More Patina Experiments... This Time Sealants

June 20, 2022

I decided to expand my patina testing to include sealants... as in how do certain sealants affect certain patinas.

I spent some time applying patinas via my torch scrap pieces of copper and bronze (see end of post).

Then I took six 24 gauge copper disks. 
 
 
I added texture then dapped them into dome shapes. 
 
 
I added holes.  (Normally it's easier to add the holes before dapping.)
 
. 
Finally I cleaned them with Penny Brite followed by alcohol.  
 
Next I added patina to the pieces using ammonia and liver of sulfur (for measurements see previous blog post ). 
 
To be able to compare the coloration before and after adding sealant, I photographed these pieces along with the group of bronze and copper that were only heat patinated.

I started with Mixwax Fast-Drying Polyurethane.
 
 
I made a contraption to hold the pieces as they dryby taking some heavy gauge brass wire and forming three pieces as shown below.  I shoved the wire ends into a styrofoam square, then suspended each piece from a thinner piece of brass wire,
 
I write which number each set is, so I can match it up with my notes when I’m done. 
 

The second test was Krylon Make it Last! Clear Sealer. 
 
 
Don't forget to go outside for aerosols and most pungent varnishes and sealants.

Test #3 was Renaissance Wax. 
 
Here are photos of the fronts and backs of the patinated dome pieces before any sealants were applied.
 
 
And photos AFTER the application of the sealants.
 
 
For the heat patinated copper and bronze scraps, I used Minwax polyurethane on the right half of each piece (could see distinctive color changes immediately upon application) and Renaissance wax on the left halves of the pieces.

Here are those results:

BEFORE
 
 
And AFTER
 
 
For the piece that had that beautiful red I decided to keep a strip of it down the middle for comparison. So on the right is the varnish, on the left is the wax sealer and in the middle is au naturel. 
 
 
My conclusions afer this day of sealant testing are as follows:
  • The varnish is nice but it leaves a very glossy shine. Perhaps that can be avoided with a can of “semi-gloss” or “satin” for comparison.
  • The spray sealant seems to leave the piece feeling coated.
  • The wax leaves a nice feel to the piece, but I do think it dulls the color more than the other two coatings.
  • As can be seen in the bronze/copper scrap pieces, both the wax and the varnish significantly change the patina color. The lovely reds turned to lovely orange/yellows.
  • Most of the subtle blues and greens disappear after sealants are added.