AGC plannibel glass

[tonyroberts]

Hi

For years I've been using Pilkington optifloat supplied by Pearsons in Liverpool. Today, Pearsons told me they no longer deal with Pilkingtons, but are selling glass from AGC called Plannibel.

So I killed the delivery that they were about to send until they can tell me how this glass behaves. Pearsons don't know ANY of the technical details any warm-glass guy would need. I have found an AGC document online (http://www.yourglass.com/agc-glass-euro ... -glass.pdf) that seems to indicate that the glass has a CoE of 91 and an annealing point around 600C - very different to the Pilkington specification - but it's not a formal specification.

Has anyone used this glass? Is it any good? What is its annealing range?

Tony

[Bert Weiss]

Tony, I have not used it. In my region, everybody uses PPG Starphire.

Starphire has a published COE of 90, but is certainly not compatible with Bullseye glasses, because the viscosity is so different.

I used to anneal the Starphire 30ºF hotter than regular float. But I lowered it to the same schedule as regular float(538ºC). 600ºC sounds really high. I would probably use 550ºC. The numbers these companies publish are not made with the samesort of parameters that we are looking for. COE is an average, for one thing. Annealing takes place inside a range, and it happens faster at the lower end than the upper end.

Test it to see how it looks and behaves.

[Morganica]

Dumb question: Given the price of Starphire, why would you choose it over cheaper PPG stuff?

[Rick Wilton]

I use a fair amount of low iron float glass from various sources, I haven't noticed that much of a difference between brands in regards to how it behaves. A few degrees tweak up or down but nothing drastic. Now the appearance is another story, I have used low iron that is virtually colourless (starphire and Optiwhite) through to others that are "piss yellow" (sorry but there is no other way to describe it) to a faint hint of green. My regular supplier has also stopped carrying starphire and are bring in a Chinese low iron that has a tiny hint of green. Not all that noticable except when I cast three layers of 10mm together then it's really noticeable.

As for why starphire, no green colour. It's like why crystal clear tekta compared to regular.

[tonyroberts]

Your figures are curious, bert. I anneal pilkingtons optifloat between 570C and 510C, and work on a CoE of 83. For Optiwhite (low iron) I give a slightly wider range.

Obviously different floats are different...

But has no-one used this new stuff? I think I shall avoid it, too risky. There are plenty of other suppliers who sell pilkingtons, and I know that well.

Thanks for the comments!

Tony

[Bert Weiss]

Dumb question: Given the price of Starphire, why would you choose it over cheaper PPG stuff?

Personally I would not choose Starphire. My cost is a bit more than double regular float. Sometimes people make me use it. There are some colors, golds and yellows, that the regular green tint is not friendly to. It kinda sucks when you do a gold and it looks chartreuse. I do most all my enameling behind the glass.

Problem one with Starphire is that it was reformulated a while back, and the current formula is more devit prone than their original glass. The manufacturer is concerned about what happens at 600ºC, which is the tempering process temperature.

One of the reasons there are not a lot of low iron choices, locally, stems from a lawsuit one glass supplier lost. They supplied a different company's low iron glass to a jobsite, after having used a different one. The colors did not match. The architect sued and won.

[Bert Weiss]

Your figures are curious, bert. I anneal pilkingtons optifloat between 570C and 510C, and work on a CoE of 83. For Optiwhite (low iron) I give a slightly wider range.

Obviously different floats are different...

But has no-one used this new stuff? I think I shall avoid it, too risky. There are plenty of other suppliers who sell pilkingtons, and I know that well.

Thanks for the comments!

Tony

Tony, notice that my anneal soak point is right in the center of your range. We are getting job done using different strategies. Both can work if done right.