Rust-proof steel finish

||I'm a first-time poster here, so go easy on me. I'm getting ready to ||fabricate some steel hardware for a timber frame home we're just ||breaking ground on. These pieces will be machined and welded from bar ||and plate stock. Most will have planished surfaces achieved by ||careful hand work with a ball peen hammer. This hardware will mainly ||be used inside, but a few pieces will be on the exterior, tucked up ||under a 4-foot eve (i.e. they'll see condensation and occasional ||wind-driven rain). || I'd like the hardware to have some sort of a blackish/brownish ||finish, while avoiding large amounts of orange rust bleeding onto the ||timbers. I'd like to achieve a somewhat mottled appearance, similar ||to an old piece of cast iron cookwear. I'm after something more ||natural-looking than paint. In prior projects, I've achieved this ||sort of finish by coating steel with linseed oil and baking it in the ||oven for an hour or so. This "baked-oil" finish probably provides a ||bit of rust protection, but I'm not sure how it would hold up when ||exposed to the elements over time. Any better ideas...

Old-style corrosion browning is the look you are after. Basically controlled rusting. It's neutralized, then oiled or waxed. I don't recall any of my older pieces leaching into the surrounding stock. Nor do I recall any of them starting to corrode further. ||P.S. I mistakingly posted this to alt.rec.crafts.metalworking, prior ||to posting here. Not sure what kind of response that one will ||generate...

None, since it doesn't exist Texas Parts Guy

A quote - but I've no record of the source.

Thomas Telford built Conway suspension bridge in 1874 and treated suspension members by heating to red heat and dipping in Linseed oil. Inspected in 1989, these items were in better condition than ironwork added this century and protected with conventional paint systems.

Jim

Hi, Rich. I make hardware like that sometimes for money. I'd never do the peening cold (I'd take a heat on the bar stock in the forge and do the peening before all the welding) and I wouldn't even think of trying to get a black iron finish on Camano Island, I'd paint the parts. There isn't any finish period that will stay rust-free for more than some period of time. The longest is galvanizing, but if you ever walk by an old schoolyard you'll see tons of rusting steel which was once shiny galvanized, so even galvanizing doesn't work long-term. Paint it and then paint it every 10 years or so. That's my 2¢ worth. If you want to experiment, heat the metal to maybe 800° (still black but just barely) and then brush on old oil. It will smoke, but it will turn a rich black color which is probably what you're looking for. Then you can clearcoat it but again it'll start rusting in just a few years. Better to do a good paint job while the steel's on the bench, that will delay the rusting as long as possible.

An ironworker comes in real handy doing this kind of work. It can shear your bar stock accurately, it can punch your holes quickly and accurately, and may be able to do bends.

Grant Erw> I'm a first-time poster here, so go easy on me. I'm getting ready to

Unfortunately this won't work with modern steel. Wrought iron (such as in 1874) comes from the furnace with a lot of glassy impurities. It was refined by repeated hammering, folding and welding (with a hammer). This forced the worst of the impurities out, and left many layers of a very thin layer of glassy slag through the iron. These layers greatly aid in blocking the action of corrosion. Wrought iron which has corroded shows an almost fibrous structure. So while linseed oil provides some protection, it is not why the iron lasted better than modern additions.

Modern steel has no layers whatsoever. Once the surface coating is breeched, corrosion starts. Red iron oxide molecules take up more room than straight iron or steel, thus the rusted area bubbles up. The bubbled area provides nooks and crannies for moisture, etc. Modern steel needs coating and regular maintenence.

Steve Smith

Unless you've done a *lot* of hammering, be careful you don't get "blacksmith's elbow" (tendonitis). Don't overdo, and stretch before, during and after working. The best stretch for this: hold your arm straight in front of you, fingers pointing horizontally, palm down. Now bend your wrist so your hand flops down. Use the other hand to push the first hand further, like you're pushing your palm toward your wrist. You should feel a stretch in the tendon that runs across the top of the forearm and attaches at the outside of the elbow. The attachment at the elbow is what gets inflamed in this form of tendonitis. You should hold a stretch for no more than 60 seconds.

One method for a dark brown rust is to rust the metal with Clorox or other bleach. I haven't done this, so don't have any specifics. Try several methods and see what you like, bearing in mind that a pretty finish like linseed oil or hot wax will need reapplication. You'll be able to paint the metal, but how can you heat it to do hot wax after it is installed?

Steve Smith

Rich->I'm a first-time poster here, so go easy on me. I'm getting ready to

let the metal rust and when it does you can go to the auto parts store and get a plastic bottle of rust restore liquid.. it is a milkish white colored liquid that turns rusty metal black.. i used it on a 75 datsun pickup truch under the hood where the battery acid ruined the paint on the metal battery tray.. it kept the veh. battery tray black and rust free for the next 15 yrs. when i sold it... never did see any more rust on that tray... used some last year on an old swing set from the kids... cut the swing set for a new wooden swing for adults.... the feet on the set was all rusted.. painted over the rust and now they are black.... got the stuff at auto zone in the body and fender/paint section.... also got it years ago from NAPA, national auto parts store.. its been around for years....

I appreciate to look that you want for your hardware, but here in WA, rust never sleeps. The smart folks are now using powder coating for a lot of architectural hardware such as yours. Powder coating will last you a lifetime if it's done by a quality shop and they now have a lot of different finishes available, even hammertone. The best shop in the area is in Kingston WA, Kitsap Powder Coating, 360-779-4040, ask for Dale. I have no financial interest in this shop, they have done work for me for the 4 years and the quality is excellent.

Ed Angell

On Thu, 08 Jul 2004 01:02:12 GMT, " snipped-for-privacy@sprynet.com" wrote:

||Rich-in-WA wrote: ||> ||> I'm a first-time poster here, so go easy on me. I'm getting ready to ||> fabricate some steel hardware for a timber frame home we're just ||> breaking ground on. These pieces will be machined and welded from bar ||> and plate stock. Most will have planished surfaces achieved by ||> careful hand work with a ball peen hammer. This hardware will mainly ||> be used inside, but a few pieces will be on the exterior, tucked up ||> under a 4-foot eve (i.e. they'll see condensation and occasional ||> wind-driven rain). ||> I'd like the hardware to have some sort of a blackish/brownish ||> finish, while avoiding large amounts of orange rust bleeding onto the ||> timbers. I'd like to achieve a somewhat mottled appearance, similar ||> to an old piece of cast iron cookwear. I'm after something more ||> natural-looking than paint. In prior projects, I've achieved this ||> sort of finish by coating steel with linseed oil and baking it in the ||> oven for an hour or so. This "baked-oil" finish probably provides a ||> bit of rust protection, but I'm not sure how it would hold up when ||> exposed to the elements over time. Any better ideas... ||> ||> Rich Johnson ||> Camano Island, WA ||> ||> P.S. I mistakingly posted this to alt.rec.crafts.metalworking, prior ||> to posting here. Not sure what kind of response that one will ||> generate... ||let the metal rust and when it does you can go to the auto parts store ||and get a plastic bottle of rust restore liquid.. it is a milkish white ||colored liquid that turns rusty metal black.. i used it on a 75 datsun ||pickup truch under the hood where the battery acid ruined the paint on ||the metal battery tray.. it kept the veh. battery tray black and rust ||free for the next 15 yrs. when i sold it... never did see any more rust ||on that tray... used some last year on an old swing set from the kids... ||cut the swing set for a new wooden swing for adults.... the feet on the ||set was all rusted.. painted over the rust and now they are black.... ||got the stuff at auto zone in the body and fender/paint section.... also ||got it years ago from NAPA, national auto parts store.. its been around ||for years....

That is a very good option. I have used the stuff for years. In the Permatex or Duro brand it is called Extend. Comes in aerosols and bulk. To use it, let the steel rust, remove scale with a wire brush, wipe off dust, apply chemical. Works best if you have a good, uniform layer of rust. Use gun chemicals or try the Clorox method. You will want to treat all surfaces, uncluding the inside of bolt holes, so they may need to be a small amount oversize. Texas Parts Guy

I second Ed's suggestion. Powdercoating is the way to go for this application. Paint has to be re-applied every few years and I guarantee the homeowner won't even think about repainting until the hardware is 1/2 rusted...

I'm a metal sculptor and Dale at Kitsap Powdercoating has done work for me (even a 12' high sculpture) with GREAT results.

James Kelsey, Port Orchard

Thanks for all the ideas on finishing my hardware. I think it's time to do some experiments prior to the real deal. About 90% of this hardware will be indoors and the outdoor pieces can be removed one at a time for future refinishing. With this in mind, I may opt for a "rust-resistant" finish versus a "rust-proof" finish. I'll watch the stuff closely, and if it's starting to get any bad bleed-through, I'll pull it and coat it with something more durable. Powder coating would certainly be a good option for durability, but this is way more "finished" a look than I'm after. I'm curious why the advice to heat the steel prior to planishing. I did a test piece - about 3" x 1/4" x 6" - and quickly got the texture I was after by working it cold using an 80 lb anvil as backup. I can see that the steel would be easier to work when hot, but this might be ofset by having to heat it up and handle it tongs, etc. My home shop is set up for mig welding and light fabrication, but I don't have a forge. I designed most of the hardware so I could have the steel supplier (Everett Steel) do the bulk of the cutting for me. These pieces are designed mainly for aesthetics, and are grossly oversized for the actual loads they see in service. In other words, if the heating is for something like stress relief, I can live with the reduced properties.

Thanks again,

Rich Johnson (PE)

Hmm... I can't think of an easy way to make this in a continuous roll. Other than several (say 10 for 1024 layers) machines that cut the hot steel in half, flatten it out to twice the thickness, and then reunite the two layers after surface coating.

Why heat? It's a force issue. The steel will easily indent when hot. Cold, it will also dent, but you'll have to hit a lot harder. Depends on how much you have to do. I know a smith who made a set of power hammer dies on which he'd welded a lot of little dots with hardface rod. He could produce a hammered finish on a large flat bar in one heat, both sides.

Unless you are a seasoned smith, the amount of hammering you describe might be enough to hurt you. If you do take this on, pay attention to your hammering posture and technique. (And don't say I didn't tell you so!)

Grant

Rich-> Thanks for all the ideas on finishing my hardware. I think it's time

Ya. No wonder Bessemer invented a new method!

Tim

-- "I've got more trophies than Wayne Gretsky and the Pope combined!" - Homer Simpson Website @

I would use stainless steel. Get some powered metal and mix it with water to make liquid rust... Soak your stainless in this solution and it will take on an old rusty look that will not bleed into your wood...