Metal Prep Questions

[Backlash]

I have some aluminum pieces that I plan to have anodized. What is the best "Prep" for the metal? Should it be polished to a mirror finish first, or should I leave it somewhat rough, like 600 or 1000 grit? I'm not entirely familiar with the anodizing process but I'd like the finish to be as nice as possible. Thank you in advance!!

 

[t-bag]

It will need to be polished first. The better the polish job the better the anodizing will turn out.

 

[Backlash]

Thank you! I was starting to polish some parts, and then I thought "Maybe the metal needs to have some 'Tooth' to it for the anodizing process."

Thank you @t-bag

 

[monkeyswrench]

Depending on the color and if trying to match existing stuff, I'd check with the anodizer. If parts you're trying to match weren't prepped the same, the color could end up different.

 

[Backlash]

Depending on the color and if trying to match existing stuff, I'd check with the anodizer. If parts you're trying to match weren't prepped the same, the color could end up different.

Thank you Monkey! I've had everything stripped using the same process, and will polish them all out in the same manner. Should turn out pretty nice once everything is all said and done.

 

[RIVERBORN]

Like monkey said. Call the person doing the work. I don’t think they have to be polished necessarily. Maybe save yourself some work.

 

[lenmann]

Generally what you give the plater is what you will get back as far as surface condition goes (aside from the anodize color itself). Platers typically give parts a light caustic "etch" prior to anodizing to clean the parts but unless the etch is really long in duration it doesn't change the surface condition of the parts much. This etch along with the anodize process itself will knock down some of the brightness and reflectivity a polished part had prior to plating but it remains as smooth as it was when polished.

A part that is sanded with an orbital D/A type sander will still look like it was sanded after anodize. A bead blasted surface will look like a blasted surface after anodize. Machining marks likewise remain after. As @monkeyswrench wrench noted the surface condition can effect how color anodized parts look after plating.

 

[Backlash]

Generally what you give the plater is what you will get back as far as surface condition goes (aside from the anodize color itself). Platers typically give parts a light caustic "etch" prior to anodizing to clean the parts but unless the etch is really long in duration it doesn't change the surface condition of the parts much. This etch along with the anodize process itself will knock down some of the brightness and reflectivity a polished part had prior to plating but it remains as smooth as it was when polished.

A part that is sanded with an orbital D/A type sander will still look like it was sanded after anodize. A bead blasted surface will look like a blasted surface after anodize. Machining marks likewise remain after. As @monkeyswrench wrench noted the surface condition can effect how color anodized parts look after plating.

Thank you Lenmann! These will be black so I'd like them to be as deep and glossy as possible. So it makes sense to polish them prior to dropping them off.

 

[Wizard29]

Thank you Lenmann! These will be black so I'd like them to be as deep and glossy as possible. So it makes sense to polish them prior to dropping them off.

Why not powdercoat? Anodizing sometimes has a tendency to fade in the sun. If the black will see sun, you might expect it to be a darker shade of brown eventually.

No need for polishing for powdercoat to come up shiny either.

 

[Backlash]

Why not powdercoat? Anodizing sometimes has a tendency to fade in the sun. If the black will see sun, you might expect it to be a darker shade of brown eventually.

No need for polishing for powdercoat to come up shiny either.

I was going to replace the new finish with what was previously on the pieces......just a different color. These won't be out in the sun for extended periods of time, so I think the ano should be OK. Worse case scenario, if this finish doesn't last, I'll take them off, strip them and then go a different route.

 

[lbhsbz]

Thank you Lenmann! These will be black so I'd like them to be as deep and glossy as possible. So it makes sense to polish them prior to dropping them off.

Black can be done in a UV stable manner…different process/chemistry, but one of my customers does it on his parts…otherwise they eventually turn purple in the sun. You might explore that, if you haven’t already.

Doors/window frames on commercial retail buildings are done like this.