Who has used Acid to prepare their Fal for parking

[Nwfal]

what type of acid was used and how well did it work compared to abrasive blasting?

[GEM]

Not sure if you are referring to using acid instead of, or in addition to, blasting. Some people use an acid bath (muriatic, maybe) to help clean/prepare the metal prior to immersing into the park bath. But I don't believe it is used in place of a good mechanical preparation such as blasting or sanding. For good parkerization, it is essential that the metal be free of surface oxidation, scale, bluing, old park, etc. (hence the mechanical prep). I don't believe acid dipping would achieve this as well. Another pre-dip process sometimes employed involves the use of an akaline solution. This is considered by some to be a "grain refiner", or "accelerator" for the park process.

[bnz43]

A muratic acid bath can be used to make sure there is no oil or grease on the parts prior to parkerizing. If you have a lot of parts to bead blast prior to parkerize you can use a product sold by Brownell's called "hold" it will keep the parts from rusting until ready to parkerize. If you use WD40 or any type of oil you will need to remove it prior to parkerizing or you will get poor parkerizing results. Some industrial plating companies use a muratic acid bath prior to black oxide coating or parkerizing to ensure good results with the coating.

[kotengu]

Is the acid bath dilute, and if so how much?

[Offctr]

I did and it worked fine as a final de-greasing step after sandblasting and rinseing SB residue it really helped my results I mixed up solution of about one cup Hcl (hydrocloric acid ) to 3 gallons water and immersed the parts in it for a minuite or two then a clean water rinse and into the park solution. I found that depending upon the park solution used use the instructions as a loose guide -experiment but the two overridding factors were 1 temperature you must getthe temp up to the recomended heat range prior to parking and make sure to go to the high side if you are doing large parts as the solutions temp will drop for a few after you dump it in .AND 2 Cleanliness any oil,finish ,dirt,dust or anything will interfere with the parking so get it as clean as you can ---watch out for the oil in your skin as well --
I used the brownells park solution and got their free phamplet on parking as well it was very informative my first run was ok --not what I wanted but ok the second run was great! I learned alot from the first and everything I have done since has come out good. BTW Parking gets darker 24-48 hours after you do it so keep that in mind when you pull out the parts and wish they were just a little darker....
I got good results but like I said experiment a little you can always re-sandblast and repark !