Ferrous metals are those that either contain or derive from iron. They
are commonly used in the manufacture of castings, fabricated sheet steel,
and wrought iron, all of these metals will rust, which can eat away at
the metal undermining applied coatings.
Rusting can start almost immediately when unprotected ferrous metal
is exposed to moisture in any form. The objective is to stop any rusting
that has begun and to keep moisture and air from interfacing with the
metal after painting.
Accordingly, ferrous metals call for very thorough and meticulous surface
preparation. Anything less will seriously compromise the durability of
the finished job, not to mention the integrity of the metal itself.
Power wire-brushing or disk sanding with aluminum oxide paper, or sand
blasting are effective preparation methods. Whether you use hand tools
or power equipment to prepare the surface, be sure to wear personal protective
equipment, including eye protection and a good dust mask. Use a scraper
to take off heavy rust and loose paint, and then follow up by wire brushing
the surface to remove the rust. It is necessary to remove every bit of
rust and take the surface down to bare metal.
After wire-brushing, the surface will be covered with small particles
of loose rust and dust, which should be removed before any coating is
applied. Brush these particles off with a soft bristle brush, then scrub
the surface with a detergent-and-water solution, followed by a thorough
rinsing with clean water.
Surface preparation should not be omitted just because an iron or steel
surface is new. New ferrous metal often has mill oil on it or small amounts
of rust that are not readily visible. Not removing these before applying
a coating could result in premature failure of the paint job.
Once a ferrous metal surface is free from rust and other impurities,
priming should be done as quickly as possible. This timing is vital because
rust can begin to re-form on iron or steel if the surface is exposed
for as little as a day or two. If that happens, you’ll have to
prepare the surface again.
When painting ferrous metal, it is important to apply a top quality
metal primer and a high quality topcoat.
As you can see, this is a very time consuming and costly method for preparing
metal pipe for insulation; and after all that cost and work, it is not
permanent!
RG-24000 can be applied to
bare metal, rusted metal, and corroded metal with little or no surface
preparation at all – just glove it on
the pipe until all you can see is blue (when It’s blue you’re
through) and install your insulation and jacketing system! It’s
that simple.
Cost comparisons versus paint show that RG-2400 is far less costly to
install, and you get a permanent solution to the corrosion under insulation
issue.
