Spec me a grinder/belt for finishing aluminium.

Hi all.

Looking for suggestions on what grinder/sander or combo to help finish my aluminum product case.
I am anodizing matte black so want a smooth but not shiny/mirror finish.

Thinking of using Scotch-Brite belt or wheels to get a nice satin finish that will take away any burs and give a nice flat finish.

Been looking at these;
http://www.hollisonsupply.co.uk/surf...BoCNQMQAvD_BwE
http://www.hollisonsupply.co.uk/r-we...x100x19mm.html
http://www.cooksongold.com/Jewellery...ite&channel=uk
http://www.cooksongold.com/Jewellery...ite&channel=uk
http://www.ebay.co.uk/itm/RDGTOOLS-6...38.m2548.l4275


There is vat-free next Sunday at MachineMart so I have been looking at their bench grinders and belt sanders.
https://www.machinemart.co.uk/p/cbs1...t-disc-sander/
https://www.machinemart.co.uk/p/cbg6...r-with-sander/
https://www.machinemart.co.uk/p/cbg6...bench-grinder/

Anyone got any suggestions?
I know there would be some modding with the wheels and Clarke stuff but might work well?

If you want matt/satin, I'd be looking at some form of blasting/media polishing.
How big are the parts?

Anything that involves rotating disks/belts will leave a swirled/brushed finish.

1. To get it flat linish or sand.
2. To get it smooth polish.
3. To get rid of the mirror finish blast, vibrate or tumble with a media to break the surface.

This will give you precise control of your surface finish, I use triangular ceramic media in a tumbler to matt the finish of some parts I manufacture to match the WD originals,

- Nick

I sort of discounted vibration/tumble because of cost.

If it is the best method to get me the finish I need then I might invest.


The parts are up to 80*65*15 and 100*42*15

https://www.frost.co.uk/motor-parts-...isher-8kg.html

I got mine when they were still £99. Not the most robust of machines, but does the job, and was the cheapest tumbler I could find that would handle reasonably sized parts, without spending 4 figures on an industrial machine.
The media is very expensive from Frost though. The last batch I got was from Moleroda (https://www.moleroda.com/product-cat...and-compounds/), but have a search.

Hard to tell how big it is without seeing it. Do you know/think it could take the size of the part I am working with?

Quite big!

From the description-

Quote:

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The drum opening is 10-1/2" in diameter allowing the easy addition or removal of items

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I'm about to head to the workshop so can get some accurate measurements, but it's about 18" tall, and is currently sat on my 12x18" granite surface plate.
It'll easily handle those size parts, but it'll takes a fair bit of media. Just checked my last order, and it was for 5kg bags, which give a reasonable level in the bowl.

Okay that is pretty good then.

Found it on eBay for same price but free shipping, https://www.ebay.co.uk/itm/302084901600

As for media. I have some button holes that are 12x12mm. Would be nice to be able to have it finish them and make them smooth to the touch.
What media should I be using and what size?

From what I have read, the plastic stuff is ideal for aluminum as it is not too abrasive compared to the stone which is better for harder metal like Steel.

[edit] I also have this thing, it comes out a bit steppy. Would like to be able to have this come to a nicer finish.

https://s1.postimg.cc/13y5rapen3/Capture.png

Just measured it, and the base is about 14" diameter, and overall is height is about 19.5".

I use plastic 20mm pyramids, as I use it for deburring and finishing smallish aluminium parts. A 5Kg bag of the pyramids fills it up to around the mid level of the bowl.
I normally throw in what parts I'm doing, and let it rumble away for an hour, which seems to be enough to flatten all the surfaces and knock the burrs off.

I do also have some ceramic prisms, but I've never had a reason to try them.


However, it may be worth considering bead blasting, as I think it gives a nicer finish on flat surfaces, provided you get the technique good. It does however take more time, and you need good extraction/filtering, as you really don't want to be breathing sand or glass dust.

Would going to 10mm be better for the small wholes within my design and the concave part?
As for bead blasting, I don't really have the room. That and I need something I can just turn on and get on with other things like anodizing.

Given they are fairly small parts with tight nooks and crannies I'm not convinced you'll be happy with anything other than sand blasting.

You could try tumbling in a finer abrasive material like aluminium oxide grit (Like often used for blasting), that's more likely to get into the internal corners etc than the large tumbling media. You might need to experiment a bit.

Hmmm

Well I ordered the tumbler so will try it I guess.
Just need the media.

[edit]
I am not looking to finish the inside of the case, only the rounded bit a the front.
It is quite stepped so probably wont do much.

Dam this thing is gigantic.
And for £150 shipped that is quite impressive. I just hope it lasts long enough though.

Been talking with Moleroda Finishing and they are suggesting 10-20mm media.
10mm being higher chance of getting into the button holes I have so went for that.
Should arrive tomorrow and will get to tumble all day :)

Thanks for all the help guys.
Hopefully will come back with good results.

https://www.youtube.com/watch?v=bEyAsjIf_-E

I assume that's an Anodised part going in the colour pot, is the noise your giant tumbler running in the background? :D
The part looks good BTW,

- Nick

Quote:

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Originally Posted by magicniner

I assume that's an Anodised part going in the colour pot, is the noise your giant tumbler running in the background? :D
The part looks good BTW,

- Nick

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Posted the wrong video to the wrong thread.
Edited the post with the actual one.

And thanks!

PS, the noise is a server fan extracting fumes from the shed.

Crikey, that tumbler is a bit of a beast!
Looks like you're nearly there with everything, do we get to see the finished product when it's done?

- Nick

Quote:

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Originally Posted by magicniner

Crikey, that tumbler is a bit of a beast!
Looks like you're nearly there with everything, do we get to see the finished product when it's done?

- Nick

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It is really good and bigger than I expected. Only £150 too. Originally I discounted tumbling as I thought it was at least a couple grand for one that could take my parts.
The media is a bit expensive. This 10mm stuff is £66 with postage.
20mm is a lot cheaper, over half the cost. But I needed a bit more fine media to get into the smaller bits of my part.

Yea ill post photos somewhere.

Get some water and detergent in that tumbler and get the lid on!

The emphasis is on some - you want just enough water to keep things wet and clean, as too much dampens everything.
And it's noticeably quieter with the lid on.

Quote:

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Originally Posted by m_c

Get some water and detergent in that tumbler and get the lid on!

The emphasis is on some - you want just enough water to keep things wet and clean, as too much dampens everything.
And it's noticeably quieter with the lid on.

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Regular dish soap works fine right?
And I normally tumble with the lid on. Only had it off for the video.

Same tumbler I have from the looks of it.

Do you have a high res pic of the finish with the 10mm?

Quote:

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Originally Posted by Zeeflyboy

Same tumbler I have from the looks of it.

Do you have a high res pic of the finish with the 10mm?

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Can get the DSLR out tomorrow.

Just put some old parts into it today for like 6 hours and they came out quite nice. Though I think I put too much soap in there...
Annoyingly the tap that was included with mine could not screw in all the way and the thread was a bit off/loose.
Means I can't half empty it with the pipe. Will have to get after market pipe to fix that. The amount of dirt that is coming off makes me want to put it through a filter?

I've got no idea if household soap will work or not, I just bought a bottle from Moleroda.

The way commercial systems work, is they periodically inject some water/soap in, and there's a drain plug at a suitable height to let excess run out.

I think the drain plug on the tumbler is at a suitable height for a similar setup, but you are correct in that the supplied tap is a rubbish fit. I bought new fittings to create a more robust setup, however it's still on my roundtuit list.

For filtering, letting the run off sit in a container would probably be enough to let the vast majority of debris settle out.

Before
https://s1.postimg.cc/33ts857awf/IMG_1351_1.jpg

https://s1.postimg.cc/216ubfec4f/IMG_1352_1.jpg

After
Come back at 7pm :p

The sun went away so here is inside workshop. I should have taken a photo of them inside instead of outside but should show you the difference.
These 2 bits are just test pieces I did when I first got the 6040. So really bad edges and I left about 0.02mm on the deck then cut them from it using a knife.
Left a really sharp edge but as you can see it has taken most of it off.

https://s1.postimg.cc/1v8zc7e10v/IMG_1357_1.jpg
https://s1.postimg.cc/2gimyiamhb/IMG_1358_1.jpg

Cheers.

Looks pretty decent - might have to grab a bag!

I wish I had something to compare it to.
But does what I need..

£55 a bag though. Lot more than 20mm which is less than half the price. Wonder if one could make their own....?

Quote:

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Originally Posted by magicniner

1. To get it flat linish or sand.
2. To get it smooth polish.
3. To get rid of the mirror finish blast, vibrate or tumble with a media to break the surface.

This will give you precise control of your surface finish, I use triangular ceramic media in a tumbler to matt the finish of some parts I manufacture to match the WD originals,

- Nick

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That should be written in big bold black words. Finishing is an art itself. I believe i have invested in finishing as much money as all else together in my workshop. And am constantly piling up different machines and materials related to that.

The finest sand, almost dust like at 1-2 euro 25kg bag+mini sandblaster gun from Lidl gives me the nice matte finish for small parts. For seconds.