Tuesday, February 26, 2013

Adding Resist to Brass or Copper Tubes.

Resists are materials that will "resist" the corrosive action of the acid, leaving your design as the un-etched or raised metal on your finished piece. These are the options I've tried so far.
  • White Out 
  • Paper resist
  • String or cord
  • Sharpie brand markers
  • StaZOn ink
Clean brass thoroughly before applying design - scrub with green scrubby and Barkeepers Friend or Penny Brite or other powdered cleansers to remove any oil if using rubber stamps or toner transfers. Water should sheet off, not bead up. Refrain from touching with fingers which adds body oils and interferes with adhesion of the resist.  
After-etching cleanup is important:
  • neutralize the etching acid with a baking soda and water solution
  • remove plugs and rinse again if needed
  • scrub with toothbrush, soap and water to remove all the gunk from design
  • use solvent of your choice to remove ink and adhesive (Goo Gone, Acetone) or steel wool, green scrubbie to remove marker or stamp ink.
Don't forget to protect your hands with gloves.

White Out use as a scraffito (scratching through a surface of plaster or glazing to reveal a different color underneath) resist. Paint casing with white out, let dry then scratch designs into paint with sharp tools. White out flakes easily, not very satisfactory results, IMHO.

 But the options are endless, and there may be better ways to do a scraffito method, especially if the materials is less flakey than white out. Or maybe with a better scratching tool.
 Or try
•    Gesso
•    Gel  medium
•    Nail polish

Paper resist I used standard 3x4" label stock from the office supply store.

Cut shapes with paper punches, scissors or get fancy with a Silhouette or Cricut cutter and computer designs. The design is the important thing….too detailed or tiny is very difficult, but the possibilities are good! You can also use the negative of the punch. The center bullet in the photo shows the stained label punches after etching, on the right after removal and cleaning.

String or Cord applied by winding tightly and tying. I tried both cord soaked in PVA glue and waxed linen, which worked even better! Just wind tightly and tie to prevent slipping while etching. This gives a random look to the etch.
Sharpie (or red Staedtler) brand markers Markers give lots of options, especially if you have a steady hand. Staedtler brand markers are supposed to work really well, but may be hard to find unless you order them online. Black Sharpie markers work best - other Sharpie colors  do not provide enough opacity to block the acid. Shown here, on the left marks made with a Sharpie, center after etching but before cleanup, on the right following removal of ink with Acetone.
A trick to put even stripes around the tube with a marker is to use a wood dowel with a diameter just slightly larger than the opening and 3" to 4" long. Use coarse grit sandpaper to file down the end to fit SNUGLY into the casing pushing it all the way in. Fit the other end into your drill press chuck. Spin the drill on its SLOWEST speed, and touch with marker, moving it up or down the side to put a spiral mark. Touch at intervals to add stripes.

StayzOn Ink and Rubber Stamps give great results and permit the most detailed designs. The metal must be very clean for this and remember to let the ink dry before touching. Apply ink to the rubber stamp and roll the tube one full turn. Remember the circumference of the bullet casing is only about 1.3" so over-rolling will result in a double image. Using a long bamboo skewer (or dowel) will help you roll smoothly.
 As with any other etched design, longer in the acid gives a deeper etched design. Shown,two pieces etched together, the front one has been cleaned.
These two were etched with a stamped design, then cleaned and treated with Liver of Sulfur to highlight the design.
Finish your brass with some type of protective coating such as Rennaisance Wax, PYM, Permalac, Gilders' Paste, spray varnish or your favorite finishing.

You can also experiment with other patinas, maybe you like what the metal looks like after etching before cleaning. These patinas will need to be protected with a layer of protective sealant.

To get a high polish on brass (etched or not) use Simichrome Polish, in small amounts with a soft cloth.

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