Friday, June 20, 2014

My Metal Clay Sealants Testing Finally Begins

I realized too many of my projects were being put on hold because of my indecision about sealants so I decided to put everything on the back burner and get on with the testing.

Here are the five test pieces. Created as equally as I could. Each piece has an unpolished steel backing (more on that in a minute), and three panels in front that are from left to right: bronze, steel, and copper.


I added a patina to the copper because I often patina my copper metal clay pieces and I need to know how the sealants work/react in real world applications.

I’m also testing out a theory that one of the spray sealants I was using was creating little dots on my copper.

The reason I didn’t give the backs of my charms a high polish (like the fronts) is because sanding and polishing metal clay burnishes the metal and makes all the metal molecules lay flat (I’m probably not saying this correctly) thus creating more of a water-tight barrier.

I’ve done plenty of experiments and water will totally soak into a non-polished piece of fired metal clay, while a burnished surface will repel water.

I recently coated some non sanded pieces because I wanted to see if I could “lock in” the cool kiln patinas I get. The problem is, 99% of these pieces have to remain unpolished and I’m just not sure how that whole absorbent thing works with sealants… do they also sink right into the interior of the fired piece? If so, that defeats the purpose of the sealant. I'm watching those recently coated pieces to see if there are any changes over time.

Now back to this experiment…

While I’m saying what type of sealants I’ve used on each charm, I’m not giving exact brand name for two reasons. One, I think half the fun of learning is doing your own experimentation. And two, I don’t want my results to encourage or dissuade anyone from any particular product. Your own experimentation is the best for you because you may apply a coating completely differently than I do.

For the liquids, I dipped the entire charm into the solvent. If I end up liking this sealant, I will try brushing on as sometimes dipping is less than optimal.

For the aerosols, I coated according to the directions on the cans

What I’ll be looking for is:
  • What the sealant looks like on the piece (does it make the piece shiny, tacky, dull, etc?)
  • How well does the sealant resist water (I work with a lot of non-stainless steel)
  • How durable is the sealant (will it last a long time?)
I will wait 24 hours for the coatings to cure, then I will attach the charms to a sterling silver chain and wear the bracelet non-stop except for during the stress tests.

Come back for the results of that.

For now I’ll assess my first impressions.
  • Charm 1 (non-lacquer solvent-based liquid): too glossy
  • Charm 2 (lacquer spray): fine
  • Charm 3 (acrylic spray): fine
  • Charm 4 (lacquer spray): fine
  • Charm 5 (acrylic resin spray): a bit too matt… lost some of metal’s natural gloss

Let the testing begin!






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