micro-cracks, some of which will expose the base material.
If the point is to protect the base material from corrosion
hard chrome plate is not a good choice.
Chrome plate is about 30% harder than e-Ni but e-Ni is still
extremely abrasive resistant, and is commonly used in industrial
applications where highly abrasive resistant surfaces are
required.
e-Ni/ptfe is self lubricating.
stuff has a hard time sticking to e-Ni/ptfe surfaces.
e-Ni/ptfe surfaces are very easy to clean.
e-Ni/ptfe is not highly reflective and shiny.
e-Ni/ptfe, since it is an electroless process, yeilds an
extremely uniform coating.  Chrome and electroplated Ni
tends to collect and build up on corners and edges.  The
variation in thickness for e-Ni/ptfe is effective unmeasurable.

My feeling is that if after years of use I am able to wear the
e-Ni/ptfe coating off ( I find this hard to imagine ) I'll just
have it replated.

I'll quickly mention another process that I would Not recommend.
e-Ni with ptfe impregnation.  In this process the e-Ni surface
is sprayed with ptfe and then "Baked" in at high temp's. The
resulting surface is all teflon and can be scraped off.   Good
for frying pans not for metal vs metal interfaces.  Be careful
because this process is not at all like co-deposition and is
probably worthless for guns.

If people are interested I can describe some other processes
that are probably the Ultimate for abrasion resistance and
corrosion resistance.  The involve vapor deposition and
plasma deposition.

-bye
Clayton Carpenter, Mechanical Engineer
503-685-3473

From: claytonc@pogo.wv.tek.com (Clayton Carpenter)
Subject: Re: What finish should I get?
Organization: Tektronix, Inc., Wilsonville,  OR.

Hi,
I have gotten a few requests for more info on plating so
I will respond here.

The best way to find potential platers that I can think of
is to go to the thomas registrar of manufactures.  You can
find this registrar in any good library.  You may find a
plater within 30 miles or so of your home who does e-Ni/ptfe
codeposition since it is quite common.  If I were interested
in saving some money I would try to find a local plater and
see if I could talk them into slipping my small job in with
a schedualed production run.  I would'nt be surprised if you
could get the job done for <100$ and maybe <50$, depends on
the situation and communication skills.

Since my last post I've done some more research and talked
to some of our plating experts.  One thing I said earlier
that may have been misleading relates to the hardness of
e-Ni/ptfe codeposited surfaces.  Normal e-Ni plated surfaces
run about Rc 45-49 (Rc=rockwell hardness, c scale).  If PTFE
is codeposited though it will reduce the surface hardness in
proportion to the percent PTFE.  It gets more complicated by
the fact that normal e-Ni surfaces and codeposited surfaces
can be heat treated to increase surface hardness.  I know that
normal e-Ni surfaces can be heat treated to the point that they
just as hard as chrome plate.  Depending on the plater they
may heat treat the surfaces differently for different
surface hardnesses.  It's best to ask about hardness and
more importantly abrasion/corrosion resistance of the plater
your working with.

Unfortunately abrasion resistance is not just a function of
surface hardness.  The best way to predict performance
is real world field tests.  I would be very interested if anyone
out there has a e-Ni/ptfe coated gun that has seen alot of use?
How did it hold up?  As I mentioned before e-Ni/ptfe surfaces
can be very different depending on %ptfe, %sulfate, %phosphorous,
heat treating etc.  So for any field data to be valuable it would
be neccessary to know as much as possible about the plating.

k-coat is done for SIG presently by Coating Technologies
in Arizona (Phoenix area I believe) 602-581-2648.  If someone
has experience with k-coat I could probably find out exactly
what the plating was.

I've gotta jam, so I'll tube some more to ya later

-bye