HWooldridge

Rust finish

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I'm looking for solutions for producing a nice, deep rust finish on a fairly large and complex piece. I already use Birchwood Casey's Plum Brown on little stuff but it's too cumbersome for my patience in anything of size. I have heard of using Clorox, ammonia, acid, etc. Old gunsmithing books talk about damp boxes with light bulbs and such but I figure some applied chemical would work better. I tried a muriatic acid solution but the color was not consistent and the acid has to be removed before the finish coat.

In a perfect world, I would sandblast all the scale and get a good soft rust going then card it with a soft brush, followed by clear coating with urethane or acrylic.

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I will offer the following; I have had success with de-scale and then using Watco Danish Oil - natural ( stock warmed, applied while warm and heat post application and continue to have rag ready for touchup ). This stuff will spontaniously combust and the process is dangerous somewhat. I have however retained a really nice dark brown finish. This should be done outside the shop in daylight to get the complete unit covered and of course for safety reasons. Weed burner works great for the heat. YMMV. I'm just gonna add this...I know my solution isn't a rust finish. It is however a nice dark brown patina.

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to get a uniform coat i think a blast ,sand or cabrundum, will be needed ,i have had a try but big areas i have had a galvanizing firm do the job for me and they sand blasted first they used muric acid ,it looks great if its done well,

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I am not familiar with what grade of steel you are using or what time frame you have. Buttt....I have made a gate out of mild steel and put it outside in the elements until it had a uniform brown finish. Then I lightly carded it and oiled it up good to stop the rust. Best finish I ever did.

DanL

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I have a customer who wants an "old world" look on a forged iron port-cullis, which in this instance is best described as a rust color. They call it "bronze" but it's a little redder than my view of that.

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Mix one bottle of hydrogen peroxide with equal part vinegar and add about a cup of salt. Spray on de-scaled metal let stand till dry. To speed things up spray bleach on after the peroxide. DO ALL THIS OUTSIDE! Gives off some pretty mean fumes. Repeat until you get the color you want,then rinse and let dry. I have used this method many times with satisfaction. May be top coated with clear also. Hope this helps

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Radio Shack sells a quite inexpensive product called "PCB (Printed Circuit Board) etchant." In a plastic spray bottle mix a little PCB with water. Apply light and even mist over everything you want rusted. Reapply to any areas where heavier rust finish is desired. BTW: Works best outside in direct sunlight and/or on warm piece. Solution may stain concrete so avoid spills.

Once completed, the rusted finish can also take on an almost leather looking finish by simply applying a coat or two of a good paste wax product.

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Hi, I use 60mL muriatic, 2400mL 3% peroxide to one gallon of warm water. use a pump up weed sprayer set to a fine mist to hose the thing down compleately as quick as you can to avoid dark runs.
Do this after you have descaled, on a warm day when the piece is about 100 degrees. In ten to thirty minuets when you see about two shades lighter than you want on the piece, rinse it thourghly with water. ( wet it will look very close to the final color) Then let dry comletely and clearcoat w/ Permalac.
With care and a little practice you can produce a patina ranging from a translucent gold through orange,red,yellow,and brown,up to a very opaque purpleish black.

To go darker use more heat. To bring out brighter orange and yellows use more peroxide. Don't add much more acid or it will lift the rust off faster than it can grab and give you an unattractive mottled apearance.

You can re apply over the original patina to achive darker shades several times, just make sure that you rinse it well and let it dry before clearcoating.

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Johnny99,

Thanks for the input. I tried S. Willis' formula on a test piece and got a nice dark brown (like an old gun barrel) in three applications of the vinegar/salt/peroxide mix followed by the bleach. The bleach really makes it fire off quickly so I'm thinking Clorox over your acid mix would also speed up the rust process.

I'm due to finish this piece in about 4 weeks and the customer wants a "500 year old" look so I'm going to rust and card it until the finish has an aged patina.

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A Ferric Nitrate/Ferric Chloride + water mix (or either of the two by itself) will rust steel in a heatbeat. These chemicals are easier on your squirt bottle as well and will not eat up the internal spring for quite some time. (unlike the solutions with salt) No hazardous chemicals to deal with either. My pieces regularly go from bare steel, to patina, to Permalac in just a few hours. Leave some scale on as well for color depth.

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No decon needed with these chemicals. I guess I should rephrase that sentence and define what I meant by "hazardous". The previous formulas were using muriatic (HCL) and thats a far more aggressive acid than Ferric Chloride. There is no need to use an acid like HCL just to get a rust finish.

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try using some cooper sulfate solution. just dump some in a cantainer then put in the peice and let it sit. i let mine site for six hours or so. i dont know where you would get it i tryed mine with my chemestry teacher at school.
good luck

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