Why Is My Door Glass Becoming Crazed?

I am now 1 month into my first coal stove. It is a Pine Barren unit that I bought used from a hobbyist refurbish-er in Allentown, PA. So far I am very satisfied with the stove itself. It burns well but is not as efficient as I would like. However that is another story. What I am most concerned with right now is the condition of the glass within the door.

I know that there will always be a slight build up of fly ash on the glass and that it will need to be cleaned occasionally. That I can deal with. What concerns me is the slight increase in crazing that I notice after cleaning. It is not particularly noticeable when viewing the fire from across the room but why is it happening and is it a standard reaction to being near so much heat. I looked up what should be in there (type of ceramic glass) and all the information gives me is a thermal shock rating of 1380° but nothing about how high temp glass behaves.

Any help or information out there.

John

It's very common. As far as I know, it doesn't hurt anything. My glass has been crazed for years. If it was a safty issue, I'd put my brand new spare glass in.

Normal, could be the contaminants/impurities in the coal. Mine are the same way. Been that way for years.

WNY wrote:Normal, could be the contaminants/impurities in the coal. Mine are the same way. Been that way for years.

Ok guys, Thanks for the reassurance. So I guess what I should do in the spring is to remove the glass and carefully measure and purchase a replacement window to have on hand. I did replace a few fire bricks at my last cleaning and now I have an even dozen on hand as that is exactly the number the stove takes. At 2 bucks a piece they are cheap replacements. The glass on the other hand is going to be around 100 according to the glass place I checked.

Thanks again,

John

DigicamLife wrote:

WNY wrote:Normal, could be the contaminants/impurities in the coal. Mine are the same way. Been that way for years.

Ok guys, Thanks for the reassurance. So I guess what I should do in the spring is to remove the glass and carefully measure and purchase a replacement window to have on hand. I did replace a few fire bricks at my last cleaning and now I have an even dozen on hand as that is exactly the number the stove takes. At 2 bucks a piece they are cheap replacements. The glass on the other hand is going to be around 100 according to the glass place I checked.

Thanks again,

John

Just learn to live with it. No use in spending money just to see the fire for a while. You will learn to love the orange glow as many of us have done.

I have not noticed anything but the fly ash on mine. What is crazing? Pitting of the glass? I clean mine with a soft wet cloth and it stays clean for about two weeks before I do it again.

It looks like tiny spiderwebs if you look at it closely.

The best way to minimize it is to keep the upper & lower channels clean on the top & bottom mounting points of the glass (at least with Harmans). If you have good airflow through both the top & bottom, you'll get very little crazing. .. or I should say LESS crazing.

gambler wrote:

DigicamLife wrote: Ok guys, Thanks for the reassurance. So I guess what I should do in the spring is to remove the glass and carefully measure and purchase a replacement window to have on hand. I did replace a few fire bricks at my last cleaning and now I have an even dozen on hand as that is exactly the number the stove takes. At 2 bucks a piece they are cheap replacements. The glass on the other hand is going to be around 100 according to the glass place I checked.

Thanks again,

John

Just learn to live with it. No use in spending money just to see the fire for a while. You will learn to love the orange glow as many of us have done.

I agree; Don't spend money on spare glass because the glass you have is crazed, and you want to be prepared in case something happens due to the crazed glass. I have a spare glass in case someone throws a brick through the glass. Not because my glass is crazed. I don't know why I have a spare glass. My uncle said he was going to buy a spare glass in case something ever happens to the glass in his stove. I thought it was a good idea. So I bought a spare glass. Don't ask me why. Should something ever happen, I'll be glad I have it.

oliver power wrote: I agree; Don't spend money on spare glass because the glass you have is crazed, and you want to be prepared in case something happens due to the crazed glass. I have a spare glass in case someone throws a brick through the glass. Not because my glass is crazed. I don't know why I have a spare glass. My uncle said he was going to buy a spare glass in case something ever happens to the glass in his stove. I thought it was a good idea. So I bought a spare glass. Don't ask me why. Should something ever happen, I'll be glad I have it.

Well thanks Oliver,

That was a most convoluted way of telling me that it is OK to have a spare glass on hand.

Not because of the crazing but because if ever something was to happen to the glass, (brick, baseball, angry wife or kid) I would not want to be without the use of the stove for the length of time it would take to replace it. The other reason I can think of for ordering one is that I will have an intact piece of glass to measure against. I am not going to shut the stove down for more than a quick cleaning until spring, so until then lets hope nothing goes wrong.

John

The first glass in my Hitzer crazed in fine lines running vertically after a few months of use. A year later it cracked from top to bottom for no known reason. I bought a new glass from Hitzer (Robax). A year later it has not even crazed yet. I have never overheated the stove. I kept the cracked one for a spare because it is still air tight or close to it.