Pre dip black parkerizing post dip black dye parkerizing.

[bigduke6]

Topfmine,

I don't use any pre dip, but the item will need to be cleaned to a high standard and after this I bead/sand blast it, for the dark Manganese finish I use fine wire wool as BR mentions, don't waste your money on solutions etc, two main ingredients can be bought on ebay, as for water I now collect the water from the drain on my condensing boiler.

The link below is when I first started to experiment, there is a formula near the end which I now use but still add the wire wool.

I did a few bits for a forum member some time back and one part I couldn't get a nice finish on, could not work out what was wrong until I was finishing another part, it turned out the part was resting on the bottom of the tank so was taking more heat than normal.... lots of head scratching but eventually got to the bottom of it.

Home DIY phosphate/ parkerizing process

[browningautorifle]

was resting on the bottom of the tank

All covered in the crap...so no clean finish.

[bigduke6]

All covered in the crap...so no clean finish.

Kind of Jim, it was a bayonet and the edge was touching the bottom, the rest looked ok but the blade ..... it turned out the owner didn't want the blade doing anyway and happy with just the sand blasted finish on the blade.....

[browningautorifle]

Kind of came out covered in scale?

[Trap4570]

I have seen stove black used to darken the finish. It's a brush on affair and a hair dryer helps it to take a set.

[Topfmine]

Many thanks vincent for the info, I have tried to contact ILVE but have not heard back yet. I did read on other forums that those who pickled the part with hydrochloric /acid mutric acid the finish turned dark using zinc phosphate, in one case a 1911 turned black. Usually when using zinc phosphate the colour is even but using manganese the phosphate picks out the temper of the steel. This 1911 was an even black all over. I have notice this darker zinc finish when picking with hydrochloric acid especially If the finish has not been bead blasted, I sometimes pickling to get rid of pitting that cannot be removed by blasting. To get a black I wonder what the other chemical would be.

[Vincent]

You should be able to get jet black using manganese without much trouble.

Over time the free acid goes up and the result is a lighter coating. If nothing is done, the free acid will eventually increase to the point where it consumes the coating and nothing is deposited on the surface. The surface will look gray, but it’s just acid etched.

To get it to work again you need to bring the free acid level down. Adding steel wool or scrap steel will use up the acid. The problem with doing that is you end up with a lot of iron and it ends up in the phosphate coating. It looks black as well digger’s a___ , but it is going to rust. And when you think about it you have been putting parts in the tank….. adding iron. So there should be plenty of iron.

You can test a small amount of your solution by putting it in a glass and heating it in the microwave. Then add a little disodium phosphate to bring the acid level down. Dip a test part in it. Add a little more disodium phosphate if needed. It shouldn’t take much in a glass. If you get a good black result, add disodium phosphate to your tank. If you don’t get an improvement, try adding acid. It’s unusual for the acid to be too low but it can happen.

[Vincent]

The pre dip MSDS shows <1% Hydrochloric Acid, <1% Phosphoric Acid, 10-30% Sulfuric Acid by weight. pH: < 2.5

So remove 250 ml from a liter of deionized water. Add 230 ml Sulfuric acid, 10 ml Hydrochloric acid and 10 ml Phosphoric acid to the remaining 750 ml. Remember, always add acid to water, NOT the other way around. Adjust from there.

I am going to test it tomorrow. Will let you know how it turns out.

[Vincent]

I should add that most types of stainless steel are attacked by sulfuric acid when it’s in intermediate concentrations. So you should NOT use a stainless steel container for this.

I am surprised acids, Parkerizing solutions, etc, are available in the UK. With all the legal restrictions there I thought they would be verboten.

[bigduke6]

I am surprised acids, Parkerizing solutions, etc, are available in the UK

Acids are available but never seen any parkerizing solutions here. Be interesting to see the pre dip results any chance you can do an item with and one without?