contolled rust

[cal-k]

hey
my moms birthday is comin up and she is looking at iron garden sculptures. i think they could be quite easily made with just half inch square stock, so no problems there. but the ones she likes have a very vibrant orange rust to them that doesn't seem to get worse. any suggestions on how to get a controlled rust, and then stop it?
thx

[Frosty]

There're a couple options.

Using Core-ten would probably be the best but I don't know if you can find Core-ten in 1/2" sq.

Another is to rust then seal mild steel. Before any of these will work right you need to have a bright surface, sand blasting or tumbling works very well. Make sure there are no oils say from touching it with bare fingers.

A solution of salt and peroxide in water will rust steel in minutes to hours depending on it's strength and temperature. It needs to be applied to warm steel then misted with water till you get what you like.

Chlorine bleach will rust steel quickly as well.

Once you have what you like seal it. I won't make suggestions here as I don''t know of a good sealer for rusted steel outdoors that will prevent further rusting.

[oakwoodforge]

POR -15 makes an awesome clear top coat " GLISTEN PC is a High Gloss, Rock Hard, Water-clear topcoat designed for spray or brush application over all metal surfaces" ( GLISTEN PC-POR-15 Inc. )


Jens

[frogvalley]

If you are leaving them outdoors, don't top coat at all. If rust is what you are looking for, 1/2" stock takes about 100 yrs to rust through so dont' bother stopping it. That bright color of rust has been chemically enhanced, by that I mean usually treating with a mild acid, acetic (white vinegar is what I use), or diluted hydrochloric to give a quick rust. Rinse thoroughly if you do decide to topcoat.

This will get darker with time, although that time is years. I am currently looking out at a series of sculptures sitting ready outdoors right now, some with acid enhanced rust and some natural, some bright some dark.

Oh and hydrogen peroxide can be used too, not that weak grade you get from the drug store, but go to a beauty supply house or the like to get the stronger stuff. Mixed with some browning solution for gun barrels it makes a very rich brown color. Again rinse thoroughly if topcoating.

[Ice Czar]

Patinas and Finishes

Hydrogen Peroxide Grades


sort of explains and illustrates from dark browns to bright oranges
acetic acid (white vinegar) as a pretreatment in place of the muriatic gets you more towards the red.


orange is the least stable patina, progressing to more stable as they darken
(how closely bonded the oxide is) what they call slow rust bluing (in gunsmithing) was the carding away for normal rust (red oxide) leaving the more closely bound black oxide, repeating till all the surface area was black oxide

Iron Oxides
FeO
Fe3O4
Fe2O3

and don't get too excited if you note the green rusts at the bottom of that first link
they don't last in the presence of oxygen

PS the "orange" in those panel photos is about as good as it gets once its sealed, which darkens any patina considerably (stopping the oxygen supply) those orange spots started out very bright

PPS
sandblasting the metal makes a huge difference in the total surface area available, speeds up the patina process, and provides far more tooth for the loosely bound red oxides to hide in the valleys of. Ive found it damn hard to get a good orange without blasting in any reasonable timeframe

[frogvalley]

Wow. I learn stuff here again. More about patinas and rust.

Cool.

[Falconer]

I've learned a good deal from this thread as well. One caution however, Chlorine bleach does NOT cause rust...it causes pitting which is far worse.

[Ice Czar]

Originally Posted by Falconer

it causes pitting which is far worse.

unless of course you want to really age the steel
or I wonder if it can stand in as a ghetto sandblast
hmmm...now where did I put that bleach?


I learn something too, thanx