I'm not sure that I would say I know what I'm doing , but I have parkerized.
I used these sites for info:
http://www.blindhogg.com/parkerizing.html
http://www.theboxotruth.com/docs/edu52.htm
I bought the solution from Midway USA. (under $7 less s/h for either the zinc or manganese phosphate solution). I now buy it straight from
http://www.lauerweaponry.com/
Surface prep is an important thing. I abrasive blasted, washed, and wiped with acetone. I don't see any reason chemical stripping followed by cleaning/degreasing shouldn't work.
The instructions want you to heat (and maintain) the solution to a certain temperature. Parkerizing solutions work best in the 180-190 degrees F range. They work outside that range but may take longer (cooler) or shorten the working life of the solution (hotter). You are also supposed to put some coarse, degreased, steel wool into the solution and cook it for 30 minutes. The tank needs to be stainless steel or ceramic (porcelain works). The solution does contain phosphoric acid, so it would be best follow the product instructions and be careful.
There are fumes; so do it in a well ventilated area.
I don't like using their sealer (found it isn't needed) and had better results with motor oil.
My first effort (let me say; this isn't intended as instruction; it's just how I did it): I experimented by using a microwave oven to heat some of the solution mixed with water in a large, microwave safe glass.
I think it worked out pretty well.
The parkerizing seems to be holding up pretty well after about 6 months use. There is a little wear around the front of the slide and the ejection port, but that's about it.
I also did a 1911 following the directions more closely in a heated porcelain pot. I left the slide in longer than the rest of the pistol so it came out darker for a two tone effect.
http://gbrannon.bizhat.com/DSCN4177.jpg
I still do small parts by just heating some of the solution and a few strands of steel wool (lesson learned from the first effort) in the microwave. The microwave method isn't very exact (as I do it) and kills the solution quite quickly. This grip safety was done using the microwave:
All this to say; it's not all that difficult to get decent results. Hopefully a pro will chime in and set you straight on any or all things I led you astray on.
Regards,
Greg