Black Phosphate/Grey Phosphate question

[Greg L.]

Is black and grey phosphate the same proceedure with the black phosphated parts being exposed to the solution for a longer time?

If this is the case, can "black" appear to be grey in some cases? The reason I ask is because the TIM&JG states that the rear seat anchor plates of my 69 should be black phosphate when in fact they are grey, the same as my hood latches and under body heat shields.

[Fred Oliva]

Re: Black Phosphate/Grey Phosphate question

Black phosphate, in most cases appears to be really gray. There are different phosphate chemistries that supposedly make the color darker or lighter. My experience has been that the actual color is more dependant on the steel rather than the chemistry.

Sometimes I'll phosphate a bunch of stuff in the same tank & some will come out light, some really dark.

Hope this helps.

[Fred Oliva]

Re: Black Phosphate/Grey Phosphate question

Black phosphate, in most cases appears to be really gray. There are different phosphate chemistries that supposedly make the color darker or lighter. My experience has been that the actual color is more dependant on the steel rather than the chemistry.

Sometimes I'll phosphate a bunch of stuff in the same tank & some will come out light, some really dark.

Hope this helps.

[Robert C.]

Re: Black Phosphate/Grey Phosphate question

In this instance, black is grey and grey is black. Doesent matter. Just make sure the finished plating has the little "diamond dust sparkle" when viewed in the sunlight

[Robert C.]

Re: Black Phosphate/Grey Phosphate question

In this instance, black is grey and grey is black. Doesent matter. Just make sure the finished plating has the little "diamond dust sparkle" when viewed in the sunlight

[Randy R.]

Re: Black Phosphate/Grey Phosphate question

Do you know if grey phosphate treatment affects the strength of cast iron or steel? I am considering treating some "not to be painted" parts such as the rear suspension strut rods with the grey phosphate solution but am concerned about adversely affecting the strength of the pieces. In my opinion, these bead blasted parts are too bright to be original.

[Randy R.]

Re: Black Phosphate/Grey Phosphate question

Do you know if grey phosphate treatment affects the strength of cast iron or steel? I am considering treating some "not to be painted" parts such as the rear suspension strut rods with the grey phosphate solution but am concerned about adversely affecting the strength of the pieces. In my opinion, these bead blasted parts are too bright to be original.

[Fred Oliva]

Re: Black Phosphate/Grey Phosphate question

Good question. The stuff I use, zinc phosphate or manganese phosphate, does not seem to affect the material strength. I've phosphated suspension parts for people with excellent results. I've also used this for grades 5 & 8 bolts.

I've heard of problems of hydrogen embrittlement when plating (zinc, cad?)
hardened steels, but not with phosphates. Maybe some of the chemical engineering guys can comment on this.

[Fred Oliva]

Re: Black Phosphate/Grey Phosphate question

Good question. The stuff I use, zinc phosphate or manganese phosphate, does not seem to affect the material strength. I've phosphated suspension parts for people with excellent results. I've also used this for grades 5 & 8 bolts.

I've heard of problems of hydrogen embrittlement when plating (zinc, cad?)
hardened steels, but not with phosphates. Maybe some of the chemical engineering guys can comment on this.