Tumbling finish plastic vs ceramic media on aluminum

Wanted to get some input on the finish I am getting using some plastic media in my tumbler, in my opinion it is not nearly as good as the finish I was getting with ceramic. The reason I went with plastic is I pretty much only tumbled aluminum parts and I needed to buy more media since I was only running the tub roughly 1/3 full. I was happy with the appearance using ceramic but the feel was a bit rough and everyone said plastic for aluminum and not ceramic, so I bought 100 lbs of plastic

I just want to know if the finish I am getting with plastic is on par with what everyone else gets. At this point I have ran the plastic stuff for about 10 hours. The finish does feel a little bit smoother but I do not like the look. Another downside I have discovered is the green foam, I have been needing to keep an eye on it/scoop it out to stop it from overflowing in the water bucket.

Not sure if I need to break it in longer or if I should have bought a different shape or if I just need to go back to ceramic


Machine - Burr Bench model 2016
Ceramic Media - Mission Abrasives P40 angle cut tri star (their general purpose ceramic)
Plastic Media - Mission Abrasives green plastic triangles (sold as their less aggressive perfect for aluminum media)

I use a similar plastic in tetrahedron
Looks similar
Dunno what you are looking for in finish

I use a little bigger plastic media to debur and it comes out similar. Almost like a fine galvanized finish. About like yours but I can't tell real well. I then tumble them in porcelain spheres or cylinders depending on the shape of the part and that shines the parts up pretty good. I can still see some of the scratches after this and I would like to fix this. The porcelain supposedly does not reallly remove much metal at all it is more of a burnish as I understand it.

My media comes from c&m topline. It's on my list to contact them and see if there is a plastic media that will debur but leave less scratches.

I am certainly no expert but I though ceramic was more for steel.

@gustafson - ideally the finish I am looking for is like the part I did with the ceramic media but maybe a bit smoother/brighter

@pete deal - you hit it on the head with the almost galvanized look. Good to know about the porcelain, any chance you have any photos of parts after the porcelain treatment? Another media I read about from UM Abrasives is their ULP ceramic, they said its a great alternative to plastic. Do you have any preference with the spheres to cylinders with porcelain?


Another concern/theory I have is if I fill the tub with ceramic it may be too aggressive. The tumbling action seems to be faster with a full tub and I imagine the parts having more weight on them when they're at the bottom would result in faster material removal.

Ceramic works for tumbling alum but it rounds edges fast(wont break the burrs off just round them over on top of a feature. the green you have I dont like it personally as its too hard and rounds edges also and dents thin parts and thin edges.
we use GTC1660 1/2 x 9/16 Synthetic Cone, SX Formula its pink in color. Its softer than the green and doesnt break down edges(we have .005 breaks on edges)
I run between 15-30 mins depending on parts. get a nice even sheet metal type finish with no burrs. leave it in longer and your finish is finer not sheetmetaly as much, but you also risk rounding corners.
Water flow will make your media go faster ie more aggressive and Slower less aggressive.
one thing for sure dont let your water get to dirty as your part may look like the finish you want, but once you run the soap and clean water again it will show the sheet metal finish. looks are deceiving on finishes because of this..

Also never run plastic media with steel, brass etc etc then use the same media for alum as it will scratch your alum parts and embed metal into it.

HI Woz,

We use Professional Finishing Systems pink plastic for our 6061 deburr, and get a finish about like what you're seeing. The advantage to the plastic versus ceramic is we get that finish in about an hour, rather than 4-6-8 or so. So the cycle time is *MUCH* faster. Also actually deburrs and grinds a bit, rather than just burnishing down.

I second the recommendation about running with water flow through the machine. Really no other way to fly. Otherwise the gunk from the plastic just loads up everything and it stops cutting. Remember to buy or build a settling tank to get the crud out of your outflow water, or you'll be replacing pipes and explaining yourself to the local wastewater folks. Neither cheap nor fun.

I used to run a line of tumblers working precious metal parts for jewelry. (Silver and gold) The thing with those is that there are *several* steps through various types of abrasive to get from raw casting (or machined part) to the final mirror finish. For the parts I was running, it took four days for any one part to get through the system. 24 hours in each of four different machines, with four different media in them, stepping up from rough cut down, to medium, to a fine burnish with ceramic, to a final polish with rouge coated walnut shell.
It was just the routine: come in the morning, dump the rouge machine, reload with contents of ceramic burnish, reload with contents of grind 2, reload with contents of grind 1, and fresh load grind 1. Rinse. Repeat. For years. Very little actual hands-on polishing on any one piece. So it worked great for production parts.

FWIW,
Brian

Delw said:

one thing for sure dont let your water get to dirty

Click to expand...

Do you have any suggestions or links to something that filters the water?
We have a Burr Bench and are using the thing pretty much daily on aluminum and copper. But for now the water is just a 2-3 gallon tub inside the tumbler and of course it gets nasty very quickly.

We put only clean hot water in our tumblers, the old goes out the drain. After deburring with plastic or ceramic these go in the little white balls for 20 min or so and come out shiny. We use a tablespoon or so of liquid tide in both operations. Hot clean water.

These parts are tumbled about 30 minutes in plastic media. 3/4" wedge plastic media from CM Topline (see link). Then about 2 hours in porcelain spheres or cylinders. The cylinders get into cracks better but get stuck pockets in my parts and it is a total pain to get them out. About a 1/2 hour in the plastic media rounds the edges about .003"-.005", which I like because these are rifle scope rings. These are pretty low value parts with lots of angles coming together so it is not practical to totally debur in the machine. They look a whole lot better after the porcelain but I think you can see in the photo that the scratches are not totally removed.


Wedge 1 X 3/4 X Green Plastic Media, 50 lbs



– C&M Topline

Getting a shiny finish on aluminum is not difficult. It just takes a little knowledge, which you are accumulating. It can be done with ceramic, porcelain or even plastic/synthetic. Regardless of media you want to use a burnishing compound. This is a soap that you mix with the water that goes in the machine. I'm not sure how pretty/shiny you want those parts. Nor do I know how much deburring needs to be done to them. This would dictate which media I would use. There maybe something in this article that will be helpful.

Fundamentals of Mass Finishing Vibratory Finishing Steel Ball Burnishing

Alberic said:

HI Woz,

We use Professional Finishing Systems pink plastic for our 6061 deburr, and get a finish about like what you're seeing. The advantage to the plastic versus ceramic is we get that finish in about an hour, rather than 4-6-8 or so. So the cycle time is *MUCH* faster. Also actually deburrs and grinds a bit, rather than just burnishing down.

I second the recommendation about running with water flow through the machine. Really no other way to fly. Otherwise the gunk from the plastic just loads up everything and it stops cutting. Remember to buy or build a settling tank to get the crud out of your outflow water, or you'll be replacing pipes and explaining yourself to the local wastewater folks. Neither cheap nor fun.

Click to expand...

Thanks Brian! When you say the finish you get with the pink plastic is similar to what I'm seeing do you mean what I'm seeing with the plastic or ceramic? Also, do you find the pink plastic foams less than the tradition green? (I see on professional finishing systems website their plastic is synthetic and supposed to be less messy than the tradition green polyester)

Pete Deal said:

These parts are tumbled about 30 minutes in plastic media. 3/4" wedge plastic media from CM Topline (see link). Then about 2 hours in porcelain spheres or cylinders. The cylinders get into cracks better but get stuck pockets in my parts and it is a total pain to get them out. About a 1/2 hour in the plastic media rounds the edges about .003"-.005", which I like because these are rifle scope rings. These are pretty low value parts with lots of angles coming together so it is not practical to totally debur in the machine. They look a whole lot better after the porcelain but I think you can see in the photo that the scratches are not totally removed.

Click to expand...

Thanks for the photo Pete, those parts looks great, sounds like I may need to get some porcelain and do it as a 2 step process. Seems like about the same process kustomizer is using and those levers are also look really nice.


@mtndew - Yesterday I put a hole in the side of my burr bench cabinet so I can run the recirculating pump in a 5 gallon bucket instead of the smaller one thats in the bottom of the cabinet, this also meant extending the tubes. I built a shelf from some perforated stainless to keep the pump about 5" off the bottom of the bucket to avoid sucking up any muck. This doesn't exactly help filter the water but it does allow me to change out the water easily with a 2nd bucket. It also allows me to scoop off the foam which I put in a large plastic bin and dispose of once it dries to a powder. I haven't fully thought it up yet but it seems like some sort of filter could be added easy enough to this external system.

Alberic said:

HI Woz,

We use Professional Finishing Systems pink plastic for our 6061 deburr, and get a finish about like what you're seeing. The advantage to the plastic versus ceramic is we get that finish in about an hour, rather than 4-6-8 or so. So the cycle time is *MUCH* faster. Also actually deburrs and grinds a bit, rather than just burnishing down.

I second the recommendation about running with water flow through the machine. Really no other way to fly. Otherwise the gunk from the plastic just loads up everything and it stops cutting. Remember to buy or build a settling tank to get the crud out of your outflow water, or you'll be replacing pipes and explaining yourself to the local wastewater folks. Neither cheap nor fun.

Click to expand...

Thanks Brian! When you say the finish you get with the pink plastic is similar to what I'm seeing do you mean what I'm seeing with the plastic or ceramic? Also, do you find the pink plastic foams less than the tradition green? (I see on professional finishing systems website their plastic is synthetic and supposed to be less messy than the tradition green polyester)

Pete Deal said:

These parts are tumbled about 30 minutes in plastic media. 3/4" wedge plastic media from CM Topline (see link). Then about 2 hours in porcelain spheres or cylinders. The cylinders get into cracks better but get stuck pockets in my parts and it is a total pain to get them out. About a 1/2 hour in the plastic media rounds the edges about .003"-.005", which I like because these are rifle scope rings. These are pretty low value parts with lots of angles coming together so it is not practical to totally debur in the machine. They look a whole lot better after the porcelain but I think you can see in the photo that the scratches are not totally removed.

Click to expand...

Thanks for the photo Pete, those parts looks great, sounds like I may need to get some porcelain and do it as a 2 step process. Seems like about the same process kustomizer is using and those levers are also look really nice.

Mtndew said:

Do you have any suggestions or links to something that filters the water?
We have a Burr Bench and are using the thing pretty much daily on aluminum and copper. But for now the water is just a 2-3 gallon tub inside the tumbler and of course it gets nasty very quickly.

Click to expand...

Yesterday I put a hole in the side of my burr bench cabinet so I can run the recirculating pump in a 5 gallon bucket instead of the smaller one thats in the bottom of the cabinet, this also meant extending the tubes. I built a shelf from some perforated stainless to keep the pump about 5" off the bottom of the bucket to avoid sucking up any muck. This doesn't exactly help filter the water but it does allow me to change out the water easily with a 2nd bucket. It also allows me to scoop off the foam which I put in a large plastic bin and dispose of once it dries to a powder. I haven't fully thought it up yet but it seems like some sort of filter could be added easy enough to this external system.

rickseeman said:

Getting a shiny finish on aluminum is not difficult. It just takes a little knowledge, which you are accumulating. It can be done with ceramic, porcelain or even plastic/synthetic. Regardless of media you want to use a burnishing compound. This is a soap that you mix with the water that goes in the machine. I'm not sure how pretty/shiny you want those parts. Nor do I know how much deburring needs to be done to them. This would dictate which media I would use. There maybe something in this article that will be helpful.

Fundamentals of Mass Finishing Vibratory Finishing Steel Ball Burnishing

Click to expand...

Thanks Rick, going to read that article now! I have been using mission abrasives MSI-60 compound which is what they recommended to me. My primary focus is finish, I want the parts to be matte or have a pretty low shine, but mainly I want the finish to look consistent (not the galvanized look like I'm getting) As far as deburring/corner rounding I am not too concerned with the corners getting too rounded over, I feel it gives it less of a machined part look and a bit more of a cast look, which I'm OK with.

HI Woz,

With the PFS Pink, we get a finish about like what you saw with your plastic. We get the little 'galvo' stripes, which I don't mind, particularly. They disappear under ano. (or at least *dark* ano.) There are umpteen different media manufacturers, so 'green' doesn't tell me much about what you're running. No idea if yours foams more or less than mine. But the PFS stuff doesn't foam much at all.

One thing I will tell you from running a gold finishing line where a jewelry class mirror finish was the end goal: you'd be shocked at how much damage the parts can take from whacking into other parts in the barrel. To get a really good finish, you need to run many fewer parts than you're probably used to. For most machined parts, it doesn't matter so much, but the better the finish you want, the fewer parts per run.

As far as water, our inflow is piped in straight from building plumbing. We have a little metering widget that mixes the soap straight into the inflow water, based on water flow. (Some number of ML/Ltr, or somesuch. Don't remember off my head what its set to. Fire and forget, mostly.) Then the water flows out into a bucket under the machine. Wherein lives a sump pump that pumps it, sludge and all, over to the settling tank, every so often. There are somewhere between 3-5 chambers to the tank, depending on how you want to count it. But the idea is it pumps into chamber 1, which overflows into 2, which overflows into 3, which drains into another bucket, with another sump pump, and then out to wastewater. The goal is to get all the sludge and crap out of it before it hits the wastewater stream, which is monitored by grumpy California environmental folks. Best make sure it's clean before it gets there. Total volume of each chamber is roughly 20 gallons, with chamber one (the first one) being twice the size of the rest.

Actually, seriously, if you're running copper, or anything with much copper in it, you really want to make sure that's out of the wastewater stream before you dump it. Copper in the outflow water is pretty seriously toxic to all sorts of wildlife. It is, however, attractive for lawyers. Again, best make sure it's out of the stream.

Hope this helps.
Regards,
Brian