Enameling on Brass

Everyday someone visits this site asking if you can enamel on brass. Recently I had the pleasure of meeting Barbara Lewis whom has not only developed torch firing enamels but has produced a line of brass jewels for enameling.

Here at her store you can pick up and the supplies and instruction you need to achieve enameling on brass! She sells Thompson’s Unleaded Enamels for this so if you already have your enamels get some of her brass jewels and get started playing!

http://www.paintingwithfirestudio.com

Enamel on Brass

Happy enameling!

The Gum Bichromate Process for Enamels on Steel

Demo by Brenda Radford,  The Gum Bichromate Process for Enamels

This process is an old photographic printing technique, and I learned it from Gretchen Goss in a workshop she gave in Oakland, California in 2009.  She adapted it from photography colleagues at the Cleveland Institute of Art.

I have always been interested in creating images in enamel and this process, though it can be labour intensive, captured my imagination and so I have continued my learning and experimentation in my own studio.  I have created a line of jewelery based on the famous swans we have here in Stratford (some of them come down our stream to visit my studio) and on theatre related images.

Recommended reading on the subject:

Photographers Formulary – instructions for Gum Bichromate – gum printing www.photoformulary.com

Webb, Randall & Reed, Martin  Alternative Photographic Processes:  A Working Guide for Image Makers

James, Christopher The Book of Alternative Photographic Processes Clifton Park, New York

Livick, Stephen  Gum Printing Toronto: Stephen Livick 2001

FACILITY

●      a well ventilated space

●      a source of water, preferably warm

●      a kiln

●      a spray booth for applying emulsion (see photo)

●      compressed air and gravity fed dual action airbrush

●      enclosed exposure booth with a UV light source or photo bulbs 12-18” above surface (see photo)

MATERIALS

●      B/W negative laser printed transparencies

●      photoshop or other photo editing software

●      greyscale images in the size of the finished artwork

●      ceramic oxides – black and dark colours

●      gum arabic

●      potassium dichromate (label it poison)

●      ml measure with tube

●      teaspoon measure

●      porcelain coated steel 24 ga cut to size

●      prepared copper (counter enamelled, white or light colour foundation stoned down)

●      plate of glass that is not UV protected

●      photography developing trays

●      gram scale

●      glass beaker 250 ml

●      liquid thermometer with clip

●      glass stirring rod

●      small crock pot or hot plate

●      plastic funnel

●      clean hydrogen peroxide bottle or other darkened plastic bottle

●      plastic film container

●      panty hose

●      minute/second digital timer

●      gloves and mask

PROCESS

PREPARING IMAGES

●      use your own negatives as long as they are the same size as your finished artwork

●      for all other images:  using photoshop or other photo editing program, convert to greyscale, increase the contrast, resize to the size of your finished piece and finally, invert the image so it is a negative.

●      print your image negatives on a laser printer as a transparency

●      cut each image out, leaving some space around the image for handling

MIXING CHEMICALS

●      potassium dichromate is purchased in crystalline form – you have to mix it with water, as follows:

●      heat 200ml distilled water in a glass beaker to 120 degrees F on hot plate or in crock pot.  Use a thermometer clipped to the side of the beaker

●      add 40 grams of potassium dichromate and stir with a glass rod until dissolved

●      using a funnel, pour the solution into a clearly marked darkened plastic bottle.  It will store for some time.

PREPARING METAL SURFACE

●      make sure surface is clean of all grease and oil using whatever you normally use: pumice, windex, heat cleaning, etc but make sure it is CLEAN

●      if you want to create more than one piece at once, without touching the surface of the clean metal, use masking tape to attach all of them to a piece of cardboard

●      move prepared metal to spray booth.  Stand vertically against back wall

MIXING LIGHT SENSITIVE EMULSION

●      into an old film container or other container that closes tightly, mix 30 grains (a scant teaspoon) of oxide, 6 ml of potassium dichromate (solution) and 6 ml gum arabic.  Shake vigourously to mix and remove all lumps.  You can sieve through panty hose to ensure no lumps

●      pour emulsion into bowl of airbrush

SPRAYING EMULSION

●      set airbrush regulator at 35-50 psi

●      keep airbrush 12” away from the surface while spraying

●      apply in very thin coats, starting the spray off the edge of the enamel surface, turning the metal or cardboard 1/4 turn after each coating for an even and consistent application

●      move cardboard with sprayed enamels to the light booth.  (Emulsion is viable up to 20 minutes)

●      do not touch sprayed surface

EXPOSING THE IMAGE

●      once the sprayed pieces are on the floor of the exposure booth, place the transparency negatives on the surface of the emulsion (dull side down for a film negative)

●      you can place a piece of non UV coated glass over the negatives to hold them tight to the surface

●      turn the light(s) on and time for 15 minutes

DEVELOPING THE IMAGE

●      develop in warm water, upside down, agitating slightly

●      experimentation at this stage results in many variations

●      while wet the oxide is extremely fragile so touching it to anything will wipe it right off

●      let dry with enamel propped vertically

●      once dry, the surface is more durable and can be drawn or painted on, or rubbed off to create brighter whites

FIRING THE ENAMEL

●      fire at 1450 F for about a minute

●      repeated firings can eliminate the image

●      varied temperature and time will create different results

Thank you Brenda for sharing this! Visit Brenda at  www.radfordstudio.com

Enameling on Gold

The Hibiscus are chased on 18k gold. Then the surface is depleted by heating to 800 degrees and dipped in nitric acid repeated times until there is no fire scale. A layer of flux for gold is applied which is Bovano #2 then the red enamel in two layers.

Enameling on Sterling Silver

Tom enameling his Sterling Silver Egg.

He has made this to support a gorgeous Chased Gold and Blue Lapis with Diamond Bracelet.

I asked Tom how he planned to enamel this sterling silver egg. He plans to paint Klyre Fire on and sift the enamels. I asked are you planning to counter enamel it? And he said he did not want to.  But he knew he wanted opaque enamels.

Here you can see the egg open, and a bit more of the bracelet. Tom has some leaded enamels with several shades of blue. He is going for a look, close to that of the lapis. I  mentioned he would need to deplete the surface. This means to raise the fine silver by heating to a red glow and quenching it in acid or pickle bath. He is removing the copper from the surface so the enamel will adhere to it. I have read it can take 4 times. I use 18k gold in my work and when I want to remove the copper in the surface layer before I begin enameling, I have had best results heating and quenching 7 – 10 times.

Tom has enameled and started sanding to get his final finish on the enamel, using sanding pads and in his last application he plans to use cerium oxide. In this case it is not necessary to counter enamel  this piece because it is domed and he is only apply a thin coat of enamel. Remember thick metal =  thin enamel. He did not have to use flux because his choice of blue will not burn against the silver. But he is unhappy with the uneven surface of the enamels, and believes he had some soft and some hard firing in the group.

After several attempts to sand and re – fire the enamels still are not smooth. An option at this point could be to apply a top coat such as Ninomiya N4. that is a soft firing enamel.

With his multiple firing bubbles started forming. The depleted surface on the sterling silver was not sufficient, for this many firings. He was heating at 1450 for up to 5 minutes. One thing I have found to avoid some of the bubbles would be to raise the temperature thus shortening  the firing time. The enamels on the surface will melt faster and give the underneath metal less time to heat.  At this point he has to clean or break any bubbles that might hit the surface on this last firing of a soft enamel. A soft enamel means it will flow at a faster rate than a medium enamel thus not firing long enough for the bubbles to resurface.

And a beautiful Enamel Jewel!

Enameling with Argentium 970

Argentium 970 is currently sold in grain and only from this one dealer, G&S Metals. I just spoke with them and asked why they do not offer it in sheet and other forms. The answer was they have not had the request for offering it. I explained the interest of enamelist. And was told they have a blog on the home page top left. They would be happy to listen.So enamelist here is an opportunity.   www.gsgold.com/ blog away!

I will purchase the grain and start some testing for plique a jour. I do not see a need for cloisonne as fine silver is great. But it would also be a good metal for vessels.

Happy Enamels