A few comments on parkerizing
I've done quite a bit of parkerizing over the yrs using both the manganese and zinc based commercial solutions. I won't comment on homemade recipes as I've never tried them and see no need to when good chemical kits are available. I would like to offer a few comments on set-up and metal preparations.
- This is an acid based process and I do not think it safe or healthy to do it indoors in an un-vented location where the toxic fumes/vapours are released.
-rather than pre-heat the metal in hot water after degreasing/blasting, I suggest heating it in the oven to 180deg on a disposable aluminum sheet. This serves to keep the metal from cooling the solution and I think that the park is a bit more reactive with pre-heated metal( you will note that color change follows immediately after immersion in the park solution). Pre-heating in the oven gives you a known temp and avoids having the freshly blasted metal surface oxidize in a hot water bath and interfere with the take-up of the parkerizing chemicals.
-I ALWAYS sandblast the metal prior to parkerizing and have it in the park solution within an hour of doing so to minimize the possibility of steel oxidization ( living in the Okanagan with a desert level of humidity is a real plus ). Sandblasting cleans any residual grime and scale from the metal after degreasing with laquer thinner. Pre-brushing/scrubbing and an acid bath will not do this. I just finished parkerizing 3 Garand receivers plus beaucoup additional parts which were from the batch of rifles imported from the Middle East 2-3 years ago. The metal on these was sound and unpitted,but very scuzzy with encrusted dirt,dried oils and scale. Blasting got it down to the bare steel and the results were very satisfactory. Also, blasting produces a uniformly reactive steel surface which an acid etch will not.
-in some cases you will find a part which will not take the park uniformly due to deeply imbedded oils. In this case I recommend boiling the part in a mild lye solution which will remove the oil. After boiling rinse in distilled water and re-blast prior to re-parkerizing.
-parkerizing takes some time to "cure" after neutralizing the acid and oiling. I keep the parts wet with oil (ordinary 3 in 1 oil is good) for at least 5 days after parkerizing.The park seems to darken a bit after several days and I think this helps. Wipe off the accumulated oil with paper towel and lightly re-oil parts with gun oil prior to re-assembly.
-A good vessel for parkerizing parts,other than a barrel or an operating rod,is an oblong shaped ceramic crock pot. The advantages of these is that they are non-reactive with the park solution and are economical on the use of chemical. You can do the job outdoors and achieve a stable temp (monitor with a candy thermometer) and the lid will minimize the loss of solution due to evaporation (solution is re-usable after cooling and straining thru a coffee filter to remove any sludge). If the outside temp is cool I put the crock pot in a cardboard box with wood underneath for insulation and cover the pot with metal faced bubble sheet insulation to help get the solution up to temp.
-Once degreased, metal must only be handled with rubber gloves to avoid contamination from skin oils. Wear heavy rubber gloves to hold the parts while blasting and before immersion in solution.
- All parts must be as clean of oil as a hounds tooth to avoid a poor finish and contamination of the solution. Parts like a Garand buttplate and a trigger housing assembly must be stripped right down to clean away hidden grime and oils and avoid a crappy amateur looking outcome.
