What media to use?

[UBRacing]

I want to finish some machined alum parts.

I have medium ceramic and dri shine ( I think its walnut with red rouge) as of now.

Do yo uadd any additives to the dry shine for it to work faster. I seen some one advertizing a flitz product for brass, does it work on alum?

Will a fine ceramic media give the alum a nice smooth fine with abit of shine?

I tried the medium but it comes out with a matte finish.
I'm looking for a deburring and bit of shine out of the parts.

I done some searching on this but theres not whole lot of info out there.

How much water are you adding to the ceramic media?
How much are you adding to the vibrator tumbler 3/4 full?

Thanks

for anyhelp.

[Kevin Taylor]

Hard plastic media work's the best on alum with a waterbased compound I use a wedge shaped media with a liquid I got from C&M Topline meida is also in MSC and Mc Car Depending on the size and shape of the part's and the size of your machine there are different shapes and grit's ceramic is very agresive I would only use if I was only wanting to debure blank's I'v sawed and don't run for long Good luck Kevin

[UBRacing]

Thanks kevin.

Is that waterbased compound recirculated in to a tank or do you just add it to the tumbler bowl?

I see lot of mention of recirculating the water in to a tank to keep the media clean. Im thinking of adding a system to my setup soon.


Thanks

[xiphmont]

Originally Posted by UBRacing I want to finish some machined alum parts. I have medium ceramic and dri shine ( I think its walnut with red rouge) as of now.

The problem with the creamic bonded abrasives is that they're usually an aluminum oxide grit. You'll be trying to polish through an aluminum oxide layer by using aluminum oxide-- so the going could be really slow unless you use an activator (oxide stipper) or heavy oxidation inhibitor. It'll be easier to just go to a silicon carbide abrasive (the oft-mentioned 'green triangles') if your ceramic triangles don't work fast enough for you.

Walnut/rouge is a good media for final polishing aluminum. Corn cob works about the same.

Originally Posted by UBRacing Do yo uadd any additives to the dry shine for it to work faster. I seen some one advertizing a flitz product for brass, does it work on alum?

Yes. My own experience is that Flitz (or Turbo brite, etc, but *do not* use Brasso) speeds up polishing aluminum with dry media like corn cob by a factor of three or four. The drawback is that it removes metal (it strips off the oxide layer, keeping the surface soft/reactive metal-- that's why it works faster) and this oxide will slowly gum up the media, so you'll go through media faster. In my shop, I change the corn cob in my vibratory tumbler rougly weekly (tumbler runs 24/7)
.

Originally Posted by UBRacing Will a fine ceramic media give the alum a nice smooth fine with abit of shine?

No, not by itself. It will look almost exactly like using the medium ceramic media. The difference will not be visible without very close inspection.

Originally Posted by UBRacing How much water are you adding to the ceramic media? How much are you adding to the vibrator tumbler 3/4 full?

Only enough water to keep the media itself wet; there should be no leftover water pooling in the bottom of the tumbler.

BTW, flow-though is greatly recommended for wet media! Otherwise, you'll have to be rinsing the media out every few hours to avoid your parts getting caked with dark oxide.

Don't bother spending $$$ on the commercial add-on systems. They'll charge you $300 for a $10 collection of parts. You just need a drill, an NPT tap, some nylon hose barbs, two buckets and a needle valve to regulte flow. If you want to get *really* fancy, turn your own drain fitting out of polyethelyne on a lathe so that you can make the drain a bunch of fine holes instead of one big opening that will tend to get partially blocked. I used 1/8" ID tubing/fittings on the feed and 1/4" on the drain of mine. The flow-through system works like an IV drip, you just need a *teeny* amount of water moving through to keep it wet and running clean.

[mxtras]

What equipment are you using?

Scott

[xiphmont]

Originally Posted by mxtras What equipment are you using? Scott

Minisonic MT-14SV vibratory tumbler. My post should be applicable for any vibratory tumbler-- but my only direct experience is with the Minisonics.

Monty

[mxtras]

Just looked at your write-up. Thanks!

I am basically just beginning to learn about mass finishing, so your write-up and commentary are helpful - except I am not looking to polish - just deburr.

Thanks again!

Scott

[xiphmont]

Originally Posted by mxtras Just looked at your write-up. Thanks! I am basically just beginning to learn about mass finishing, so your write-up and commentary are helpful - except I am not looking to polish - just deburr. Thanks again! Scott

Ah, then you can ignore all the parts I wrote about walnut/corn cob and Turbo-Brite. The additive will only help with polishing; it will have no effect on deburring or cut down. Corn cob / walnut shell are just too light to do anything but burnish/clean/polish. If it was all you had, or didn't mind running parts for a week or more, it would eventually do a good job of taking off very light burrs or the snags along sharp edges. Since you already have it, give it a try but don't expect it to do much at all without running for a few days.

Triangles and water with a little detergent are a much bigger hammer. A few hours to deburr, a day or two to completely remove any evidence of tooling. This will also progressively round off sharp edges, which may or may not be desireable (the result will look alot like the results of building up a copper layer for triple-chroming, but it's the literal opposite process)

And to be honest, I usually skip the detergent part myself, or run the flow-through with straight water and just toss in a capful of Raytech B when I add new parts that still have cutting oil on them from tooling. The water here is exceptionally low-mineral so a little detergent goes a long way.

You can add surface activators that continuously strip off the aluminum oxide layer to super-turbo-charge the process, but this runs the risk of going *way* too fast. You run the risk of literally dissolving the piece. (Here's one place where I wouldn't mind someone else chiming in-- it seems like you could make a combo activator/oxidation inhibitor for aluminum flow-through tumbling that would avoid the 'dissolving problem' by removing the oxide layer and preventing a new one from forming. Unfortunately, the vendors who like to sell additives usually never say anything more detailed than 'compound 67B! high pH! Great for everything!' which unfortunately tells me almost nothing. I can gather some useful information from the MSDS to tell what the stuff is actually trying to do, but usually not enough. I'm not made of money, so I can't just try every product every vendor wants to sell me... has someone else found something that falls into this category?)

Monty

[bob1112]

I am not looking to steal the thread but curious since you seem to have tested it all on Al deburring and finishing, what is your pref for deburring and prepping Al parts for mirror finishing? I have been using the buffer for months now and is getting old. I bought several bags of Walnut shell from a pet supply shop. small beads. I am looking for my own concoction and really hate buying "special" conditioners if I can avoid.

I am wondering what to use for an oxide remover with maybe some green triangles to accelerate that process? See, we kick out many parts that just need a uniform, non marked surface. My personal race parts require polishing.

What is a good solution for the untreated walnut media? My buffing experience says jeweler or red rouge is out unless you have 3 weeks for finishing. I prefer tripoli or a white Al oxide rouge for final production finshing. Still some marks but production oriented, (aka, fast!)

I only have one doughnut tumbler and don't want to tie it up for days on end for polish work but maybe weekends will do.

[xiphmont]

Originally Posted by viper6383 I am not looking to steal the thread but curious since you seem to have tested it all on Al deburring and finishing, what is your pref for deburring and prepping Al parts for mirror finishing? I have been using the buffer for months now and is getting old. I bought several bags of Walnut shell from a pet supply shop. small beads. I am looking for my own concoction and really hate buying "special" conditioners if I can avoid. I am wondering what to use for an oxide remover with maybe some green triangles to accelerate that process? See, we kick out many parts that just need a uniform, non marked surface. My personal race parts require polishing. What is a good solution for the untreated walnut media? My buffing experience says jeweler or red rouge is out unless you have 3 weeks for finishing. I prefer tripoli or a white Al oxide rouge for final production finshing. Still some marks but production oriented, (aka, fast!) I only have one doughnut tumbler and don't want to tie it up for days on end for polish work but maybe weekends will do.

Don't use anything with the green triangles except water + a little detergent to suspend dirt. Skip the detergent in a pinch. You don't want an oxide stripper or anything else or you'll melt the part like it was wax. If you want faster cut down, get a coarser abrasive (eg, go to graded loose carbide).

For polish, I add turbo-brite to walnut shell or corn-cob, whatever was cheaper that week. Untreated walnut or walnut with just red rouge would take weeks to make a dent in the uniform matte that comes out of cut-down. Turbo-Brite is the key to making this work fast. You can use anything similar to turbo-brite, but be careful it doesn't contain its own abrasive (eg, Brasso) or it will just continually scratch/cloud the finish.

Steel and ceramic shot are useless. At least for Al.

Lately my process is:

part comes off mill ->
1-2 days of green triangles ->
1-2 days of walnut+turbo-brite ->
1 day of untreated walnut or corn cob (final burnish)

Depends on the exact part and Al alloy.

Anything involving a tumbler is measured in days, not minutes or hours. Maybe the doughnuts are faster than my minisonic. In my experience, the only thing that the vibratory tumblers give you is hands-off polishing. They take forever, and the results won't be *quite* as good as a really good hand job. But... you can fire and forget.

(And if anyone knows I'm wrong, please, share your secrets! I'd love to find faster ways myself!)