Fireplace glass temp question

[reaperman]

Here is the story. My brother in law recently had the glass on his fireplace (not woodstove) break during use. He was told the glass got too hot because a piece of wood settled against it and continued burning. Also that the glass that was on his fireplace was only good to 400 degrees, to me that's had to swallow. Unless glass used for a fireplace is different than glass on a woodstove. Because we all know how hot woodstoves can get, and I've never heard of someone breaking glass on a woodstove due to heat. Is there something I don't know?

 

[CaseyForrest]

To my understanding, the glass doors that are installed on open fireplaces are not designed to be closed while the fireplace is being used. It's not the same type of glass you'll find on a woodstove.

sent from a field

 

[moresnow]

To my understanding, the glass doors that are installed on open fireplaces are not designed to be closed while the fireplace is being used. It's not the same type of glass you'll find on a woodstove.

sent from a field

Really? You could certainly be correct but growing up we had 2 fireplaces that had glass doors. We always shut them, off and on, as well as when heading to bed. They are still both fine many years later. Dunno?

 

[CaseyForrest]

Prior to our insert being installed, I'd shut the glass doors as well. It helped slow the heat going up the chimney.

But I also never had a burning log roll into the glass either.

sent from a field

 

[TeeMan]

I have a double-sided fireplace and it states on the mfg. tag that the doors on each side need to be both used shut or both used open. I always burn with them all open. The only time I close them is after the fire dies down and it is just coals left.

 

[Conquistador3]

Standard tempered glass will withstand 300-400°C for extended periods of time but won't last long when exposed to higher temperatures. Sounds about right.

That's why the trend these days is towards glass-ceramic, with the old PyroCeram (now mostly sold as KeraLite) having become cheap enough for household applications and NeoCeram being the new wonder boy everybody talks about. Both materials are mostly manufactured in Europe (Corning facilities in the US were closed around 2000; all production is now undertaken by EuroKera, a Saint-Gobain/Corning joint venture in France) and both can withstand about 1200°C for long spells of time and 1400-1500°C for a short time.
Both materials won't shatter when suddenly cooled and can be supplied in sheets just 3mm thick. As said they are considerably cheaper these days than they used to be, but still expensive enough to put most homeowner off.

 

[Wood Doctor]

Standard tempered glass will withstand 300-400°C for extended periods of time but won't last long when exposed to higher temperatures. Sounds about right.

That's why the trend these days is towards glass-ceramic, with the old PyroCeram (now mostly sold as KeraLite) having become cheap enough for household applications and NeoCeram being the new wonder boy everybody talks about. Both materials are mostly manufactured in Europe (Corning facilities in the US were closed around 2000; all production is now undertaken by EuroKera, a Saint-Gobain/Corning joint venture in France) and both can withstand about 1200°C for long spells of time and 1400-1500°C for a short time.

Both materials won't shatter when suddenly cooled and can be supplied in sheets just 3mm thick. As said they are considerably cheaper these days than they used to be, but still expensive enough to put most homeowner off.

I recently received a quote for two small pieces of identical ceramic glass for my wood stove, cut in an arched pattern on each side. To my shock, the amount was close to $300 with sales tax. I believe it was about 3 to 4 mm thick. The flue gases from this stove directly above the secondary combustion chamber (right below the two pots shown here) can easily reach 14oo F on a day with a brisk NW wind:

Seems to me that fireplace glass doors when closed could easily reach 500 F. These ceramic doors have never broken from the heat, but they eventually cook so much they can no longer be cleaned with any glass cleaner.

 

[Marine5068]

Most ceramic woodstove or fireplace glass can withstand temps up to 1250*C and is rated such.

 

[al-k]

I recently received a quote for two small pieces of identical ceramic glass for my wood stove, cut in an arched pattern on each side. To my shock, the amount was close to $300 with sales tax. I believe it was about 3 to 4 mm thick. The flue gases from this stove directly above the secondary combustion chamber (right below the two pots shown here) can easily reach 14oo F on a day with a brisk NW wind:
View attachment 633253
Seems to me that fireplace glass doors when closed could easily reach 500 F. These ceramic doors have never broken from the heat, but they eventually cook so much they can no longer be cleaned with any glass cleaner.

try some 0000 steal wool

 

[Conquistador3]

I recently received a quote for two small pieces of identical ceramic glass for my wood stove, cut in an arched pattern on each side. To my shock, the amount was close to $300 with sales tax. I believe it was about 3 to 4 mm thick. The flue gases from this stove directly above the secondary combustion chamber (right below the two pots shown here) can easily reach 14oo F on a day with a brisk NW wind:
View attachment 633253
Seems to me that fireplace glass doors when closed could easily reach 500 F. These ceramic doors have never broken from the heat, but they eventually cook so much they can no longer be cleaned with any glass cleaner.

I don't know how prices are in the US, but for ceramic glass here it would be a pretty damn honest price: the stuff may be cheaper than it once was and present materials can be cut the same as tempered glass (meaning no need for expensive extra tooling) but it's still very expensive in absolute terms... remember how much was Pyrex/PyroCeram cookingware before Corning had a stroke of corporate genius and eliminated what was a nice fat cash cow? They were so expensive my mother still holds onto her set like some kind of treasure of the greatest rarity because back in the days that stuff was rabidly expensive. These days a standard (2 liters) PyroCeram casserole is about €60 on Amazon and if you factor inflation in the price has come down a loooong way from the 70's, but that's still three or four times as much as a non metallic casserole.

 

[Wood Doctor]

try some 0000 steal wool

I tried that also. I even made the mistake of trying sand paper. That scratched the ceramic glass and made things worse (aluminum oxide is harder than ceramic glass). Paint scrapers won't help either. Once that gets baked on, its a gorilla to remove. I live with it. At least I can see the flames enough to judge the fire's intensity. If I really want to see the flames, I just open the doors and attach the screen for awhile.