I need some advice on hot bluing

[freddygotarf]

This was my first attempt at bluing. Decided to do it as a challenge as I wanted to do
all the work myself on this gun.When pulling pieces out of dip tank they had a greenish tint to them.
After hot water rinse they where rust brown.oiled and cleaned up and this is what it looked like.

they have a antique brownish look to them. What I think happened here was that my tank got contaminated with zinc. I had a couple of pipes that was galvanized that I was hanging pieces off. Some caustic spilled
on them and dripped into tank.
Decide to try again.No pipes to hang off this time. I was very careful this time and watched temp closely.
Got a new batch going today and test piece was a floor plate.Came out nice and blue.
Then put action in and trigger guard.They turned out nice also.Put in some small pieces with another trigger guard and a action. Now the trigger guard and action started to get the greenish color and when dipped it boiling water after got rust brown. I have to go and take some pictures of it and post them.
Anyone have any idea what could be going wrong here?
Recipe I used was 5lbs of lye and 2.5lbs of nitrate to US gallon water.I used distilled water.

 

[freddygotarf]

Here is a couple of pictures of pieces that turned out great.

these are the pieces that did'nt work out.

 

[SkytopBrewster]

That's the same solution I use and never had any issues like that. What temp?, I run mine 270-280f. It almost looks like there was oil or polishing compound on the parts?

 

[freddygotarf]

I wiped them down with aceton before a degreaser dip then boiling water.temp was between 270-290F.

 

[SkytopBrewster]

So are those the same parts redone in fresh solution? I know Aluminum will ruin a bath not sure about zinc. I just use wooden dowels or sticks to suspend the parts across the tank, hanging the parts with mechanics wire. Also are you using pure nitrates or fertilizer or something, I use pure kmno3 and lye. Bath looks like this.


Video clip

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[freddygotarf]

yes I cleaned them and started fresh with new solution. I have same solution as you.
Went out on Sunday after watching some youtube videos and tried again. I think I got it figured out.
What I think happened was that to much water boiled off and after refilling it worked good.
I didn't know that it boiled off that quick. Rest off my parts look good. Thanks for your input.