Galvanized roofing too pretty

[gafftaper]

I'm doing "Night of the Iguana". I want to do tin roofs on the cubicles. Home Depots got some great galvanized roofing. Unfortunately, it's REALLY bright and shiny. I want my dull, aged, and preferably rusty.

Any suggestions? My only thought is to paint it with a flat glaze that's got some rusty brown in it. Any other ideas? Also thought about going after it with a grinder or sander to scuff it up and leave it out in the rain... but not sure how well that will work.

 

[elite1trek]

I would do a light textured glaze over it. A light brown glaze with some fine sand in it. Then I would spatter it a little.

It might also be worth it to check out your local junkyard, to see what they already have rusted.

 

[cdub260]

Paint is definitely the way to go here. If you can find a reasonably talented scenic artist in your area, you should be set. If we can make a styrofoam horse look like a bronze statue, you can make galvanized steel look like old, rusty tin. Unfortunately, I can't give you any specific advice as I have no talent for painting.

 

[Footer]

If this is in your black box, I would suggest going the "real" route. Take a grinder to it, rough it up, put salt on it, and throw it outside and get it wet. With that show you are going for the salt air rust look, so spray it down with salt water and keep it wet. You should get pretty good rust going fairly fast. You just have to get the zinc dip off.

 

[cprted]

I once saw an acid wash recipe for exactly this purpose. Making new shiny galvanized sheet metal look old, rusty, and deteriorating (depending on how much acid you used). I'll see if I can dig it up for you, though I think Footer's idea is pretty solid too.

 

[Sayen]

I would second the junkyard suggestion, or depending on where you live drive around the outskirts a bit. Plenty of rusted roofing around the Phoenix area, for example, rotting in the desert sun.

 

[Footer]

rust

I have treated sculptures with somethings similar to this before, it does work.

 

[Van]

I've done a couple 'o few corrugated tins roofs, and even when really painted well you can almost always see through the painted patina to the shiny surface. You can use Muratic Acid, sometimes sold as concrete or driveway wash. This'll strip off the zinc pretty quickly. If you are uneasy about using Muratic acid < which is borderline dangerous> you can lightly sand then pour on an Acedic Acid solution, if you can find Vinegar stronger than 10% it'll work, you just need to etch into the zinc coating. Um, I'm trying to remember there's one other, ...... Ferric Chloride, I think. It might be Ferrous Chloride, depends on which Ion, you know. Anyway it's usually sold at Radio Shack or some other electronic retailer as an Etching compound for making circuit boards. It's made for copper, but will work on Zinc. And Finally as Footer said, I believe, a salt water solution will really move the process along, especially if you make a super saturated solution by heating/booiling the water first then adding rock salt and stirring until the salt won't dissolve anymore. Strain the solution put it in a pump sprayer, and coat the heck out of the "tin".

 

[Kelite]

I would second the junkyard suggestion, or depending on where you live drive around the outskirts a bit. Plenty of rusted roofing around the Phoenix area, for example, rotting in the desert sun.

I wish you weren't so far away in WA state, as I have 15-20 eight foot sheets of the rusty corrugated steel roofing by my barn. Perhaps they need to go to Craig's List for a project within the Ind/Mi/Ohio area. (?)


Saltwater will certainly do the trick once the zinc coating has been violated. (Can I say that here?)

 

[jwl868]

If you go the acid-etch route, try to neutralize the waste acid before you pour it down the drain so as not to corrode the drain piping. Baking soda is effective, is pretty safe to handle, and doesn't swing the pH too far into the caustic direction. You probably get some heat and gas generated doing this, too.

Joe

 

[Footer]

If you go the acid-etch route, try to neutralize the waste acid before you pour it down the drain so as not to corrode the drain piping. Baking soda is effective, is pretty safe to handle, and doesn't swing the pH too far into the caustic direction. You probably get some heat and gas generated doing this, too.

Joe

Um... aren't you supposed to take it to a proper disposal facility? I can't see pouring this down the drain even neutralized to be a good thing.

 

[jwl868]

I guess I've become too cynical about what I've seen go down drains to public wastewater sewers.

Maybe I've underestimated the volume of liquid.

In any case, the used acid will have a low pH, plus a lot of zinc and iron.

At the very least, add enough baking soda (sodium bicarbonate) to get the pH above 2 and out of the hazardous waste regulation world. If your organizational rules do not permit you to neutralize this (and I am assuming that the pH is low enough to make it hazardous waste)when you generate it, you have a 90-day clock running to get rid of it. Find out quickly what to do.

The waste can be sent to a disposal facility. But it would also be worth a phone call to the wastewater utility. They may well allow the discharge of a small volume with little or no paperwork or additional fees.

Joe

 

[Sony]

I've got a PERFECT easy/cheap solution to this problem...

Bleach

Chlorine rusts steel like it's it's business, it should eat off the zinc coating too..

Go get some Chlorox Bleach and pour/brush it on the metal and it will be rusted within a day or two...no joke.

Chlorine is one of the most powerful Oxidizers around.

 

[DaveySimps]

If you do decide to pursue any of the aforementioned techniques, be sure to wear (or have your crew wear) the appropriate splash protection: goggles, proper gloves, long sleeve tyvek type suits, respirator, etc. I would hope it goes without saying, but all to often people neglect this in our industry out of convenience. I also second the thought of looking into the proper disposal of the waste water that results in the process.

~Dave

 

[Kelite]

The waste can be sent to a disposal facility. But it would also be worth a phone call to the wastewater utility. They may well allow the discharge of a small volume with little or no paperwork or additional fees.

As a FORMER large waste generator, Apollo was responsible for the waste etchant 'from cradle to grave', as our local EPA laws dictated. Since we have gone to lasers (woo hoo!), we aren't handcuffed by the nasty etchant guidelines any longer.

I too would suggest either pre-rusted (read- used tin from the junk yard), or use the bleach method. Bear in mind the chlorine gas is the fun stuff that gets spilled from railways cars now and then, causing entire towns and cities to be evacuated. SO, don't stand downwind and breath the toxic fumes. And don't do this indoors. Ugh!

 

[Van]

Um... aren't you supposed to take it to a proper disposal facility? I can't see pouring this down the drain even neutralized to be a good thing.

Not sure about the exact regs on this. If one were to use Muratic acid < which is really just a strong mixture of Hydrochloric> then the by-products of the reaction are going to be Zinc Chloride and water, if the resulting run off were mixed with a a bit of Draino <Sodium Hydroxide> then any left over acid would be nuetralize into H2O and NaCl, salt water, which I guess you could pour back onto the steel to make it rust, the Zinc Chloride you could dry out put it in capsules and take it as a zinc supplement.
< No not really that would be stupid, toxic and probably result in somebody dying.>

 

[gafftaper]

Well as much fun as all this chemistry is, I don't I want to deal with the hazardous waste issues. I've spent the morning on the phone calling junk yards and think I have what I need tracked down. If I don't find what I'm looking for I'm not using anything stronger than bleach. I don't want to deal with the disposal and I don't have a safe place to work with the acid in the first place.

 

[Sony]

Household bleach will get the job done and most likely doesn't need any special disposal techniques. People use bleach in their laundry and for cleaning all the time and the wastewater treatment plant uses bleach to clean the water that comes into the plant, so it's totally fine.

 

[lieperjp]

Household bleach will get the job done and most likely doesn't need any special disposal techniques. People use bleach in their laundry and for cleaning all the time and the wastewater treatment plant uses bleach to clean the water that comes into the plant, so it's totally fine.

Yes, that's true, but most people don't throw zinc in with their laundry. Water diluted household bleach and household bleach with zinc (Zinc Chloride) are different, although it appears that diluted Zinc Chloride is fairly harmless.

 

[Les]

Make sure your Tetanus shot is up to date!