Anodized Aluminum differences?

[Kit Dumph]

Hey guys I create a product that uses full sheets of black anodized aluminum, but I am having trouble getting a nice white engraving like I do with other anodized products. Are there certain anodization process's that are better for a C02 laser in terms of getting a better contrast? I have tried just about every setting, but I'm at the point where I think it might be the metal I have. I go through a local large metal supplier, and I don't think the aluminum is "dipped" as only one side is anodized. Any ideas, and or recommendations on metal suppliers that I could order quality anodized alum from in bulk?

[Jack Clague]

Not sure about your local suppliers but there can be major differences in the quality for engraving depending on how the metal is treated both before and during the anodization process, the tags I get from my local supplier come up a vibrant white and I pay more for this as they process the metal before the anodization to give that white punch.

[Kit Dumph]

Any way you could figure out what that actual process is?

[Mike Null]

Are you certain it has been anodized? In 20 years I have never seen anodized that was done on only one side.

[Tony Lenkic]

Mike, I've seen it done one side only and still have some strips of it in my garage 0.080" clear anodized.

[Scott Shepherd]

Yes, I've also seen (and used) 1 side only material. I don't know how they do 1 side only, but they do it. In my limited experience, it's more in the industrial side of the business and supplier network.

[Mike Null]

Good to know. I just ran a prototype for a military job yesterday and it was the best example of anodizing I've ever seen. I had to power up over my normal settings but it came out looking great.

[Kit Dumph]

Not sure, but got in contact with these guys http://www.idplates.com/sheet-metal/aluminum/. Very helpful and have some samples coming my way, will see what they price me for 50 pcs of 18X24.

[Ross Moshinsky]

Find out where you can buy wholesale sign supplies in your area. Contact them and find out if they carry anodized aluminum sheets. They should. Then either ask them or the mfg for a sample. It will likely save you more than a few bucks doing it this way.

[Kev Williams]

Find a good sheet metal shop in your area and have your own made to order. I pay less for 21" x 32" x .094" sheets than prices I see online for 12 x 24 x .040 sheets. And I always know what I'm going to get :)

As for differences in anodizing-- yup. I've ran into so many different blacks it's amazing. One place brings me these small anodized covers that some guy with his own special recipe anodizes, and they're literally useless to try and laser. Hit it with 20% power and it goes dark blue, and that's as light as it'll go. Any less power, it barely goes anything. 30% and above, the more power you use, the darker it is. I just tool engrave the things.

Lately it seems the plating shops are really anodizing on the "light" side... looks great, jet-black and smooth, but hit it with 60% or more power and it burns off. Go down to 40% and now it's too dark... There's usually a sweet spot, but finding it is a pain, and it never seems to be consistent.

The stuff I have made for myself, it's very un-finicky, and it always goes a nice bright off-white with high power.