Making my own Olive green

[Josh Bernbaum]

I am hoping to find some guidance from you guys (and gals) on what colorants I might be most successful with in trying to get a similar shade in melting my own version of this sample of bar-colored Olive green from Gaffer. Sorry for the shitty photo but hopefully it gives you the gist of this shade. I'd be mixing them into SP "plain" batch (no Er). My first thought was the majority of colorant being K Dichromate with a bit of nickel and maybe a tiny bit of cobalt. Thoughts?
Thanks in advance.

[Jeff Thompson]

I'll go out on a limb here and say that I doubt there's any cobalt in that green.

[Dave Bross]

I went trolling in a few of the old books I have. Here are some suggestions.

From the Penland color book, no notation on what amount of batch this was added to, so just take it as a ratio of the colorants:

Pistachio Green

16 grams pot. dichromate
5 grams copper carb.

From the old "Recipe Book" Finn Lynggaard reprinted:
I'll just give you the sand and colorant amounts, you can figure it from there:

Fine Sap Green

100 kilos sand
2.5 kilos copper oxide
1 kilo iron oxide
750 grams potassium chromate

Olive Green Bottle Glass

sand 100 kilos
potassium chromate 500 grams
manganese dioxide 1500 grams


From Henry Helmer's Batch Book:

Lead Crystal Sap Green

sand 1000
K2CR2O7 5
Bl. Ox. Copper 1 1/5
Iron Oxide 1 1/5

From "Elements of Glass and Glass Making" by B.F. Biser -1899- (Special thanks to Terry Crider for giving me this book)

Green Yellow

flint batch 16 pounds
lead 16
oxide of copper 6 ozs.
crocus martis 48 grains - explanation: https://digitalfire.com/4sight/mater...artis_249.html
if too green increase the amount of crocus martis

Olive Green

flint batch 112
brass 2 (copper & tin)
red ochre 4 (red iron) http://www.digitalfire.com/gerstleyb...l/m-011181.htm

[Donna Milliron]

back up here - what is the Penland color book???

Donna

[Dave Bross]

Over the years the glass program at Penland had a sort of guest book that they suggested anyone coming up with a good glass color could write the formula into the book.

It's not anything available as an actual book and I don't know that it exists at Penland any more.

I have random formulas and pages people have sent me or been posted here over the years.
Most of them don't have the whole formula so they're good mostly to get a ratio of colorants to each other, not, say, how much of these colorants to 100 pounds of sand, or batch.

[Pete VanderLaan]

No magic bullets Donna. None at all...

[Peter Bowles]

looks like iron and chrome to me. maybe try 1% iron chromate

[Pete VanderLaan]

or iron oxide and potassium dichromate if you don't have what Peter refers to. Remember that chrome is a carcinogen. Crush it before you add it and try to mix it in a bit of lithium carb ( a tiny amount) to help it melt. A little lithium bath if you will.

[Josh Bernbaum]

Thanks Peter and Peter.
Yes, I would be using the dichromate. Remember just mixing it in the coffee grinder without lithium added in the class though. Is the lithium recommended sometimes but not other times? I don't have any lithium carb. right now anyway, but will get some. My first guess on adding a bit of nickel was that this olive green just looks a tiny bit brownish, but I'll try with just the iron and chrome first.

[Pete VanderLaan]

If you don't have lithium, use soda ash or a tiny bit of borax. Baking soda from the gorcery store would work. Do grind it up. I sometimes put it between two pieces of schott optical to crush but whatever works. The point is to get the chrome attacked right away when it goes in the pot. Do not use Chrome oxide under any circumstances. It's just too hard to melt making little black corundum stones . In 10 lbs of batch maybe add 10 grams soda in the crushing routine.

Lithium in 50 lb bags is godawful expensive. I'm not sure at all about small quantities. My stock is remainder from back in the '90's when I was doing a lot of color bar work.

[Josh Bernbaum]

Thanks! I will give that a try with the baking soda.

[Dave Bross]

Pottery supplies have small quantities of lithium carbonate available.

[Pete VanderLaan]

US Pigment has Lithium carb at $9.00 for one lb. That's way down. Probably $15.00 by the time it's shipped.

[Donna Milliron]

Pete, there you go again, dashing my dreams of the magic bullet. Smoking guns all over the place, no damned bullets! lol