Posts by DustinGebhardt

I've never had a problem using a high voltage in my nickel baths, both rack and barrel.  The biggest problem with the baskets dissolving is when the nickel anode material gets too low.  I would suspect that the same thing applies in acid chloride zinc. 

What kind of properties are you looking for?  Typically, stainless steel is safe to cook on. 

The alloy of the aluminum does play a big part in how it can be finished successfully. The alloy is usually chosen with other parameters in mind too, like machinability, corrosion resistance, strength, etc.  If you are open to changing your alloy, then by all means try out some different stuff.  However, if you are getting some good parts with the current alloy, it is more likely that the anodizer does not have good control over his process, which is resulting in the creation of bad parts. 

When looking at a different alloy, avoid silicon, magnesium, and copper.

You can easily create some very stubborn compounds when you subject dirt and oils to the high temperatures of welding. I would agree with you that the problem most likely is that the parts are not properly cleaned. I would suggest that you try to clean some parts before welding and see how these come out. If you are doing the cleaning yourself, you should be able to see any cleaning deficiencies with a water break test. After cleaning, the parts can be dipped in water and it should sheet evenly off of the part. If the water beads up or "breaks", the part is still dirty.

Try to find a supplier for masking products.  They make several different types of plugs, caps, and other items that may work for you.

Blistering is usually caused by poor adhesion.  Have you checked your pretreatment process baths?  Your acid solution is usually the first to cause adhesion problems, and it is also usually the least expensive to make up new.  Have you done a water break test to verify that the parts are clean?  If, after the acid tank, any water beads on the surface of the part, it is not clean.  The water should run off in a smooth sheet. 

What thickness of nickel are you plating?  Sometimes a thicker deposit will not stretch and bend when heated in an oven.

Typically pitting is caused by gas bubbles formed during the plating operation.  Usually, a wetting agent is added to the bath to facility the removal of the bubbles during the process.  This, when combined with some sort of solution movement (via air agitation, mechanical movement, etc), usually eliminates the pitting.  Your supplier could also try to use a lower current during the plating process to slow down the formation of the gas bubbles, in effect giving more time for the bubbles to dissipate.  But first I would have them check the wetting agent and solution movement.

A copper strike under the Ni wouldn't have much affect on the pitting (although it would help with the corrosion, as you mentioned)

Unless you are stripping down to the base metal, polishing the base metal, and then going through a complete replate cycle, you are probably not removing all of the rust. The residual rust will easily come back.

First, I have a question for you: what is the alloy of the brass? Does it contain any lead?

To answer your questions:

1.Yes, I would put in an alkaline anodic cleaner. Just because the wire is "clean" does not mean that it is plating-quality clean. Beware anything with too much caustic, as it can easily oxidize and discolor the brass, making the downstream acid have to work that much better.

2. I love cathodic acid cleaning. I've always used sulfuric acid for this application or a sulfuric acid derivative (GBS acid salt).

3. I've used carbon/graphite anodes. They have a limited amount of current that they can carry, so take this into consideration.

4. Rinsing can be a difficult item to decide upon until the line is actually in production. The primary function of the rinse is to prevent carryover from one process into the next. While fresh water sprays would probably be best, reusing the water should be okay, assuming that …

I'm not familiar with laser cutting. Does it leave a physical residue, or is it more like a heat stain? Each has its own recommended cleaning process.

I've always used aluminum contacts for my Type III work.

And regarding your wall thickness, remember that anodizing converts the existing metallic aluminum into aluminum oxide. So, it will continue to consume the metal Al as it forms the oxide. If you have a very thin part, it is possible that the entire piece will be converted to the oxide. And this process is never 100% efficient, in that some of the aluminum will be dissolved into the anodizing bath.You may want to consider this and redesign your part so that you yield a finished piece with the dimensions you require.

Do you have any pictures? This might help us identify any problems.