Pyrex Collector Forums

I found a green primary bowl and it's one of the really thick glass bowls. I am wondering what year they started making the glass thinner? I know this one is an older bowl but I'm not sure how old.

My oldest green and yellow primaries have no model numbers and the finish on them has a fine stipple to it. Those oldies with the more pronounced foot ring and thicker walls are supposedly 1945 to late 1940s.

I just had a discussion with Jessica about this. I read the information on pyrexlove and it said the thick ones were from the 40s but mine has a model number on it. I'm still not clear on when they switched to the thinner glass. I'm thinking mine must be 1950s-1970s.