Removing sharp perforation edges on stators with ferric chloride

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I have some stators and I have some high voltage corona proof lacquer. However, the edges of the holes on my stators are too sharp so the lacquer wont stick to them - the most important part. Is it possible to dip the panels in a dilute ferric chloride solution to smooth out the edges?
 
Hi Bigwill

Do you have any powder coaters in your area. Last time I checked there were a few cheap ones in Hull, so there might be one closer than you think...that would be my first port of call.

Also...is it the natural edges or burrs that are causing the problem...if it is burrs then I would be tempted to go over the whole side of the stator with a wire brush tool in an electric drill before coating.

Regards

Ed
 
A chemical deburring is superior to any "wire brush" technique, short of a tiny deburring tool used on each and every hole.

The choice of chemical will depend on the metal to be used.

A safe and sure way is to take the stators to a plating shop and tell them that you want them to etch the stators until the sharp edges (which you show them, bring a magnifier) are rounded off. That's fast and effective, safest.

The only other means that would work well is an abrasive deburring, but given that this is a flat sheet with holes, it is difficult to set it up and make it work, unless you do a "sand blast" type of deburring - and you would NOT use sand to to the job. Glass bead in a very very fine grade might be ok. IF you do it at home you must wear a professional grade dust mask, not one of those paper things with the elastic straps. Permanent lung damage can and will result if you breathe the dust.

_-_-bear
 
you don't need a tray.

but you can make a tray of any size you like with a wood frame and some plastic sheet, the thick stuff they sell at the home improvement/harware stores.

do it outside.

or if ur bold, in ur bathtub - with the plastic.

but, i'd opt to try the spray on "oven cleaner" - it's lye.
you may have to do quite a number of applications to get the desired effect. definitely do that trick outside.

of course, when you build them, you put the burr side away from the diaphragm!

_-_-bear
 
Bigwill,

In your place I would not do it with my precious stators. Just try with a piece of aluminium sheet in a plastic (!) tray with well diluted NaOH. NaOH is still more "friendly" than FeCl3, that is a killer material, etches everything. You realize too late that your dress has holes on it. Do it in open air, the gases released make you cough strongly. But the result will be a rough tarnished piece of junk, not a nice shiny metal sheet with rounded edges what you wanted. Countersinking sounds more safe, alhough time consuming... Flexible sandpaper disc in a drill, just to make the surface flat is not enough?

Laszlo
 
Electropolishing would probably be the ideal technique for removing the sharp asperities. I'm not sure it's very diy-friendly though. You'd certainly end up working with a large quantity of nasty chemicals (usually acids). Perhaps it would be worth looking into a local commercial electropolisher. You could be confident that your stator wouldn't be dented or kinked by your mechanical polishing efforts.
 
I'm a physical chemist but I haven't tried electropolishing aluminum and so can't speak from experience. The site I mentioned previously includes aluminum in their list of suitable metals, so I take it that it can be done. You do have to be careful, though, because the various aluminum alloys behave quite differently in electrochemical processes. For example, I've found when anodizing aluminum that the results depend strongly on the alloy used. I do think electropolishing holds more promise than simply dipping the stator into a corrosive bath. I would anticipate extensive experimentation being required as you try to figure out the details of the conditions that yield the desired results. If the pros can do it for a reasonable cost, relying on them might be the better approach---even though it isn't fully within the diy spirit.
Few
 
This is silly.

Take a small piece, place in the solution of your choice, TEST.

Consider a small piece in a "ziplock" plastic bag.

I say properly done the "lye" will do the trick. The sharp edges will react more than the flat edges, the result should be deburring.
Agitation may help.

Temperature plays a role too.

Once the aluminum forms an oxide, or if it forms an oxide layer, it will cease to react.

BE SURE TO WEAR EYEPROTECTION AND RUBBER GLOVES whenever you work with chemicals like these!! It is also a good idea to wear clothes that fully cover your body.

DO NOT POUR LYE DOWN YOUR DRAIN!!!


Have a mild acid on hand (citric acid based is good) like vinegar or similar and a hose to clean off any splashes or spills. Especially on your clothes or skin.

Shiny alumininum should not be the prime criteria - working panels should, imho.

_-_-bear
 
Perforated Al ESL stator prep

First post- Back in the 70's, Sanders etched his aluminum stator panels with lye (sodium hydroxide). Ferric chloride is a real stain pain.
The panel should be first wet sanded with 4-600 grit "wet or dry" emory paper. Use a soft rubber sanding block. This may be enough to knock down the ridges.
If you feel the urge to use the NaOH, as a follow up, wear eye and hand protection. The stuff will blind you and eat your flesh!
 
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