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Type III Anodizing, Black

bkervaski

Hellloooooooo!
Testing
We are looking for someone who can anodize various 6061 parts, such as brake/rudder pedals in black Type-III "Hard".

Anyone have experience or recommendations on who to use?
 
This is one of those things best sourced locally, since it's a pretty common thing around any medium sized or larger city.

On the other hand, are you opposed to doing it yourself? I've anodized a bunch of things (black, make loud noises 30 or so times before needing to be refilled, etc) and it's not terribly difficult.

I might also ask if you've tried anodized pedals? Not very grippy, especially if your shoes have any moisture. I used spray-on truck bed liner instead after thinking about it - cheaper/easier/much more grippy.
 
Hard anodizing is fairly commonly available since it is used industrially. Check your local listings. I've found sources local to me in three of the towns I lived in across the country.

If you are hardcoating the brake pedals, consider making a rough surface before coating so it will stay rough and not wear off. I used a pattern of sharp punch marks, leaving the 'volcano' burrs in place on purpose.

Brad, good on you for home anodizing. Thought about it a few times. My understanding is that Type III hard anodizing requires a bit more amperage and cooling to get the crystal growth correct for the thicker and harder surface.

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I had my rudder pedals done locally in the bay area. You should shop around in your area. Some places don't really want to deal with these small jobs. The place I found did a good job and I was happy with the results.

If you go down this path I suggest you sand using not too fine of sand paper. I started trying to use a finer grit but I couldn't get rid of all the scratches. I then went back to 220 and that seemed to work better. Some small scratches are still there but then again they are the rudder pedals.
 
We're coming up short finding anyone locally that can do Type-III. Plenty of Type-II shops and lots of DIY for Type-II. To setup for Type-III DIY looks like around $500.

I'm going to put a rubber grip on them as well.

Plan "B" is to just high polish them.
 
Hard coat anodizing is not he same as the diy process mentioned above. Type iii uses sulfuric acid to convert the surface to an oxide that turns black, or a shade of brown when you use 6061. It is a very tough finish and not subject to UV degradation like Type I or II anodizing which use a dye for their color.

I used type III for my instrument panel. I love the way it turned out. Fortunately I live in a city large enough that I found a local source.

Don
 
@rzbill ooooh, love the pattern! How did you manage that with such consistency?

That was just a matter of accurate layout. May have used a spring punch to make starter marks. Don't remember.

I hit the main solid punch HARD as I could. Clear the bench. Stuff will bounce off. :D Held the punch with vice-grips to protect the fingers. If you look in detail, you can see where the punch bounced and nicked the surface in a couple of places. Oh well.

Googling while listening to a work conf call....:rolleyes:

Try Valmont Coatings in Steele Alabama perhaps?
 
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Type III

For the last half of my career I sold high current rectifiers to the metal finishing industry.

Type III is indeed a higher current, lower temperature, sulfuric acid process. It produces a thicker and denser anodic coating than Type I and II.

IIRC the resulting coating is either clear or slightly gray, depending on the aluminum allow. I believe to achieve a black color a dye is used that fills the anodic film pores. Then the part is submerged in very hot water to seal the top of the pore and contain the dye.

At least that's how I remember the process. It's been five years since I retired, and my memory ain't what it used to be!!! :(
 
Hard coat anodizing is not he same as the diy process mentioned above. Type iii uses sulfuric acid to convert the surface to an oxide that turns black, or a shade of brown when you use 6061. It is a very tough finish and not subject to UV degradation like Type I or II anodizing which use a dye for their color.

Type III is certainly possibly for DIY. It comes out cloudy grayish (not black) and needs to be dyed if you want it colored something else. It's definitely more work than type II (which also uses sulfuric acid, BTW). I've done multiples of both for the lower portion of certain tools. Caswell Plating has everything you need for this.
 
My minimum lot charge was around $85 if I recall correctly. I too was worried about color variation since I wasn't sure if all of the pieces were the same alloy and I had read that there could be some color variation. The shop I went to said in there process that isn't a problem. The results were very consistent.
 
I sent the parts to Alpha Metal (alphametal.com), very friendly and responsive.

I'll post pics when I get them back in 5-6 business days. They are doing an acid etch and then a black Type-III process.

I almost geared up and did this myself but I have a plane to finish :D
 
I've had a lot of product go through commercial anodization, type III, black, maximum boil. Very beautiful and rugged finish on all the extruded aluminum alloys. I've also played with DIY, type III, for very small parts count, and it was fun, interesting, useful, and easy to make a mess.

Please note and research this on your own , but my understanding is that anodization will affect the strength of your parts. If the parts are designed to be anodized or are massive, then strength loss is negligible. However, given the typically very thin, lightweight nature of aviation parts, structural parts should not be anodized unless the design engineer states otherwise.
 
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