I have started this forum to discuss and share info on what is available for the coloring of copper and copper alloys.

When we share these formulas and techniques we must be aware that they may be tried by the amateur and there may be liability in presenting these on the forum. I do my best to provide relatively safe techniques with easily acquired chemicals.

I hope this will be fun for all.

Fred

...a litle while ago, we started getting into this topic a bit, several threads down...

http://forum.arts-crafts.com/eve/forums/a/tpc/f/9886045532/m/5921017231

...but I'm sure there is lots more to discuss...

Thanks Fred for getting this thread going.

My one experience with colouring modification was through a compound that I was told contained selenious acid as the active ingredient. It was purchased from an antique dealer who bottled it himself and who has since vanished.

It seemed to work quite well for the projects on which I used it. I would like to replentish my supply but am not quite sure where to look. Any suggestions as to sources.

There are several patinas that use Selenium Dioxide in combination with an acid such as Nitric. These patinas are photosensitive and are best used in full sunlight.

Novacan Industries of Canada manufactures a product "Nova Black" that is used for stained glass and can be acquired at local stained glass suppliers. This works great with brass and so-so on copper.

Fred

The commercial formula I have is called 'Brass Antiquing Solution' from Clark's Antique Hardware Corp. Strathroy, Ont., but no website or info with a Google search. The label says 'contains Selenious Acid (less than 0.4%)' and the instructions say: black finish - do not add water, brown finish - add 1 part solution to 2 parts water. I just picked up a brass tray I want to try it on, so I'll take some pictures and make a project log, and post the results, hopefully this weekend.

This book http://www.bibliopolis.com/cgi-bin/biblio/warriorbooks_022356.html has 18 formulas for coloring brass and copper, a section on annealing and pickling copper, plating without current, even a section on how to copper plate nonmetalic objects. I'm not really into metals but that section of the book always intrigued me. There are a million other things that would interest anyone visiting this forum as well.

Wabash

I think there are endless recipes for patina formulas, old and new. I have a few books with formulas that range from witches brews to chemical concoctions requiring a Phd, if you can even find the ingredients. The problem like so many other 'projects' is filtering through what's good and bad, what's safe and what isn't, how long does it take, and so on. I suppose we all want a quick fix but in the spirit of Arts & Crafts philosophy and technique, shortcuts probably produce less than the best results. Personally, I like learning the basics from whatever sources and materials I can find and then experimenting to learn hands-on. That's how I figured out how to restore and refinish furniture. It doesn't seem to me that there are any standard and easy approaches for metal patinas. If there was, we would all have the secret Aurora Brown from the Roycrofters on our shop shelf. I started my brass tray job tonight and I have no idea what I'm going to end up with by tomorrow night and for me that's the fun and beauty of it.

Stonecat,

You are right-on. There are many books on metal coloring/patination that have been published for at least a hundred years. One book I have, even discussed the formulas that did NOT work. It is important to understand that working with chemicals has it's risks.

The most common of formulas for coloring copper deals with a solution of Sulfurated Potash "liver of sulfur". This can give a nice color if used correctly. It will be fun documenting and experimenting for this forum.

I am currently experimenting with buried patinas and find them exciting and they offer a whole different range of colors and mottled textures. I will share these as well though they are less likely to be used with traditional A/C Movement pieces. I suspect Heintz used the buried method for alot of their patinas.

Fred

First off, sorry this project is brass not copper, but it's a relatively cheap and safe piece to experiment with.

Top and centre left - Before - polished brass tea tray by Beldray (English maker, early 1900s, mix of Arts & Crafts and Art Nouveau style)

Top and centre right - First I tried rubbing some of the solution on by hand but the results were fairly blotchy, so I made a highly diluted bath and let the tray sit in the bath overnight - no major change after about an hour, so overnight didn't make a difference - colour evened up somewhat on the top but patchy on the bottom

Bottom left and right - Used good old ketchup (slightly acidic and an old time polish) and super fine steel wool (grade 0000) with a really soft touch and rubbed out the colour to try to hit the highlights of the hammering, edge of the recess, the handles, etc.

Results - Not great, not bad; If I hadn't done the rub as the first step but had just put the tray in the bath at a higher concentration, I think the overall colour would have been much better. Nonetheless, hopefully the lighter colour areas will darken up in time to a deeper butterscotch and make it look better overall. On the other hand, I could polish the whole thing out and try again!

i posted my latest adventure under a separate discussion, but it also pertains to this subject.

i went to a local foundry today to ask about patinas they use. a person was doing a patina on a brass statue while i was there and was using liver of sulphur. i had a piece of copper with me so we did some experimenting. i am posting the sample here as well. this was a very quick trial, uneven at best, but gives an idea of the color in the center leaf, where we wiped and buffed a bit. i am going to try the actual clock face and see how it turns out. i will post that when done.

..uneven???..looks pretty darn even to me..where does a person buy liver of sulphur? drugstore?

i just bought a 4 0z bottle at a local art supplies store. seems to be a stock item.

i saw it online at Dick Blick graphic arts. a great source of all kinds of art stuff.

it comes dry (hard nuggets or rock like) or liquid like i got. the guy at the foundry gave me a chunk so i can try both the dry and mixed to see if there is a difference.

i'll post my results.

it is also called sulphurated potash if that helps. google will give you lots of info.

Liver of Sulfur (sulfurated potash) is available at chemical suppliers or from jeweler supply store. Check in local yellow pages. You can also order from Bryant Laboratories. Bryant also provides a booklet of old patina formulas upon request.

Liver of sulfur patina is the traditional patina of old and appears in most metal technique books.

Some formulas suggest a drop of two of ammonia water added to the solution.

Don did the founder apply the solution hot or on warm metal?

Fred

Fred

no heat, it was cold application.

Don,

I believe the hardest thing is to start with a grease free surface and to limit handling it while the patina is applied. Did the man at the foundry spray the solution on or was it daubbed on with a rag?

I will be looking forward to seeing the results of your clock face. Is the metalwork your's? Nice design and even depth in the chasing and embossing (repousse). I am currently filling an order for light switches. The patina I am using is torch induced and then wiped with cotton cloth.

Fred

he applied with a rag, let darken and then wiped with a dry rag.

attached is my experiment from last night. i used the liquid liver of sulphur, mixed per label. it got very dark quickly. i buffed with 0000 steel wool and got the lighter brown i was looking for. just a bit redder than i hoped, but not bad for a first try.

if you heat the metal with a torch, does it go the color change from the heat from orance to blue? does the sulphur even out to a uniform brown?

and yes, i did the design and the metal work.

what gauge copper do you use? this was pretty thin stuff. i dont have the label so not sure of actual thickness. i am curious how stiffer metal would work.

how does heat effect the process? hotter=darker? browner or blacker? does a hot solution on cold metal make a difference? in using a torch, do you apply the solution directly to the metal as the flame heats or heat the whole surface and then apply? would heating the copper in an oven work?

next, do you prefer the dry nuggets or liquid?

wow, am i asking for all your secrets or what....?

I willingly share what I know. I use 20 to 18 ans sometimes 16 gauge copper in my work. The torch technique I use does not include any chemicals. The heat from the torch produces oxides on the surface. These start with the colors you describe and these are not long lasting unless you cover with a lacquer or other coating. I take the heat to beyond that point and then rub vigorously with a denim rag. You have to be careful not to burn yourself.

Liver of sulfur does work faster (not better) at hotter temperatures. You might try darkening as you did and removing the high spots with the steel wool and then repeating the liver of sulfur application with a diluted solution or wiping it off sooner. Document your steps. Invest in a set of kitchen measuring spoons for use with chemicals only and a measuring cup. Cut sample sheets of copper and texture with hammer lightly and then experiment, document and when you find a result you like see if you can duplicte it. It is much like any craft.. It takes discipline and a bit of skill mixed with luck.

Fred

Fred

My son has taken up copper work and is enrolled in a workshop in July 2006 for chasing & repousse (sp?). The master-artist teaching this workshop is based in NYC, but is coming to Denver to teach this class. If anyone is interested I can pass on more info.