QUESTION:

Hi Bill!

Would you kindly let me know how to clean cold rolled steel in preparation for your products? I’m not worried about slag, dross, etc. I will use flap discs for sanding/polishing (80 grit). In the last step, do I need to degrease it completely? [sic]

Could I use a degreaser from either H-D or Lowes?

This project is a low garden retaining project. The steel is 8″ high x 71 linear feet long. Thanks! Jeff

ANSWER:

Bill

Hi Jeff,

Unless You’re Using P&O Steel (Pickled & Oiled), No Cleaning, Especially With Solvents of ANY Kind is Advised or Necessary.

Any solvent cleaning of steel, which is a usually just an unnecessary step, especially with CR Steel or HR Steel that has had the mill-scale removed in an acid bath, Should be Done PRIOR to Flap-Discing, Never After!

If you feel you need to do any cleaning after flap-discing, use a base (alkali) or mild, weak acid product (Barkeeper’s Friend) to clean, e.g. Comet or Ajax.

Totally unnecessary, though.

Note: Any solvent containing hydrocarbons or petroleum distillate/s will cause the water-based patinas to repel. All Solvents and Degreasers contain oil, in some form or another. I’ll do a short video on how to do a Water-Break Test, to check for fingerprints (skin oil), or any other oily surface contaminants. See image below for a brief summary of checking your steel surface with water before patination. It’s only necessary to do this simple ‘Water-Break-Test’ when in doubt. It’s not a critical test in most cases, if you’re careful in the handling & preparation of your steel.

Thanks,

Bill

Is It Clean? – Oil and Hydrophobic Films – Water Break Test

Credits: Posted on August 10, 2011 by John Fuchs http://www.ctgclean.com/tech-blog/2011/08/is-it-clean-oil-and-hydrophobic-films-water-break-test/

The last thing you want on a surface that is to be plated, painted or otherwise coated with something that needs to adhere to that surface is a film of residue that prevents that adhesion. The water break test is a simple, quick and usually non-destructive test to test for hydrophobic films. The test is most frequently applied on freshly cleaned metals including steel, aluminum, brass and other metals that, in a totally clean state are hydrophilic.

Although the test is usually applied on large flat surfaces like sheet metal, it can, in somewhat modified form, also be applied to some surfaces with relatively smooth surface geometry. It is not applicable on parts with complex geometry including acute angles and undercuts for example.