Extremely coarse crystal growth on parkerized knife?

L

Leon Husock

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Jul 17, 2019
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I just tried parkerizing a knife for the first time (never parkerized anything else before either) and it turned black alright, but I got this super coarse ugly crystal growth in patches on the blade. Does anyone have any experience with this or know what could have caused it? I used a black pre-dip solution too if that makes a difference (not sure what it is, the website I bought it from didn't say, but it seems like some kind of acid).
 
What's unfortunate. The surface will have to stripped. Then done all over again and it's not easy to strip parkerizing.

Everything has to be pure and clean. If it's a solution you pour in water. The water has to be distilled. The container for the bath also has to be clean. No contamination at all.

Rubber gloves, no touching it with bare hands either.
 
Ahhh. Sounds like I might have underestimated the level of clean. I used dish soap, then a degreasing spray, then rinsed thoroughly with cold water (all while wearing gloves), then ground clean at 120 grit on the belt grinder. But I didn't use acetone, and I used a piece of mild steel tubing for a tank that I burned clean in the forge and then boiled with soapy water. Sounds like time to get a stainless tank. Can I wipe it down with acetone, or do I need to physically immerse it in acetone?
 
I used those stainless restaurant buffet pans. The only thing at the time of length I had.

Electric burner to heat the solution. Thermometer.

I was doing shotgun barrels and receivers.

One mess up, it's back to a hard square 1.
 
Grasshopperglock said:
I used those stainless restaurant buffet pans. The only thing at the time of length I had.

Electric burner to heat the solution. Thermometer.

I was doing shotgun barrels and receivers.

One mess up, it's back to a hard square 1.
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I just ordered a stainless restaurant buffet pan, 6x6x20". My plan was to buy a hot plate. Are you saying that's not a good idea, or that it'll work fine?
 
Leon Husock said:
I just ordered a stainless restaurant buffet pan, 6x6x20". My plan was to buy a hot plate. Are you saying that's not a good idea, or that it'll work fine?
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The stainless doesn't react to the solution. It doesn't change the PH of the solution.

If you pour it in a soft steel tank. Not only are you coating your knife. You're also coating the tank. I'm not sure how a mild steel container will help.

And where in the ever living hell are you gonna get a mild steel tank?

You're not unless you make it. Weld the thing up.
 
Oh, the problem knife I made the post about was done in a mild steel "tank". It was just a piece of 3" square tubing with a bottom plate welded onto it. What I'd heard was that basically the first time you use mild steel container, the solution coats the inside of the tank and that after that it stops reacting. That, or it just works fine but reduces the life of the solution. In hindsight though it does seem a bit messy at the very least; I was just impatient and had the tubing on hand whereas the stainless tank cost money and required waiting.
 
I did everything in a horizontal bath. Where the item is covered by 3-4 inches of solution along it's side.

No vertical dipping. I could see the more heavy ingredients of the solution, falling towards the bottom. Leaving other areas with a diluted solution.

You're not etching the knife or quenching it.
 
Got it. How do you keep the knife on edge? Or do you have a mesh basket in the tank or something like that?
 
Leon Husock said:
Got it. How do you keep the knife on edge? Or do you have a mesh basket in the tank or something like that?
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It's gotta be sharpened afterwards. There's a variety of ways to hold the very tip. Any blemish is removed during sharpening.

Stainless safety wire to hold both ends. Harbor freight sells a roll.
 
I advise against using the crap "Acetone for Cleaning" that is available at hardware stores. It's filthy and will leave a film. I'd use 90-100% isopropyl alcohol. Check for how much residue it leaves by putting a decent size spot on glass and letting it evaporate.
 
Grasshopperglock said:
It's gotta be sharpened afterwards. There's a variety of ways to hold the very tip. Any blemish is removed during sharpening.
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No, I mean if I lay the knife flat on the bottom of the tank it won't get exposed to the solution on the bottom side (I assume). I figured I'd need to keep it with the spine parallel to the sides of the tank, so I'd need something to hold the knife so it doesn't fall over in the tank.

fitzo said:
I advise against using the crap "Acetone for Cleaning" that is available at hardware stores. It's filthy and will leave a film. I'd use 90-100% isopropyl alcohol. Check for how much residue it leaves by putting a decent size spot on glass and letting it evaporate.
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How about the acetone McMaster-Carr sells? Any experience with that?
 
He's talking about something similar to Denatured alcohol. You can get it from the box store.

It's pure ethanol with an ingredient to make it not drinkable.

My advice, pick the can that's cheaper. Acetone or Denatured alcohol.

And if you're worried about residue. Rub some on a mirror. See if it leaves anything behind.
 
Grasshopperglock said:
.......

And if you're worried about residue. Rub some on a mirror. See if it leaves anything behind.
Click to expand...
Indeed, do that, Leon, with whatever solvent you choose. That's what I said in the first place, for those who missed it. Your best bet always is to rinse clean and hang to dry without wiping. That may be overkill for your process, but sounds like you might just want overkill until you get it down.

And, sorry, Leon, but no experience with the McM-Carr acetone. The best way to know is to see if the can says something like "acetone for cleaning" or "recovered". Crappo. When I want super-clean I get 90% isopropyl alcohol from the pharmacy, make that my very last rinse, and hang to dry. That may be overkill, but the chemist in me gacks when I see the dirty solvents on store shelves nowadays. That little bit of impurity can cause lots of issues. Good luck with your Parkerizing.
 
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