Crud off steel

[MtnWelder]

See a lot of really nice paint jobs on projects.

What is the best way to clean off the crud of hot rolled steel prior to painting?
I've tried sandblasting but its slow and a real mess.
Tried grinding off - works but can't get into lots of places.
Tried meritric acid - works but only on small stuff (dip).
Must be an easy way.

Thanks for any help.

[Customwelds]

Just a few things you may try, sanding works well for some types of things. You also may want to try a die grinder in the things you can't get too with a full size angle grinder. Depending on what the "crud" is, it's possible you could burn it off with an O/A setup. Just make sure it's not something that would boil and harm you if you do that. Also, you have to be carefull on the input of the heat on the steel too. If I can think of anything else, I'll post more! Hope this was a help.

[1911Man]

mtn Weldor
I think what you are dealing with is mill scale and can be a pain to remove. when I built my welding table, I wound up using a belt sander on it. That stuff was harder than chinese arithmatic!

[MtnWelder]

That's it - mill scale - a real bitch!

Someone suggested that since it's so hard to get off - paint over it! I'm also an old painter and it goes against the grain to leave something under there. I think I will try a sample and just cleaning it off with acetone or lacquer thinner and painting over - see how long it lasts.

Is that 1911 as in 45? My mentor always said: 1) something every man should not be without, and 2) you can't have too many.

[Jerry]

In maufacturing cold rolled is used more often then hot rolled in a application that is to have an astetic look. HR will have a heavy mill scale which is difficult to get off unless you sand blast parts, where as CR will be clean, just wipe with acetone and paint.

[Mike W]

I don't bother taking it off. I just paint over it. :)

[Franz]

Ways of removing Mill scale
Scarifiers ~ http://www.thomasregister.com/olc/73602930/rotary.htm
Acid Removal ~
http://www.hdgasa.org.za/process.htm
Media Blasting ~
http://www.metalfinishingsystems.com/tt-blasting.html

[1911Man]

You and your mentor are correct on all counts. And American made !

[Crithpy_Critter]

4 1/2 " - 24 grit flapwheels will make short work of mill scale..