6101 vs. 6061 aluminum alloy - 6101 safe for furniture applications?

[sonambulo]

UPDATE: Everyone has been especially helpful in this thread, ModelWorks especially so. I really appreciate it everyone!

However, in my research I found a website that is selling Aluminum Piping (my first choice) at a cost comparable to steel even after cutting and shipping. The link is here. What I am looking at is pipe made out of the 6101 alloy. Is there any reason it would not be suitable for a standing height work bench that will hold up to 500 lbs?

*****

So I'm building a stand up workstation out of pipe. Unfortunately there is a dearth of plain, rolled steel pipe suppliers in the Boston area :hmm: I'm going to be going with galvanized pipe as a result but I hate the look that it already has. I want something a little more corroded, in the vein of this guy's pieces. Does anyone have ideas how to remove or distress the finish to match the look of his pieces? I'll gladly go with aluminum if I can find a way to distress it since it is FAR less hazardous.

As far as I can tell, there are three main ways of removing the galvanization:

• Torching
• Muriatic Acid
• Vinegar

The fumes released by torching are extremely dangerous so that's a no. Muriatic acid is also pretty dangerous and neutralizing/disposing of it is a royal pain. It does work very quickly though which is an advantage. The HCL would allow me to build a drip pan setup and I could just brush the acid on thereby preserving the finish on the inside of the pipe and allowing me to avoid waxing it (which is a huge PITA). Vinegar's main disadvantage is the amount of time it takes and there's also the issue of it removing the interior finish. I'd have to submerge the piece and there's no great way to protect the inside if I do that AFAIK (although maybe I could cap the pipes?). However if I could skip all three and 'simply' apply a patina I'd go for that method in a heartbeat. Whew! Thanks for reading all that.

So does anyone have any ideas or helpful reading for me? I'd be eternally grateful

 

[Modelworks]

Galvanized pipe is coated with zinc.
One fun way to remove or change the coating is to electroplate it. You need acid and a power supply.
Place the pipe in something non conductive. Cover it with your choice of acid, stronger acids like muriatic work better but vinegar will also work. Clamp one electrode on the pipe and the other on a piece of metal. The metal can be copper, nickel , iron, steel. Watch the magic as metal moves from one electrode to the other. Reversing the electrodes will reverse which item gets metal deposited.

Current needed is about 12VDC @ 2-3 amps for a start. Higher currents work faster but if you are in no hurry a 12VDC wall adapter works fine.

The benefit of electroplating is you can add metal over the zinc already on the pipes and you can choose what that finish looks like by choosing the metal colors and by brightening areas of the pipe with sandpaper or a file to make that area more receptive to the flow of current.

For metal sources you can use copper water pipe, brass fittings, nickels or pennies.


Aluminum isn't recommended for this because it takes a whole another approach with more complicated acids and currents.



One caution is to make sure you do this in a well ventilated area. The process gives off gas, not a lot but enough to make your eyes water.

 

[Paperdoc]

As Modelworks says, Galvanized means zinc-plated, and his / her suggestion to use electroplating to remove it or add a new plating metal over top of the zinc gives you some interesting possibilities.

Aluminum usually does not come plated with some other metal. It is usually "passivated", often by an accelerated process rather than just waiting for it to happen. Aluminum is more reactive than many metals with things like oxygen in the air, so it will naturally oxidize, producing on its surface a fine film of aluminum oxide which, itself, is pretty unreactive. Thus the passivated aluminum surface becomes pretty stable, until you work on the metal and abrade the surface oxide layer off. That Aluminum Oxide, as a very fine thin layer of particles, gives the metal surface a dull gray look (pure aluminum is shiny silvery), and some of it can be rubbed off. A cloth rubbed on aluminum comes off with a gray stain, and enough rubbing leaves the metal surface shiny. In fact, Aluminum Oxide is the "rust" that forms on it, just as the reddish stain on iron surfaces is Iron Oxide. So you'll never get Aluminum to "rust" and look like old reddish steel or iron - the oxide color is wrong.

Check into Black Iron. It is usually available in piping and sometimes as angle iron. It is basically pure iron, and so it oxidizes easily. It usually arrives with a black surface of mixed iron oxides. But if you abrade it slightly and remove that, you're down to pure iron surface that will oxidize and acquire a reddish color. You can really accelerate this if you wet it and let it sit around just damp for a few days.

Unless you want your creation to continue to rust and deteriorate, once you have it looking as you wish you will need to prevent further oxidation. That usually means coating with some clear film that will keep air away, like a varnish. NOT Marine Varnish - maybe Urethane varnish would work well.

 

[PottedMeat]

which pictures shows the galvanization removed?


i usually remove the zinc from steel conduit before welding using HCL and it doesn't really look any better than without. i guess if you don't clean off the HCL immediately you can get that rust look and then clean & neutralize it - that may look pretty nice.

 

[sonambulo]

Modelworks & Paperdoc,

MUCH obliged for the information. Unfortunately electroplating is out of the question since I am working out of an apartment. There is no way the landlady (who lives on premises) is going to allow it. I actually wanted to go originally full aluminum and do a chemical corrosion but it is quite cost-prohibitive. The aluminum Kee Klamps and piping would cost nearly double the same amount of steel.

PottedMeat,

Actually none of the photos show the galvanization removed. I guess the best approximation of what I'm going for would be this followed by close-ups of other pieces here and here.

I may just use a rub in patina like the one applied in this video (youtube) and use a very light acid wash on certain parts to corrode it even further. I very much *want* the final piece to look like it's been beat to hell and back.

 

[Gardener]

Look for a place that sells salvage material, hand pick your level of "patina".

 

[Modelworks]

dp

 

[Modelworks]

I very much *want* the final piece to look like it's been beat to hell and back.

I found a really old book today that has formulas for coloring and aging metals. It was printed in 1914 but has lots of good information, these are the formulas it list for various metals . I think the last one is the one you want. Also consider hydrogen peroxide and muriatic acid. Used commonly for etching pc boards but also damages steel quickly.

For steel or iron:
Item placed in small box and heated to the point the mix vaporizes.

Iron chloride (muriate tincture of steel) 1 ounce
Alcohol (spirits of wine) 1 ounce
Corrosive sublimate (mercury bichloride) .25 ounce
Strong nitric acid .25 ounce
Blue stone (copper sulphate) .12 ounce
Water 1 quart

The vapor arising from this bath forms a deposit on the articles,
which are allowed to remain in the receptacle a number of hours, and
rubbed off with a cloth; the operation is repeated if a darker color is
desired. Very rich coloring can be obtained by this process, after a
little experimenting, and the temper is not affected.

--------------------------

Gun metal black coating

Another process employs a solution of mercury chloride and ammonium chloride which is applied to the work three times and dried
each time; a solution of copper sulphate, ferric chloride, nitric acid,
alcohol and water is then applied three times and dried as before; a
third solution of ferrous chloride, nitric acid and water, is applied
three times and the work boiled in clean water and dried each time;
the third and last solution of potassium chloride is then applied and the
work boiled and dried three times. The work is then scratch brushed
and given a thin coating of oil. Ordnance for the French Government
was treated in this way.

-------------------------------------

A variety of colors can be produced on iron and steel by immersing
the pieces, for different lengths of time, in a boiling hot solution of
the following composition: Lead acetate fifty grains, sodium thiosulphate fifty grains, water five fluid ounces. A half-hour immersion will
make the work black and a shorter time will make it steel-gray, blue,
mixed purple and blue, purple, dark brown and light brown. By con-
trolling the time, the desired color can be obtained. These colors are
very beautiful but fade quickly. A coat of lacquer on top of the color,
however, will preserve them for years. On top of a nickel plating these
colors are exceptionally brilliant.

A good brown color can be obtained as follows: Coat the steel with
ammonia; dry it in a warm place; then coat with muriatic or nitric
acid; dry in a warm place; then place in a solution of tannin or gallic
acid; and again dry. The color can be deepened by placing the work
near the fire, but it should be withdrawn the minute the desired shade
is reached or it will turn black.

The U. S. Government adopted the following formula for browning
gun barrels: Alcohol three ounces, tincture of iron three ounces, cor-
rosive sublimate three ounces, sweet spirits of niter three ounces, blue
vitriol two ounces, nitric acid one and a half ounce and warm water
two quarts. The solution is applied with a sponge, allowed to dry for
twenty-four hours, and after this the loose rust is removed by scratch
brushing. A second coat is given in the same manner. After that the
piece is boiled in water and dried quickly. A thin coat of boiled lin-
seed oil or. lacquer is then put on to preserve the color.
Another process for browning iron and steel consists of dissolving
four ounces of copper sulphate in two quarts of water and then add-
ing one ounce of nitric acid, one ounce of spirits of niter, two ounces
of alcohol and one ounce of ferric chloride. Scratch brushing and
rubbing with a piece of smooth hard wood will polish and burnish the
work and a coat of shellac or lacquer will preserve the color. Rub-
bing with the polishing wood will give the lacquer or shellac a pol-
ished surface.