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From: (Gunfreak)
Newsgroups: rec.crafts.metalworking
Subject: Re: Is phosphating/parkerizing simple?
Date: 25 Aug 1999 02:41:11 GMT

I do a LOT of parkerizing, and yes, it's very simple.  Don't use Brownell's
chemicals if you want good results, though.  Plus, their chemicals require that
you "season" the solution with a bag of iron filings first.  Crazy.  Buy the
chemicals from Palmetto Enterprises, (864) 246-3836.  For really small stuff,
you can microwave the solution in a coffee mug, dump your parts in and be done
in 5 minutes.  MSC sells various sizes of stainless steel tanks (under some
weird name which I forget) and you can do it on the kitchen stove.  I have a
large, dedicated  tank, but the results are just as good with the coffee mug.

Mark Serbu

>"Robert S." wrote:
>> Can I get a good corrosion resistant finnish on mild steel by simply
>> boiling the part in phosphoric acid.
>> How concentrated should the solution be? what temp? How long?
>> Thanks in advance
>If you can boil water you can do it.  Brownells, a gunsmith supply house
>sells the solution, with instructions. You need a stainless steel container
>and a thermometer. Get a hot plate,
>don't do it in the kitchen. Takes 45 min to an hour.
>Their number is 515-623-400.  Also on the web

From: dave <>
Newsgroups: rec.crafts.metalworking
Subject: Re: Is phosphating/parkerizing simple?
Date: Thu, 26 Aug 1999 00:54:54 GMT

to expand a bit:
"Parkerizing" became a broad generic term for a whole variety of
conversion coatings, and it's been difficult to ascertain what any one
individual really meant by the term.  Parker Chemical (and competitor
Amchem - both now owned by Henkel last I heard, but I'm now pretty
remote) made a wide range of products for spray or submersion or wipe-on
applications ranging from mild and gentle pre-paint treatments, to
aggresive pre-paint treatments,and to compounds intended for
anti-corrosion or anti-galling coatings that stood on their own or were
subsequently treated with oils or other absorbed adducts. Almost any of
them could be treated with a chromic conversion afterwards.
Applications were made ranging from room-temperature products, up to
nearly boiling.  Generally, the pre-paint coatings were sodium or
sodium/zinc phosphates, and were usually grey or grey-ish colored
Heavier zinc based treatments usually had a grainy appearance.  The
Manganese based products tended to be the stronger anti-corrosives and
anti-galling coatings, and were generally black-ish colors, although the
chemistry of the bath and the treated metal occasionally produced colors
ranging from dark greeny-grey to a black with a real purple cast to it.
I don't think Parker or Amchem ever advocated their products for
chemical blackening - there were just too many variables to get the same
color consistantly.  And color per se was not an indicator of how well
the product was going to do the job.
For us hobbyists, blackening is a real judgement call, and any product
we use will probably see us dragging the metal out and in and out until
we get a satisfactory appearance.   The industrial user would do
chemical analyses to control the bath - long term technical and economic
control.  And we generally don't need to be this stringent. - Just
If the CPR was Parkerizing locomotives, I'd guess it was a pre-paint
treatment on the streamlined or semi-streamlined boiler lagging, cabs,
etc, and done warm or hot with a spray.  I don't think the manganese
phosphates stood up to heat well, and i'd be surprised to find them on
the smoke boxes.
With regards to adding iron filings to the bath.... Commercially the
baths that needed priming with iron usuallly ran hot.  If cold, the iron
phosphate complexes would salt out.  They also added useless weight to
the drum of product, and the customer preferred to adjust the iron
content to his particular bath and temperature and steel etc etc.   I'd
rather add iron to suit than to make my process fit whatever came out of
the jug - but I like to tinker.
Both Parker and Amchem made conversion coatings for aluminum, and in
this case, it was the Amchem product that provided the  generic name -
That's another story for another day.
Key to any and all of these processes is the preparation done
Trust this is some help and interest.
Regards,  Dave M.

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