This Old Tony - Will it Black an Entire Aluminum Part?

[PeterT]

Skip to 17:00 if you want to just see the blackening results.

I thought maybe it was just me but this exactly the sh*tty results I experienced on aluminum. No appreciable difference on 6061, 2024, 7075.
It behaves nothing like the stuff for steel. If your results are better, let me know what you did or didn't do,

 

[Darren]

I watched that the other day. Pretty disappointing results for sure. Could do better with a black sharpie

On another note, my stainless coffee percolator spent some time a few years ago on the campfire and was permanently blackened with the most durable finish you've ever seen. I've scrubbed it with steel wool and it won't touch it.

 

[jcdammeyer]

You go through the effort to machine something which takes time and resources or even costs if done commercially and then use some sort of silly metal finish?

Much better to pay for anodizing.

 

[PeterT]

I agree, anodizing is a better end result. This was more intended as a flag to others. If it just didn't work it would be bad enough, but it also etched the finish. So just not a great product, at least from my experience.

But for hobbyist / shop made one-off, it may not be cost effective to job it out commercially. At least form some of the quotes I received. Most were not interested in small unit counts or had a steep $ minimum. The best deal I found was a small shop guy who would do it when he was doing others parts, but I had to leave it there & he was not exactly close.

If you don't mine me asking how much to do those (assume heat sink) parts?

 

[jcdammeyer]

For the one-of, I took a CPU heatsink and did some carving after first modeling it with the 3D printer.

The end result not only fit but did the heat dissipation required for the 250W DC-DC power supply regulator and FETs.

\
I'm not set up to do flood cooling high speed milling like the CNC shop does with their HAAS so they cost me $40 each in minimum quantities of 20 to 30. The anodizing done in Vancouver, not including shipping costs run their minimum so I had 41 done for about $90 at their convenience with other batches of the same color etc.

Notice the finish on the heatsink. There's no post machining labour. This is all done with the HAAS. I was told, to get the corners all rounded and edges smooth by hand would cost more than having the machine do it. Even if the fins were an extrusion the machining to make it fit would still be expensive since it's machined on both sides.

 

[Six O Two]

But for hobbyist / shop made one-off, it may not be cost effective to job it out commercially.

I recently bought some supplies to try anodizing at home (mostly a power supply). Youtube videos lead me to believe it's super easy, ha. I'll have to let the board know how it goes.

This video from Mark Presling goes into nice detail

But this is the one that made me think that it can't be too hard.

 

[PeterT]

The anodizing done in Vancouver, not including shipping costs run their minimum so I had 41 done for about $90 at their convenience with other batches of the same color etc.

That's a very reasonable price. I'll keep this mind for next time.
I watched Mark's videos too. I'm sure there is satisfaction in doing it in the shop. Keep us in the loop how yours turn out.

 

[jcdammeyer]

I recently bought some supplies to try anodizing at home (mostly a power supply). Youtube videos lead me to believe it's super easy, ha. I'll have to let the board know how it goes.

There are a lot of videos out there about this. The ones I like the least are the ones where the host is learning as he goes with lots of mistakes. Really a waste of time unless one gets paid for the length of the video and advertising I guess.

Then there's one where it's not an anode or cathode but an anoide and cathoide. OTOH, that video had the guy actually anodizing parts he's machined in aluminium and they look really nice.

I worry about the haphazard way of doing things. Yes, gloves but random ventilation. I'd rather see a video where someone sets up the process from left to right, start to finish on a counter top.

Of course, I'm not much better when I was etching PC boards with ferric chloride etchant. So I'm the pot calling the kettle black.

But do be careful. A mistake with acid can have long reaching side effects.

 

[PeterT]

Some model engineering post I ran across long time ago, guy had the vats of acid & bubbly witches brew going. He may have been doing electroplating not anodizing, I cant recall. Anyways it was a small shop & next day he noticed many of his prized engine parts on the bench beside had a coating of unexpected rust. He was ready to jump off a bridge.