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Parkerizing (manganese phosphate) different types of metal

(-----) 2006

I'm parkerizing an ornamental piece of cast iron and hot rolled steel.

The formula I'm using (phosphoric acid, manganese, water) works great on the cast iron. I get a very durable finish.

On the hot rolled steel however the finish is much less durable. I can't rub it off with a finger, but an aggressive stroke with a wire brush leaves bare metal scratches.

I've tried increasing the temperature, using more acid, using more manganese, cleaning the steel better-- nothing seems to help. Is it simply that different metals "take" the parkerizing better?

Thanks alot

Sam Hardy
artist - Phoenix, Arizona
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---

2006

Phosphated surfaces must be oil,wax or lacquer finished.Instead your solution you can use 20 gm tannic acid/15 ml phosphoric acid/0,8 lit water solution/ 0,2 lit pure alcohol(simple and cheap do it yourself rust converter). Hope it helps and good luck!

Goran Budija
- Zagreb, Croatia
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---

2006

Thank you Goran

I've appreciated your responses on other threads too!

Sam Hardy
- Phoenix, Arizona
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