[63gpman]

some good stuff on the caswell forums
http://forum.caswellplating.com/elec...ing-questions/

[dataway]

Originally Posted by 63gpman

this looks like a nice power supply. My hopes would be that i can do some larger parts also like brake brackets and such. Any thoughts on this one?
http://cgi.ebay.com/ws/eBayISAPI.dll...ht_3541wt_1362

That power supply looks like it was probably made by the same company as mine. I assume there are only a couple of suppliers of these (Chinese made I think) power supplies and many companies that rebrand them to their name.

If I had it to do over again I would go with at least a 5A like the one you found. To give you an approximate idea of what you can do ... when I was plating a 68 transmission cross member bracket (the one that holds the rubber insulator) my supply was drawing about 1.6 amps most of the time ...and I don't think I'd want to run the supply at it's max 3A all the time. So yes I'm limited in the square inches I can do at one time.

Yeah I've got to through the Caswell forums ...I'm assuming someone has asked just about every question I would think to ask.

Dave, I ran across that website in my research a while back and was baffled by it ...now however I must revisit it as I have a better understanding of the process. Obviously barrel plating would be vastly superior if you have a whole lot of parts to do.


JohnnyB

[dataway]

A couple of of before and after pics of a bolt, and an OEM original shim. Hard, if not impossible to get these shims exactly the same as originals despite what many vendor say, so it's nice to be able to bring them back to original condition.

Both these pieces (the shim is not the same shim, just from the same pile of identically rusted shims), were not sand blasted or cleaned. Just soaked a while in Muriatic acid, rinsed in alcohol, and re-plated in zinc.
JohnnyB

[gtoric]

Where do you get, or what is the formula for the solution used in yellow chromating?

[dataway]

This wikipedia article gives the details of the Cronak method using sodium dichromate. It's basically what I am using, but you'll need to reduce the strength of the "recipe" about 50% ..it's just too strong in the concentration given in the article.

http://en.wikipedia.org/wiki/Chromat...ersion_coating

You'll see the formula in the "composition" section.

You can also find various yellow chromating formulas in this patent description.

http://www.google.com/patents/US3457124

You can also get an idea of ingrediants and approximate ratios by looking at the MSDS info for Caswell products.
Or ....you can just buy the yellow chromate concentrate from Caswell.

Sodium Dichromate can be found on ebay.

After playing around with this stuff a lot I would recommend the Caswell concentrate for yellow and clear/blue chromate ....it works well enough, and you can just use it without all the fiddiling around and chasing down ingrediants.

Results various tremendously depending on how you are doing it.

See attached pic.
Lug nuts from left to right: Polished zinc plate, polished zinc plate with Caswell clear/blue chromate, polished zinc plate with weakened Cronak fomula yellow chromate.

The two front control arm shaft washers ...zinc plated, one polished, one not, dipped in Cronak formula.

Results with the Cronak formula can be all over the place. Try the Caswell formula, it has all the extra stuff in it like nitric acid and such. A LOT is going to depend on what you are trying to coat.
JohnnyB

[dataway]

Did a batch of original alignment shims tonight.

These were rusty pieces of crap when I started.

Soaked in pure Muriatic acid for 15 minutes removed every trace of rust. Rinsed, power brushed off any random paint that was still on them.

Zinc plated, then dipped in Caswell's "clear chromate" solution.

Have about a dozen done ... will probably have to find about a half dozen more to actually get the car aligned someday.
JohnnyB

[Engine-Ear]

Thanks for bringing this back up, dataway!!

Does / how well does the muriatic acid attack engine grease on hardware bits?

[Super Duty D]

Engine-Ear,
Any grease or oil will act like a 'mask' for the acid and will not clean/prep there properly.
Clean and dry first. Soak your parts in Mineral Spirits for a few days, mix them a few times and repeat as necessary, may need to brush some stuff too.

SDD

[dataway]

Like he said, grease, paint etc. will block the acid for the most part. But 15 minutes in Muriatic acid will get rid of every trace of rust. I guess that's why they acid dip bodies. The fumes can be a bit harsh, and you don't want to leave a container of Muriatic acid open in your shop or everything ferrous will rust. But it's a tremendous rust remover ... I mean complete, aggressive, fast.

Still trying to find a "perfect" zinc plating solution. I've found the Caswell clear chromate dip to be excellent for brightening the zinc plating and leaving that iridescent coating.

If you make small batches it really comes in handy for restoring the odd bit of hardware. I had a small basket of parts I was playing with about 8 months ago ... the pieces I acid dipped without plating are all very rusty again ... the plated pieces look like the day I plated them.

It can be hit and miss ....but, about 15 seconds in Muriatic acid removes every trace of zinc (careful of the fumes) and they can be plated again.

For grease ... you can try a caustic solution like lye ... which breaks down any organic material .... but again Lye can be very corrosive, not something you want to let sit around in an open container.

I'll be doing a few other parts in the next week or so. I'll post some better before/after pics.
JohnnyB

[vidguy]

Any of you guys that do this plate for others for $$? I have some small parts.

[Cardo]

Subscribing.... wanting to start doing some of this for myself shortly.

[unruhjonny]

does anyone use any of this to recolour carburetor bodies?

I see alot of over-restored Quadrajets, and components, but not too many people doing it right - hence my hesitation to outsource...

[dataway]

I have some zinc chromate I use to color some parts ... comes out a bit different every time, but does give the zinc plated parts that old school sorta brass/rainbow look. I'm sure not as durable as the factory stuff.

Problem is, it's the Hexachromate stuff ... dangerous. Banned in the US for treating parts these days, still legal in Europe I think. It's a treatment that is done over the zinc to stabilize the surface to resist corrosion better. All you do is dip the freshly zinc'ed part in ..but the key seems to be temp, time and mixture .... only takes like 30 seconds .... sometimes it works, sometimes it doesn't. Haven't figured it out, and it's likely I never will.

[PurelyGTO68]

Originally Posted by dataway

I have some zinc chromate I use to color some parts ... comes out a bit different every time, but does give the zinc plated parts that old school sorta brass/rainbow look. I'm sure not as durable as the factory stuff.

Problem is, it's the Hexachromate stuff ... dangerous. Banned in the US for treating parts these days, still legal in Europe I think. It's a treatment that is done over the zinc to stabilize the surface to resist corrosion better. All you do is dip the freshly zinc'ed part in ..but the key seems to be temp, time and mixture .... only takes like 30 seconds .... sometimes it works, sometimes it doesn't. Haven't figured it out, and it's likely I never will.

Agree....it's hard to get consistent results with the dichromate conversion, but I wonder if that has always been the case because I've seen several different 'levels' of the golden chromate finish on new and NOS parts.

The Zinc plate process I use is 4.5 liters of water, 300 grams of Epsom Salts, 100 grams of Zinc Sulfate, 200 ml of white vinegar and about 8 oz of Karo brand corn syrup (zero fructose). I order the Zinc Sulfate from ebay....everything else is available locally. I doubled the mixture and work with a 5 gallon bucket. I order pure zinc anodes from eBay but you can also get them from Home Depot. (evaporative cooler zinc anodes). The Home Depot anodes are convenient since they have a wire on them already but I like to use the pure zinc anodes since it gives a better quality plating in my opinion.

I usually plate and brush the part 2 or 3 times to get the results I want. The parts come out with a dull blue/grey finish at first so I then have to brush them lightly with a brass brush and some water. The surface coating comes off quite easily to reveal a nice shiny zinc coating underneath. (The Karo Brand corn syrup is the brightener...). I then toss the parts in my vibrating tumbler with polishing media to shine them up some more. Doesn't take long....the zinc polishes up fairly quickly. I then dip in the sodium chromate conversion if I want that golden iridescent look. For me, two quick dips of 3 seconds each does the trick....I probably have too much sulfuric acid in my solution because the sodium dichromate bites quickly. It does seem like every part you convert takes a little bit of bite out of the solution so the next item requires a little more time in the dip to get the same results. Large pieces seem to make the biggest difference. When your solution is weak, just add about 1/2 oz of sulfuric acid to the solution and see if that rejuvenates the process. The golden dichromate solution that I use is 10oz of Sodium Dichromate and 1/2 oz of sulfuric acid per gallon. Sodium Dichromate is available on ebay....the sulfuric acid is battery acid available at NAPA or other auto parts stores.

Some zinc plating things that I made note of.......

1. a variable electrical supply is ideal. Adjust the voltage (and subsequent amp draw) to a level where you barely see any bubbling action. Too much bubbles plates the part too fast and your anodes plate out quicker.
2. Don't use stainless steel wire to hang your parts unless you need to boost the electrical field.
3. Make large loops with your hanging wire to avoid shadows
4. rotate your part often to avoid shadows.
5. Make sure the part is clean before you start. A muratic acid dip followed by a rinse and then cleaning with denatured alcohol works great.
6. Practice on small parts first until you get the feel for it. The learning curve is quick so it doesn't take much time to figure out what works best for you.

I recently applied the gold conversion to some larger parts and that was a bit tricky. I wasn't able to polish the zinc in my tumbler so I just hit them with a brash brush, dried and straight into the sodium dichromate solution. The first time I dipped the part for about 10 seconds and that was way too long. When it dried, it was too dark and didn't look correct. I stripped off the coating, cleaned the part and tried again with a shorter dunk time and it worked much better. After the dip....rinse the part in a water bucket and then let hang to dry over night. The finish is delicate until it dries and gets hard. Once dry, then you can handle it. The golden dichromate finish takes some trial and error but it actually is quite easy....just takes some practice.

[dataway]

Freakin excellent results in my opinion. I will have to try your dichromate formula ... I'll have to check and see if what I am using is the same as what you are. The dichromate I am using is the bright orange powdered stuff.

Do you have anything you are using for clear chromate dip? The stuff that leaves a slightly iridescent clear finish?

[PurelyGTO68]

Originally Posted by dataway

Freakin excellent results in my opinion. I will have to try your dichromate formula ... I'll have to check and see if what I am using is the same as what you are. The dichromate I am using is the bright orange powdered stuff.

Do you have anything you are using for clear chromate dip? The stuff that leaves a slightly iridescent clear finish?

Yes, the sodium dichromate powder was neon orange....sounds like we both are using the same stuff.

Are you looking for a clear iridescent finish to apply to the zinc plating? I am not sure what to use for that application. I will check my books and see if I can find anything for that.

Sent from my XT1585 using Tapatalk

[dataway]

Previously I used one of the clear chromate solutions sold by one of the plating company .... worked ok. Obviously did something ...but not a very noticeable iridescence.

[RAJ7395]

Nice tutorial!!

How much voltage/amperage are you typically running??

I want to buy a power supply and don't know where to start.

[dataway]

I got one of the Chinese examples off ebay ... without going down to look at it I think it goes about 15v and 5-6 amps.

You can zero in on what works with your solution pretty fast .... go more by bubbles than charts Every solution seems to like a different voltage/amps. I've seen recommendations all over place. Some based on mil-amps per square inch, some of voltage.

Typically you are going to be in the area of 1.5-3v with amps varied based on the square inches being plated. The power supply I got was about $60 and would operate in either constant voltage or constant current (again if I remember correctly).

[RAJ7395]

Thank you!