What type of abrasives are compatible with Aluminum?

[Danny7]

I'm trying to find some polishing/ deburring attachments, and i remember some note about avoiding certain abrasives.

the 3m cut and polish wheels come in both aluminum oxide and silicon dioxide, is one better than the other?

regarding sandpaper or wet/dry paper, i've found both ao and sd, also garnet.

anything special to look out for?

is it safe to use the polishing compound in the dremel tool package?


edit- I know to not use steel based abrasives such as steel wool. probably copper as well.

[roee]

Danny,

I'm not sure about the specific abrasives you asked about. But a piece of general advice about deburring: where possible, use cutting tools rather than abrasives to deburr aluminum. Deburr holes with a countersink bit, deburr straight edges and outside curves with a mill file, and inside curves with a round or half-round file or any number of commonly available specialty tools. Where you still need to use abrasives to smooth out an edge even more, scotch-brite abrasives work well and have no compatibility problems with aluminum.

I have no experience and no advice to give on polishing aluminum, but there have been quite a few threads on the subject. I'm assuming from your question that you intend to have a polished aluminum finish on your airplane. Otherwise, if you plan to paint it, then polishing is not necessary.

[Danny7]

Originally Posted by roee

Danny,

and inside curves with a round or half-round file or any number of commonly available specialty tools.

can you tell me more about these?

i'm looking at one in particular:

http://www.widgetsupply.com/page/WS/...l-polish/BEN93

it says it is aluminum oxide based. Is that ok?

it looks like avery and probably everyone else sell this:
http://www.averytools.com/p-76-6-sco...ing-wheel.aspx

which if is this:

http://solutions.3m.com/wps/portal/3...glN9XV9L9H84bl

must mean aluminum oxide is ok, because that is what 3M says it is based on.

so AO is ok?

[billnaz]

Get a Scotch Bright wheel for your grinder. It's a necessity, and provides all the polishing you'll need. A vixen file for edges and you're set. Never use black sand paper (anything with carbon in it will promote corrosion). For roughing in parts a 1" belt sander works great.

[Danny7]

Originally Posted by billnaz

Get a Scotch Bright wheel for your grinder. It's a necessity, and provides all the polishing you'll need. A vixen file for edges and you're set. Never use black sand paper (anything with carbon in it will promote corrosion). For roughing in parts a 1" belt sander works great.

I have the scotch brite wheel, i have files.

thanks for pointing out the black sandpaper, i used that some, but followed it up with scotch brite hand pads.


I was in general looking for guidelines on specific abrasive used such as silicon carbide, aluminum oxide, garnet, etc.

the particular tool i wanted to buy was a lot like the scotch brite wheel, maybe a bit looser in density, but about 1/4 in diameter. i figured it would work really well in corners of ribs. someone once told me to get a similar tool, but through sears. i was trying to buy something over over the internet, not at a sears store.

[Transporter]

Use aluminum oxide products.

Do not use silicon-based products, garnet sandpaper, etc. as these contaminate the aluminum. [EDIT: I checked my source again and garnet is allowed by AC 43.13-1b]

I used the Scotchbrite wheels and (one roll each grit) of aluminum oxide emery cloth from leevalley.com (listed as 'abrasive rolls for turners'). Norton 3x sandpaper is also aluminum oxide and should be available locally.

Mike

[John Tierney]

Danny,

Avery also has the 1" and 2" wheel and mandrels for use in die grinders or cordless drills. Comes in handy when deburring the inside of holes, like lightening holes. I also found a tiny (1/2" dia?) deburring wheel of the same material for the dremel. Then there are the maroon and grey scotchbright pads available in the paint section of any decent hardware store.

If you are going to get deburring wheels from another source be aware that there are different consistencies. The 3M scotchbright 7A wheel that Avery sells for the bench grinder and die grinders is tough and is for "cut & polish". There are softer grades that break down faster for straight polishing. They look the same but are spongy to the touch.

John Tierney
Salem, WI

[az_gila]

Originally Posted by Transporter

Use aluminum oxide products.

Do not use silicon-based products, garnet sandpaper, etc. as these contaminate the aluminum.

I used the Scotchbrite wheels and (one roll each grit) of aluminum oxide emery cloth from leevalley.com (listed as 'abrasive rolls for turners'). Norton 3x sandpaper is also aluminum oxide and should be available locally.

Mike

...and the conclusion is that Silicon Carbide is OK for aluminum.

Check out the post from Bob Avery here...

http://www.vansairforce.com/communit...carbide&page=3

This NASA document also says it's OK....

http://corrosion.ksc.nasa.gov/pubs/tm584c.pdf

...and if NASA says it's OK for spacecraft, it's probably OK on our RVs....

[Transporter]

As always, I learn a lot on these forums. Hadn't seen the NASA paper before; when I stocked my shop last year I based my shop supplies on what I read in AC 43.13-1B.

Table 6.1 shows silicon carbide as OK for ferrous metals and titanium...and the row for "aluminum alloys other than clad aluminum" specifically says "do not use silicon carbide abrasive."

Based on this table, aluminum oxide is good for everything, while silicon carbide and garnet have only limited uses in corrosion removal. I've edited my earlier post to delete the reference to garnet, since it's allowed in the table for aluminum.

NASA research seems like a better source...maybe the FAA and NASA can get together on their research!

Mike

[MJarreau]

Pardon my ignorance.... I have searched for ceramic abrasives in these archives and found none. Anyone have any idea if they can be used on our little toys?

TIA,
Mike