Harman Magnum Stoker Glass

hello - I replaced my glass yesterday after 10 years .. I remember reading somewhere not to have a very hot fire the first time, but to do it in steps with a small fire first or the glass may crack .. is this true?

thanks - tom

My Dad told me same.

Smart like Father, he was a big Dope.

Makes sense to introduce fatigue lightly

i'm privileged to receive an answer from both of you. I knew i'd heard it before.
thanks for replying!

Its something like trying to reduce the glass surface strain rate of change so the initial microcracks that inherently occur due surface to interior thermal variation due internal tension or compression, especially the areas in between tension and compression. Less heat, less stress, less strain.

As Dr.Kardenscer extorted with a hardened enthusiam, "Stess causes strain ! "

Uglysquirrel wrote:Its something like trying to reduce the glass surface strain rate of change so the initial microcracks that inherently occur due surface to interior thermal variation due internal tension or compression, especially the areas in between tension and compression. Less heat, less stress, less strain.

As Dr.Kardenscer extorted with a hardened enthusiam, "Stess causes strain ! "

CORRECTED
Its something like trying to reduce the glass surface strain rate of change so the initial microcracks that inherently occur due surface to interior thermal variation CAUSING internal tension or compression, especially the areas in between tension and compression. Less heat, less stress, less strain.

Dr Kardenscer would have my hide if he found out about my error. He's dead. Don't tell him.

Thanks

Ug

I learned early that glass sight tubes on boilers should never contact the metal parts. If they do they are commited to destruct at an exponential rate.

coaledsweat wrote:I learned early that glass sight tubes on boilers should never contact the metal parts. If they do they are commited to destruct at an exponential rate.

thanks uglysquirrel for the responses.

i'm not sure coaledsweat what your response had to do with my question?

When the glass comes in contact with the metal, it increases the stress introduced to it. Metal can move around a bit and still be stable, glass doesn't live through a lot of movment, especially at high temps.

coaledsweat wrote:When the glass comes in contact with the metal, it increases the stress introduced to it. Metal can move around a bit and still be stable, glass doesn't live through a lot of movment, especially at high temps.

All, around, profound awe at the practical knowledge within these e-walls.

I also need to be nice to Coaledsweat, he could upon a whim boot my sorry mind off this place.

Ug

you're a pisser UG .. you have very lucky neighbors.

ginski wrote:you're a pisser UG .. you have very lucky neighbors.

His neighbor is a missle silo.

coaledsweat wrote:When the glass comes in contact with the metal, it increases the stress introduced to it. Metal can move around a bit and still be stable, glass doesn't live through a lot of movment, especially at high temps.

So I think the take-away from this info is to be sure to use the appropriate rope gasket around the glass so it does not directly contact the metal......but I haven't had too much coffee yet.....

titleist1 wrote:

coaledsweat wrote:When the glass comes in contact with the metal, it increases the stress introduced to it. Metal can move around a bit and still be stable, glass doesn't live through a lot of movment, especially at high temps.

So I think the take-away from this info is to be sure to use the appropriate rope gasket around the glass so it does not directly contact the metal......but I haven't had too much coffee yet.....

Tada!

Thanks everyone .. very informative!

ginski wrote:Thanks everyone .. very informative!

No problem.

We are all retired leeches of the System at your technical disposal.