Fresh copy cad system leaving white swirls

[MrPontiac]

Plating the rear plates on my 4 bl. carb., just started my new copy cad system, parts are coming out great when wet,nice glossy shine to them, when they are drying the copy cad parts are turning white with swirl marks on them, any idea why??
Temp set at 130 degree,s plating at 1.8 volts with .9 amps. wondering could temp be to high??

[KCV6]

Are you doing a post plate 0.5% nitric acid dip post plating followed by a real good rinse in hot water? This will brighten up the zinc. I use to use 10% sulphuric as a post plate dip. Compared to Nitric 0.5% it is chaulk and cheese.

130 does sound high to me. I plate zinc at 28 deg Celcius (83f).

Cheers

Mark

[MrPontiac]

Kc Yep, im using mauratic acid dip10% with distilled water and before that im dipping my parts in accetone air drying em to clean em. Never had this problem before, confused for sure!!

[seanc]

I'm confused about your procedures. Do I have this right?

You are:

1. plating
2. cleaning w/acetone
3. drying
4. acid bright dip
5. drying

Why the acetone/dry step? I don't know what affect it might have, but there's no need for it.

Are you using brightened electrolyte? Are you chromating? Unprotected zinc will oxidize (white rust), and the excess temperature (130º is too high) will accelerate that.

Sean

[MrPontiac]

Nope!!
1st glassbead parts
2nd cleaned with acetone or simple green
3rd polish part to a luster
4th clean again
5th etch in mauratic acid bath
6th plate the part for 20 min.
7th take out part rinse with distilled water
just starting to after parts are plated re acid dip for about 8 to 10 sec. and rinse with distilled water
No Improvemants so far!!

[MrPontiac]

I can only go on what im told, ok, Jason, at caswell tells me temp. that high is ok??Just trying to figure it out?? I am willing to try almost anything right now.

[seanc]

Odd. I've been told the range is 90-120º, w/100-110º optimum.

Sounds like after step 7, it's just raw zinc? No chromating?

How are they being dried? Drip-dry, warm air, hot air, oven?

Again, sounds to me like accelerated oxidation.

If the parts are NOT chromated, you might try spraying w/WD-40 after final rinse, then let that drip-dry for a day.

Sean

[MrPontiac]

Funny you ask, ive never read anywhere to where it says dry with hot air, another hidden cost i asume. i was letting them air dry overnite hanging from the wires i dipped parts with,within 5 min. of out in open drying it starts to turn white, Ijust tryed last nite more parts,instead of 20 min. soaking upping it to 40 min. and it seems to help alot, 50% is gone. Drying with hair dryer did not help at all.Oh, yes with the 40 min plating time im loosing all gloss on parts

[seanc]

Originally Posted by MrPontiac

.. ive never read anywhere to where it says dry with hot air

Well, it doesn't say that anywhere for the electrolyte, but can be helpful. It DOES say "best hot air dryed @ 150º" for the chromates, and it's useful to prevent water stains. You can't get it TOO hot though.

So again, are you chromating?

Oh, yes with the 40 min plating time im loosing all gloss on parts

Time should not be an issue. Are you using the "brightener"? Perhaps that's been depleted.

How big are these "rear plates"?

Sean

[MrPontiac]

Sean, all im doing is copy cading parts. Then using yellow cad system, works super on the yellow, no problems at all, Still cannot figure white streaks out??
Totally a lose on the green drab though, nothing at all is happening with that system.