Special file for aluminum

[Alex Eisenhut]

I was a little surprised when I noticed people at work using regular flat bastards for steel with aluminum. Of course the file clogged up instantly and you have to work 5 times harder to make little progress.

I asked them "why not just get an aluminum file?"

Turns out they never heard of that, so I brought mine in the next day and it was a revelation to them.

To be fair, I don't work in a metal shop, we make RF stuff and I guess we just need tools for touch ups and what not, but still, the difference is like night and day.

What do you use? You got a nice set to recommend?

[ataradov]

I know about them, but I don't have a set. So I use steel files and a metal bristle brush to clean them from clogging.

[v8dave]

I used to use chalk on a metal file and this reduces the clogging and makes it easier to clean. Handy for the odd times you need to file some aluminium. I learned that technique when I was doing mechanical engineering in my teens. If you can find single cut files, they work good on aluminium too.

[nctnico]

Never heard of such files but then again the files I have don't tend to clog when using them on aluminium. I did see a metal workshop where they had seperate files for non-ferro metals like brass.

[Paul Moir]

I recommend you throw them out when you wear them out.  They're files, not family heirlooms.
We're in Canada so you can get Nicholson files cheap.
(Note I'm a rabid anti-file-snob snob.  I use files "both ways" just to annoy others.)

[ataradov]

I recommend you throw them out when you wear them out.

It is not about wear. Steel files will never "wear" when used on aluminum, but they will clog like crazy after just a few strokes and will not cut as well after that without cleaning. Separate files solve this problem.

Separating files for ferrous and non-ferrous metals is a completely different story and totally relevant unless you run large scale fabrication shop.

[Paul Moir]

Or you can just throw them out and get new ones.

[ataradov]

Or you can just throw them out and get new ones.

After each use?

[Paul Moir]

No, when they get worn obviously.  WD-40 or similar (like chalk above, I have to try that one.)  work well enough to keep chips from building up in a regular mill or bastard file, and you need a file card anyway.  Just that it's not worth keeping separate files if you do mixed work.

[sarepairman2]

oh shit i need one of those 

[Ian.M]

Use a brass wire brush first. A file card has hardened steel bristles, and doesn't do the cutting edges any favours even brushing in line with the teeth.  If a file is badly pinned with light alloys, warm lye solution will clean it up pretty quick by dissolving the Aluminium or Magnesium.  Don't use lye if its pinned with copper alloys. Scrub out any remaining dirt with the line of the teeth,  Wash off thoroughly with boiling water, dry in a warm place and wrap in VCI paper as it will now be absolutely grease and oll free so can flash rust if left out in damp polluted air..

[Tomorokoshi]

Welding shops have a paraffin wax kind of thing that you can scrape into the file first that makes it easier to clean the file.

[calzap]

There are also special grinding wheels for aluminum (or aluminium or element 13).  They have a rubber base material with silicon carbide grit.   Changing wheels on grinders can be a pain though, and one has to do a lot of aluminum work to justify a separate grinder.  Regular grinding wheels clog pretty quickly with Al.  Frequent dressing works OK, but wears them down pretty  fast.

Flap type grinders, available in disc, cylinder and wheel forms work pretty well on Al. 

Mike in California

[d-smes]

So what's different about the teeth?  Looking at the image at http://www.amazon.com/Nicholson-Aluminum-American-Pattern-Rectangular/dp/B006P2XB4E it looks like a rasp style.   Please enlighten us!

[ataradov]

So what's different about the teeth?

They are coarser and grooves between the teeth are wider, so filings don't have a place to stay jammed.

[mikerj]

No, when they get worn obviously.  WD-40 or similar (like chalk above, I have to try that one.)  work well enough to keep chips from building up in a regular mill or bastard file, and you need a file card anyway.  Just that it's not worth keeping separate files if you do mixed work.

Yep, I just use WD40 (or it's equivalent) and it works perfectly.  A quick brush with a wire brush afterwards and the file is clean.  This also leaves a smoother finish on the aluminium being filed.

[TerraHertz]

Nobody has mentioned the *best* way to file aluminum. Just squirt some kerosene on the file first. Suddenly it's like filing butter. The teeth never get clogged, and the workpiece gets an amazingly smooth, shiny surface as you file.

I keep a screw-lidded jar half full of kerosene, with a glass syringe in it. Just pull some kero into the syringe, then squirt onto the file. No need to keep buying spray cans, etc. Kerosene is cheap, and you probably already have a drum of it.

If you have any files already clogged with aluminum, use a scriber point or something sharp to run along the file grooves to clean out the chunks of aluminum. Then apply kero, and never have to do that again.

Edit to add: Kerosene also works wonders when using a power jig saw to cut aluminum sheet and plate. Run a bead of kerosene along the marked cut line before starting. The blade stays clean, and the cut runs much easier. The only consequence is your cut line marking must be a scribe line, as marker pen, pencil etc will be washed away by the kero.

[KL27x]

I recommend you throw them out when you wear them out.  They're files, not family heirlooms.
We're in Canada so you can get Nicholson files cheap.

I'd throw Nicholson files away, too.

[robrenz]

I have my files re-sharpened up to four times before they get thrown out. The service I use is very reasonable and they are usually sharper than when they were first purchased.  Yes, I do a lot of filing.

[KL27x]

A good file lasts a long time. My favorite is from an estate sale. I can't find any logo on it. It's a relatively fine grit, yet it cuts a lot faster and smoother than any file I have bought new at a hardware store, and it just keeps on trucking. I lucked out, because I wouldn't have known how good it was by looking at in. In fact, I bought two files, and one turned out to be a total bust.

I have my files re-sharpened up to four times before they get thrown out.

I'm sure there are some newer and more expensive methods for sharpening special/expensive files. One very simple method is putting the file in some phosphoric acid for few hours. You can do that yourself. It works well for a limited number of sharpenings.

[langwadt]

Nobody has mentioned the *best* way to file aluminum. Just squirt some kerosene on the file first. Suddenly it's like filing butter. The teeth never get clogged, and the workpiece gets an amazingly smooth, shiny surface as you file.

I keep a screw-lidded jar half full of kerosene, with a glass syringe in it. Just pull some kero into the syringe, then squirt onto the file. No need to keep buying spray cans, etc. Kerosene is cheap, and you probably already have a drum of it.

If you have any files already clogged with aluminum, use a scriber point or something sharp to run along the file grooves to clean out the chunks of aluminum. Then apply kero, and never have to do that again.

Edit to add: Kerosene also works wonders when using a power jig saw to cut aluminum sheet and plate. Run a bead of kerosene along the marked cut line before starting. The blade stays clean, and the cut runs much easier. The only consequence is your cut line marking must be a scribe line, as marker pen, pencil etc will be washed away by the kero.

I find ethanol works much better and it doesn't leave a mess

[cs.dk]

I find ethanol works much better and it doesn't leave a mess

I agree, it works really well and everyone has it in their home. Easy to wipe off afterwards, or just a blow with compressed air - and your done.
It's also great for drilling and tapping aluminium.

[krivx]

I have my files re-sharpened up to four times before they get thrown out. The service I use is very reasonable and they are usually sharper than when they were first purchased.  Yes, I do a lot of filing.

How does that work? The sharpening process I mean. A tiny grinding wheel between the teeth?

[MikeW]

I have my files re-sharpened up to four times before they get thrown out. The service I use is very reasonable and they are usually sharper than when they were first purchased.  Yes, I do a lot of filing.

Are you trying to escape from prison?

[FrankenPC]

I wonder if aluminum shrinks significantly more than high carbon steel when dipped in a ice bath?  It would be awesome to rig up a ultrasonic ice bath with a mild lubricant to just shake the aluminum bits off.