tinting pot furnace amber

[Emily Lombardo]

We are switching our pot furnace and often tint it with cobalt oxide before we turn it off. This time we want it to be amber. I have done some research and I found that manganese oxide or a sulfur compound is best for amber. is that true? If so where can I get that? Any suggestions would be great.

[James Ennis]

morgan says hello

[Kenny Pieper]

sulfur can be had at your local nursery

[Dave Bross]

sulphur is nasty smelling to melt and can reboil if the furnace temps. vary enough. Any form of carbon with iron and sulphur should give amber. Old recipes used sugar, coal, oats, or damn near anything that would turn to carbon.

You can get amber through dark brown colors with manganese and iron.

Here's an old batch recipe from American Glass Practice that may help in guessing what percentages to use:

100 pounds lead batch
1 pound Borax
4 pounds Red Iron Oxide
13 ounces Manganese

Note the "lead batch", lead glass tends to make for different colors than straight soda lime glass. I don't know if that's the case here.

They also had a recipe for a carbon amber in soda lime that called for 1 !/4 pounds of sugar to 100 lbs. of batch. One problem with carbon amber is that you can't use oxidisers to fine the glass.
Another is that need for a little iron and sulphur, you would have to add that to modern batch.

Another amber recipe:

by percent
.8 manganese carbonate
.6 crocus martis (red iron oxide)

Art Glass Magazine Aug. '74