Rust & Paint Removal

5/23 ~ by Griz (aka Steve Stovner) ~
For 40+ years Vinegar & Salt has been my method for removing rust and zinc galvanizing from steel. I stir in as much rock salt to plain white vinegar as will stay in solution. Drop a part in the bucket and the next day, brush it under running water and dry it (I use heat gun). Grease blocks the action so degrease before putting part in solution. Very heavy rust may require several cycles (which works better than one extended time session). Be careful with other metals, especially those containing zinc. Keep a lid on it and it lasts a long time. I think I have dumped and started fresh only 3 times over the years. When I detect that the solution is getting weak I add more vinegar and salt. My bucket looks nasty but is a very effective tool.

Removing paint from steel & iron, especially epoxy paint has always been a real pain. Very strong chemicals or grinding, work. But both carry a large cost ($, danger, surface damage, manpower, environmental impact, etc.).

Recently. I wanted to remove rust from a very large part and 50 gals of vinegar was a bit spendy. I also needed to remove expoy paint from a steel cylinder. So, I went searching for current thoughts on the subject and found an article on "Electrolysis Option for Stripping Paint & removing rust". My short summary is below but for all the safety tips and other considerations, you should read the entire article, either ad free text or the web page.

• I used 50 gallon nylon pickle barrel. Cut the top off such that flipping it over makes a decent lid.
• For sacrificial electrode I used 60 feet of 0.16" dia. steel fence wire. Coiled tight, it fit in my vinegar bucket for zinc coating removal. The wire layout gives lots of surface area, uniform coverage and min. volume.
• Added 30 gallons water (5 at a time) while marking levels on barrel.
• Added 1/3 cup Arm & Hammer Washing Soda per 5 gal. water.
• Hung part from over-head so it was submerged and centered in tank (V & H).
• Connected DC Power Supply positive lead to electrode and negative lead to part.
• Adjusted Power Supply voltage for 7.5 amp. draw.
• 4 hours later the epoxy paint washed off with light brushing.