Help from home platers

[Michael L.]

Guys,

I have just started to plate my hardware for my resto and I'm not getting a great finish. I'm using the Caswell Copy Cad/Zn system with a CC rectifier and I'm getting a very grey finish, like galvanized. When I add the brightner, the finish looks light grey/white, almost like Cad. I'm starting with very bright polished pieces that have been tumbled to a nice shine. I checked and rechecked my calculations but I don't see anything that is off. Any suggestions?

ML

P.S. I know about the hydrogen stuff and I have that covered.

[William G.]

Re: Help from home platers

Michael, There are a number of variables with any plating process. I have been successful using the Caswell copycad/zinc system on my Corvette parts . I owned a small jewelry manufacturing company for 30 years so I am pretty well versed on general plating techniques. First, I hope your parts are extremely clean and that your tumbling finish did not introduce any contaminants. Caswell has a hot bath that you need to use before plating. Second, The amount of current you use per square inch of plating surface is very important. I have settled on 250 ma/ sq in or 1/4 amp per square inch of steel to be plated.You can tell if it is correct by watching for the point where the hydrogen bubbles just start to rise. Thirdly, the temperature of the bath is important. I use about 100 degrees F. Make sure that you use the enclosed pump/agitator to move around the liquid. Lastly, My surfaces always come out slightly gray and I use the very finest 0000 steel wool to clean the surface of the finished piece. That will remove the gray smudge and brighten up the piece a bit. You can always go on thrt caswell Forum for advice. Hope that helps.

[Gerard F.]

Re: Help from home platers

Guys,

I have just started to plate my hardware for my resto and I'm not getting a great finish. I'm using the Caswell Copy Cad/Zn system with a CC rectifier and I'm getting a very grey finish, like galvanized. When I add the brightner, the finish looks light grey/white, almost like Cad. I'm starting with very bright polished pieces that have been tumbled to a nice shine. I checked and rechecked my calculations but I don't see anything that is off. Any suggestions?

ML

P.S. I know about the hydrogen stuff and I have that covered.

Michael,

Here's a couple of suggestions which might help:

1. Make sure that your anode plates are very clean and shiny at the beginning of your plating session. I usually dip mine in a muriatic solution (3 to 1 cut), neutralize (baking soda solution), dry off and then wire wheel brush them.

2. Make sure your solution is clear with no suspended particles. Use the brightener each session at the recommended dose. It wears out over time.

3. After tumbling the parts, wire brush them to a shiny finish, degrease them in SP degreaser (160d to 200d, I use a crock pot), throughly flush off with distilled water (in a Windex spray bottle), and then into the plating tank.

4. In the plating tank, adjust your volts and then amps until you see a light effervescence from the part. I find that 1.0 to 1.5 volts is best, average 1.25 volts. Move the part around in the tank once in a while, change positions of it towards the anode halfway through. Each time you take the part out flush it with the distilled water spray back into the tank.
Plating tank temperature should be 110d, a little cooler is OK.

You can check your plating solution by just trying a piece of copper wire beforehand.

Here's how a bright zinc part should look coming out of the tank:



After the dichromate tank, like this:



The dichromate process is very temperature sensitive (80d) and only a dip for 20 to 30 seconds.

If you continue to get that dull gray, you can always post finish with a wire or medium-fine nylon wheel, prior to the dichromate dip, or if you want a bright zinc finish.

I'm using the older Caswell mix with pure zinc ingots as anodes, so the settings above might be a little different with your setup.

Hope this helps.

[Michael L.]

Re: Help from home platers

Thanks for the advice. I'm using a new system so the settings seem like they have changed somewhat. The Caswell manual states to have the temp at 140 and to use .14A/Sq in, so that is what I have been using. The parts are spotless when I start, with a five minute bath in the SP degreaser and rinse prior to going into the tank. These things have been shined in the tumbler so nicely that if not for immediate rusting they would look great as is. I can't adjust the voltage since the rectifier I'm using only allows either controlling the amps or the volts, but not both at the same time (CC/CV rectifier). Your parts look great! That is what the goal is and mine don't look anything like that. I'll have to check my calculations again and see if anything is off. How quickly does the brightner wear out? I used some to plate a couple of bolts and then tried to do some more about an hour later and it seemed like it had worn out already. Is this possible. Anybody out there using the newest Caswell system and have similar problems?

ML

[Gerard F.]

Re: Help from home platers

Thanks for the advice. I'm using a new system so the settings seem like they have changed somewhat. The Caswell manual states to have the temp at 140 and to use .14A/Sq in, so that is what I have been using. The parts are spotless when I start, with a five minute bath in the SP degreaser and rinse prior to going into the tank. These things have been shined in the tumbler so nicely that if not for immediate rusting they would look great as is. I can't adjust the voltage since the rectifier I'm using only allows either controlling the amps or the volts, but not both at the same time (CC/CV rectifier). Your parts look great! That is what the goal is and mine don't look anything like that. I'll have to check my calculations again and see if anything is off. How quickly does the brightner wear out? I used some to plate a couple of bolts and then tried to do some more about an hour later and it seemed like it had worn out already. Is this possible. Anybody out there using the newest Caswell system and have similar problems?

ML

Michael,

I think you are plating too hot. Although I'm using the pre 2006 Caswell mix, I have the Version 9 manual for the new formula after 6/26/2006.

It says 110d for the plating solution, same as my old manual (Version 8).

I find that the brightener usually lasts a plating session over a weekend. But if the solution cools down and sits a week, you'll have to replenish it.
I usually do a short test run on a copper wire, or scrap part, before I add the brightener to see if it is still good.

Maybe the higher temperature is the problem with the plating results and the runout of the brightener. Maybe try plating a little cooler, see if that works for you. Also try less time in the degreaser for your tumbled parts, maybe they are so clean that you don't need much degreasing. But always do the water bead test on the part prior to plating. If it doesn't bead up, maybe forget about the degreaser.

You could also try that optional fast dip in 5% muriatic in the manual.

I have found that it is all trial and error with this plating setup.

[Michael L.]

Re: Help from home platers

Jerry,

Yes, the manual indeed does say 110! I must have been thinking of the degreaser solution when I set it at 140. I'm sure that will help alot. I also realized that while I was setting this thing up, I left the anodes hanging in the solution for several days. I assumed they were clean because they were brand new, but I just checked them and they are BLACK!. I wire wheeled them down to a shiny finish and will try this with the lower temp and more brightner. I'm sure this will solve it! One other question. What do you think of dipping in a 20-25% muriatic acid for all the parts to remove old finish? It seems I remember reading somewhere you can't plate over an old finish. Do I have to remove every trace of old plate prior to plating?

Thanks,
ML

[Gerard F.]

Re: Help from home platers

Jerry,

Yes, the manual indeed does say 110! I must have been thinking of the degreaser solution when I set it at 140. I'm sure that will help alot. I also realized that while I was setting this thing up, I left the anodes hanging in the solution for several days. I assumed they were clean because they were brand new, but I just checked them and they are BLACK!. I wire wheeled them down to a shiny finish and will try this with the lower temp and more brightner. I'm sure this will solve it! One other question. What do you think of dipping in a 20-25% muriatic acid for all the parts to remove old finish? It seems I remember reading somewhere you can't plate over an old finish. Do I have to remove every trace of old plate prior to plating?

Thanks,
ML

Michael,

I use the stronger muriatic dip as the first step, sometimes on an old corroded part, and to remove the dichromate finish (The dichromate finish will be instantly gone, and the dip will eat the zinc, cadmium and even chrome with some time in the dip. You will see it bubbling off.

If the part was originally plated in cadmium, you should strip it in the dip.
However, if you think the part was originally zinc plated, it is not necessary to strip off all the zinc. Zinc will take over old zinc as long as the part is clean. Zinc over cadmium will give you some spotty results.

Don't use the stronger dip on an already tumbled bright and shiny part, it will take the shine right off. Use the dip only as a pre-prep for tumbling on crummy looking parts.

I'm sure you will do well with the lowered temperature.

Cheers

[Michael L.]

Re: Help from home platers

Just wanted to update you on the progress and ask another question or two. Here are my latest results in the pics posted below. The lug nut and eye hook are store bought for comparison of the finishes. You can see that things dramatically improved with the changes made. Still, the finish on some of the parts is not quite up to the store bought parts. Do you see subtle differences in the plating quality on some parts based on their unique metallurgy or the advanced pitting on some of the worn parts? Also, I have been adding additional zinc brightner to help bring up the shine. What is the upper limit of that stuff? What can happen if too much is added? Also, I notice the zinc anodes get dark quickly. How often do you have to clean them up? I don't want to be wire wheeling these things for every singel bolt I plate. Thanks for any info.

ML

[Gerard F.]

Re: Help from home platers

Just wanted to update you on the progress and ask another question or two. Here are my latest results in the pics posted below. The lug nut and eye hook are store bought for comparison of the finishes. You can see that things dramatically improved with the changes made. Still, the finish on some of the parts is not quite up to the store bought parts. Do you see subtle differences in the plating quality on some parts based on their unique metallurgy or the advanced pitting on some of the worn parts? Also, I have been adding additional zinc brightner to help bring up the shine. What is the upper limit of that stuff? What can happen if too much is added? Also, I notice the zinc anodes get dark quickly. How often do you have to clean them up? I don't want to be wire wheeling these things for every singel bolt I plate. Thanks for any info.

ML

Michael,

Looks like you are getting it down by the looks of the screw in the first and second pictures. That's the way they should come out. Are you sure that lug nut isn't chrome plated, I see what looks like a little copper in the second picture.

If you want something to come out bright and shiny zinc, it must be brought to a bright and shiny finish prior to the plating. The zinc layer you are putting on is so thin, it just reflects the substrate. It will not take out any pits or roughness. That would need to be done beforehand.

The store bought eyebolt in the picture probably has a clear coating on it to protect the bright zinc finish. Fresh bright zinc plating gets dull very quickly unless protected with a clear coat, or dichromate. Thats why some bolts are even black phosphated, or blackened with black oxide.

I'm not sure whether there is an upper limit to the brightener, but I would use it sparingly, as it is expensive. (I buy it by the pint.) Using too much might be the reason your anode plates get dark quickly. The brightener is a cleaning agent for the cathode (the part being plated). The dark stuff being cleaned from the part either goes into solution and settles to the bottom of the tank or goes on the anode plate.

I wouldn't worry about the anode getting dark, unless it is effecting the brightness of the part being plated. I usually only clean the anodes at the begininning of a day's plating session. Don't leave them in the solution overnight, remove the anode plate at the end of the session.

I always do a test plating with a piece of copper wire at the beginning of the plating session and occasionally during, when things are not coming out right. If the copper wire doesn't come out bright, then it is time to add more brightener, or clean the plates, or both. I've never had to clean the anode plates during a day's plating session.

If you start seeing a dark sediment building up in the bottom of the plating tank, you can siphon the bottom stuff off and run it through a cheese cloth or microfiber cloth (better) in a funnel. then dump the clear liquid back into the tank. Some use a coffee filter, but it takes forever. You can also filter through these activated charcoal packs that Caswell sells. This will take out any of the zinc brightener. I think hydrogen peroxide also takes out the zinc brightener.

Like I said above, it is all trial and error with this system, whatever works for you. But you are getting it down.

[Jack H.]

Re: Help from home platers

I can't adjust the voltage since the rectifier I'm using only allows either controlling the amps or the volts, but not both at the same time (CC/CV rectifier).

You don't want to adjust BOTH voltage and current at the same time! Disconnect the anode/cathode from the plating tank leaving the power supply open circuited.

Now, switch the supply to its voltage control mode and turn the voltage control dial until you get the voltage potential you seek (1.5V, 5V, Etc.). Leave the dial there. Switch the power supply to current control mode and crank the current control knob down to ZERO.

Reconnect the supply to your tank anode/cathode. ONLY turn the current control, raising it from zero, up to the level appropriate for the specific geometry of anode/cathode you're working with. That's typically until you JUST see H2 bubbles forming on the part you're plated that's connected to the cathode...

The SLOWER you lay down plating, the more regular/uniform the resulting surface is that you make. That'll make it shine/gleam more brightly without post-plating, secondary 'buff out' operations.

The more irregular the surface is that you create, the more 'dull' it will appear as it's reflecting light non-uniformly (random scattering)... This is why pre-plate polishing, part cleanliness + controllling electrolyte temperature and the rate of plating deposition make such a difference in the visual aspects of a finished part!

[Michael L.]

Re: Help from home platers

Thanks, guys.

Jerry, what is the nature of the "clear" coating on the store bought stuff? Is it a dip similar to the dichromate, or are you talking about a spray like the Eastwood diamond clear? If by chance I do plate something and it comes out dull because the brightner has run out can I just add the brightner and plate a little while longer or do I need to strip the dull stuff and start over? ( BTW, the "copper" is an artifact, the lug is zinc plated.)

Jack, thanks for the tip, but what is the voltage potential that I would want for this kind of hardware plating? I was under the impression that a CC setting meant that the current would stay constant and that the voltage would be automatically adjusted to meet that current setting. I don't recall seeing anything in the power supply literature about setting the voltage. How do I determine what this setting should be?

Finally, even the finish of the screw in the picture required some polishing with fine steel wool to make it look that way. But I have so many parts to do, I'm wondering if I can just put them back in the tumbler for 2-3 hours with some walnut shells or similar mild media to polish them up. Do you think the plating would be stripped off if I use a mild media and tumbled them for several hours? For larger bolts a quick hand buff is not that tough but I'm also plating some small items like my hardware harness screws and all my nuts and washers that make hand buffing tough. It would sure make life easy if I could put these into the tumbler. What do you think?

ML

[Gerard F.]

Re: Help from home platers

Thanks, guys.

Jerry, what is the nature of the "clear" coating on the store bought stuff? Is it a dip similar to the dichromate, or are you talking about a spray like the Eastwood diamond clear? If by chance I do plate something and it comes out dull because the brightner has run out can I just add the brightner and plate a little while longer or do I need to strip the dull stuff and start over? ( BTW, the "copper" is an artifact, the lug is zinc plated.)

Jack, thanks for the tip, but what is the voltage potential that I would want for this kind of hardware plating? I was under the impression that a CC setting meant that the current would stay constant and that the voltage would be automatically adjusted to meet that current setting. I don't recall seeing anything in the power supply literature about setting the voltage. How do I determine what this setting should be?

Finally, even the finish of the screw in the picture required some polishing with fine steel wool to make it look that way. But I have so many parts to do, I'm wondering if I can just put them back in the tumbler for 2-3 hours with some walnut shells or similar mild media to polish them up. Do you think the plating would be stripped off if I use a mild media and tumbled them for several hours? For larger bolts a quick hand buff is not that tough but I'm also plating some small items like my hardware harness screws and all my nuts and washers that make hand buffing tough. It would sure make life easy if I could put these into the tumbler. What do you think?

ML

Michael,

Not sure what they use commercially to preserve the bright finish on store bought parts, but it is probably a very cheap dip, similar to the more expensive Eastwood Diamond Clear. Wouldn't be dichromate, as the parts would take on a yellow gold finish, or different color with various dichromate compounds.

I think if the part turns dull during plating, you could pull it out, buff it up then put it back in the plating tank with a little more brightener, (rather than stripping it down).

I kind of think that with your rectifier you should just stick to the volts with a range of 1 to 5 Volts. If you just adjust the volts until the parts show just a light effervescence, you probably won't have to worry about measuring the part, or the amps. The amps will just self adjust to the resistance over the tank. I think they call that, Ohms Law.

If you want a nice bright clear finish with less hand buffing, try the tumbler after plating for various times, then plan on clear coating to preserve the brightness. Remember, trial and error. There really isn't any exact science with this home process.

[Gerard F.]

Re: Help from home platers

Michael,

Not sure what they use commercially to preserve the bright finish on store bought parts, but it is probably a very cheap dip, similar to the more expensive Eastwood Diamond Clear. Wouldn't be dichromate, as the parts would take on a yellow gold finish, or different color with various dichromate compounds.

I think if the part turns dull during plating, you could pull it out, buff it up then put it back in the plating tank with a little more brightener, (rather than stripping it down).

I kind of think that with your rectifier you should just stick to the volts with a range of 1 to 5 Volts. If you just adjust the volts until the parts show just a light effervescence, you probably won't have to worry about measuring the part, or the amps. The amps will just self adjust to the resistance over the tank. I think they call that, Ohms Law.

If you want a nice bright clear finish with less hand buffing, try the tumbler after plating for various times, then plan on clear coating to preserve the brightness. Remember, trial and error. There really isn't any exact science with this home process.

Michael,

Here's a couple of photos of a masked part showing the effervescence, clear finish, and yellow dichromate finish:







The masking was just 10 mil PVC pipe wrap to protect the aluminum base plate. As I remember, the plating was done at 1.25 volts.

[Jack H.]

Re: Help from home platers

Jack, thanks for the tip, but what is the voltage potential that I would want for this kind of hardware plating? I was under the impression that a CC setting meant that the current would stay constant and that the voltage would be automatically adjusted to meet that current setting. I don't recall seeing anything in the power supply literature about setting the voltage. How do I determine what this setting should be?

One thing nice about Caswell, is they not only publish a plater's handbook for their chemistry products, they have a Q&A web site for information interchange. If I remember correctly, the handbook cites 'target' working voltage range(s) for each of their chemistry products. THAT'S the voltage you want to use.

On voltage and current, let's take a quickie refresher course. Voltage is a measure of potential energy (the ability to do work). Current is an expression of kinetic (work being done). V=IR.

With a passive system, you won't get more current flow than what's dictated by the driving voltage AND the resistance of the specific circuit. But, when you have active components (the 'rectifier' or power supply gobbles energy from the wall plug and uses transistors to 'pump' out current) that changes...

Power is the time rate consumption of energy. P=IV. It's a measure of how much work per unit time is being performed.

The higher the driving voltage, the greater the power in a given system. So, all things the same (resistance of the plating tank is fixed for a given job, and you've dialed in a given MAX current), the higher the working voltage, the faster the deposition rate of your plated surface will be.

When you form a molecular layer NICE AND SLOW, it'll tend to be uniform and orderly. The faster you SLAM down the new atoms of your plating layer, the more dis-order/non-uniformity you create.

That's why for a given chemistry, there's an 'ideal' or 'optimum' voltage setting. Fall below that optimum and you're simply squandering time. Drive above the optimum and you can expect to complete the job faster but with a duller finish.

That'll require post-plate polishing to make the part gleam. With the post-plate polishing process, you're essentially 'sanding out' the surface irregularities of the plated surface you just laid/made...

[Ronald L.]

Re: Help from home platers

Has anyone tried to replate the 65-66 427 barrel plug shields with one of these? Comments anyone?