How to accelerate rusting of square tubing?

[wasabi]

I have been asked to make an arbor for the customer of a plant nursery. I am going to use 2x2 square mild steel tubing that will come as bare metal from the metal supply place near me. They want it rustic and I know it will rust over time. But I do not want it to rust unevenly - instead I want to deliver it with a good even base of rust (red, not the initial orange).

Is there a home concoction I could make to keep costs down?

[glass attack]

Clean of all of the oil and spray the tubing with water and pool chlorine mixture. If the the steel is warm it will work quicker. I'm sure there are other additives that will ensure a red color.

For a quick fix, over the counter solution, try Sculpt Nouveau's Red Patina.

[PeterG]

I usually degrease and then spray on a soloution of ammonium chloride and then keep the item as moist as possible. It will rust within the day. Dont allow it to pool on the metal or it will make it black.

To get a deeper reddish colour, try a mix of ferric nitrate and a blowtorch.

These will only get the rust started. Regardless of what colours these produce, the rust will even out to normal colours after a week or 2.

[Arrow]

Sandblast then hydrogenperoxide + salt water mix.

[chapman A]

Degreasing the metal is key to getting a good even rust finish. it is easier to degrease the metal befor assembly. for a nice rust finish you should try PCB etching soulution. it is sold at radio shack, i think it is used for circut board work. it is relatively cheap. just mix it with a little water and brush it on. let it sit for a couple of days. the solution will pull the moisture out of the air so you project will appear to be swetting. after the desired finish is achieved you have to stop the reaction with baking soda and water. as always test the process on some scrap first. rubber gloves are recomended.
good luck.

[iowasculptor]

Basically you want to get your surface clean and also open the "pores" of the metal, this is done by either sandblasting or using an acid to etch into the metal. once this is done you can just put salt water on it and it will rust. If you have ever been to the Midwest you will notice that cars as new as 2 years will have rust and thisis because of the salt put on the roads in the winter. I would not go overboard on the salt or acid because you are essentially eating away the steel, this will decrease the lifespan of the piece. Once you get the piece to the color you want I would wash it off to get all of the salt off and seal it up to prevent more rusting, and preserve the piece for a greater duration.
Good luck
Matt

[wasabi]

What should I use to degrease? I only have my driveway to work in so I don't want any harsh chemicals...

How much hydrogen peroxide to water? I could put this in a spray bottle and mist it.

Sometimes people mention chemicals that I would not know where to obtain. Where does one look (preferably locally) for chemicals? Are there chemical supply places that just are not on average joe's radar? Are they at Lowes and I just never have seen them??? :confused:

[Arrow]

http://www.lametalsmiths.org/news/page9.htm

"It is a fantastic way of getting different colorful rusts fast without the nasty chemicals. Peroxide works much faster if you add about a 1/4 cup of vinegar to the pint of peroxide and a couple of tablespoons of salt. If you heat the iron so that the solution almost boils off you get absolutely instant rust. You do have to put up with the vinegar smell. Sandblasting works great for cleaning the metal of oils, scale etc and gives the solution a nice surface to bite. Clyde Wynia "
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Hydrogen peroxide from the supermarket. Not sure where to buy the stuff in bulk.

[grimlok]

Use hydrogen and salt acid mixed. Add water if too strong.

One other good way is to use some sour stuff or just something liquid, and pass oneway electrical current through it. It's kinda interesting to experiment with, since you control the speed by gaining voltage.

You can mix these two methods ;).

[sculptorsam]

Another vote for sandblasting and salt water.

[Merlion]

I am curious as I have not tried giving steel surfaces an uniform rusted finish.

I suppose subsequent rusting from outdoor exposure would be uneven. Thus this question is for all those who have experience in this matter. Do you coat the surfaces afterwards to prevent further rusting?