Questions on tumbling aluminum

jeg5263 · Apr 7, 2020

Hello all,

So I recently bought a used Mr. Deburr DB300. Wonderful machine so far. Having a few issues achieving my desired finish. I run a metal finishing business and quite often have to take cast aluminum parts and polish to a mirror finish. My hope was that a deburring machine could reduce the time it takes to smooth out castings. I'm tumbling all media with water and a detergent.

First issue I'm having is getting all the casting marks out. Starting out with a general cutting ceramic media. After 24 hours surface finish is not bad but could be better. I believe a more aggressive media could be the solution there. Has anyone ever used a fast cutting media on cast aluminum?

Next I switch to green plastic triangles and no problem with the finish there.

Final step im using porcelain balls. This is where I'm having my biggest issue. After 24 hours the part turns dark grey. I'm wondering if I should be using a burnishing fluid, could that be my issue? I've even went as far as to throw a mirror polished valve cover in and it turned grey.

I've attached a few pictures here to give an idea of what's going on.

Part before going in tumbler

After ceramic tumbling

Third and 4th pic are after porcelain balls

5th pic is a comparison between what cover went in as vs what porcelain did

Finally the finish I want to achieve

I know I will not get away from buffing the pieces but I want to take some of the sanding and prep time out of the job. Any help or suggestions would be greatly appreciated.

GregSY · Apr 7, 2020

I've had the same problem so I'll be interested if there is an answer...

jeg5263 · Apr 7, 2020

GregSY said:
I've had the same problem so I'll be interested if there is an answer...

Is your issue also with the porcelain balls?

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Finegrain · Apr 7, 2020

On the roughing media, I thought the green plastic media was the roughing media. C&M Topline has a "Fast Cut" plastic media, maybe that is what you want instead of the ceramic?

On the burnishing, do you have a recirculating tank to allow sediment to fall out before going back in the tub? IME that makes a big difference in getting a decent shine from the porcelain balls. Might even need to run an inline filter to make sure what goes back into the tub is as clean as possible.

One other thing -- are you running more than one of these parts at a time? One of the picture shows what looks to be impingement of one part against another. That seems like a bad idea.

Regards.

Mike

kustomizer · Apr 7, 2020

Your balls are dirty, so step one is DO NOT RECYCLE THE WATER. We find a couple of tablespoons to start of liquid tide and hot, hot water. Add the water slowly as the balls will quit moving or go backwards in slow motion if you have too much. I think you may have to wash the balls with hot water a few times in 24 hours. Ideally you will maintain a head of bubbles about as big around as a beer can across the back of the machine. When you notice the bubbles to be any darker than snow white you need to rinse them with hot water. Depending how hard your water is you may have to add a bit of dish soap to get the bubbles started. We have used burnishing compound from C&M but have not found it helped much if any. Keeping the balls clean by adding some clean hot water and a bit of tide from time to time is how you get shiny clean parts. That grey shit is all but impossible to remove.

rickseeman · Apr 7, 2020

jeg5263 said:
Final step im using porcelain balls. This is where I'm having my biggest issue. After 24 hours the part turns dark grey. I'm wondering if I should be using a burnishing fluid, could that be my issue? I've even went as far as to throw a mirror polished valve cover in and it turned grey.

I have 1,700 vibratory finishing customers. I've sold over 800 vibratory finishers since 1978 and set up over 1000 processes. You and I have never seen a customer get good looking, shiny aluminum parts without burnishing compound. It can't be done. Your wife's laundry won't come clean without detergent. Your hair won't come clean without shampoo. You always want to use burnishing compound. And as already said above, you don't want to recirculate your water. Your wife doesn't reuse her laundry water. Fresh soap and water in, dirty water out. Another thing about burnishing aluminum. You should be getting maximum shine in around 10 minutes. 3 minutes is my record low and I don't think I've every run any over 15 minutes. When you achieve your best shine remove the parts. If they are as good as you can get them then the only thing that can happen after that is they get worse.

Rick
Vibratory Finishing Mass Finishing Ball Burnishing Deburring Media Compound Equipment

jeg5263 · Apr 7, 2020

Finegrain said:
On the roughing media, I thought the green plastic media was the roughing media. C&M Topline has a "Fast Cut" plastic media, maybe that is what you want instead of the ceramic?

On the burnishing, do you have a recirculating tank to allow sediment to fall out before going back in the tub? IME that makes a big difference in getting a decent shine from the porcelain balls. Might even need to run an inline filter to make sure what goes back into the tub is as clean as possible.

One other thing -- are you running more than one of these parts at a time? One of the picture shows what looks to be impingement of one part against another. That seems like a bad idea.

Regards.

Mike

C&M actually suggested starting with ceramic being that my parts are rough cast. I was just running a pump a few inches from the bottom of a setting tank. So the water is being recirculated. That may be my issue then for sure. Also I'm only running one part at a time.

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jeg5263 · Apr 7, 2020

kustomizer said:
Your balls are dirty, so step one is DO NOT RECYCLE THE WATER. We find a couple of tablespoons to start of liquid tide and hot, hot water. Add the water slowly as the balls will quit moving or go backwards in slow motion if you have too much. I think you may have to wash the balls with hot water a few times in 24 hours. Ideally you will maintain a head of bubbles about as big around as a beer can across the back of the machine. When you notice the bubbles to be any darker than snow white you need to rinse them with hot water. Depending how hard your water is you may have to add a bit of dish soap to get the bubbles started. We have used burnishing compound from C&M but have not found it helped much if any. Keeping the balls clean by adding some clean hot water and a bit of tide from time to time is how you get shiny clean parts. That grey shit is all but impossible to remove.
View attachment 284221
View attachment 284222

Thanks for the reply I think your right my media is dirty. I also bought the media used with about 10 hours on it so I suppose I should have cleaned it from the get go.

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jeg5263 · Apr 7, 2020

rickseeman said:
I have 1,700 vibratory finishing customers. I've sold over 800 vibratory finishers since 1978 and set up over 1000 processes. You and I have never seen a customer get good looking, shiny aluminum parts without burnishing compound. It can't be done. Your wife's laundry won't come clean without detergent. Your hair won't come clean without shampoo. You always want to use burnishing compound. And as already said above, you don't want to recirculate your water. Your wife doesn't reuse her laundry water. Fresh soap and water in, dirty water out. Another thing about burnishing aluminum. You should be getting maximum shine in around 10 minutes. 3 minutes is my record low and I don't think I've every run any over 15 minutes. When you achieve your best shine remove the parts. If they are as good as you can get them then the only thing that can happen after that is they get worse.

Rick
Vibratory Finishing Mass Finishing Ball Burnishing Deburring Media Compound Equipment

Rick thanks for the reply I'm going to get some burnishing compound and do as you said. Hopefully I get better results.

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EPAIII · Apr 7, 2020

Rick, I am a beginner at this, for sure. And to date, I only have done things that are a lot smaller than that aluminum valve cover. It sounds like you know a great deal. I have heard of using a polishing compound/grit with walnut shells. Haven't tried it yet as most tumbling I have done was to remove rust or dirt. What media do you recommend for polishing and just how much of the abrasive should you add? What grit size? Is this measured per gallon or how?

mjk · Apr 7, 2020

If using the walnut shells dry,use breathing protection
I opened the closed tub after the parts were running for a while
Dropped me to the floor
Foretunatly shop door was open and a good 15 minutes of coughing was the worst of it

Delw · Apr 7, 2020

mjk said:
If using the walnut shells dry,use breathing protection
I opened the closed tub after the parts were running for a while
Dropped me to the floor
Foretunatly shop door was open and a good 15 minutes of coughing was the worst of it

if your using corn cob or walnut dry grab a bunch of use dryer sheets and throw them in there. this will take the dust out and keep the media clean ie keeping your parts clean. its an old reloading trick and works great on the mr deburr with walnut and corncob.

as far as shiny finish, I been curious as well. I was going to grab some ceramic balls and still might, then heard stainless balls was better.. but damn 5k to fill a mr deburr is quite a bit. I was thinking of trying a bunch of steel shot and see how that works.

Delw · Apr 7, 2020

rickseeman said:
I have 1,700 vibratory finishing customers. I've sold over 800 vibratory finishers since 1978 and set up over 1000 processes. You and I have never seen a customer get good looking, shiny aluminum parts without burnishing compound. It can't be done. Your wife's laundry won't come clean without detergent. Your hair won't come clean without shampoo. You always want to use burnishing compound. And as already said above, you don't want to recirculate your water. Your wife doesn't reuse her laundry water. Fresh soap and water in, dirty water out. Another thing about burnishing aluminum. You should be getting maximum shine in around 10 minutes. 3 minutes is my record low and I don't think I've every run any over 15 minutes. When you achieve your best shine remove the parts. If they are as good as you can get them then the only thing that can happen after that is they get worse.

Rick
Vibratory Finishing Mass Finishing Ball Burnishing Deburring Media Compound Equipment

Thanks for that Link,you have stuff I havent been able to find.

rickseeman · Apr 8, 2020

Delw said:
as far as shiny finish, I been curious as well. I was going to grab some ceramic balls and still might, then heard stainless balls was better.. but damn 5k to fill a mr deburr is quite a bit. I was thinking of trying a bunch of steel shot and see how that works.

A Mr Deburr won't handle steel media so forget that. It will handle porcelain balls. (Which are also expensive.) Use a good burnishing compound.

Rick

rickseeman · Apr 8, 2020

EPAIII said:
Rick, I am a beginner at this, for sure. And to date, I only have done things that are a lot smaller than that aluminum valve cover. It sounds like you know a great deal. I have heard of using a polishing compound/grit with walnut shells. Haven't tried it yet as most tumbling I have done was to remove rust or dirt. What media do you recommend for polishing and just how much of the abrasive should you add? What grit size? Is this measured per gallon or how?

I used walnut shells and jewelers rouge decades ago to polish copper. Nowadays I use cob or treated cob for dry polishing. Bear in mind dry polishing is a long cycle time, not something I normally sell, because my customers are running millions of parts. You don't use grit, that would scratch the parts. To polish small aluminum parts, run them in small plastic media with burnishing compound to get them very smooth. When they come out they will look terrible, but what you don't realize is they are super smooth and perfectly primed to polish. Now put them in treated cob (this is ground corn cob with aluminum polish mixed in) and let them run. The finished part will be beautiful. This will only work for low volume parts like you and I would run. My customers make parts by the millions. The only good way to do that is to throw the virgin part in steel media with burnishing compound and be happy with the burnished (not polished) finish that you get in 7-8 minutes.

jeg5263 · Apr 13, 2020

So I've cleaned my media thoroughly and also ordered some additional porcelain balls because I think I need more weight in the machine. Also going to order some burnishing compound today and see if that helps. Finally I'm going to try and make a settling tank. Gonna see if I can find a prefab square or rectangular aluminum box and modify for my needs. If I cannot I'll have to make one from scratch. I'll try and update once I get everything done and share my results.

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SRT Mike · Apr 13, 2020

I have gotten a mirror finish on tumbled aluminum parts. I start off with green triangles and I use a little Dawn dish soap and water and run that for maybe 30min. Before the cycle finishes, I stand there with a spray bottle with water and a tiny bit of soap (like half a teaspoon at most) and spray until the parts are very clean.

Then I dry 'em off and put them in walnut shells treated with polishing compound. I found that just using red rouge works too and is cheaper than buying the treated walnut shells. The problem is it takes 12-24 hours tumbling this way to get a mirror finish. I'm lucky in that I can run 30-40 parts at a time, and at least there's no handwork involved in getting that finish. It's not quite as bright as hand polishing with a soft fine buffing wheel for final finish, but it's really close. I was doing it as a pre-chrome plating finish and it worked perfectly.

I really would love to find something that doesn't take so long finishing though... will be interested to hear how you guys make out with ceramic balls.

zschary · Jul 31, 2022

rickseeman said:
I have 1,700 vibratory finishing customers. I've sold over 800 vibratory finishers since 1978 and set up over 1000 processes. You and I have never seen a customer get good looking, shiny aluminum parts without burnishing compound. It can't be done. Your wife's laundry won't come clean without detergent. Your hair won't come clean without shampoo. You always want to use burnishing compound. And as already said above, you don't want to recirculate your water. Your wife doesn't reuse her laundry water. Fresh soap and water in, dirty water out. Another thing about burnishing aluminum. You should be getting maximum shine in around 10 minutes. 3 minutes is my record low and I don't think I've every run any over 15 minutes. When you achieve your best shine remove the parts. If they are as good as you can get them then the only thing that can happen after that is they get worse.

Rick
Vibratory Finishing Mass Finishing Ball Burnishing Deburring Media Compound Equipment

Rick.. I contacted that link on the bottom of your post here and got some burnishing compound and a bunch of media for my 5 CF vibratory tub.. I am getting a very smooth galvanized look finish, which is ok for powdercoat, but want it a bit brighter and more polish looking for anodize, and even shiny .. i read this post above and have followed it.. thinking about adding another smaller machine, i think it will end up being a two step process..
two questions.. what is the brightest i can get with one machine, and what media should i get for the second step machine if i add one? running automotive brackets in 6061 machined aluminum.. Thank you for any help.. Zach

latheman78 · Jul 31, 2022

I have to agree with SRT Mike, walnut shells are great for cleaning the gray finish off and then add polish to shine. Harbor Freight sells perfectly usable walnut shells.

rickseeman · Aug 5, 2022

zschary said:
Rick.. I contacted that link on the bottom of your post here and got some burnishing compound and a bunch of media for my 5 CF vibratory tub.. I am getting a very smooth galvanized look finish, which is ok for powdercoat, but want it a bit brighter and more polish looking for anodize, and even shiny .. i read this post above and have followed it.. thinking about adding another smaller machine, i think it will end up being a two step process..
two questions.. what is the brightest i can get with one machine, and what media should i get for the second step machine if i add one? running automotive brackets in 6061 machined aluminum.. Thank you for any help.. Zach

I retired last year. But there is a new synthetic media that I tried called SM. Wow did I like it on aluminum. Ask them to run a sample for you in it. Small size for best/shiny finish. It gave me the best one step finish on aluminum.

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