New-To-Me Fisher Grandpa Bear

[WRG1]

I have recently purchased a Fisher Grandpa Bear stove for use in my 40x50 garage. In my house as my primary heat, I have a Grandma Bear stove which does wonderful!My question is neither has had a baffle installed, although I do see the small baffle in the Grandpa Bear which may or may not be factory. Are the baffles beneficial in holding fire longer and increasing heat? Also, with the recent purchase I was told the stove had not been used much at all and the condition shows this to be true. First Question: What is the best product t to use and what process would you recommend on removing the surface rust on the stove. Second Question: Should it be painted and if so what product is best used? Third Question: Can anyone tell me the year this stove was fabricated?

Thank you so much for your help!

 

[Todd67]

Welcome to the forum!

I've used PB Blaster on some stoves (for rust removal) and WD-40 on other stoves. I prefer WD-40 and various scrub brushes and wire brushes that fit a drill or angle grinder. I buy the WD-40 by the gallon. I then use mineral spirits to remove oil residue from the stove (the clear mineral spirits that evaporates). Once dry, I apply 3-4 coats of paint.

Stove Bright and Rutland stove paint are the best brands of paint that I know of.

@coaly will be able to help you with the year your stove was made.

That shelf in your stove is not a baffle plate, and appears to be factory installed. A baffle plate will help make your stove more efficient. But again, coaly is our resident expert on that.

 

[bholler]

You do realize installing a stove in a garage is against code in the US. That means if you ever have to make an insurance claim concerning that stove it will without a doubt be denied.

 

[coaly]

1978 or '79.
I'd lean towards later since it has the long angle iron on the sides for brick retainers instead of clips. They started full length pieces in the 1980 redesigned stoves.
No doubt a Dunn Brothers stove if there are no numbers.
Wire wheel in a drill. I like to wet them with a petroleum based product such as kerosene, diesel or fuel oil, PB Blaster, or WD-40, to keep the dust down. Wipe with mineral spirits to clean as you go, and give it a final wipe dry with lacquer thinner before paint.
Satin Black Stove Bright.
You should paint outside and fire it for final cure outside with at least one piece of pipe on it. Stove Bright is one of the best paints but it does stink when painting and curing with heat.

The baffle increases firebox temp and burns off more smoke particles before exiting into chimney. Since creosote is the formation of smoke particles sticking to pipe and chimney flue surfaces, this decreases creosote formation and prevents more heat loss up chimney than necessary. It also prevents the "hot and hotter" spikes, directing more heat to the lower cook top instead of the stove pipe, making them more efficient as well. Lots of benefits installing a baffle. Do not weld in place, so it is adjustable. Read through the baffle thread for more specifics.
simple-baffle-solution-for-your-old-fisher-more-heat-less-smoke-under-25.74710

 

[coaly]

Put a pipe surface thermometer on the pipe before it enters chimney. You can't tell what you're doing without knowing the temperature. A surface thermometer reads about half the actual inner flue gas temp.

The setting will be different for everyone. You are adjusting for chimney height and diameter, your elevation, fuel...... and how much heat is required, many variables.

The object is to keep the flue gasses above 250* f. to the top of chimney. (when smoke is present) The better the flue is insulated, the easier it is to keep it hot, with less wasted heat. 250* is the condensation point of water vapor from combustion rising out of the chimney. Below 250 the water vapor condenses on flue walls allowing smoke particles to stick. This is creosote. So burning more particles in the firebox allows lower flue gas temps, but keeping above 250* is also critical for the proper draft since this is what allows atmospheric pressure to PUSH into stove feeding the fire oxygen. (A low pressure area is created in stove by rising gasses in chimney)
If you currently use a pipe damper to slow draft, (it is a chimney control that affects the stove) you will be able to run it more open with a baffle since the baffle adds a slight amount of resistance in the firebox instead of adding it in the pipe with the adjustable damper.
Otherwise the baffle doesn't change your air setting much. With more heat radiating from stove instead of loss up chimney, you should be able to run it closed a bit more increasing efficiency of stove.

The air intakes are simply a resistance to flow. The chimney creates the low pressure area or draft, and the pipe, elbows, tee, variable damper, even top screen or rain cap all create resistance in the system. The most resistance is the air intake opening size. The baffle adds resistance within the firebox as well, which is adjusted by the "smoke space" above baffle that the exhaust gasses must travel through to get out. The angle of the plate also affects resistance as well as technicalities such as flame impingement (flame tips dissipating too much heat into plate), so keep it angled upward to prevent unnecessary resistance. The smoke space cannot be smaller in square inch area than the stove outlet, pipe and chimney diameter.

 

[Eightball1313]

Put a pipe surface thermometer on the pipe before it enters chimney. You can't tell what you're doing without knowing the temperature. A surface thermometer reads about half the actual inner flue gas temp.

The setting will be different for everyone. You are adjusting for chimney height and diameter, your elevation, fuel...... and how much heat is required, many variables.

The object is to keep the flue gasses above 250* f. to the top of chimney. (when smoke is present) The better the flue is insulated, the easier it is to keep it hot, with less wasted heat. 250* is the condensation point of water vapor from combustion rising out of the chimney. Below 250 the water vapor condenses on flue walls allowing smoke particles to stick. This is creosote. So burning more particles in the firebox allows lower flue gas temps, but keeping above 250* is also critical for the proper draft since this is what allows atmospheric pressure to PUSH into stove feeding the fire oxygen. (A low pressure area is created in stove by rising gasses in chimney)
If you currently use a pipe damper to slow draft, (it is a chimney control that affects the stove) you will be able to run it more open with a baffle since the baffle adds a slight amount of resistance in the firebox instead of adding it in the pipe with the adjustable damper.
Otherwise the baffle doesn't change your air setting much. With more heat radiating from stove instead of loss up chimney, you should be able to run it closed a bit more increasing efficiency of stove.

The air intakes are simply a resistance to flow. The chimney creates the low pressure area or draft, and the pipe, elbows, tee, variable damper, even top screen or rain cap all create resistance in the system. The most resistance is the air intake opening size. The baffle adds resistance within the firebox as well, which is adjusted by the "smoke space" above baffle that the exhaust gasses must travel through to get out. The angle of the plate also affects resistance as well as technicalities such as flame impingement (flame tips dissipating too much heat into plate), so keep it angled upward to prevent unnecessary resistance. The smoke space cannot be smaller in square inch area than the stove outlet, pipe and chimney diameter.

So when im running my stove and the surface thermometer on the pipe reads 250 degrees, you think the actual flue gasses are around 500 degrees? I was never quite sure what they would be inside the pipe, i just always made sure the surface of the stove pipe was at least 250 degrees.

 

[bholler]

This is may be true in some instances, but in Virginia, per my insurance broker, and in an. unattached workshop garage, if installed properly it is perfectly legal and insurable. This will be my third detached workshop/garage built in the past 5 years that I have heated with a wood fired conventional heater. Maybe rather than commenting based on presumption, one should ask for more information before concluding and making false accusations.

Your insurance broker is not a code officer or the adjuster who will do an inspection in the case of a claim. He is just the salesman. So unless he gets the underwriter to give you written consent for a non code compliant install a claim involving that install will be denied.

Virginia follows nfpa 211 like almost all states in the country. And that says in 12.2.4
Solid fuel burning appliances Shall not be installed in any garage.

Also in 12.2.3

Solid fuel burning appliances shall not be installed in any location where gasoline or any other flammable vapors or gasses are present.

It is against code period. You can choose to ignore that as many do but you need to be aware of the risks involved in doing that.

 

[coaly]

So when im running my stove and the surface thermometer on the pipe reads 250 degrees, you think the actual flue gasses are around 500 degrees? I was never quite sure what they would be inside the pipe, i just always made sure the surface of the stove pipe was at least 250 degrees.

Yes, approximately twice the surface temperature. Blow a fan on it and decreases even more. That shows you how much heat radiates off thin wall pipe. So if you check the surface temp where it dumps into chimney, double that to have an approximation of flue gas entering chimney. This is where you will need to use an infrared thermometer inside at the top of chimney, or it becomes a guess how much temperature drop you have at the top. I can tell you from measuring pipes that increase in size from 6 to 8 inches in diameter (that almost doubles the cross sectional area) the expanding gasses drop almost in half when allowed to expand from 6 round into an 8 round pipe. That's a lot. So if you have a 6 inch stove connected to an 8 X 8 masonry flue, (28.26 square inches increasing to 64 square inches) 250* which is 500 internal drops to less than 250 internal at the bottom of chimney, and cools as it rises. So obviously you would need to run much hotter than a surface temp of 250 when allowing gasses to expand. (that is the reason all inserts now must be connected to liners instead of using the original fireplace flue) The amusing part about codes is the Inserts in 1980 were UL Listed to be used with the larger exiting flues, and todays codes prohibit their installation as printed in the UL approved manuals! Time has proven what was considered safe when it passed is not so!

IR thermometers are cheap enough, and I've found many other uses such as brake temperature, exhaust manifold temps to diagnose a dead cylinder, stove top and wall temperatures....... Once you know what temp you have about 2 feet down from the top, check the surface thermometer and mark it down so you know exactly what temps to expect at the top when reading pipe temp inside. It will change with wind and extreme cold, otherwise it's a guess. Erring on the side of caution keeps the chimney cleaner, but takes way from the available heat the stove could be radiating into the house. This becomes critical the smaller the stove, since BTU output goes by surface temperature of each square inch of radiating stove surface. The first time I measured the actual temperature of different parts of the stove I was surprised to find how cool the sides are near the bottom, so you can't simply figure the total square inch of entire stove surface area at any given temperature. I learned a lot designing baffles for the different stove models with the IR thermometer.

The other thing I've learned from experience is when we get extreme ice storms or cold wind with 'Nor-easters, many screens will clog giving indoor smoking issues and sluggish operation of stoves. That shows how much more heat you need to leave up the stack during extreme weather since the cold wind cools the screen and chimney cap so much it can load up quickly.

 

[Eightball1313]

Yes, approximately twice the surface temperature. Blow a fan on it and decreases even more. That shows you how much heat radiates off thin wall pipe. So if you check the surface temp where it dumps into chimney, double that to have an approximation of flue gas entering chimney. This is where you will need to use an infrared thermometer inside at the top of chimney, or it becomes a guess how much temperature drop you have at the top. I can tell you from measuring pipes that increase in size from 6 to 8 inches in diameter (that almost doubles the cross sectional area) the expanding gasses drop almost in half when allowed to expand from 6 round into an 8 round pipe. That's a lot. So if you have a 6 inch stove connected to an 8 X 8 masonry flue, (28.26 square inches increasing to 64 square inches) 250* which is 500 internal drops to less than 250 internal at the bottom of chimney, and cools as it rises. So obviously you would need to run much hotter than a surface temp of 250 when allowing gasses to expand. (that is the reason all inserts now must be connected to liners instead of using the original fireplace flue) The amusing part about codes is the Inserts in 1980 were UL Listed to be used with the larger exiting flues, and todays codes prohibit their installation as printed in the UL approved manuals! Time has proven what was considered safe when it passed is not so!

IR thermometers are cheap enough, and I've found many other uses such as brake temperature, exhaust manifold temps to diagnose a dead cylinder, stove top and wall temperatures....... Once you know what temp you have about 2 feet down from the top, check the surface thermometer and mark it down so you know exactly what temps to expect at the top when reading pipe temp inside. It will change with wind and extreme cold, otherwise it's a guess. Erring on the side of caution keeps the chimney cleaner, but takes way from the available heat the stove could be radiating into the house. This becomes critical the smaller the stove, since BTU output goes by surface temperature of each square inch of radiating stove surface. The first time I measured the actual temperature of different parts of the stove I was surprised to find how cool the sides are near the bottom, so you can't simply figure the total square inch of entire stove surface area at any given temperature. I learned a lot designing baffles for the different stove models with the IR thermometer.

The other thing I've learned from experience is when we get extreme ice storms or cold wind with 'Nor-easters, many screens will clog giving indoor smoking issues and sluggish operation of stoves. That shows how much more heat you need to leave up the stack during extreme weather since the cold wind cools the screen and chimney cap so much it can load up quickly.

I have two surface thermometers (one on stove top, one on stove pipe like a foot above stove collar, which i have a kodiak stove aka fisher copy) and an IR thermometer that ive been using to check how accurate the surface thermometers are, which theyre not dead on but theyre close. so you think i should get the stove going and shoot up to the chimney cap with the IR thermometer to get an idea of the gasses coming out of the chimney? I have an exterior masonry chimney so i feel like thats my only option to truly know what the gasses are at the top of the chimney to ensure a clean liner. youre the man tho, thanks for the long informative response!

 

[coaly]

You have to get up there and aim on the flue wall about a foot or two down to get an internal temp. The cap will be much colder.

 

[Eightball1313]

You have to get up there and aim on the flue wall about a foot or two down to get an internal temp. The cap will be much colder.

Ah ok actually aim right down into the chimney a foot or two while its burning, ill give it a shot next time im burning, weather has been bipolar here, one night its 70 degrees, next night its 30...