Is Simple Green safe to clean aluminum in an ultrasonic?

[creia]

Has anyone tried this? If so, what were the results and what mixing ratio did you use? I have been using Dawn Dish Soap on these 40-50 year old Briggs aluminum engine blocks for years with what I would call "OK" results. I am looking for something a little more aggressive and thorough as a cleaning agent, however, I do no want to darken, discolor or otherwise damage these aluminum blocks, ESPECIALLY the bores.The Simple Green bottle does not say anything about NOT using it on Aluminum. I welcome and appreciate your experiences.
Michael

[bgsengine]

I'd suggest testing first on a scrap block but most of the discoloration or damage would come from when the moisture oxidizes on the metal. to prevent that oxidation, you got to either prevent moisture, or prevent oxygen - chances are anything you use, you'll never get that shiny new polish of aluminum that is left from a casting mold or press and you may have some color shifts over pattern areas (darker-lighter-darker) but other than that if you can scrub it clean in ultrasonic and immediately remove moisture once done (in other words, minimal acidity of the cleaning solution, and minimal exposure to oxygen after it comes out, immediate drying and then immediate sealing with a coat of something that don't mix with water) chances are you'll be able to do fine.. but any case, simple green and dawn are both just surfactants that break surface tension of water to allow it to penetrate where it otherwise could not, and then the soaps bind with loose dirt and debris to rinse it away (and leave residue on the surface too) So, pretty much it is gonna be all about controlling the acidity (Ph balance) of the solution, and making sure anything that lets aluminum react with oxygen (water, soap, etc) is eliminated from the remaining surface and then coating with a water repellent finish (oil, obviously, but if you plan to paint the outside, may want to use something like mineral spirits and then a light blast of spray-on shellac, which readily dissolves with plain old alcohol)

[38racing]

I just made a mistake with my usc. I had an old Briggs starter clutch that had a bit of rust in it. I put it and the ball bearings in it and since it was rust I used vinegar. When cleaning up I noticed it had softened the outer later of the clutch. Major problem is the cover no longer has a pressure fit. Held down by the screen now. Also wonder if bearings will eat more material from it. Live and learn.

[bgsengine]

I just made a mistake with my usc. I had an old Briggs starter clutch that had a bit of rust in it. I put it and the ball bearings in it and since it was rust I used vinegar. When cleaning up I noticed it had softened the outer later of the clutch. Major problem is the cover no longer has a pressure fit. Held down by the screen now. Also wonder if bearings will eat more material from it. Live and learn.

USC/Vinegar didn't soften anything - metal had probably already oxidized, a thousandth of an inch or so makes for a .002 difference, which would kill the friction fit. Me, I always just flushed the rust out with some penetrating oil and wiped things down.. if the balls were rust pitted, I had a big bottle full of new ball bearings packed in oil to replace them.

[KE4AVB]

Try simple green aircraft cleaner which design to be use on most aluminum. But here I am using Alcojet which is a 12.5 pH powder soap. which does fairly good job except for corroded carburetors that I bring the sulfuric acid to clean it up. The sulfuric acid is rough on the plastics and steel components and hte aluminum can't being left very long as it remove the aluminum oxidation layers. Heavy oily carburetors I still do an initial round with Platinum Dawn. Most the carburetors comes looking new.

[creia]

Thank you very much for the replies.
In the interim I did a Google search and found some previous discussions on this very topic on other websites. Some reported that the Simple Green DID discolor/darken the aluminum while others reported it had NOT, so I am leary about trying this out the first time on one of my good blocks. I will try Brian's suggestion of using a "sacrificial" (junk) block first to see what happens and report back with the results. I am very happy with the Design Technology, Inc. ultrasonic cleaner for carbs, however, it would be too expensive to use for cleaning engine blocks for the quantity I would have to mix up. KE4AVB, I also "pre-clean" really dirty carbs in Dawn dish soap before I do the final cleaning in the DTI cleaner. Thank you for the information on the "aircraft" Simple Green as well!
Michael

[KE4AVB]

It is something that I haven't tried mainly because I only have a 10L unit for one thing and just haven't had the need an unit of larger size yet. But of course I started out with those 1.5L then the 6L, and now for the last 3 three years a couple 10L (one in reserve as a backup) units.