Re: Brush Plating [ Started by The/apprentice in General Discussion : 3 replies ]

Assuming that the 10A @ 30V capacity works for your application, I don't see why it shouldn't work.

Re: Rack Plating Work Bars [ Started by TBrooks in Zinc Plating : 1 replies ]

Are you talking about stripping the plating from the work bars?  If so, many shops use hydrochloric acid to strip zinc.

Re: Sealing Edges for PVD [ Started by D Breslin in Other : 1 replies ]


   I'm not sure I would want to seal any sort of entrapped material during a PVD process.  The level of vacuum (or low pressure) generated during the process could cause any entrapped gasses to violently erupt.  PVD frequently causes solids and liquids to sublimate or evaporate, again causing (potentially violent) eruptions. 

I have never heard of any product that can seal a gap or edge of a surface prior to a PVD process. 

Re: Electropolish Mask [ Started by beetlebum in Polishing : 1 replies ]

Look at the Tolber line of stop-offs and maskants

Re: clear coat problems, runs, milky colour [ Started by wayne73 in General Discussion : 1 replies ]

It definitely looks like you put too much total powder on.  I can't say if you are using too much base, color, or clear.  What does your powder supplier specify for ideal thickness?

The level of gloss in the finish is typically a quality defined by the powder itself, not by the amount of product applied.  Once you reach the minimum amount of powder to cover the surface to the recommended thickness, adding more powder will not give you any  more shine.  It may even reduce the shine.  Most powder coating shops that specialize in high-gloss finishes will wet sand and polish the final coat.

You could try to sand down the drips, but if the drips go down to the base or color layers, you will have to strip the powder to base and start again.

Re: PPE [ Started by platingengr in General Discussion : 1 replies ]

You need to have an Industrial Hygenist study and document your environment, and then make recommendations on your PPE requirements.

(For the following comments, I can only speak to my experience with regulations in the USA)

For airborne chemicals:

Typically, they will examine your ventilation system, using tables and formulas, to calculate the amount of a substance that is in the air. The manufacturer of your system will typically specify the equipment to operate at a certain level, but poor maintenance and system modifications will change that performance level. The MSDS for each product is consulted and the various exposure levels are noted. Going a step further, air monitoring can be conducted to come up with an actual value for chemical concentration. Typically, if the results from either (or both) studies is under the PEL, no respirator is required. It is also worth noting that anybody wearing an air-purifying respirator must be FIT …

Re: Reverse plating to remove rust [ Started by 3v0 in General Discussion : 4 replies ]

Here are my thoughts on the questions you listed:

1) No, you can't strip some scrap, attract the unwanteded minerals to the anode, and keep the "clean" water. It just doesn't work this way.  As Ray said, you need to have some minerals in the water to conduct electricity.

2) Borax is not nearly as good as carbonates to soften hard water and increase alkalinity. In your case, hard water shouldn't be a huge issue. I wouldn't worry about minerals in the water. I'd stick with the washing soda as my source of alkalinity.

3) A pulsed DC supply might be beneficial, but I'm not sure the effort of making a system is worth the outcome. You would be better off agitating your solution with either a pump or low-pressure air.  You might also see better results if you put a bit of (low-foaming) surfactant, like the kind they use in automatic dishwashers.


Re: no cyanide silver plating over copper [ Started by daginhun in Electroplating : 5 replies ]

For a hot alkaline cleaner, you can try using a solution of sodium carbonate or sodium bicarbonate, along with some normal dishwashing soap.  Heat it to 150-180'F and it should clean away most buffing compounds.

Re: no cyanide silver plating over copper [ Started by daginhun in Electroplating : 5 replies ]

The second
sequence should be sufficient to get good adhesion. I'm not very familiar with non-cyanide silver plating baths, so I can't answer any questions regarding that. I will also mention that your cleaning step will probably not be adequate. If you are polishing using a fat-based compound, you will need to you some sort of alkaline, heated cleaner. After the hot alkaline cleaner, you can rinse the part and then go into your acid bath. Rinse after that, then go into your copper strike/plate. If, after the acid bath, your part shows water break or beading, the part is not sufficiently clean for plating and the cleaning process must be started over again.

Re: WHITE RUST ON TRIVALENT BLUE ZINC PLATED PARTS [ Started by swd in Zinc Plating : 2 replies ]

White rust is caused by the failure of the chromate coating, leading to the oxidation of the zinc layer.  How many hours of corrosion resistance is your chromate bath rated for?  How many hours are you experiencing before failure?

If your bath is not performing per its specifications, there could be several causes:

chromate bath contamination (zinc, iron, etc)

poor rinsing after zinc plating

poor pH and/or chromate concentration control

If you bath is performing at or above its specifications, then a higher rated chromate bath is required.

Re: How can I achieve a mirror finish on Cast Iron [ Started by clanger in Polishing : 2 replies ]

Are you sure that the tub in the picture is not plated? How do they keep the cast iron from oxidizing?

I've never worked with cast iron before (other than my personal cookware), but the usual process for something like this would go as follows:

grind/sand with a ~80-120 grit compound or wheel

sand further with a ~300 grit compound or wheel

Polish with a tripoli-type (brown) compound

Polish with a green compound (I forget the industry term)

Buff with a white compound (I forget the industry term again)

At this stage, parts are usually ready for decorative plating. I'm not sure how cast iron would look. I wonder if there is a electropolish or chemical polish that would work in this case? If so, you'd still want to take it to at least the green compound stage.

Re: Powder removal from masking [ Started by mas_sin1980 in Powder Coating : 2 replies ]

Just so I'm clear, please tell us your process, step by step. From your description, I am assuming it looks like this:

mask part

spray part

remove mask

bake part

In my process, we leave the masks in/on the part all the way through the baking process. Once the powder has cured, we remove the mask and can reuse it with a minimum of cross-color-contamination. The cured powder flakes right off of the silicone masks, and the metal masks we can process through our strip line.

Re: How was this finish created? [ Started by Yeller in General Discussion : 2 replies ]

It looks like a weathered/oxide finish. You can try to duplicate this by cleaning the steel, acid dipping it, letting some rust form, then going into a mid-to-high-temp black oxide tank. If you are not set up for this, please seek out a local professional. Black oxide baths for steel are typically made from concentrated sodium hydroxide (plus some other goodies)heated to 270'F.

Re: Hi All [ Started by alexer in Forum Announcements : 2 replies ]

Zam, to answer your post, you typically raise the alkalinity level in your adjacent zinc dissolution tank. If you do not have an adjacent tank for this purpose, get one.

Re: Chrome turned copper color? [ Started by LloydC in General Discussion : 1 replies ]

Decorative chrome plating (and chrome plating in general) is typically very thin. When you grind the chrome, you quickly remove all of it and expose the layers underneath. It looks like your part was copper plated under the chrome, which is unusual. Normally, there is a nickel layer between the copper and chrome, at least for decorative and corrosion-resistant applications. And I suspect that you are now buffing/grinding through the copper layer to the actual substrate. What color is the next layer?

And no, grinding the chrome layer should generate no real health hazard, other than the dust particles themselves. Chrome is typically only hazardous when still in a trivalent or hexavalent form (like most clear/blue fasteners, iridescent steel parts, olive drab, and black)

Re: Copper plating + Hard chrome plating - reg [ Started by K.chandrasekaran in Electroplating : 4 replies ]

@Eastern: I think you are referring to chromate conversion coatings.

Re: Can improper mixing affect color? [ Started by ACI in Painting : 1 replies ]

Sure. Improper mixing can cause this issue, as can other problems during the cure. Can you provide more details of your process?

Re: problems with adhesion [ Started by sk8 in Forum Announcements : 6 replies ]

Yo don't need to heat the acid. It should be about 5% acid at ambient temperature.Immerse the part for about 30 seconds. If the parts show a low of copper oxidation, you will need to go longer.

Re: problems with adhesion [ Started by sk8 in Forum Announcements : 6 replies ]

If you are trying to re-plate over copper, you will need to go into an acid activator before the silver bath.

A strike is typically a bath with similar properties to the main plating bath, but with less metal and a lower efficiency. Changing the voltage and current in your bath is not going to improve adhesion. If anything, it may hurt adhesion.

Re: problems with adhesion [ Started by sk8 in Forum Announcements : 6 replies ]

What is your substrate? Do you have an acid activator before the silver bath? Why do you go into the silver at a high voltage, remove, and then go back in at a lower voltage? Usually you enter a bath at a low voltage then ramp up to a higher voltage.You shouldn't need to remove the part, rinse, and go back in.

Re: NICKEL BUILD UP [ Started by Daniel in Electroplating : 2 replies ]

High levels of nickel in a Watts bath is typically not an issue for bath performance. It can be an issue as the drag-out of material can be more expensive than what is required. However, if the excessive nickel comes from high amounts of nickel chloride or nickel sulfate, the other ions could cause issues. Excessive sulfate can cause issues with various brightener packages. Excessive chloride can lead to a host of issues, poor ductility mostly.

Re: Part is longer than the tank [ Started by mike blood in Anodizing : 2 replies ]

#1: Generally, this approach will fail.

#2: Typically, the lower the temperature and the higher the current density, the harder the oxide layer will be. When you see kitchenware that is hard anodized, this is what they are doing (kinda sorta). A lower current density and higher temp will give you a softer layer, and your colors and dyes may look washed out. If you want repeatable, consisten color, you need to control your temperature. Use an ice bath outside of your tanks. Make sure you have good solution movement.You can even use a small pond pump (Eheim) inside of an ice bath and have it pump the ice water through a heat exchanger (titanium or aluminum), which is inside the anodize bath.

Re: problem on small anode area [ Started by Daniel in Electroplating : 1 replies ]

Small anodes themselves are nto problematic. It is the ratio of anode to cathode that is a better indicator of a problem. I will assume that you mean to ask about the effects of a low anode to cathode ratio.

In electroplating, the formation of gas on the anode and cathode is a part of the process. The anode usually releases oxygen gas. When you have sufficient surface area, the rate of the reaction is slow enough to minimize the oxidation of the anode material. However, with a small anode:cathode ratio, the rate is increased. There is more oxygen present, which drives the reaction towards the formation of metal oxides. And this only gets worse, as the oxides are usually poor conductors, forcing more current through the un-oxidized anode material, which then gets oxidized, etc, etc, etc.

Low anode ratio also can cause quick metal depletion from the bath and non-uniformity of the deposit (especially on larger parts, as the anode to cathode distance becomes highly v …

Re: Powder Coat Spitting [ Started by LFIAdamD in Powder Coating : 1 replies ]

Humidity is your culprit here.  Are you spraying in an air conditioned area?  Are you using a fluidized bed?  Is the hopper fed with moist, compressed air?  Is your air source dry?  Really, really dry?

Re: How to plate silver over chromium. Help! [ Started by shsy in Decorative Plating : 1 replies ]

I have never seen anybody plate on top of chrome.  It might be possible, but I am not aware of it.