I am not a mfg of aluminum parts. I have no equipment to tumble or or vibrate... I had those parts made for me. They are unusable. I need to know how to clean them by hand. Should I use muratic acid? Is there something better?
I would think that you could get either a hobby rock tumbler or a cartridge cleaner tumbler for less than $100 new or even less on E Bay --- I would use one of the metallic cartridge medias that are treated with a brass brightener typically tolyltriazole to passivate the Cu in the 6061 and thus keep the parts brighter over an extended period of time -- the media should be available either on line or at a good gun shop that sells reloading supplies
Thanks for the posts. I appreciate the feedback. Honestly, though. I have only 1000 of these parts. There is no way to just dump these in a bucket with diluted muriatic acid, then rinse? Isn't muriatic acid what is used to clean aluminum? I said by hand, but I only meant no machine. There has to be a better way...
What did the place that made them say when you told them that the parts were unusable because of the poor surface finish?
Engineering is the art of modelling materials we do not wholly understand, into shapes we cannot precisely analyse so as to withstand forces we cannot properly assess, in such a way that the public has no reason to suspect the extent of our ignorance.
-A R Dykes
I got a real good price so I'm not bitching, and he's buying new media and stuff for his tumbler. But for these parts I need to do something before I can use them.
Muriatic acid is an old name for hydrochloric acid. This definitely will not brighten your aluminum parts - it will create pits and smut that make them dark. The options provided to you have been good ones, there really isn't a do-it-yourself alternative using a simple chemical.
For a safer method...
You could try boiling 4 tablespoons of white vinegar to 1 quart of water, drop in aluminum parts for 10 minutes, remove and rinse.
Acid or lye will brighten the parts but not polish them. You can get a matte silver appearance. Lye is often better than acid because it also removes grease and oil. Etching too long will create a black smut, so watch the parts carefully as you do this. Rinse well afterward.
CoryPad has it right--Muriatic/ hydrochloric acid will ruin your parts. Leave them in long enough and your parts will go away. Don't use it! Ditto for Lye or other strong caustic.
If the OP goes the mechanical route he needs to use a vibratory finisher in lieu of a tumbler unless it operates a very low speed.
Another option to try is to go to a chemical cleaning supply house and get some Al truck cleaner to see if it gt the parts clean to an acceptable level.
They make caustic cleaners for Al that leave a fair finish. The secret to using alkaline materials on Al is there has to be an inhibitor in the solution. The best one is sodium metasilicate.
If the OP wants bright and shinny Al he will have to use mechanical or hand polishing to such a finish.
mfgenggear, There are a couple of processes that will electropolish Al through it is a very complex process and very expensive power supply. I don't think any of the processes are a commercially available.
Attach a piece of maroon "Scotchbrite" pad to a black and decker sander.
Line all the parts up on the table, side by side.
Polish them all at once.
flip.
Repeat.
