Tried my hand yesterday at Homebrew Parkerizing. Had mixed results.
Followed several step-by-step walkthroughs for zinc-phosphate parkerizing. I had on hand a gallon of Kleen Strip Prep-and-Etch, a bottle of Naval Jelly, a bunch of pennies, some 0000 steel wool, a huge stainless fish poacher, a BBQ grill, a candy thermometer, and an ORF sideplate.
Started out just like the walkthroughs said, I ground off the copper cladding on four pennies, and went to dissolve them in a quart of Prep&Etch. Man, I thought they would dissolve in about 20 or 30 minutes, but it took several hours. At this point, I was thinking that the P&E didn't have a high enough content of phosphoric acid, so I added a couple big globs of naval jelly to the mix to try to speed things up. (Mistake). Well, that didn't really speed things up, so I started to theorize that maybe the P&E solution was becoming "saturated" with zinc. So I dump another quart of P&E into the mix.
Another hour or two goes by, and those pennies are STILL dissolving. At this point I'm scratching my head. I had assumed that they should be dissolved by now. So more P&E at this point gets added, I chop up the pennies with tin snips (to get more surface area exposed to the acid) and I light up the BBQ grill thinking that heat will speed the process. Let it cook a couple more hours, and the pennies are still not dissolved completely. In goes the last quart of prep&etch (one gallon total in there now).
I come back two hours later, and the pennies are now dissolved to my liking. I add about a gallon of water to the mix, bring it up to 190*, and toss in half a degreased biscuit of steel wool. That sucker was dissolved in about 5 minutes. (This should have been my first clue).
So out comes the test piece. A nicely sandblasted piece of square tubing. Into the bath, it it starts bubbling like CRAZY! (Again, another warning sign). After about 5 minutes of this, my curiosity gets the better of me, and I fish it out. WOW! A nicely light gray parked piece of tubing! That's awesome! Parking was a little thin, but I chalked it up to the short time in the bath before I fished it out.
"Cool!" I'm thinking, so into the bath goes the properly prepped sideplate. You talk about FIZZING! It looked like I tossed an entire bottle of alka-seltzer in there. Oh well, must be normal.
There was so much fizzing, that the park solution actually got a "head" on it, like a glass of beer. About 5 minutes later, it actually begins boiling over.
I did my best to control the boilover, and seeing as how this was the piece I wanted to come out "nice", I left it in a little longer than my test piece so that it would have a good heavy parkerized coating. Heck, the tutorials said it would stop fizzing when it was done, right? Well it fizzed right along, and after about 20 to 25 minutes, I fished out the sideplate.
Horror of horrors!
My beautiful ORF sideplate with personally-done-hand-engraving was ETCHED LIKE A MOFO! Oh, it parkerized alright. The finish is fine, but the metal is so etched that it is now about 3 or 4 times rougher in appearance than hot-rolled steel. It's so rough in fact, that wiping it off afterward with an old rag will rip little fibers off the rag, and leaves little "fuzzies" all over the plate. And it actually thinned the plate significantly, too. Where the RSP inserted into the bottom plate, before it was quite snug, and now is almost sloppy. The profile near the feedway, where it is supposed to be filed to fit, is now etched away so it sits BELOW the feedway (it did not during initial mockups).
Pics WILL be coming.
So.... I just ordered a new ORF plate (backordered! Nuts!
) and I'm re-mixing a new batch of witches' parkerizing brew. This time using ONLY ONE quart of prep and etch, and I've got the pennies in there dissolving right now. They've got at least three weeks before my new RSP shows up, so that should be plenty of time. 
Followed several step-by-step walkthroughs for zinc-phosphate parkerizing. I had on hand a gallon of Kleen Strip Prep-and-Etch, a bottle of Naval Jelly, a bunch of pennies, some 0000 steel wool, a huge stainless fish poacher, a BBQ grill, a candy thermometer, and an ORF sideplate.
Started out just like the walkthroughs said, I ground off the copper cladding on four pennies, and went to dissolve them in a quart of Prep&Etch. Man, I thought they would dissolve in about 20 or 30 minutes, but it took several hours. At this point, I was thinking that the P&E didn't have a high enough content of phosphoric acid, so I added a couple big globs of naval jelly to the mix to try to speed things up. (Mistake). Well, that didn't really speed things up, so I started to theorize that maybe the P&E solution was becoming "saturated" with zinc. So I dump another quart of P&E into the mix.
Another hour or two goes by, and those pennies are STILL dissolving. At this point I'm scratching my head. I had assumed that they should be dissolved by now. So more P&E at this point gets added, I chop up the pennies with tin snips (to get more surface area exposed to the acid) and I light up the BBQ grill thinking that heat will speed the process. Let it cook a couple more hours, and the pennies are still not dissolved completely. In goes the last quart of prep&etch (one gallon total in there now).
I come back two hours later, and the pennies are now dissolved to my liking. I add about a gallon of water to the mix, bring it up to 190*, and toss in half a degreased biscuit of steel wool. That sucker was dissolved in about 5 minutes. (This should have been my first clue).
So out comes the test piece. A nicely sandblasted piece of square tubing. Into the bath, it it starts bubbling like CRAZY! (Again, another warning sign). After about 5 minutes of this, my curiosity gets the better of me, and I fish it out. WOW! A nicely light gray parked piece of tubing! That's awesome! Parking was a little thin, but I chalked it up to the short time in the bath before I fished it out.
"Cool!" I'm thinking, so into the bath goes the properly prepped sideplate. You talk about FIZZING! It looked like I tossed an entire bottle of alka-seltzer in there. Oh well, must be normal.
I did my best to control the boilover, and seeing as how this was the piece I wanted to come out "nice", I left it in a little longer than my test piece so that it would have a good heavy parkerized coating. Heck, the tutorials said it would stop fizzing when it was done, right? Well it fizzed right along, and after about 20 to 25 minutes, I fished out the sideplate.
Horror of horrors!
Pics WILL be coming.
So.... I just ordered a new ORF plate (backordered! Nuts!