Steve, thank you for your reply. I left out some details. This gate is
wrought iron. Two 7 foot posts at about 200 lbs and two gates, six feet
high by five feet wide at about 300 lbs. It was bought at an antique
store and when painted it will decorate a small park in south east
Pennsylvania. It is quite massively built, thick metal bars and flat
work. Because of how it is built sand blasting seems the way to go to
get off the rust. I thought at a minimum this was something that needed
to be done. The people I am doing this for are in a rush to get it in
place. What could be the life of the paint job if it was powder coated
verses going with a good oil base paint?


SteveB wrote:
"andy everett" wrote in message
...

This Saturday I will rent a large sand blast set-up and blast 500 lb. of
steel ornamental fence and gate which will be set up outside. I stopped
by a NAPA auto store and bought "Rust Treatment, Destroys Rust". The
stuff is supposed to turn the surface metal black after two coats.
Should I use this stuff or should I just paint on a primer after sand
blasting, is this rust treatment step worth the effort?

After sand blasting I suspect there will be trace amounts of oil on the
fence from the air compressor. If I spray the gate and fence with an
airless sprayer with some paint thinner will that remove most of the
surface oil, there are too many cracks and crevices to wipe it by hand?

Will Rustoleum brand paint and primer sprayed from an airless sprayer
give good results, from this newsgroups it seems that the best paint for
exterior metal is an automotive type finish, though some people have
said they got good results from Rustoleum.

Thank you in advance for any help or suggestions.



Let me start by stating that I owned a wrought iron business for nine years.

Your answer depends on the part of the country you live in. In the dry
southwest, it is different than in Oregon. And no matter what you do, if
you live in a humid place, it will rust.

Welding can have a lot to do with it. If you weld all four sides, and make
it impervious to water, you will do better than welding only two sides.
Also what happens if it is left open is that water enters, freezes, and
bursts the tubing. All the rust preventive measures you do will not
compensate for cracks that water can penetrate into and rust from the inside
out and leak rusty water out onto the surface. You will never be able to
treat the inside, so you have to seal it up.

Cleaning is important, but not critical. Removal of the "fish oil" rust
preventative is most important, as that will keep the paint from sticking.
Surface imperfections and some surface rust can be neutralized with a good
paint such as Rustoleum. I would wire brush all the welds to clean off the
oxidation from them, as they are usually the first things to rust.

In recent years, more and more restrictions have been placed on the types of
paints that are used. You used to just apply enamel, and go with it. Now a
lot of those are not available, and you have to go get the $25 per gallon
stuff.

You might be overthinking this and doing too much work. Sandblasting is
nice, but not really necessary. A good cleaning with gasoline, done safely
outdoors, will get off what you want to get off. Now, if you have a
sandblaster available, you might use that, but then, you are blasting thin
materials, and you might take off more material than you protect. A double
coat of the same color paint with the recommended time between will do you
as good as a separate primer and topcoat.

It's only wrought iron. Unless it is for a special piece, or has to look
very good for a very long time, I wouldn't spend all the time on it you are
willing to spend. If it IS for a special place, take it and have it powder
coated.

Steve