Is 850 Stove Top Really Too Hot?

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wkpoor

Minister of Fire
Hearth Supporter
Oct 30, 2008
1,854
Amanda, OH
I'm starting to think stove top temps over 700 aren't hurting anything. Do any mfg give limits for this. US Stove doesn't. Basically even 850 is not cherry red yet. Bud that I sold Nashua too routinely fires it till the baffle is red and thinking back about years ago we never had a thermometer on the stove to know anyhow. You just fired it till it was putting off good heat. My guess is we were always in the 800 degree range.
 
wkpoor said:
My guess is we were always in the 800 degree range.

Maybe not. That was a much larger stove with a lot more radiating surface area. If you had it up to 800º it would have been putting out more heat than the Magnolia rather than less heat.

I've seen folks here talk about 800º tops on their steel stoves when they need the heat. I don't think the extra 50º would be the straw that broke the camel's back, at least not for the occasional burn. I alway run my cast stove real hot - 700-750º when it's real cold, with the occasional spike to 850º here and there. I've accidentally got it cranking to over 1000ºF a few times (door temp, not stove top), and the only damage I see inside the stove is that the left andiron in getting oxidized away. And that's after about 25 years of use by the guy I bought it from.
 
It might be okay but for peace of mind I surely would not want to run at 800+ on any stove. Simply put, why take any chances because this is a big fire we are talking about and that big fire happens to be inside your home.
 
A lot of stoves can run that hot, but at the risk of premature aging and earlier failures. It's hard to compare many stoves to a Nashua. The thing was seriously overbuilt which allowed it to take more abuse. They once lit off a stick of dynamite in a Nashua to prove how tough they are!
 
Manual for my Lopi Endeavor says, OverFiring is when any part of the stove body or pipe collar turn red.
High burn is 700 to 800 degrees...
I see north of 700 on mine frequrntly when temps drop to 15 and below...been burning like that since installation 12 years ago.
Only damages, have had to replace the air tubes and baffle supports about every third year, until I installed SS tubes from the Liberty,
ended that problem but the baffle supports still need replacing at about that frequency...will need to replace them after this season again,
this will make the third replacement set since new...I may make this set out of stainless angle and be done with it...
 
BeGreen said:
A lot of stoves can run that hot, but at the risk of premature aging and earlier failures. It's hard to compare many stoves to a Nashua. The thing was seriously overbuilt which allowed it to take more abuse. They once lit off a stick of dynamite in a Nashua to prove how tough they are!
I remember that ad well, one of the reasons I bought it, paid 1000 dollars in 1980 and worth every penny.
 
Steel starts to glow dull red at just below 900F. As steel heats up, it's properties change. For example, when it starts to glow it becomes softer and interestingly, it becomes non-magnetic.
 
oldspark said:
BeGreen said:
A lot of stoves can run that hot, but at the risk of premature aging and earlier failures. It's hard to compare many stoves to a Nashua. The thing was seriously overbuilt which allowed it to take more abuse. They once lit off a stick of dynamite in a Nashua to prove how tough they are!
I remember that ad well, one of the reasons I bought it, paid 1000 dollars in 1980 and worth every penny.

I wondered what they were selling for then. That's almost twice what a Defiant was selling for. Sounds like you made a wise purchase, both then and hopefully now. :) Did you get some temp pipe on the flue?
 
BeGreen said:
oldspark said:
BeGreen said:
A lot of stoves can run that hot, but at the risk of premature aging and earlier failures. It's hard to compare many stoves to a Nashua. The thing was seriously overbuilt which allowed it to take more abuse. They once lit off a stick of dynamite in a Nashua to prove how tough they are!
I remember that ad well, one of the reasons I bought it, paid 1000 dollars in 1980 and worth every penny.

I wondered what they were selling for then. That's almost twice what a Defiant was selling for. Sounds like you made a wise purchase, both then and hopefully now. :) Did you get some temp pipe on the flue?
Weather is too cold to do it now but hope to get it done soon.
 
I went back and reread the manual. All it says is flue pipe 200-500 and stove anything less than red. I've noticed flue runs right a about 1/2 stove top. I finally have enough flue temps to hopefully ward off the creosote I was getting. Changing stoves proved the cold flue issue was the stove.
Yesterday was the 1st day we were gone for an extended time, about 9hrs. Came home to a nice deep bed of blue flame coals. Had er back to 800 in just a few minutes. Through big splits right in and they took off instantly.
 
BeGreen said:
As steel heats up, it's properties change. For example, when it starts to glow it becomes softer and interestingly, it becomes non-magnetic.

I thing you're thinking of the point where magnets themselves lose their magnetism. Regular steel loses its ability to be attracted to a magnet (called the critical temperature) at a lot higher temp than 900ºF. The critical temperature of plain carbon steel is up around 1350ºF, which would appear bright cherry red in a semi-darkened room.

I actually use a magnet to decide when tool steel is hot enough to quench-harden in oil. The traditional way to tell the correct temp is by looking at the color of the steel. That takes a lot of daily practice to get right, something I will never get with my occasional usage of the forge.

Using a magnet is a lot more sure for me than judging by the color. The instant the magnet won't stick to the steel, into the oil it goes. Then you agitate it like crazy until it cools. Of course, sometimes the magnet sticks to the steel at lower temps, and then you had better have a pair of pliers handy to pull them apart real quickly. Next time I forge something I'm gonna try using the IR gun. Mine goes up to 1400ºF, so I'll just squeak by the critical temp with it.
 
I didn't mention the temp for that reason, but will remember that the next time I overfire the stove. Point being when steel is heated up past the glowing stage it starts to change.

I have had a stove pipe hot enough for the magnetic thermometer to fall off. Guess it hit the magic moment.
 
I know that a 3/8" plate stove top glows at 1145 degrees and that is the point where the paint on a magnetic stove top thermometer goes poof and disappears. :red:
 
LOL, that's worth a picture.
 
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