Mason jar COE

Shrimp · #1 2011-07-01, 8:47pm

Quick question. Anybody know the coe of a mason jar? Had an accident with one tonight, and thought it would be interesting to see what the glass looks like melted. It made a very clear, non bubbly rod.

JEK3 · #2 2011-07-01, 10:45pm

I think bottles and jars are made of a very low COE glass, so they don't have to be annealed (cheaper that way). I've seen lots of people complain that it takes a long time to melt bottle glass.

Karen Hardy · #3 2011-07-02, 1:26am

I treat those as COE 90-96, and use a soft glass annealing schedule.
Haven't had one of those beads break yet. Just don't ever mix the glass
with another bottle of unverified COE.

Lisi · #4 2011-07-02, 6:26am

The Ball mason jars in a pale aqua color with aluminum lids that had been in my family for over 100 years cracked in the house fire. I would like to make some beads with them. We recovered two out of the 11 that were not cracked. It was heartbreaking, but oh well, I can make beads with them and it will mean something.

Mark Parkinson · #5 2011-07-02, 9:30am

my father used to work for Dominion Glass they made beer bottles,mason jars,baby food botles and for a long time the fancy bottles that Avon used for their "collector" bottles

I aked him a whule ago about the coe of the glass they used and he said that it depended on the "batch" but that in most cases it ran from 85 to 100 depending on the addatives that they put in to get the colours the more colour the softer the glass in most cases

I would not count on the glass being compatable with any other than its self and a conservative 104 annealing schedule seems to work well for bottle glass

as for bottles not being annealed thats just incorrect ALL bottles that are manufactured for use by the public have to be annealed ... I was in the Dominion factory several times and the annealing kilns ran 24/7 the hot bottles going in on a conveyor at one end and cycling though to the other end in about 90 minutes they were still about 400 degres when they came out the "cold" end .... the kiln was in an s shape and about 1000 feet long all gas fired.

Shrimp · #6 2011-07-02, 6:44pm

Thank you all for your replies. My son decided to make some marbles with the glass. The ones that he used bits of Bullseye coe90 in, all cracked. The one that he didn't add any other glass to it, is still in one piece and not cracked.....yet.