Afternoon chaps, Do you guys have any tips on cleaning aluminium castings I've got a few castings that are a bit dull, try'd soft brush and soapy water but to be honest it now looks worse I have heard of citric acid but not sure...
A hit on the bench grinder wire wheel works wonders for new and old castings, taking care to be gentle and not smear aluminium by being too rough. A scotchbrite wheel on a spindle is pretty awesome for any type of casting: rusty iron, brass, aluminium. I did the castings below with a scotchbrite wheel and then a run on the buffing mop.
But MAN are they pricey! That drill press above looks awesome. No one will ever spend 100hrs restoring a HF drill press.... EVER!
Amazon to the rescue. Thanks! oh... FWIW, simple green should cut that black crud that builds up. When I polish aluminum, I do it with a bucket of soapy water for my wet sand paper.
Just a disclaimer: that's a new hard chrome column and Jabobs 1A chuck on that drill press the rest is original iron and aluminium castings.
I've used "Mother's Mag Aluminum Polish" to give a few aluminum castings that little extra bit of shine on one or two occasions. Jeff
If all you want to do is clean the casting I use a light (not stiff wire) stainless wire brush either by hand or on a wheel. If you use a carbon steel brush or shot, sometimes you can get material transfer and the oxidized steel (rust) can later appear on your aluminum casting surface over time. If you want to cut, polish or otherwise disturb the as-cast surface there are many options from media blasting, tumbling, abrasives, and combinations of the two and they all provide uniform color to a degree. When you blast with abrasive media you should expect some of the media to imbedded in the aluminum surface. Blasting the inside surface of an engine part with glass beads is a bad choice because the imbedded glass will eventually find it's way into your lubrication system. Stainless steel shot has less tendency to transfer but rust on carbon steel shot does. Dilute Phosphoric or hydrochloric acid will also etch, clean, and color but it may work threads and sharp edges more aggressively than the rest of the casting. If you don't want to disturb the casting surface and just remove dirt and grime, I like blasting with walnut shells. Best, Kelly
