What kind of black plating on Gpz fastners?

Does any body know what kind of plating it is on the fasters on a Gpz?
I guess its black zink, cos its not black oxide or black chrome.


// Anders

Not sure about all the types but I've seen zinc with black or green chromate. I've got a Caswell's Plating zinc kit and have some black chromate. It works well but the finish is dull, not shinny like the OEM parts. Better than nothing though.

Pretty expansive these kits, for some pretty basic chemicals, but you are happy with how they performe Ed?
If the zink is dull it could be Black nickel, but then again not as a nickle plating should be thicker an sturdier.
I really would like to pep up my bolts and nuts.

/A

Don’t know but I don’t think it’s black oxide. I did learn a trick to use gun blue after stripping them. Turns out great
Barney

It’s not Black oxide as that doesn’t give any protection against corrosion and basically rust faster than an Alfa Romeo.
/A

That is a zinc chromate finish and it is a sacrificial coating just like cadmium or regular zinc. Zinc chromate is a finish used in the aircraft industry as a corrosion inhibitor. I use almost all of the original hardware on the bikes I restore and I have used the Caswell kit for over 4 years and the results are equal to the plating places you send your stuff to for zinc plating. The level of shine on the particular fastener is determined by the finish it has prior to plating. I chemically strip all of my hardware so the edges aren't softened, then give a quick buff with 0000 steel wool and plate. The brightener that comes with the kit will give a shine almost like chrome if you want. To reproduce the finish on the dark green Kawasaki hardware I strip and plate like normal and then use the black chromate. The shade of green is determined by the length of time you leave the piece submerged in the chromate bath. If you leave it in for a minute or more it will be black but if you take it out after about 30 seconds it will be dark green. A poster above said he didn't get good results but that can be from a lot of different factors. I have a lot of experience with my plating kit so I get very good results.

Tks guys. Will give it a try to source the cemicals localy the + 300 USD for the kit sound a little steep for the cemicals.

/A

Just to be clear, hardware plated with the Caswell's kit will come out bright and shiny if you get everything just right: proper amount of brightener added, proper current for the number of parts in the batch, and the electrolyte balance is just right. Main problem is the last part and I can't explain why but sometimes the parts come out amazing and other times they are dull, and the reason is the electrolyte sauce. Even if the plating turns out dull it's easy to bright it up with a soft stainless steel wheel on the part so no crisis though.

There are various type of chromate dips: yellow, black, green, and blue. Blue is for bright plating and in effect, is clear. The chromate increases the corrosion resistance of the zinc, even the blue that you don't really see the color. A bright and shinny part dipped in the black will come out dull. There is no way I've found to make a shinny black part with the Caswell's kit.

I've got photos of my zinc setup in my rebuild tutorial (linked in my signature) if anyone want to take a peak. Top of page 2.

Nessism wrote: Just to be clear, hardware plated with the Caswell's kit will come out bright and shiny if you get everything just right: proper amount of brightener added, proper current for the number of parts in the batch, and the electrolyte balance is just right. Main problem is the last part and I can't explain why but sometimes the parts come out amazing and other times they are dull, and the reason is the electrolyte sauce. Even if the plating turns out dull it's easy to bright it up with a soft stainless steel wheel on the part so no crisis though.

There are various type of chromate dips: yellow, black, green, and blue. Blue is for bright plating and in effect, is clear. The chromate increases the corrosion resistance of the zinc, even the blue that you don't really see the color. A bright and shinny part dipped in the black will come out dull. There is no way I've found to make a shinny black part with the Caswell's kit.

I've got photos of my zinc setup in my rebuild tutorial (linked in my signature) if anyone want to take a peak. Top of page 2.

Of course it will come out shiny if you do it correctly, if you read my post above I use this kit every week and my results are excellent. If the part you zinc plated was prepared correctly(most people are to lazy to do all the proper prep and then say the kit sucks)and it has the shine you want, it will have the same shine after you put it in the chromate. The main problem with most home setups if the way the voltage is supplied. You work in milliamps per square inch. I use a variac to adjust my voltage and it works great I am not trying to act like a dick, it's just that I restore motorcycles for a living and I have to have my plating correct so through many rounds of trial and error over the last 4 years I have finally figured it out. I've had my parts come out all different ways that weren't right so I had to figure out why and correct it. Not to long ago I had a problem with my parts coming out dull and fuzzy no matter how long I left them in or how much voltage I put to the anodes. I thought I knew everything about this stuff and thought surely I was doing every thing right and there was nothing I could be missing yet the finish just plain sucked. I finally noticed that for a particular setting(you vary the voltage depending on the surface area of the part)my meter showed slightly lower than usual. I stripped back some of the insulation on the negative lead that attaches to the anode and found verdigris inside going down into the sheath about 2 inches. It was not the connection I needed because of this so I cut the greenish part off and re-attached my clip and it worked great again. My point is the kit needs to have everything right to work right and you need to keep ahead of the glitches.

Please post up some photos of a black chromate part that's shiny. I'd love to see some. Regardless of how bright and shiny the zinc goes on when I dunk it in the black it goes dull. I'm okay with that mind you but since you seem to get bright black parts you got me curious.

Regarding prepping the parts, I've done them a few different ways. Stripping in acid is one option but I typically leave any zinc that's already on the part and bead blast and then wire wheel to bring out the sheen. Mind you I've done loads of parts using different methods and during that time I've gravitated towards using the simpler method because I was happy with the results and it was faster.

Regarding dull and fuzzy parts, I've experienced this phenomenon and noticed a relationship between that and electrolyte balance. I've talked to professional platers and they have protocols where they test their electrolytes often and add ingredients to restore balance as needed. Something we can't do with Caswell's electrolyte. My first batch of electrolyte chemicals lasted through two different bike restores plus lots of other parts but at some point there was nothing I could do to get bright plating again. I got some new electrolyte chemicals from Caswell's and the first run was right back to beautiful.

Lastly, my power supply is variable current but not variable voltage. I adjust the current based on a formula of amps/surface area. If the current is right a light effervescent fizz comes off the parts. I've read about power supplies that provide 3V and would like to try one to see if it makes a difference so please share specifics about your particular power supply.

These are the nuts that hold the meters in the housing on a 1975 Kawasaki S1A 250. I use a 6 volt charger hooked to this variac and it works great. I also bead blast my anodes after each use. I strip my hardware with acid and if need be buff with 0000 steel wool before plating. I keep my solution temp. between 100 and 110 degrees. I start the pieces out with very low voltage for a few minutes and then turn it up to where it should be. There is no reason to not get great results with the Caswell kit.

Tks guys for all your insights.
I will definitely give it a go.
There is a kit in the UK that has a more reasonable pricing that I will give a try
www.gaterosplating.co.uk/zinc-plating-kit

Most likely Ed will be right again and I will be the fool, but it worth a try.
/Anders