How to "Clean Up" Satin Finish Aluminum???

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toddalin
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Re: How to "Clean Up" Satin Finish Aluminum???

Post by toddalin » Sun Apr 07, 2019 3:58 pm

Alternator for a <'69 small block Chevy, though they will work on SBCs up to '92. Originally the alternator was attached to the exhaust manifold and there were no bolt holes in the front of the heads. That changed in '69 when accessory bolt holes were put into the heads.

shorttrackhack
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Re: How to "Clean Up" Satin Finish Aluminum???

Post by shorttrackhack » Mon Apr 08, 2019 10:03 am

I use Scotchbrite finishes on bare aluminum routinely on race car parts. One thing that helps keep the finish nice, is to run through through grades (I don't usually bother with gray), and then buff the parts up through the usual buffing wheels and compounds, and the put the pattern back in with a blue pad or belt. It cancels errant scratches, closes up the surface, and leaves a surface that is more forgiving than a full polish. This also works really well on stainless steel.

toddalin
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Re: How to "Clean Up" Satin Finish Aluminum???

Post by toddalin » Mon Apr 08, 2019 1:10 pm

I tried the tumbler and after 2 hours, you could see that it was having a positive effect in closing up scratches. But this would take at least a day a piece to get significant results and who has a month of days just to clean these up? At 2 hours, you could see the "peens" in the metal. Also, because these things move about, I could only do one at a time so they don't bump into each other.

I think I will order some fine media and blast them. The course media (80 grit I think) did the trick, but was too aggressive and really dulls out the aluminum. Still, based on the web pics, the finish is certainly satin and hard to differentiate. I think a finer media will give me the desired effect, and is probably the overall quickest.

toddalin
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Re: How to "Clean Up" Satin Finish Aluminum???

Post by toddalin » Mon Apr 08, 2019 1:12 pm

shorttrackhack wrote:
Mon Apr 08, 2019 10:03 am
I use Scotchbrite finishes on bare aluminum routinely on race car parts. One thing that helps keep the finish nice, is to run through through grades (I don't usually bother with gray), and then buff the parts up through the usual buffing wheels and compounds, and the put the pattern back in with a blue pad or belt. It cancels errant scratches, closes up the surface, and leaves a surface that is more forgiving than a full polish. This also works really well on stainless steel.
This is the way it should be/should have been done, though maybe not to this extent.

toddalin
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Re: How to "Clean Up" Satin Finish Aluminum???

Post by toddalin » Mon Apr 08, 2019 2:00 pm

At this time I am open to suggestions as to what would be the best blast media to use. As I said, the 80 grit (as I was told) seems to coarse.

I've seen 150 grit in aluminum oxide as well as glass beads.

https://www.amazon.com/Blastite-Aluminu ... 2506&psc=1

Is there any type of media that would be perferred for the job at hand? I'm not looking to spend a lot of money, but only save my existing investment and avoid a trashy-looking product.

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GlennW
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Re: How to "Clean Up" Satin Finish Aluminum???

Post by GlennW » Mon Apr 08, 2019 2:29 pm

Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!

RSG
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Re: How to "Clean Up" Satin Finish Aluminum???

Post by RSG » Tue Apr 09, 2019 6:34 am

toddalin wrote:
Mon Apr 08, 2019 2:00 pm
At this time I am open to suggestions as to what would be the best blast media to use. As I said, the 80 grit (as I was told) seems to coarse.

I've seen 150 grit in aluminum oxide as well as glass beads.
I use sodium bicarbonate all the time! it provides a nice satin finish. Aluminum oxide 150 grit will provide a similar finish but with a bit more texture.

If you are serious about finishing without handling the parts you'll want to investigate vib finishing but you'll have to increase the size of your vib finishers. Synthetic media is the choice for aluminum and at a freq of 40 Hz/2mm amplitude +/- (most common in tub style finishers in the 1/2 cu ft range run at this cycle). Run wet with a water drip its a great media to remove scratches and take the edge off. Cycle times will run around 3 to 4 hours to get good results.

Then in another finisher of equal size with treated cob if a polished finish is desired for another 8 to 12 hours. Hence the reason why you want to increase the size of the units to get more parts through in a shorter time. You can skip this process if you don't want them polished and go straight to the cabinet for bead blasting.

Anodizing is of course the best way finish the parts for wear and longevity. I've had to go this route and as such do everything from the vib finishing to anodizing in house for both control and cost efficiency.
Vision is not seeing things as they are, but as they will be.

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Re: How to "Clean Up" Satin Finish Aluminum???

Post by toddalin » Tue Apr 09, 2019 1:08 pm

Thanks.

Any more?

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Re: How to "Clean Up" Satin Finish Aluminum???

Post by toddalin » Tue Apr 09, 2019 5:28 pm

Looks like this may be the overall best option and Harbor Freight has the best prices on it:

https://www.harborfreight.com/50-lbs-me ... 65929.html

https://www.armex.com/products/maintenance

They also make a 220 grit specifially for giving aluminum a satin finish (turbine formula), but I can't find it anywhere, and if I do, it won't be at Harbor Freight's price.
https://www.armex.com/products/turbine-formula

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