[Cob] question for Sasha on Masonry stoves

[Sasha]

Hello Mary

Yes,there could be a damper on the flue opening - the purpose of it is to 
maximaly slow down the unwanted cooling of the stove trough the 
chimney.Traditionaly, here,when the fire is out and you have only gloving 
coals you close the damper.But the damper must never ever be closed 
full,because there is a great risk of carbon monoxide poisoning.Generally the 
damper is made so it can close only about 2/3 of the chimney ,so you have 
always left some draft.Carbon monoxide is a gas without any smell - very 
dangerous.I have never heard about any tragic accidents here related to 
kachelofens.Your stove can function also without a damper - for your peace of 
mind.
Ash can be a problem ,especialy if you burn green (wet) wood
,but it can be easily solved by puttting the cleaning openings on strategic 
points so you can easily clean it out.Check the swedish stove link carefull 
and you will see some tiles that have metal covered openings for 
cleansing.Also,there can be a stove without openings and there the situation 
depends on position of chanels ,if they are vertical its easy,just take of 
the cover of the stove and vacuum it.It all depends on the inside of the 
stove.Generally as the books says if you use it properly you shouldnt have 
any problems.Thank you very much for advices regarding tile making I will 
contact you off list for some more informations if it is not a problem.

Sasha


> The book that I read about masonry stove construction stressed the
> importance of having a flue opening that could be held slightly open to
> prevent carbon monoxide (dioxide?) poisoning and also a place to clean any
> ash or buildup out of the air chambers, so how do you handle that?  Also, I
> have a kiln and fire porcelain and ceramics so maybe I can help with your
> tiles cracking.  Usually there are three causes. 1) you need to let them
> air dry longer before firing  2)  if cool down and the heating up process
> isn't slow enough then you will get a thermal shock resulting in a crack 
> 3) the tile isn't properly supported or"proped" during firing.  Acurved
> tile can be supported with a piece of the same material that is made of, so
> the shrinkage will be the same.  Here we use this cottony like stuff that
> can withstand the temperatures and we just order from ceramic/ hobby supply
> companies.  If your tile is to be flat and you want it to stay that way
> then scratch a couple of grooves across the back and fire it on a thin bed
> of silica sand. The sand acts like little ball bearings and lets the piece
> move to accomodate the shrinkage, otherwise it will warp and then crack. 
> Hope that helps you out a little.
>

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