"Ultra Bright Aluminum Cleaner" acid-based aluminum cleaner review

Hey folks,

I tried an acid-based aluminum cleaner for welding preparation, called "Ultra Bright Aluminum Cleaner". The label says is contains phosphoric acid and something called "Aluminum Biflouride."
Attachment 2577

I performed the test on a piece of relatively clean (but old / aged / lightly oxidized) aluminum 6061-T6 tubing scrap I had laying around. (.065" wall thickness, 1-1/8" OD.)

I applied the solution with a cotton swab (two applications), and as per the directions on the bottle, left it to sit for 1-2 minutes, then rinsed off with water and dried off. A few seconds after application, the cleaner was obviously doing something, at least to change the color of the oxidized surface. I noticed the cotton swab got some dark / dirty aluminum color on it when I wiped the swab over the surface a second time.
Attachment 2578

I prepared two "baseline" tests as well as the experimental test. I left a portion of the tubing uncleaned for a "known bad" baseline (shown at upper-right in picture below.) Additionally, for a "known good" baseline, I removed oxides using one of my a "tried and true" methods: of using a flap disc with light-medium surface pressure (shown at bottom.) And the acid cleaned section is shown at upper-left:
Attachment 2579

I used the AC TIG process to run some weld beads across the surface, using 1/16" 5356 filler rod. I used footpedal to regulate the welding current, and I had the machine set in minimum cleaning (20% EP) AC Balance setting, in order to exaggerate the effect of any oxide on the resulting weld beads.

I performed quick "arc burst" test (before bringing any filler rod into the picture) to verify the tungsten was clean and also to see if the acid cleaner left any residue was was burning (or otherwise generating any soot-like "smut" neaby.) All three surfaces passed the arc test cleanly, without any smut.

Now on to the weld bead results!

First we'll look at the results with the "known good", mechanical/physical method of oxide removal method. Without any oxides on the surface, the weld bead wetted/flowed out in a nice, easily controlled manner. The weld bead had a nice looking, "bright and shiny" appearance.
Attachment 2580
Here is one more view of the same weld bead with different angle/lighting:
Attachment 2581

Next we'll look at a "known bad" (unprepped/oxidized) weld bead:
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Attachment 2583
You can pretty clearly see in the above weld bead, that the molten puddle was flowing underneath an oxide "skin" layer on the top. Where the skin did break up, there were islands of oxide floating on the surface of the puddle, causing a rough / dirty appearance on the solidified puddle surface. The oxides also impeded the control/flow of the puddle (and I was not able to produce as uniform of a weld bead shape as a result.)

Now for two pictures of a weld bead in the "acid prepped" zone (these is the experimental area) - I would recommend zooming in on these to see the details:
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And here is one weld bead that I started in the "acid prepped/experimental" area and ended in the "known bad/unprepped" area:
Attachment 2586

Obivously, the acid prep cleaning method worked nowhere near as good as the physical/mechanical oxide removal method. However, looking at these pictures a little more closely, would you say that it helped some compared to the unprepared baseline? (If you ask me, I think that it might have, at least a little bit, but probably not enough for me to go to the effort of applying it.)

I do wonder if there is a different, better way that I could apply the acid cleaner that would make it work more effectively. Perhaps I should rinse or wipe it off more quickly before it has a chance to dry out as much. It seems like when I wiped the swab over it, something came up on the swab when it was still wet. Maybe I should try a heavier application, or wiping / rinsing it off while it is still wet. I guess although the initial results aren't too great, I'm certainly open to the idea that there could be better way that this product could be applied, that I just haven't figured out yet.

jakeru really enjoy your projects and testing....please keep it up and many thanks for sharing.

Chuck

I'd say this in conjunction with mechanical abrasion (scotch brite) would work well, probably with a solvent wash afterward would be the best prep. also, the longer you leave the surface wet with the acid, the more it's going to etch the aluminum.

I use PPG's metal prep for steel (DX570) on car sheet metal and it definitely cleans the metal well, but it also leaves a film to keep the metal from rusting afterward, so it's not ideal for welding prep on aluminum. it's sensitive to how long you leave it on the metal as to how much it etches, so I'd expect your cleaner to be the same way. you can't see the etch, but the longer you leave it on, the more colors it brings out when you dry it off (on steel, obviously. alu doesn't color at all).

Cleaning aluminum is something I do often at work. Try this -

1. Clean with soap and water. Scrub it good with a piece of scotchbrite.

2. Rinse well.

3. Use a spray bottle to apply acid etch. The etch should get kinda foamy looking if it is working. Scrub with scotchbrite but not the same piece you used with the soap.

4. Rinse well.

If everything is clean your rinse water should run right off with no breaks. A break would mean an unclean spot and needs to be cleaned again.

I made a post awhile back on my "Ongoing project" I acid etched the whole thing before treating with alodine and starting the paint proccess.

Thanks for the tips guys. I'm going to see if I can find a spray head that would screw onto this bottle, and give it another test. I think "spray on" application would make it a lot easier to apply the product more evenly.

I've also been reading up on other (Acid-based) Aluminum cleaners that have a different, perhaps more effective but perhaps more dangerous ingredient in them - hydrofluoric acid. There is one, amazingly, that is readily available over the retail counters of many local auto parts stores, sold as a "eagle one mag wheel aluminum cleaner", in a spray head bottle. I can't help but wonder how it would compare to this product I've got, that uses a different ingredient (aluminum bifluoride.) I've read some pretty scary stuff about hydrofluoric acid though, if it gets on your body! It can even eat away at glass. I think if I ever try that, I'll be following all the safety instructions to the Tee.