The Shop > Finishing
Parkerising technique
PekkaNF:
Your and mine experiments conform few things:
* Too much accid etches. If you look old recepies final accid contents is pretty small and much spent on aging. There seems to be benefit of adding up clean water to replace evaporated water.
* Some sources claim that the water quality is important and copper/zink ions?? chlorins, carbonates or something should be avoided. I have used battery water, but read a lot of pro/con, looks like local water and it's treatment are very differet from place to place.
* Surface preparation and cleanless is very important. Some instructions go pretty deep with sand blasting, even down to sand and air quality.
* I noticed that faster you can process from surface prep, better it is.
Then one variable is this "aging" with homebrewn park. I noticed that that I get better results if the park is brought to boiling point and kind of flaky things start to circulate (Flocking). Then I preheat the piece on "rinse" and then bring it into park to "boil". Can't remember exactly, but I made some experiment with the same metal/park/time ,only changing the temperature a little bit and least on my thermometer under 90C it did not work, and worked between 92-96C.
Industrial parkerizing solutions seems different breed.
Pekka
redshift:
vtsteam:- Thanks for the comments.
PekkaNF:- I bought 10ltrs of 81% acid for £30 inc. tax and 1kg of manganese dioxide for £3 inc tax so I think that until I get a feel for the percentages of each I will be better doing a fresh mix each time.
Up to now I have been using boiled tap water. I have a friend who works at the local laser cutting factory who will get me a load of
de ionised water to use (hopefully today) so that should be another variable out of the way.
Surface prep has been Glass bead blasting to a smooth satin finish and into the mixture within seconds.
Regarding flocking, The mixture is an opaque brown colour and as such I will not be able to see any Flocking. Having said that I notice that once the mixture has cooled there is a thick layer of sediment covered by a clear liquid, I wonder if this will still do the job if I decant it off the
sediment?
I notice also that the clouring is different for different materials so I will make multiple samples from the same material, (a 25mm dia. go kart axle in EN8, don't know the new fangled steel codes), and that's another variable gone.
I don't fully understand the chemistry of this process and I am very confused with all the conflicting information on the net but as I need to be able to do this to decent standard I will plod on until I can.
Regards
Dave
Arbalist:
This is an interesting thread, thanks for posting and those that have added to it. :thumbup:
It's a shame that many "useful chemicals" have become harder to source here in the UK.
I use gun blue for small components and it works well enough but it's too expensive to use on bigger stuff.
There are also blacking kits available but some of the chemicals are given a proprietary name and the price doubles, or triples! Keep up the good work guys!
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