james beam wrote:
Fix that developing crack right away.
and then I took this video…..
I'm guessing this is a near catastrophic fail…….
james beam wrote:
I would be concerned of how hot your wall will become especially next to the burn barrel, you might think about a temporary sheet metal deflector or something (maybe some aluminum foil sheets tacked over the wall) to protect your wall, in the event that the thing is run hard. I'm also concerned of the decorative wood slices you have embedded in the wall, near the burn barrel, I think those could possibly catch on fire, some thin cut bricks or thin rocks should be safer than wood slices near the burn barrel.
The wood pieces are part of the cordwood wall - they are 14" long and go through and through. There is a metal deflector (permanently) installed behind the barrel though, and no cordwood behind it. And a fire extinguisher in the room.
Did the thing burn easier when you had the door or window slightly open?
When you burn the sticks, generally I use a spare brick atop the mouth of the fuel feed to regulate the amount of air to the fire, allowing as much air in... you watch the fire, as the fire rises up the sticks toward your hand push the brick up against the sticks to kind of hold them in place & regulate the rate of combustion. As for the fresh air inlet pipe that goes thru the wall somewhere, (I never could see how it was placed, or constructed from your pix, it just looks like a pipe sticking out of the wall...LOL) Ideally I would want that fresh air pipe to provide air in the fuel feed area very close to the bottom of the burn tunnel.
The feed tube has a sliding cast iron door (it says Victoria Foundries, pretty cool) so I can leave it open a bit if there's a good fire going and I just want a little air. With a really good fire, I can actually close it sometimes and let it slow burn!
( Yep, it's close to the bottom, and closer to the horizontal area not the mouth of the feed tube)
This is because fire always wants to lick or travel toward the air supply, that is why the fire almost always wants to travel up the sticks toward the mouth of the fuel feed where the combustion air comes in at. If the fresh air pipe was plumbed down in the LOWER fuel feed area, toward the bottom of the fuel feed/burn tunnel, this will cause all the action to take place in the bottom of the burn tunnel instead of at the top edge of the fuel feed area, a brick is still used at the mouth of fuel feed area, to regulate air, & help support the fuel sticks.
If you feel like experimenting a little further, try finding some schedule 40 steel pipe to connect to the 'outside air inlet' and plumb the pipe from the wall, make a 90 degree bend at the mouth of the fuel feed port, and continue the pipe to 2" from the bottom of the burn tunnel floor. You may have to make a special cover to compensate for the pipe interfering with the mouth of the fuel feed port. This type air inlet arrangement should reduce 'smoke back' somewhat like the 'P-Channel' Satamax suggested.
Are you using the room for Yoga classes for only an hour or two per day?, if YES then you might want to get the house warmed up 4 hours before the appointment time, and see how it goes. (yes!)
Michael Ahlefeldt wrote:Hi Everyone
All fireplaces have a vertical chimney- thats to create a draft and get the combustion gasses out- the higher it is, the better draft you get because hot air is lighter than cold air and thus rises- going above the roof apex has nothing to do about catching a draft- its all about achieving height and draft and also a fire safety thing- fireplaces can have sparks coming out of the chimney and its not a good idea to have coals or sparks blowing onto your roof.
There is a vertical chimney there - it doesn't go quite to the roof, but there is only almost cold vapour coming out. The burn is efficient enough that there is nothing else left to come out!
Im just generalizing here but off the top of my head you need a minimum of about 15 feet of chimney to create the draft for a normal wood stove
There's about 18 feet of chimney (horizontal) and then about 5 feet of vertical. The chimney issue seems to be resolved now.
EDIT- got the J part worked out
I cant tell by your description and movie where your crack is but I doubt very much it is “catastrophic”- just fill it with a furnace cement
I did this today! (Well, regular cement). The area underneath the hole in the cob was firebrick - there was no obvious entry into the area where the heat riser is. I'll check it tomorrow to see how it's holding up.
A wild guess would be that the material was heated too quickly and/or too hot before it was dry
That could be it - and that it was too thin to begin with. We really let it dry as much as needed in order to get a fire, and then tried some small fires to heat the cob from the inside out. I think (fingers crossed) the lenght of the bench is okay, and that has very large masses of cob. It makes me think the thinness of the back wall was a bigger issue….
I just saw the new pictures and I could add that its probably a matter of your stonework drying and shrinking and the metal barrel does not- there is also different movement in the different materials- the metal expands in the heat more than the stonework and something will give.
I wouldn't even bother with all the fine points of the air supply until there is a proper draft in the cob heater- a vent of 10 sq. inches will do in the room.
james beam wrote:Hey Yvette & MGs, I modified your picture, this what I was suggesting for the additional air end up in the burn tunnel/bottom of the fuel feed area. (I'm guessing that is the air pipe thru the wall that I connected to the burn tunnel... hahaha( well~~~it looks like that might be the pipe thru the wall, I really don't know what that is but it probably needs a pipe connected to it just the same~~~)
Ha ha! fooled you! that's a decorative wine bottle in the wall! The air tube is inside the feed chamber. If I knew how to do those cool drawings on my photo, I'd be able to show you….
About that crack, that is now (2) cracks, did you all have a party and someone was dancing around and gave the old stove an old fashioned bump? That is what I think might have happened. LOL
Yup. Plus I live on the BC coast - who knows how many micro earthquakes we have in a year. (answer: over 300…..)
Michael Ahlefeldt mentioned using a damper valve on the chimney, which would probably be wayyyyyyyyy easier than disconnecting the pipe everytime & stuffing an old shirt in the pipe, yanno to keep the stove from siphoning cold air back into the house. Although your tricky Victoria Foundries feed door looks like it will stop most drafts all by itself without an old shirt or a damper valve.
Yes, it's pretty draft proof in there…..
I thought Michael's suggestion of fixing the crack seems like a good idea to me, although if you want to go deeper into the repair, I made a few suggestions in the picture with notes.
I'm hoping the repairs today will suffice and there won't be a need to remove the barrel and do it all over again. If that ends up being required, I can see me ending up with a very expensive bench….. As well as cementing the hole behind/below the barrel, I replastered some of the smaller cracks. I knew that would happen with the expansion/contraction issues, and even added a little extra plaster to a small gap forming around the entire barrel.
Yvette Menard wrote:I'm hoping the repairs today will suffice and there won't be a need to remove the barrel and do it all over again. If that ends up being required, I can see me ending up with a very expensive bench…..
Michael Ahlefeldt wrote: On the other hand Im learning a lot of things I haven't run into before- great fun!
James- What does one do you get a bad reputation here?