removing mill scale

[jlrussell4]

Someone asked a while back how to remove mill scale. Here are two pieces left in vinegar two days (I got busy and didn't get to it after the first day). The pieces were removed from the vinegar, wiped with a scuff pad and rinsed off. The center piece is the stock I cut the wider piece from for comparison.

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[anders nørgaard]

Nice tip! Thanks for sharing my friend!

[BarryA]

I often use hydrochloric for that Jim - only needs 5-10 minutes. I don't think there'd be anything left is I forgot it there for two days.....

[bob haverstock]

Hi Jim,

A blacksmith friend of mine told me to use PH Minus. PH Minus is a chemical used in swiming pools. I have very good luck with it and it is very inexpensive.

Bob Haverstock

[metal manny]

As Barry said, hydrochloric works very efficiently as does spirits of salts . A word of caution though, the fumes will add surface rust to nearby exposed metal surfaces like e-wheel anvils etc!

[Rasper]

I use acid all the time, but I learned the hard way to keep the jug outside of the shop. Those fumes will seep out around the top of the jug and rust everything nearby, like all of my new bandsaw blades.

Richard

[jlrussell4]

I always have muriatic acid (sulpheric) around to bring the ph in the pool down. I use vinegar on rust and steel because it is a lot safer. However, I have been known to put a bit of muriatic acid in the vinegar when I was in a hurry .

[custommetal]

Jim, not to be picky and the vinegar is a great tip, but muriatic acid is hydrochloric acid not surfuric acid---that is battery acid. And those bottled rust removers are usually based on phosphoric acid. the same acid used to clean aluminum wheels (spray on) so maybe that will work to clean steel although I never tried it. I do keep the jugs in a plastic bag that is tied shut as those fumes go everywhere. thanx for all your great tips over the years.

George

[jlrussell4]

Jim, not to be picky

It's O.K. to be picky George. I need to be corrected every once in a while (just ask my wife ). Thanks for the correction.