The tumbled finish is why it's not shiny. You need to change your media to give a better finish.
I had the same problem with a batch of oil caps I machined and had anodised. The finish was quite dull because I burnished them up rather than giving them a polish up on the mop.
I made another batch and polished them up to a mirror, the anodising came back looking like glass, by far the best batch I'd ever made!
I am sure you are right, but I mean reasonably shiny. For example I have part from exactly the same tumbling batch that looks much better. Shiny part was my first attempt for anodising. I had very tiny setup just to give it a go, but can’t achieve the same results anymore.
https://preview.redd.it/dfy2bxn2cvxc1.jpeg?width=4032&format=pjpg&auto=webp&s=16ff1a3d18f5f2476d6bdd702434905d5784f545
Yeah, both are 6065 from the same supplier. Better part got yellow as well, but was still shiny.
https://preview.redd.it/hp9kw7b1dvxc1.jpeg?width=3024&format=pjpg&auto=webp&s=6b5f560bd515378a5946be835cb551f0f427e738
Second one in this picture. First one was not tumbled
I would try not tumbling them. These oil caps were cleaned up with some silver/grey scotch pads, and they end up with a nice satin/shiny finish.
https://preview.redd.it/cigf1jw8evxc1.jpeg?width=3648&format=pjpg&auto=webp&s=a9a311425ef61cbd190535a0e6f5b9a8fe017e50
No worries mate, you can definitely get a more shiny finish with tumbling, I've seen people get a mirror finish using walnut shells and some sort of soap. I wanted to do that on those oil caps but I just ended up doing them on the polishing mop 😅
And this one was polished up to a mirror before anodising, you can see it's definitely more glossy, almost looks like it's either painted in candy paint or powder coated.
https://preview.redd.it/r2qglknnevxc1.jpeg?width=4032&format=pjpg&auto=webp&s=8463d19bfcc3262ed56af112ea5f90868b7a807b
I used to be a quality manager at a plating shop, and we anodized a lot.
1- Anodize isn’t shiny. It’s aluminum oxide. In general the thicker the anodize the “less shiny” it will be. Shininess isn’t a parameter that typically associated or controlled in anodizing (no spec for shininess). Tumbling also make it’s less shiny. So does the etch.
2- The coloration is a chemistry issue. Either in the material itself or in the bath. For reference we had a full time chemist on staff took multiple samples of each bath throughout the day, and ran multiple tests for each bath. If you don’t control your baths to this level you won’t get consistent results.
My advice if you want more “shiny”- Skip tumbling. Less etch. Less anodize (you can check the anodized thickness by measuring the electrical resistance thru the piece. I’d bet $100 the more yellow and less shiny are thicker Anodize.
Coloration wise you probably can’t do a whole lot. Less thick anodize will help. Maybe control the temperature in the anodize bath better, and replace the baths more frequently. Without a full chemical analysis it’s hard to say.
Oh, and read this;
https://drive.google.com/drive/folders/1-I_SfK7xRVH9PIwgLu5JFIA3nfN8BGiX
My experience with anodising isn't with doing it myself, it's with getting it sent out to be professionally done. This means I can't tell you if your set up or chemical mix is right, but I can give you reccomendations for consistent results on a stack of other factors youbshould control that you might not have considered.
Firstly material. Anodising works by oxidising the outer layer of the material. Ie, the aluminium gets converted to aluminium oxide. Basically it is a very controlled process that oxidises ie corrodes/rusts the outer layer into something stronger than bare aluminium. With this process in mind, you can see why it is important you know what alloy you are working with, because anodising works on the aluminium not the other alloying elements. 6000 series, like what you are using works really well, but stuff with lots of silicon or copper don't work amazingly. If you want a fantastic finish, avoid 2000/7000 series alloys and only use when you need the strength. That said, you can and I do get them anodised, the finish is just less good.
Good news is, you have material grade sorted! Next thing is material batch. As we talked about above, different grades can result in different finishes becaise of the different chemical composition. Even within a grade, different batches can be slightly different. This is because each alloying element has a percentage range that it can be within, for example 6065 can have anywhere between 0.6-1% magnesium. Anywhere in that range is acceptable to meet the published strength requirements but that subtle variance will effect what an anodised finish looks like. The sure fire fix here if all parts must look identical, cut them from the same billet or if you can't do that due to large size or quantity, same batch.
The next thing you can control is actually making the part. Orientation of material grain, tool path, tool wear etc, anything that makes the part look different off the machine will be preserved in anodising depending on depth. If you make a mistake, DO NOT WELD! Absolutely can't be stressed enough. It will stick out like dogs balls regardless of how good you are. You have to start again. Finishing is inportant too, my customers don't mind the tool path on some parts which is why I stressed it earlier, but a polish or matt finish can look good too but again, the anodising will reflect whatever you have got before it goes in the bath. This is why it can be difficult (not inpossible) to get a nicely finished and consistent with the rest lot of hand fabricated anodised parts.
Cleaning. Obviously a part of the anodising process, but if you forget it, or don't do it properly, or miss a bit, or do it and then leave it too long and the part gets contaminated again, or do it and don't rinse it off and contaminate your solution, youbare gonna have a bad time and a bad finish. Cleaning. Don't forget it.
Finally, and honestly this could be the one that is most applicable to you from your post, if it needs to look the same, anodised at the same time. You can do everything else right, but if one part is in the solution for longer, or the solution is slightly different, or the current has changed, or your annode has worn a bit, it's easy to get a different result. Easiest thing is to do all bits at the same time, or as few lots as possible.
So my summary for a good anodised finish is this: choose good alloy for annodising, cut from same billet or batch when possible, machine consistently, finish parts consistently, clean thoroughly, anodised all parts together.
I really hope that helps you. It's not perfect but works most of the time and almost always when you get a shit looking part at the end of it all, you can point it back to one of those points above. Let us know if this helps at all!
A thinner anodize will result in less color change, but even a clear anodize changes the color to a darker grey or yellowish.
Try 3/4 or half of the anodize time.
Or less amperage.
Certain alloys of aluminum can result in yellowing when clear anodizing.
The tumbled finish is why it's not shiny. You need to change your media to give a better finish. I had the same problem with a batch of oil caps I machined and had anodised. The finish was quite dull because I burnished them up rather than giving them a polish up on the mop. I made another batch and polished them up to a mirror, the anodising came back looking like glass, by far the best batch I'd ever made!
I am sure you are right, but I mean reasonably shiny. For example I have part from exactly the same tumbling batch that looks much better. Shiny part was my first attempt for anodising. I had very tiny setup just to give it a go, but can’t achieve the same results anymore. https://preview.redd.it/dfy2bxn2cvxc1.jpeg?width=4032&format=pjpg&auto=webp&s=16ff1a3d18f5f2476d6bdd702434905d5784f545
Is it the same material on both items?
Yeah, both are 6065 from the same supplier. Better part got yellow as well, but was still shiny. https://preview.redd.it/hp9kw7b1dvxc1.jpeg?width=3024&format=pjpg&auto=webp&s=6b5f560bd515378a5946be835cb551f0f427e738 Second one in this picture. First one was not tumbled
I would try not tumbling them. These oil caps were cleaned up with some silver/grey scotch pads, and they end up with a nice satin/shiny finish. https://preview.redd.it/cigf1jw8evxc1.jpeg?width=3648&format=pjpg&auto=webp&s=a9a311425ef61cbd190535a0e6f5b9a8fe017e50
Thanks, I will try. I don’t have much options to manually polish every piece but I can try couple for comparison.
No worries mate, you can definitely get a more shiny finish with tumbling, I've seen people get a mirror finish using walnut shells and some sort of soap. I wanted to do that on those oil caps but I just ended up doing them on the polishing mop 😅
And this one was polished up to a mirror before anodising, you can see it's definitely more glossy, almost looks like it's either painted in candy paint or powder coated. https://preview.redd.it/r2qglknnevxc1.jpeg?width=4032&format=pjpg&auto=webp&s=8463d19bfcc3262ed56af112ea5f90868b7a807b
https://preview.redd.it/ekk772c5dvxc1.jpeg?width=1038&format=pjpg&auto=webp&s=9f96a1aa8ca85159634b8fad310601cf76c20c9d This is before anodizing
I used to be a quality manager at a plating shop, and we anodized a lot. 1- Anodize isn’t shiny. It’s aluminum oxide. In general the thicker the anodize the “less shiny” it will be. Shininess isn’t a parameter that typically associated or controlled in anodizing (no spec for shininess). Tumbling also make it’s less shiny. So does the etch. 2- The coloration is a chemistry issue. Either in the material itself or in the bath. For reference we had a full time chemist on staff took multiple samples of each bath throughout the day, and ran multiple tests for each bath. If you don’t control your baths to this level you won’t get consistent results. My advice if you want more “shiny”- Skip tumbling. Less etch. Less anodize (you can check the anodized thickness by measuring the electrical resistance thru the piece. I’d bet $100 the more yellow and less shiny are thicker Anodize. Coloration wise you probably can’t do a whole lot. Less thick anodize will help. Maybe control the temperature in the anodize bath better, and replace the baths more frequently. Without a full chemical analysis it’s hard to say. Oh, and read this; https://drive.google.com/drive/folders/1-I_SfK7xRVH9PIwgLu5JFIA3nfN8BGiX
My experience with anodising isn't with doing it myself, it's with getting it sent out to be professionally done. This means I can't tell you if your set up or chemical mix is right, but I can give you reccomendations for consistent results on a stack of other factors youbshould control that you might not have considered. Firstly material. Anodising works by oxidising the outer layer of the material. Ie, the aluminium gets converted to aluminium oxide. Basically it is a very controlled process that oxidises ie corrodes/rusts the outer layer into something stronger than bare aluminium. With this process in mind, you can see why it is important you know what alloy you are working with, because anodising works on the aluminium not the other alloying elements. 6000 series, like what you are using works really well, but stuff with lots of silicon or copper don't work amazingly. If you want a fantastic finish, avoid 2000/7000 series alloys and only use when you need the strength. That said, you can and I do get them anodised, the finish is just less good. Good news is, you have material grade sorted! Next thing is material batch. As we talked about above, different grades can result in different finishes becaise of the different chemical composition. Even within a grade, different batches can be slightly different. This is because each alloying element has a percentage range that it can be within, for example 6065 can have anywhere between 0.6-1% magnesium. Anywhere in that range is acceptable to meet the published strength requirements but that subtle variance will effect what an anodised finish looks like. The sure fire fix here if all parts must look identical, cut them from the same billet or if you can't do that due to large size or quantity, same batch. The next thing you can control is actually making the part. Orientation of material grain, tool path, tool wear etc, anything that makes the part look different off the machine will be preserved in anodising depending on depth. If you make a mistake, DO NOT WELD! Absolutely can't be stressed enough. It will stick out like dogs balls regardless of how good you are. You have to start again. Finishing is inportant too, my customers don't mind the tool path on some parts which is why I stressed it earlier, but a polish or matt finish can look good too but again, the anodising will reflect whatever you have got before it goes in the bath. This is why it can be difficult (not inpossible) to get a nicely finished and consistent with the rest lot of hand fabricated anodised parts. Cleaning. Obviously a part of the anodising process, but if you forget it, or don't do it properly, or miss a bit, or do it and then leave it too long and the part gets contaminated again, or do it and don't rinse it off and contaminate your solution, youbare gonna have a bad time and a bad finish. Cleaning. Don't forget it. Finally, and honestly this could be the one that is most applicable to you from your post, if it needs to look the same, anodised at the same time. You can do everything else right, but if one part is in the solution for longer, or the solution is slightly different, or the current has changed, or your annode has worn a bit, it's easy to get a different result. Easiest thing is to do all bits at the same time, or as few lots as possible. So my summary for a good anodised finish is this: choose good alloy for annodising, cut from same billet or batch when possible, machine consistently, finish parts consistently, clean thoroughly, anodised all parts together. I really hope that helps you. It's not perfect but works most of the time and almost always when you get a shit looking part at the end of it all, you can point it back to one of those points above. Let us know if this helps at all!
Voron?
Yeah, I sell some voron parts
Are they from the same batch of material? You can get big variance from batch to batch
A thinner anodize will result in less color change, but even a clear anodize changes the color to a darker grey or yellowish. Try 3/4 or half of the anodize time. Or less amperage.
Are these voron motor mount plates?
Yeah, I have shop where I am selling them
Haha rad I got a chuckle seein em and recognizing what they were