Which type of tumbler is better for Al?

[SunsetPetey]

ok so I added some (automotive) liquid aluminum polish to my (course) walnut media and ran the machine for 12hrs... the parts didn't really polish much, there definitely clean and smooth but no where close to even your 85% mirror shine.... sorry i thought i had some pics on my phone.. but i dont ill get some today.

Should i step down to the Fine Walnut media? and is washing necessary between steps?

[xiphmont]

Originally Posted by SunsetPetey ok so I added some (automotive) liquid aluminum polish to my (course) walnut media and ran the machine for 12hrs... the parts didn't really polish much, there definitely clean and smooth but no where close to even your 85% mirror shine.... sorry i thought i had some pics on my phone.. but i dont ill get some today. Should i step down to the Fine Walnut media? and is washing necessary between steps?

What polish exactly and how much? Polishes vary widely, and I'd say most that call themselves 'aluminum polish' are pretty awful on aluminum. Even fewer would work well in a tumbler. I expect we're all fairly brand loyal people and there's a good reason for that. We've looked far and wide for things that work well. Most don't.

You also didn't say what tumbler and what settings. I use a vibratory tumbler, and those are usually fairly agressive, and run it full blast.

You also didn't say what prep on the part and what shape it was in to begin with. Aluminum is often coated or anodized; polish won't do anything to such a part. If it's clearcoated, the clearcoat has to come off. If it's anodized, you need to strip that layer (and think hard about whether that's a good idea before doing it :-)

[SunsetPetey]

im using a vibratory tumbler, it doesnt have any settings, so its just on. i tried both "flitz" and a liquid polish that i use on all the alum parts on my show truck but its a no name mix from a local supplier. as far as i know the alum is 5052 and "bare" but i will check tomorrow with my supply yard.

I ran it first with Ceramic media, then the little green triangles, then walnut with the polish..

[SunsetPetey]

This is what it came out looking like after 12 or so hours in the walnut with polish

[SunsetPetey]

So today i had a run of different parts, so i tried the process all over again, Started with grinding / sanding off any slag, then put in the tumbler for about 7 hours with ceramic media and this is what i found when i opened the lid, lots of little black "balls" stuck to the aluminum pieces i dont know how else to describe it. i washed the pieces with some dawn which removed most of it. I then cleaned out the bowl. Also pictured is what the media looked like




After i cleaned all the pieces and the bowl i put the Green triangles in the bowl with the parts and hit go.... ill let it run over night and check it tomorrow afternoon.

Does anyone have any idea what is going on?? what is the black stuff?
Any help would be appreciated!
Thanks.

[xiphmont]

Originally Posted by SunsetPetey im using a vibratory tumbler, it doesnt have any settings, so its just on. i tried both "flitz" and a liquid polish that i use on all the alum parts on my show truck but its a no name mix from a local supplier. as far as i know the alum is 5052 and "bare" but i will check tomorrow with my supply yard. I ran it first with Ceramic media, then the little green triangles, then walnut with the polish..

Flitz is one of the tumbler additives I like and use. But we're getting ahead of ourselves.

ceramic triangles: worst possible thing to start with. The abrasive in them is aluminum oxide. The surface of your aluminum parts is... aluminum oxide. You're not polishing the surface, you're just building up a deeper and deeper layer of one of the hardest substances known to man embedded into the surface.

The green triangles are a carbide grit. Carbide is harder than aluminum oxide, so that's a proper abrasive. However, after running with ceramic/alum you've just doubled/tripled/quadrupled the work the green triangles have to do, because now they need to strip the natural oxide layer, plus the oxide layer built up over it.

Your abrasive media looks completely dry in your pics. If you're running the ceramic and triangles dry, that's also counterproductive. They must be completely wet; fill it until there's just enough water that the tiniest amount pools in the bottom _while it's running_. The liquid also must be kept clean, that's why folks here are using flow-through. The alternative is to rince and rewet the media regularly. Use a tiny amount of a detergent in with the liquid to keep dirt better suspended (plenty of people here use a tiny amount of dish soap). If you don't keep the liquid clean, once again you're just peening dirt deep into the surface of the part.

If the abrasive prep step goes south, no amount of polishing with dry media will recover it. So... let's make sure that's working first.

[xiphmont]

Another thing that can wrong on a newbie and he'd probably never know it because it's just assumed knowledge--

In a vibratory tumbler things must be moving. Not just vibrating in place, but constantly flowing, mixing, turning over. If the media doesn't look like it's in a slow motion blender, something is wrong. Figure out what before continuing, or you're just going bore gouges into the parts.

That goes for wet media (abrasives and peening) and dry media (non abrasive buff/polish).

[SunsetPetey]

Thanks man! i probably would have never figured it out and just thrown the dang thing lol ok so ill ditch the ceramic, and add water and a dab of soap to the green and see how it goes! i have been watching it and the parts are moving, they come up from the outside and go down in the middle which from what i can tell is correct

[xiphmont]

Originally Posted by SunsetPetey i have been watching it and the parts are moving, they come up from the outside and go down in the middle which from what i can tell is correct

Yup, that's right.