Coating weathered steel can be a challenge but with the right products and prep, it’s a snap. The system I like to use is Amerlock Sealer which comes in a 2 component kit and Amershield Aliphatic Urethane which also is a 2 component product. Both products are pricey but worth the cost.
Often you may not need to mix a full kit as was the case this past weekend. We only needed to deal with the door threshold of a commercial location. As long as you honor the mix ratio it still works fine and you don’t end up burning a whole kit which with Amerlock is 2 gallons and with the Amershield it’s 1 gallon. The Amerlock ratio is 1 to 1 and the Amershield ratio is 4 to 1.
Coating weathered steel often means dealing with rust. In this case we wire brushed the steel and sanded it. After cleaning up the debris and vacuuming up the dust we wiped the steel with denatured alcohol to pull any remaining moisture out of it.
We mixed a small quantity of the Amerlock sealer and gave the steel a good brush coat. The next day we mixed up the Amershield and gave it 2 brush coats 2 days apart. Problem solved.
This is also a system for the exterior as well. There is a set of metal stairs in Omaha that still looks great 14 years after application.