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Joe Pelonio
08-03-2006, 4:53 PM
A wholesale customer wants a bunch of laser engraved panels made of 3/8" thick anodized aluminum for a permanent outdoor display. He found a place in Seattle to buy the aluminum and is sending it to a place in Oregon to have it anodized. They dip it so that the edges are also annodized, unlike the small thin stuff we often use. I thought I'd pass this along in case anyone else gets a request for an odd one like this. I don't know what all this is costing. He's just sent the aluminum down there, I will do a sample when it gets back. The people that do the anodizing are:

Sapa, Inc. 1-800-547-0790

Dave Jones
08-03-2006, 5:16 PM
There's an industrial anodizing place near here that I use. They have a minimum $150 lot charge, but can do a fair number of pieces in that lot.

I hope he told them it was for outdoor use. There are different dyes used when anodizing for outdoor use. The cheaper anodize dyes don't hold up to UV for more than a couple of years.

Joe Pelonio
08-03-2006, 5:25 PM
Yes, in fact that's why he went to Portland. There are places in Seattle but they only do indoor.

Dave Fifield
08-03-2006, 8:58 PM
Thanks for the tip Joe - I'll file that reference away for future use. I have never had good luck with any anodizing house. The quality seems to vary so much, just from one batch of panels to another, even run at the same place on two consecutive days. One thing I have found is that the bright aluminum parts to be anodized need to be scrupulously clean or the finish will be ruined.

Cheers,
Dave Fifield

Mike Null
08-03-2006, 11:45 PM
Have had good and bad experiences. Good, black anodized weathers extremely well and is in outdoor use at Missouri Botanical Gardens. It is not uncommon for them to get 5 or 6 years out of a sign before they replace it. They have 100's.

Bad, the anodizers are not all careful about their process and some will not engrave. I just finished a 500 piece job where we had to send back 300 pieces to be re-done. They just wouldn't engrave.

I have another marking job first thing tomorrow where the finish was so bad I rejected them and my customer sent them back for refinishing.

Just be careful not to overpower it. The best image will result from the discoloration of the anodized material, usually to a whitish color. You can engrave through the anodize to the aluminum but I think the image is not as sharp.

Joe Pelonio
08-04-2006, 8:40 AM
Thanks Mike. They sent me a couple of samples that I ran at 100 speed 30 power and they worked fine, but that was not the same aluminum that
were using for the signs. When I get that one I'll experiment on the back
(worst side) first.

Dave Jones
08-04-2006, 12:28 PM
I've been doing a lot of black anodized aluminum with very small text and photos using Photograv. I typically do the text only stuff at 50%S and 30%P at 600pdi on my 45 watt Epilog. For the photos I tend to use 25%S at 18%P, 600dpi using 300ppi images. That allows the small single dots to engrave OK. Any more power and it starts to blur. Any less and it's not quite as white an engraving. Your mileage may vary.

Joe Pelonio
08-16-2006, 11:32 AM
Update: The 3/8" thick material came in and the annodizing job is really bad. You can see streaks of the aluminum underneath through the finish.
I engraved the back as a test and the results, as you can imagine, are
not at all satisfactory due to the lack of contrast even on text, the photo worse. I don't know if it's the aluminum itself, the way they annodized it or what, but my (wholesale) customer is going to have to go back to the
drawing board on this one before I do the 16 plaques.

Mike Null
08-16-2006, 12:11 PM
Joe:
Sorry to hear of your bad experience. Your results sound exactly like what we encountered where I engraved the image several times and still could not get good or consistent contrast.

We ended up sending all back to be re-anodized. When they came back they engraved beautifully.

Good luck.

Jim A. Walters
08-16-2006, 6:13 PM
I have recently seen some black anodized aluminum that was stripped for rewelding at my brothers tool shop. The stripped aluminum was snow white. I can understand why anodizing would engrave beautifully the second time.

We use Lawrence and Fredrick in Chicago to supply us with 0.020 black anodized plates for our production job. (http://www.lawrencefrederick.com/)

When we first started, the engraving had streaks come through. We discussed this with them, and they changed the finish of the aluminum before it went to anodizing to fix the solution. I will email them to see what the best pre-anodized finish is and post the results.

Jim

Joe Pelonio
08-16-2006, 6:37 PM
Thanks Jim. This is the job that I just posted the photo image problem on,
you can see the bad annodizing in the pic between the lettering in the lower
right.