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[Neural]

Ok, so I've brought this up on another forum, but I can't seem to get the point across that I want to do these things in a non-toxic manner.

I'm venturing into making what is known as "ground aluminum" art.  In order to keep things moving smoothly, especially when it comes to applying paint, I need to be able to de-grease and prep aluminum sheet.

The suggestions I've seen so far are great, but they all involve stuff that you probably don't want to breath or allow to touch your skin.

Does anyone know of any non-toxic home-brew solutions that aren't going to be a chemical hazard to people or pets?  I'm looking at applying it outside, so ventilation isn't a problem.

I remember seeing something at one point about vinegar, but not sure what the rest of the recipe was.

If anyone has suggestions or info to pass along, I'd love to know.  Thank you.

[irockhound]

As a degreaser I would assume that you would use Vinegar straight and undiluted.  The acid in vinegar should be a natural for removing oils and grease.  I would try it straight and if need be dilute it with some water.  I do not know however if vinegar at all reacts with aluminum.

[hummingbirdstones]

Vinegar will pit aluminum.  Why don't you try Dawn?  My sister also swears by Krud Kutter.  Environmentally friendly and non-toxic.

[edgarscale]

try baking soda with water and lightly smear with a cloth or baking soda and vinegar.  rinse well.  vinegar will pit if left on too long or is too strong a solution to start with.  always end by rinsing well with water.  wipe dry the set side to air dry further.  remember oils on your finger will "grease" it too. 

[Phishisgroovin]

i second Krud Kutter, i use it myself on almost everything.

[Slabbercabber]

I use acetone followed by alcohol.

[jerrysg]

I use acetone followed by alcohol.

I second that but if you want to skip the acetone, make sure you use either 91% or 99% isopropanol (rubbing alcohol).  The 99% is hard to find and the only place I found it was at Fred Meyers in Tillamook, OR. But most places sell the 70% and 91%.  Don't use the 70% - too much water to work as a degreaser.

When I superglue anything, I just use the isopropanol. But if it's to rocks off the slab saw, I clean them first with Dawn. Seems to work well, very few failures.

BTW, Dawn is the only detergent to use on rocks. Most other detergents have optical brighteners which really means UV enhancers which give the rocks false responses to UV examination.  Proctor and Gamble has a web site (forgot the details) that list the ingredients for all of their products. I verified that all types of Dawn are free of UV enhancers. Easy on the hands too.

Jerry

[Slabbercabber]

Sorry, I should have been more specific.  I use denatured alcohol (isopropenol).  Rubbing alcohol will leave a film.

[Barclay]

Neural I think it would help us if we knew what contaminants you were trying to remove from the aluminum.  If you are removing fingerprints and light oils then a light solvent solvent or Dawn dish soap would be recommended.  For heavy preservative oils or grease you are looking at a heavy solvent and maybe scrubbing.  For the thin oxide layer on the aluminum you are looking at some kind of acid or caustic, maybe a bead blaster.

[jerrysg]

Sorry, I should have been more specific.  I use denatured alcohol (isopropenol).  Rubbing alcohol will leave a film.

Denatured alcohol is not isopropanol. Rubbing alcohol is isopropanol. Denatured alcohol is ethyl (drinking) alcohol with additives that make unpalatable or unhealthy to drink.  Often the additive is methyl alcohol (methanol) which is poisonous and can lead to blindness. (As opposed to being blind drunk! on the real stuff.) The can label should identify the denaturant. My quart can of Ace Denatured Alcohol says that it is methanol which is poisonous.

IF YOUR CAN OF DENATURED ALCOHOL SAYS IT CONTAINS METHANOL BE VERY CAREFUL USING IT. METHANOL CAN BE ABSORBED THROUGH THE SKIN.

If you are getting a film from the alcohol, it might be because the surface is not clean. I use a small plastic dropper bottle (like ear drops) for the isopropanol, hold the item to be cleaned vertical and let the isopropanol run off carrying any contaminates.  Another thought is if you are using rubbing alcohol, make sure it's the 91%.  The water in the 70% may have dissolved enough impurities to leave a film behind. 

Jerry (retired chemist)

[Neural]

Neural I think it would help us if we knew what contaminants you were trying to remove from the aluminum.  If you are removing fingerprints and light oils then a light solvent solvent or Dawn dish soap would be recommended.  For heavy preservative oils or grease you are looking at a heavy solvent and maybe scrubbing.  For the thin oxide layer on the aluminum you are looking at some kind of acid or caustic, maybe a bead blaster.

I don't really know what contaminants there are.  I'm just looking to prep/clean a bit of sheet aluminum I bought at a local metal shop.

That being said, I *did* use water with Dawn mixed in, and it did really well, but now that it is clean, I am seeing fingerprints on it that are definitely not mine, plus one side of the sheet (1/16th inch thick) has a stain on the edge.  I tried using a medium grit sanding sponge, but whatever was on that persons fingers is more than just surface damage.

Hopefully I can get rid of it with the grinder, as there are some other scratches that need to be removed.

Also thinking I need to find a different source for aluminum sheet.  I wanted to buy something locally because I could get a custom size and save on shipping, but this sheet is going to take a bit of work just to get prepared for grinding.

[jerrysg]

I am seeing fingerprints on it that are definitely not mine, plus one side of the sheet (1/16th inch thick) has a stain on the edge.  I tried using a medium grit sanding sponge, but whatever was on that persons fingers is more than just surface damage.

What you are probably seeing is the result of acids as well as oil from the skin. The aluminum has been etched into the fingerprint pattern.  I would try a uniform surface etch of the aluminum with a vinegar solution.  My bottle of Walmart Distilled White Vinegar (don't use any other type of vinegar) says "diluted to 5% acidity". Make sure there are no residual oils on the surface before trying the vinegar. Any oil on the surface will stop the vinegar from contact with the aluminum. You probably accomplished that with the Dawn cleaning.  If you are concerned with vinegar being too concentrated, try a small amount of various dilutions until you hit on the one that will work.  I think the 5% is ok if you don't leave it in contact too long.

Jerry (retired chemist)

[Neural]

I am seeing fingerprints on it that are definitely not mine, plus one side of the sheet (1/16th inch thick) has a stain on the edge.  I tried using a medium grit sanding sponge, but whatever was on that persons fingers is more than just surface damage.

What you are probably seeing is the result of acids as well as oil from the skin. The aluminum has been etched into the fingerprint pattern.  I would try a uniform surface etch of the aluminum with a vinegar solution.  My bottle of Walmart Distilled White Vinegar (don't use any other type of vinegar) says "diluted to 5% acidity". Make sure there are no residual oils on the surface before trying the vinegar. Any oil on the surface will stop the vinegar from contact with the aluminum. You probably accomplished that with the Dawn cleaning.  If you are concerned with vinegar being too concentrated, try a small amount of various dilutions until you hit on the one that will work.  I think the 5% is ok if you don't leave it in contact too long.

Jerry (retired chemist)

Ok.  I believe we have some of that, or I'll go purchase some.  What sort of time frame are we looking at in regards to how long the solution can be in contact with the aluminum, and does it need to simply be wiped off with a wet cloth, or should I have a hose/water-source ready?

[jerrysg]

Ok.  I believe we have some of that, or I'll go purchase some.  What sort of time frame are we looking at in regards to how long the solution can be in contact with the aluminum, and does it need to simply be wiped off with a wet cloth, or should I have a hose/water-source ready?

There are no hard and fast rules. It's more trial and error. This is just a guess but I would start with about 10 minutes with a 50% dilution  of the vinegar. If it looks like there is some etching of the aluminum but it's not enough then either increase the strength of the vinegar or let it go longer. Since the acetic acid is being used up as it etches the aluminum, it will do less and less the longer it goes so at some point it's useless to go longer. Then it's time to go with a fresh vinegar solution.

Removing the acid is more than a wet rag wipe but it goes slow enough that a simple rinse with running water should be fine.

Jerry