[TheForge] pitted rust

Wed Oct 1 10:51:01 2003

Hello all,
	I have a bit if a problem on a project and thought I should see =
what=20
the collective wisdom of the forge might have to offer.

I have a client who would like me to duplicate the rust finish found on=20=

an old piece of ~ 2" pipe.
This guy is very picky and I've tried several textures which have been=20=

rejected.
The difficulty is that this is some serious rust. I think this sample=20
of pipe was buried in  the ground for many years. Its surface is=20
covered with small pits maybe 3/23" average diameter and about 1/32=20
deep. i.e. it's a fairly heavily pitted rusty surface. I am imagining=20
the corrosion process could develop this way when grains of varying=20
composition and size sand/minerals of the ground being pressed against=20=

the pipe.

Typically when I do a rust finish, I treat the item with muriatic acid=20=

to remove any black forging oxide and to chemically clean the surface=20
of oils/junk/etc. I then warm the metal with a small torch and sprits=20
it with bleach solution. This gets a powdery red oxide almost=20
instantly. I do several treatments with bleach solution, then switch to=20=

a saline solution and heat for several days. I've found using only the=20=

bleach solution will develop streaks in the patina and it can for white=20=

residues. The salt water keeps the patina even, and has some nice=20
subtle color variations such as brown and black spots speckling the=20
surface.

The main fault with my 'artificial' rusting, is that it would take me=20
years to develop any kind of deep pits on a surface. Someone suggested=20=

packing the pipe in a box of sawdust permeated with muriatic acid, but=20=

this seems like a fire hazard to me, and I bet it would still take=20
years.

My current best idea is to braze a lot of small diameter ball bearing=20
balls to a set of die plates and texture the pipe in the hammer before=20=

the rusting.

Anyone have any clever tricks for getting deep rust?

Seems like there should be a way to do this electrochemically, perhaps=20=

using a plastic sponge/foam as an irregular electrode against the pipe.

Thanks for any advice.

				Cameron Stoker
				[email protected]
				"May you run like a vicu=F1a!"
				pgp key @ http://keys.stoker.net