Ash as an Insulator

soupy1957 said:

Is it that our current stoves, as good as they are in design in comparison to models from 30 years ago, are just not able to hold up to the riggers of a daily fire like say a "Cast Iron" stove of yesteryear would have? If we have to have all these protections in place (ash, firebrick), doesn't that say something about the quality (or lack thereof) of the newer materials being used?

-Soupy1957

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No, it says that the folks designing stoves 30 years ago were more metalworkers than engineers. They were not designing for efficiency, much like the cars of that era. I think your premise is laughable. As BB says in his tag line, "the good old days weren't".

PS - it is "rigors", not riggers.

My take on the ash is for keeping the coals all warm and toasty. My stove burns a little hotter without ash in the stove, but it also burns down the coals quicker because of the increased airflow around them.

Ash keeps the coals alive longer for a better restart.

After I vacuum out some of the ash in my firebox, I notice the blower comes on a lot sooner than when the firebox is full of ash, so it definitely acts as an insulator for the bottom of the stove (the thermostat that controls my blower is under the firebox). Startup is definitely easier with more ash as well.

Hanko said:

10-cc said:

It will accelerate heating up the firebox, but too much hash will prevent fresh air coming in eventually chocking your stove.

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To much hash will get you in trouble

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It will in Texas....Free Willie Willie Nelson that is..

Backwoods Savage said:

Simply put, the fire will burn better if you leave some ashes in the stove. It will also help insulate the bottom of the stove, thereby making it cooler, or not so hot underneath the stove.

Why are firebrick used inside a stove? Would we be better off removing the brick? After all, some remove all the ash.

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Exactly. Anything that serves to elevate firebox temps, improves combustion.

The stove parts just below the fire would tend to run the hottest, without ashes shielding them from intense IR. Ashes are very reflective, too.

mitchinpa said:

After I vacuum out some of the ash in my firebox, I notice the blower comes on a lot sooner than when the firebox is full of ash, so it definitely acts as an insulator for the bottom of the stove (the thermostat that controls my blower is under the firebox). Startup is definitely easier with more ash as well.

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What kind of vacuum do you use? I made a huge mistake in trying my shop-vac one time. Didn't realize that the ashes going in the hose were ground up and expelled as a fine mist right behind me. What a mess!

they make these bags for shop vacs to suck up drywall/plaster dust. I wonder if they would work well with ashes. I think I've read around here before about putting a wet sock on the exhaust. Someone here has a tale of the sock blowing off and making a mess, though, so you should be careful.
edit: disclaimer-->as always, don't be sucking hot ashes up with anything.

I usually clean out ashes pretty frequently. (OK, usually after every fire.) Guess I will let the current accumulation ride (about an 18 hour burn) and try starting the next fire on an ash bed.

bboulier

I have the Loveless Ash Vac. Loud as a jet engine, but not a speck of ash leaves the canister. The canister is also metal, and the filter is fire retardant. Lots of threads on the vac's for ash on here.

The bricks are designed to handle the heat work, but a fire gets going faster if the heat is not getting sucked into the bottom bricks. Coals last longer, fire gets going faster. That's been my understanding on the matter.

10-cc said:

It will accelerate heating up the firebox, but too much hash will prevent fresh air coming in eventually chocking your stove.

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I notice that the heat production/intensity from the T6 is better after a cleaning, and for the few of days afterwards. with 24/7 burning of hardwood and a couple inches of ash, i think the ash does insulate the bottom of the stove and reduces the heat output from the unit. this could also be related to the air distribution being limited as well.

Tried leaving about half the ashes last time. Fire started no different from usual when ashes were cleaned. I have always assumed that fire brick served two purposes: (1) protecting the metal liner of the stove and (2) acting a a heat sink. Fire burns on top of brick, brick stores heat, and then brick keeps fire hot but also gradually releases heat to the room over a long period of time. If the I am correct, then leaving ashes in the firebox would have a negative effect on heat output, as the ashes would insulate the brick from heat transfer provided by the fire. Any engineers or physicists or manufacturers who can comment on this one?