re-Parkerizing?

TRX · 05-04-2010, 09:08 PM

I have a Maadi that was gray Parkerized and then painted at the factory. I used caustic to strip the paint, exposing the Parkerize base.

I want a black Parkerize finish. Can I just drop it into the park tank with some suitably black solution, or do I have to re-sandblast it first?

zteknik · 05-04-2010, 10:34 PM

hey trx
im thinking you might have to rough up the surface a bit the gray is zinc and the black is maganese
ive re blackened and re parked without blasting but not black over gray or grey over black-degrease heat up add solution boil-
i would think it would come out brownish?if you went black over grey
try it out on a small part you dont see
just thinking out loud

kernelkrink · 05-04-2010, 11:12 PM

I don't think you can add parkerizing over existing park. Touch up over scratches down to the steel, yes, but not over the park already there. The acid in the parkerizing solution etches the base steel of the gun, the acid depletes at that location and the zinc or manganese comes out of solution and deposits on the steel to replace what was eaten away. At the point the surface is completetly covered with the phosphate the reaction stops.

IIRC, people have experienced satisfactory results using the Caswell Plating black oxide kit over the grey zinc park.

Caswell Inc. - Black Oxide Kit

zteknik · 05-04-2010, 11:41 PM

hey kernel thanks for that link

yup i forgot to mention when i did do a repark well touch up it was on scratches down to the metal thanks for jarring my memory

now on the Caswell what kind of prepping do you do?just the standard degrease?or is the prep inclusive with the kit?
(gotta check the link when my computer speeds up after i finnish downloading software)

kernelkrink · 05-05-2010, 11:48 AM

Never used it myself, but people report good results with it. If it requires special prep chemicals they would be included in the kit.

SW44 · 05-05-2010, 01:18 PM

I have used the Caswell solution as a post park treatment once. I had used manganese parkerizing and the finish was not even. The Caswell solution made the color darker and evened up the color alot. There was a dark "smut" that came off the gun when it was handled. I scrubbed it down with oil and the residue stopped coming off. I want to experiment more with it since I am new to parkerizing and the caswell solution.