Zinc Plate with Blackener

[carx7]

I am plating nuts bolts and mics brackets for my car. I begin with a thorough sandblasting of each part and am then using the SP degreaser at temp and the plating seems to be working well. Good job.

When I go to use the blackener, the manual I recieved with the product says 1part concentrate to 9 parts water and that it will work at room temp if I leave it for ~15-20 minutes. That process results ina a finish which has white almost chaulky looking streaks after teh part has dried. Coating with WD40 makes it look better... until the residual WD40 is wipped off after ~12 hours. Then the finish is un even and can be rubbed off by hand.

I read this morning on the web that the solution is supposed to be 1 part to 4 parts and that a small amount of acid is suposed to be used... and that it should be heated to a minimum of 90 degree and left for ~5-7minutes.

Which is the correct solution? I'm thinking 1 in 4 with acid makes more sense than 1 in 9 at room temp. Please help?

-Chris

[mcaswell]

We sell a couple of different blackeners. Just so we're clear on our response, can you tell us the name of the product from the label.

Thanks

[carx7]

Yep. It says:

Copy Cad & Sinc Blackener New Forumla 1 liter

-Chris

[mcaswell]

It should be 1:4.

Sorry if we sent the wrong instructions.

[carx7]

THat's OK, thanks. Should I use the battery acid in it as well? Or just 1 in 4?

FWIW, it's the directions on the bottle of concentrate that say 1 in 9... might want to look into that and make a change if necessary.

I'll try the higher concentration.

-Chris

[mcaswell]

Yes, the instructions on the web are accurate.

[carx7]

DO NOT add the acid. I tried this with detrimental results. My parts were ruined and I am re-sandblasting, cleaning, plating etc. I spoke with someone on the phone today at Caswell who said that the acid was very wrong to add.

He didn't belive the 1:9 said 1:4 sounded better and then was shocked when I mentioned the acid. I'm not sure that you have a correct set of directions anywhere for this stuff.

Mike on the phone seemed very willing to help correct the situation, but know that adding acid is not the right thing to do.

-Chris