Precleaning Aluminum

[Darmik]

Thought you might like to know.!

Although the GMAW provides some cleaning action this should not be relied on for all the cleaning.aluminum must also be precleaned mechanically or chemically to remove the oxide film and other residue or contaminants.
aluminum oxidizes so rapidly the interval between welding and cleaning should be as short as possible.
you can select one of many ways to clean the metal wiping with a clean rag or emery cloth will remove any oil dirt or oxide film.for more stubborn residue use sandpaper,stainles steel wire brush or stainless steel wool.if this doen't work you may have to use a acetone.caustic soda solutions or a sulfuric acid bath. after precleaning rinse with a distilled water.

Remember when working with any of these solutions safety comes first gloves glasses and sheild is best.

[aametalmaster]

Yup, Ditto...Bob

[Fat-Fab.com]

I would avoid "steel wool" as it will contaminate the Al with steel particulate matter.

[Darmik]

However if you use (stainless steel wool) it would be okay. It is like everything eles to do with stainless it is expensive but worth it in the end.

[fun4now]

as i undersude it sand papper was a no no!! is this all or just soem types ??
acitone is good for greasy stuff but adding heat befor can also help bring out the oily stuff.
i have never MIGed aluminum just TIGed it. but for the most part i would think cleaning fallows the same path, cleaner the start the better the finish.

[Darmik]

Your right for the most part but tig is a little more fussy I'LL discuss this one a little later unless you really need to know now kinda thing.but you have been doing this for a while now you could probably teach me a thing or two.

sandpaper is okay not the heavy stuff; Like 100G or less all you want to do is scratch the surface of the metal thats all break the oxide film.

[phila.renewal]

Acetone and a SS cup does wonders.

I've been told that the SS cup can imbed the Al oxide into the metal, but I've been doing it this way and it works very well.

A grinding wheel is a whole different ballgame. No question a grinding wheel imbeds crap into the Al.

And clean the wire with SS wool.

For MIG, definitely less critical (and less aesthetically appealing too).

[fun4now]

i generaly just use a SS cup but not on the grinder. i use it by hand. its got a better brisel pattern then the standerd wire brush dose.
it realy all depends on the aluminum you are starting with and how clean it is to start with.
i have to wonder what possesed you to make this post ???? usualy your responce is fallowing a question about how do i .....
you in school and just cover this or some thing ????
some food for thought a wire wheel on a grinder will eat up the aluminum fast so if you do use it on a grinder be verry carfull or you will have nothing left to weld.
also i have found that wax is a good cutting or sanding disk aid. keeps the aluminum from building up on the blade and cloging the teeth. and what lil residow left behind will burn right off when you get teady to weld. it never efected my TIG welds so MIG should have no truble with it. bee's wax is the preferd wax but any candle will work in a pinch.

[Darmik]

If you fined that your sanding disks are getting clogged then try using WD-40 this stuff works very well.the same goes for carbide die grinder bits.Never use a wire wheel on a grinder.

[HMW]

If you fined that your sanding disks are getting clogged then try using WD-40 this stuff works very well.the same goes for carbide die grinder bits.Never use a wire wheel on a grinder.

WD-40 on a die grinder bit! ....I'll try it. Even the bits made for aluminum clog up, might help

As far as cleaning, If the piece is small, i use a hand SS wire brush, you only have to clean where your gonna weld of course. If longer I use SS on a 4 1/2" grinder, A cup type and I found one thats a twisted stringer type, like would go on a bench grinder, real narrow, that works good in cracks. Also if nasty i wipe down with acetone or a aluminum cleaner I have. Wait I forgot, everything I work on is nasty [salty] It woudl be great to weld on something new for a change