CraftWEB Hot Glass Talk - help with adding color to 4c cullet

Quote:

Originally posted by Peet Robison
I would not use Manganese with cullet. I don't think you will ever get a strong color no matter how much you use. I consider cullet "reduced" in the sense that there is very little O2 left in it. Manganese needs O2 to be purple. This was the reason using cullet for copper reds works fine if you don't mind the swirls.

Mang works great but be ready to keep checkng your melt to keep punching it down, It foams up cullet like crazy. Stirring it takes down the "head".

I dont have any numbers just approxament scoops per 100 pounds. Half a fivegalln bucket of drained frit is pleanty for introducing colorent to 100 lbs of cullet.

when adding colerant to cullet (Chem mixed with wet frit), I put the charge in the center and then with the most bent pontil pull melted glass from the sides over the top of the charge. Then wait. I repeat this a few times (3 or 4) for each charge till it stays tented. Throwing a load of clear on top of the tent keeps it formed.

I only do this with the scoops that have colored frit added on top. Not the scoops that are clear only.

I figure it lets me maintain a consistancy in the burn off/loss factor and saves chem money. this was with the flame pointing right at the melt and might not be as important with no impingement.

After the last charge I do a few serious stirs, except with Mang as it's self stiring.

Cobalt can brighten a Mang purple nicely, but I stopped buying cobalt chem and use cobalt gabbert cullet to add it in. It dosent take much.

What order of color melting is worth consideration. Manganese isnt a bad color to melt before clear. better chance of clear then trying it after cobalt or iron. Copper isn't overly lingering.