Zinc phosphate plating/coating

[Jack J.]

Just wondering if anyone has ever considered or performed home zinc phosphate plating of glass beaded parts such as front springs, half-shafts, and flanges replicating a more restored look verses an oiled or painted appearance? Thank you, in advance, Jack J.

[Alan S.]

Re: Zinc phosphate plating/coating

Hi Jack,
I have been doing manganese phosphating using the supplies from Palmetto Industries and have the zinc phosphate too.The manganese does a terrific job on parts that had the dark gray phosphate coating originally like the hood latches, seat track bases, and various bolts.
The phosphating process is fairly straight forward to do at home and less involved than doing zinc and copy/cad plating at home.
While doing the zinc phosphate, which as you know is the lighter gray, on the parts you mention would certainly be possible, it would give those parts a very different appearance than would be typical of what they looked like originally.
Would you be o.k. with that appearance?
Also, many people have found that the phosphated parts need an immediate sealer applied to them, and then also a touch-up with sealer as time goes by. The frequency of the touch-up depends on how the car is used and stored.
Here's the set up for phoshating… a heat source (solution needs to be 200 degrees), a stainless steel or glass container, a thermometer, tongs, and rubber gloves. I'm doing the a-arm and shock absorber washers in the pictures.
Regards,
Alan
DSC_0717.jpgDSC_0721.jpg

[Tom R.]

Re: Zinc phosphate plating/coating

Here's the set up for phoshating… a heat source (solution needs to be 200 degrees), a stainless steel or glass container, a thermometer, tongs, and rubber gloves. I'm doing the a-arm and shock absorber washers in the pictures.

Alan

Tell me about that burner. Is it a typical burner from wal-mart or is it a heavy-duty of some sort. I have found the greatest challenge with home plating is heat source and keeping it constant. Nice bucket as well

[Patrick H.]

Re: Zinc phosphate plating/coating

Alan

Tell me about that burner. Is it a typical burner from wal-mart or is it a heavy-duty of some sort. I have found the greatest challenge with home plating is heat source and keeping it constant. Nice bucket as well

I use an old Coleman stove, and my IR gun to check the temperature of the solution. Once I can get it to a steady temp, the stove does a good job.

[Alan S.]

Re: Zinc phosphate plating/coating

Hi Tom,
It's just an ordinary 'hot plate'. It does have a temperature control, but for that size container, (about 1 1/2 quarts), I set it just below it's hottest setting.
The container is a ss kitchen canister from I believe Walmart. It has a tight fitting lid so I've found I can save the solution and use it again with-in a couple of weeks of mixing it.
I also have 2 'spackle' tubs (rectangular in shape like a loaf pan) also made from ss. I've used these for phosphating the bases on seat tracks. I use 2 hot plates for that process. The 2 plates support the shape of the container more securely and also heat the solution more evenly.
I'm pretty sure it's less expensive to send the parts out but it's been fun learning how to do these things at home. I also like to be able to control the finish.
I'm also having big fun with zinc plating and copy/cad. A much more costly system to set up but quite gratifying to do. I've been doing the dichromate wash on the few parts that have that finish. I believe there's quite a bit of zinc plating info in the Restorer written by Jerry F. I think.
I do black oxide too which is really quite easy since there's now a 'cold' system that gives good results.
If you have any questions please ask and I try to answer them.
Regards,
Alan

[Gene M.]

Re: Zinc phosphate plating/coating

These do it one's self home plating kits give pretty looking parts but the durability is less than what I want. Phosphate finish is not resistant to much if you plan on driving the car. Moisture causes it to rust. Black oxide is much the same. A better solution is commercial platers using black zinc chromate. This will give you a more durable black finish that is a chromate over a zinc electro plating. It is a bit brighter than phosphate and is smooth where as phosphate is rough and very flat. Commercial platers are expensive and require minimum batch but you get what you pay for. In our chapter we gather everybody's parts to be plated one finish bead blast them spray oil to prevent rust and take them to the plater. Parts done years ago still look good on my "driver". Most platers knowing these parts are for "Corvettes" are special handled and get the best treatment and finish.

[Jeffrey S.]

Re: Zinc phosphate plating/coating

Alan

Tell me about that burner. Is it a typical burner from wal-mart or is it a heavy-duty of some sort. I have found the greatest challenge with home plating is heat source and keeping it constant. Nice bucket as well

Tom,
I use the dark phosphate from ShootersSolution which works very well. I heat the solution with a heating element from an electric hot water heater. They come in various length to fit different depth containers. I simply attach lamp cord to the 2 screws and plug it in. I fabricate a crude holder from sheet metal that hooks over the edge of a plastic pail. They also sell a thermostat for electric hot water heaters that simply presses against the outside of the pail, held there by a bungee cord. Once wired in, It is temperature controlable and can be adjusted to different temps. A heating element like this can bring a gallon to a boil in a few minutes but most of the plating I do is at about 110*. The phosphate is just below boiling so I don't use the thermostat and watch the temp with the IR gun.
Jeff

[Michael G.]

Re: Zinc phosphate plating/coating

Phosphate was added to parts not because of its corrosion protection, but because of its ability to absorb substances that lend corrosion protection. GM added various oils and/or paints to phosphated parts to accomplish this. Most production phosphated Corvette parts had been dipped in oil by the plater to add this performance enhancement. Later, GM used parts that were dipped in paint after phosphating in order to further increase performance.

SO, you can get MUCH better corrosion resistance for your metal part if you phosphate it, then paint it. You can maintain the phosphate appearance by using a MAT clear paint and put several coats on the head.

[Jack J.]

Re: Zinc phosphate plating/coating

Thanks to all that replied. Lastly, what Mike said, affirmed what I thought about enhancing rust/corrosion resistance after glass beading. Jack J.

[Tom R.]

Re: Zinc phosphate plating/coating

I use an old Coleman stove, and my IR gun to check the temperature of the solution. Once I can get it to a steady temp, the stove does a good job.

Patrick

You using butane or electricity to create heat?

[Patrick H.]

Re: Zinc phosphate plating/coating

Coleman fuel, aka white gas.

[Mike E.]

Re: Zinc phosphate plating/coating

I got the temperature of 3 gallons of liquid up to 180 degrees with one of these bucket heaters from Amazon for about $40. It did take almost an hour to reach that temperature.

You should use an agitation pump running to keep the liquid moving. The nice thing about it is you can use a plastic bucket.

http://www.amazon.com/Allied-Precisi...=bucket+heater



Mike

[Jeffrey S.]

Re: Zinc phosphate plating/coating

Attached are photos of the set I use for all my plating. The first picture shows the heating element with bracket hanging in the plastic bucket. Photo #2 shows the thermostat held to the side of the bucket with the bungee cord. Photo #3 shows the heating element as purchased from the plumbing supplier near my shop. The element costs around $8 and the thermostat is around $10. and run on 110 volts. I remove the chrome plating from the element before I use it in the acid copper bath because the acid and the heat will remove it and contaminate the bath. This heating element will bring the bath up to temperature within 2 or 3 minutes. It will bring the phosphate to 200* in about 5 minutes.
Jeff

[Phil D.]

Re: Zinc phosphate plating/coating

My brother and I are restoring a 72 now with quite a lot of attention to original finishes. I've been doing all the nuts and bolts and small items at home with Caswell products mainly because we were very careful to tag and bag everything as it came off. Commercial platers do things in batches and every little ziplock bag is considered a batch. If we thought we could sort it all back out then we'd have put them all in a 5 gallon bucket and had it done for a fraction of the cost of the Caswell kits. It definitely won't be the last car I restore to this level so the investment will work itself out over time anyway.

For larger parts that had no original paint or plating whatsoever, we've researched and used a couple of different processes depending on the part and original finish. We'd read a bunch of testimonials about Gibbs penetrating oil for rust protection and so most of our bare metal has been protected with that. I can't vouch for longevity just because the chassis and body are still not even married yet, but some parts have been sitting in the garage for a year without any rust as of yet. Of course a freshly bead blasted appearance isn't correct either for most parts.

For many cast parts, we obtained a blue-gray color with the use of acids (gasp!). Muriatic acid quickly washed off and dried actually causes a very quick and thin flash rust. The part comes out still kind of bright, but with a slight orange tint. The flash rust was very quickly arrested with Ospho, brushed on and wiped off immediately (any droplets left will dry white and hard to remove). I should do a video of it because its amazing to watch it turn blue-gray instantly. Ospho leaves the surface covered in iron phosphate along with some other proprietary chemicals and theoretically acts as a primer. I suppose there is some protection at this point, but we further treated parts with Gibbs penetrating oil. For the exhaust manifolds, we simply bead blasted, then sprayed with a graphite lube as documented elsewhere on this forum.

We learned that some of the chemical rust-removal products also leave a dark gray surface. Since we'd read a bunch of people advising against blasting springs, the front springs and sway bar we just soaked for weeks in Evapo-Rust, cleaned with scotch pads and treated with Gibbs. Most of the brackets we de-rusted using electrolysis which also comes out very dark but I wasn't sure if it was a safe process for springs.

Drive shafts were "tumbled" at a drive shaft shop. I can't tell any specifics of that process, but they came out a nice natural metal finish tho brighter than any of the other methods as the surface gets beat quite smooth. Again treated with Gibbs.

[Michael F.]

Re: Zinc phosphate plating/coating

Phil, next time I have some extra time when I am in Dallas I will have to give you a call and swing by and check out your project.
Mike in Abilene