Tumbling aluminum parts

[fatcaaat]

Well, i wanted to give my vibratory tumbler a different challenge and see what it would do tumbling a brake plate and triple tree. Results are really nice. Someone told me that I need to use red rouge and walnut shells for second pass and they will come out shiny polished.

Anyone ever try this technique before with desirable polished effect?

Kirby, that is one of the brake plates you just sent me. I did nothing but disassemble and throw it in the tumbler. This is what it looks like 8 hours later.

 

[kirrbby]

That's a big improvement, for so little work. You're speakin my language. The clear coat on those things is tough to remove without chemical help. I'll bet it would shine up pretty easily from there...purple polish, by hand, is what comes to mind. Red rouge and walnut shells sounds easy tho, and worth a try.
Parts polishing the clean way. (And, lazy man's way)

 

[kawahonda]

Funny timing..I did this last night. Took about 5 minutes, and I hate polishing, that’s why I used a tool. What id like is know how tumblers do for nuts and bolts.

 

[fatcaaat]

i tumbled the parts in walnut shells...they got an even smoother surface finish but still dull. Next i'm going to tumble them in walnut shells and rouge, and we'll see what happens.

 

[wanrep]

Dri-shine. https://www.gesswein.com/p-13041-dri-shine-i-iii.aspx

 

[wanrep]

I recently bought a set of these Dedeco Sunburst Radial Brushes.
https://www.gesswein.com/p-13266-dedeco-sunburst-radial-brushes-6-8-ply.aspx

I use them on a tapered spindle on one side of my bench grinder.
They worked well. Didn't take much time.

 

[fatcaaat]

i wanted to give an update here because I think I really may have hit a jackpot here. I tumbled the brake panels and the top tree for about 24 total hours at this point. 8 in the green triangle plastic media to remove any paint or oxide and smooth the surface and 16 in straight walnut shells. The parts are incredibly smooth at this point and semi-polished. They are as smooth as if you went over them with 1200 grit sandpaper without any swirl marks. Light reflects pretty well but is not anywhere near mirror.

I am expecting the walnut shells embedded with rouge in the mail today and will run the rear backing plate in it for 24 hours and see the results. Then I will put the pictures together that show the four stages....before, green media, walnuts, and walnuts with rouge. I am expecting good results here.

As for bolts, I used just green media on two quart sized bags of ct70 bolts, springs, etc. They cleaned off all rust and made the bolts perfectly smooth but if there was any remaining zinc coating on them, it removed most of that. In the case of the bolts I put in there, the zinc was mostly gone already. It may have been better to separate the bolts into two categories...rusty and not rusty and then used the green media on the rusty ones and just walnuts on the non-rusty ones. I cleaned them off and then sprayed them liberally with wd40 and put them in a plastic bag for safe keeping.

I also applied the green media to brake parts...including the shoes, springs, and outside panel parts. They came out awesome as well. I want to put the outside parts in the walnuts to bring out a shine on them as they are super smooth but matte. I think if you were going to send stuff out to be zinc coated, or you wanted to try it yourself, tumbling them as I describe would prep them perfectly...these can probably be coated as is.

I also tumbled a complete ct70H transmission and shaft in the green media. I tumbled it for about 4 hours and it came out beautiful...almost like the parts were brand new from the factory nice.

 

[kirrbby]

Would fork lowers...like K1 CT70 aluminum fork lowers fit into that vibratory tumbler?? That would be SWEET!

 

[fatcaaat]

Would fork lowers...like K1 CT70 aluminum fork lowers fit into that vibratory tumbler?? That would be SWEET!

In mine it would be very close. I do think I could rig up a 5 gallon bucket and put it in there. I want to do the same thing as I have a set of both KO and K1 fork lowers I need cleaned up. So, we'll see soon enough if its possible, because I'm going to try.

 

[allenp42]

I could rig up a 5 gallon bucket

WOW. I think you must have a mac daddy tumbler. I have looked last few tumblers but mostly for smaller stuff like nuts and bolts.

 

[fatcaaat]

This is the tumbler I have: https://www.eastwood.com/eastwood-1..._CmlyllIIsckX7koxcYP63cg1A64KFeUaAuJfEALw_wcB

I purchased it at least 10 years ago but have not really used it all that much. I think it was 119 shipped when I got it.

 

[69ST]

Tumble-polishing can do a lot. Ever see an Edelbrock 4bbl carburetor (essentially a Carter AFB)? It also has its limitations...ever seen an Edelbrock 4bbl carburetor?

I've seen industrial units the size of a hot tub...and abrasive media that resembled ceramic tile! Those are used to de-burr heavy castings. Only point here is that this is just another tool, with specific purposes, a specific capabilities within limitations.

There are some caveats with tumble-polishing certain items, not many. If you try to process a batch of brake plates, you'd likely get some damage, as the steel posts strike the aluminum...maybe some wear to the axle & cam bores. What you won't get is a flat (i.e. mirror-like, ripple-free) surface. The aforementioned Edelbrock castings are what you can reasonably expect, after time, testing and perhaps a bit of luck. If the goal is a conventional, mirror-like finish, there's no substitute for old-school metalfinishing & polishing.

FWIW, brake plates & handlebar clamps typically require 60-90 minutes of massaging, at the buffer, once cleaned & stripped of the original clearcoat. Tumble-polishing might shorten the buffer session, which anyone with an aging spine could appreciate.

 

[fatcaaat]

Bob is correct here. on things like brake plates and anything larger or made of aluminum, I am tumbling them by themselves because they will run against one another and cause damage. On a bowl full of steel parts, bolts, springs, and other metal, i have not observed any damage. And you cannot run aluminum stuff with steel stuff. However, I am excited to see what this does as I am expecting it to save a lot of energy when I do a final polish. I don't expect them to come out done, but I do expect them to come out much closer to done.

 

[69ST]

You're on the right track, IMO, Jarred.

 

[fatcaaat]

I think this is the end result of what I'm going to achieve with the tumbler. First panel is what the aluminum looked like when I started. Second picture is after it was tumbled in green triangle media and then tumbled in walnut. Third is after it was tumbled in walnut with red rouge. This process has been completely hands off...i have not touched the parts other than to disassemble and put them in the bowls.

The surface is impeccably smooth but I don't believe i'll achieve a mirror finish on these parts. The claim is that you can use special ceramic bb's to make it mirror, but I don't believe it as I haven't been able to track down a single picture that shows it to be true.

In any event, for a complete hands-off exercise, you have to like these results. Absolutely zero elbow grease here. Once tumbled in the walnut shell, you can take them directly to the buffing wheel. If you need to dress any aluminum scratches and gouges, you need to do that before you even drop it into the first round of green triangles and you'll want to smooth it over. I would imagine if you plan to dress the wounds first, you will probably want an even more aggressive media first, then the triangles, then the walnut shell. I haven't seen enough different between the plain walnut and the walnut with rouge to justify one over the other...looks the same to me.

 

[kirrbby]

I'm sold.

That brake plate is lookin pretty fantastic to me.

 

[kawahonda]

I'd still rather do by hand. I'm too impatient to let something spin for 12-14 hours (and take up shop space) for something that I would STILL have to do a 5-10 minute blue-magic job to with dremil. That part in the picture is not complete by my standards to mount...and I'm not a AAA polish guy either. In my opinion, it's simply just "clean" (like, impressively clean!) but STILL needs polishing with blue magic...

It's not for everyone. My dad had a tumbler and has 2x the space that I do and got rid of it. It just didn't do enough for the space and time that it consumed. In-fact, he didn't really like it...

Look at my fork triple tree top that I posted. That oxidized part (common) took me 5 minutes of time with my Dremel and a wool pad with Blue Magic while drunk. It's not hard to polish stuff. For me, I think the benefits of a tumbler would be for bolts, nuts, and washers.

JMO. I know enough NOT owning one that I can't just throw a part inside of a container and pull it out the next day and have a bolt-up ready part. They don't work that way. You'll still need a wool pad and a dremel to really make it shine. It appears that if anything, it saves you the time of sanding with 320-400-600-1000 grit, but that's purely situational.

 

[fatcaaat]

kawahonda, one thing to note though...on your top tree that you have buffed, i can clearly see a lot of aluminum casting marks...that's not damage, but that's right in the casting itself. Now look at my tree...notice it does not have any...the tumbling process eliminated them and smoothed the surface down. Again, I would say tumbling them is probably the equivalent of doing a progressing sanding operation up to about 1200 grit. I agree that these are not ready to mount (unless this is the look you're going for which it is on a specific bike I"m building). I would not mount these on a full wheel restoration as is. I would also have taken the time to dress some of the wounds.

I guess if you are tight on room, this takes up some space but I find it to be worth it. Why you ask? Because I am tumbling these things off hours. Tumbler isn't running when I'm in the garage because I don't want the noise. I set it before I start work...when I come home from work I reload. When I go to bed I can reload. I like it because it'd doing work for me unattended.

Anyway, i'm not trying to hard sell on this. For me to get a plate to this condition before a final buff, would probably take me 30-45 minutes of hard work. This way it takes time, but no effort.