I'm going to send out some aluminum plate to be professionally anodized, and I was hoping others who have done this could tell me what kind of surface prep is needed before anodizing. I'd like to end up with a uniform matte finish.
I've already sanded down to a smooth, bright finish on some of my work, but other panels are raw and have reasonably deep scratches. How much work will those need?
I spoke with a gentleman at a shop here who seemed to think that simply doing a longer acid wash (2 minutes instead of 30 seconds) might be sufficient. He had a low opinion of bead blasting that I know is shared by some people here.
Also, are there alloys that won't work well? I use a lot of surplus and have 6061, 7075, and 2024 pieces. Uniformity of finish from alloy to alloy isn't important to me.
Thanks for any answers...I'd certainly like to get the finish right the first time around. Any other tips on how to get good results from professional shops are also appreciated, likely by the shop as well as myself.
I've already sanded down to a smooth, bright finish on some of my work, but other panels are raw and have reasonably deep scratches. How much work will those need?
I spoke with a gentleman at a shop here who seemed to think that simply doing a longer acid wash (2 minutes instead of 30 seconds) might be sufficient. He had a low opinion of bead blasting that I know is shared by some people here.
Also, are there alloys that won't work well? I use a lot of surplus and have 6061, 7075, and 2024 pieces. Uniformity of finish from alloy to alloy isn't important to me.
Thanks for any answers...I'd certainly like to get the finish right the first time around. Any other tips on how to get good results from professional shops are also appreciated, likely by the shop as well as myself.
Whatever your panels look before anodizing, they will show same imperfections after the process.
So it's up to you how you want the surface to be finished: either brushing, buffing, sand blasting etching or whatever else.
If you have surplus material, some of it may show surface corrosion (and although it may not visible at the moment, it will show after anodizing).
Sometimes anodizing house can do surface finishing as well, ask them what's the best.
So it's up to you how you want the surface to be finished: either brushing, buffing, sand blasting etching or whatever else.
If you have surplus material, some of it may show surface corrosion (and although it may not visible at the moment, it will show after anodizing).
Sometimes anodizing house can do surface finishing as well, ask them what's the best.
They were recommending an extra-long bath. Do you buy this as a solution? I would have thought sanding or brushing would be needed.
I think of there being two main steps when I finish Al...the first gets the scratches out and surface uniform, then second gets a nice even shine. In my experience it takes a lot longer to do step two...if you are anodizing, how pretty does it need to look before going in?
Thanks Peter!
I think of there being two main steps when I finish Al...the first gets the scratches out and surface uniform, then second gets a nice even shine. In my experience it takes a lot longer to do step two...if you are anodizing, how pretty does it need to look before going in?
Thanks Peter!
As I said, it has to look as pretty as possible, as anodizing won't hide anythig. In case your "shine" is a bit uneven it will make it more unifirm, but any small scratches/marks will be still there.
When I bruch the panels myself (100/120 grid belts) I try to make even lines and clean everything with Varsol. After that it may still appear that the lines are not that smooth as I might want them, and this is where I use the next step, which is brushing it on Scotch Brite pads (the purple color). This pretty much makes it final finish. If I make it too long on Scotch Brite pads, the surface becomes matte in some areas and this is no good.
Whatever limited experience I have with that, I would imagine that if you try shortcut proper finishing by extending acid wash, they might be able to get rid of the scratches, but in a same way your panel might shrink in size and loose some fine detail (corners and sharp edges). If this is not a concern, then maybe an acid wash is one step solution, but I don't know.
When I bruch the panels myself (100/120 grid belts) I try to make even lines and clean everything with Varsol. After that it may still appear that the lines are not that smooth as I might want them, and this is where I use the next step, which is brushing it on Scotch Brite pads (the purple color). This pretty much makes it final finish. If I make it too long on Scotch Brite pads, the surface becomes matte in some areas and this is no good.
Whatever limited experience I have with that, I would imagine that if you try shortcut proper finishing by extending acid wash, they might be able to get rid of the scratches, but in a same way your panel might shrink in size and loose some fine detail (corners and sharp edges). If this is not a concern, then maybe an acid wash is one step solution, but I don't know.
Just an info I got from the plant where I get my Al anodized :
Anodizing doesn't add any layer or any material to the Al, but just "replaces" a thin depth of the AL surface with a colored (or not) Al oxyde (from memory). So a scratch remains a scratch. But usually, pieces to be anodized are cleaned with a basic solution (high Ph) to remove (yes, remove) the surface Al oxyde and get access to the raw Al.
Just my two cents (anodized )
Anodizing doesn't add any layer or any material to the Al, but just "replaces" a thin depth of the AL surface with a colored (or not) Al oxyde (from memory). So a scratch remains a scratch. But usually, pieces to be anodized are cleaned with a basic solution (high Ph) to remove (yes, remove) the surface Al oxyde and get access to the raw Al.
Just my two cents (anodized
)
A completely different ballgame (pun intended)
Sand blasting will destroy yout box !!!!
!!!!
Glass ball blasting is a delicte treatment.....done with..you guess it...glass balls
This gives a smoothening effect like if you imagine millions of small hammrs hittitng the surface. You dont really remove any material, you just smoothen it out.
Look up a toolmaker, he will have the equipment for this. It is used in toolmaking for surface treatment after EDM.
Magura
Sand blasting will destroy yout box !!!!
!!!!Glass ball blasting is a delicte treatment.....done with..you guess it...glass balls
This gives a smoothening effect like if you imagine millions of small hammrs hittitng the surface. You dont really remove any material, you just smoothen it out.
Look up a toolmaker, he will have the equipment for this. It is used in toolmaking for surface treatment after EDM.
Magura
Hi Tiroth,
Apart from the surface cleaning issue, if you want to do anodising ask prices from different companies. Have found that prices can vary a lot, up to a factor of 4 (at least here in the Netherlands).
It is best to discuss the whole issue of surface preparation you need to do yourself with the company that does the anodising. The smoother the surface before delivery the better the result, regardless of any surface preparation the anodising company does for you. Usually you need to specify also the thickness of the oxide layer you want.
Also keep in mind that for anodising the object needs to be clamped to get the anodising current through it. These clamp points usually are not nice to see, so these points should be out of sight in you finished product. Discuss this also with the anodising company to avoid unpleasant surprises afterwards, especially if you want a coloured surface.
Cheers
Apart from the surface cleaning issue, if you want to do anodising ask prices from different companies. Have found that prices can vary a lot, up to a factor of 4 (at least here in the Netherlands).
It is best to discuss the whole issue of surface preparation you need to do yourself with the company that does the anodising. The smoother the surface before delivery the better the result, regardless of any surface preparation the anodising company does for you. Usually you need to specify also the thickness of the oxide layer you want.
Also keep in mind that for anodising the object needs to be clamped to get the anodising current through it. These clamp points usually are not nice to see, so these points should be out of sight in you finished product. Discuss this also with the anodising company to avoid unpleasant surprises afterwards, especially if you want a coloured surface.
Cheers
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