Clinkers

[ZZ Tom]

So I'm finding these "rocks" in my ashes. Just curious what is causing this. My wood is mostly dry; most catches fire nearly instantly, some larger pieces take a few minutes, and most is bark free.

 

[nrford]

Good hot fire, the high temps melt the ash into a "clinker" as you call them.

 

[ZZ Tom]

Thanks nrford, good to know we're finally burning correctly. This site is a fantastic resource.

 

[DuaeGuttae]

I believe it has to do with the mineral content of the particular wood as well. I think I’ve read that it can be silica. I’m guessing you have some sandy wood, and your nice hot fires fuse the minerals together.

 

[David.Ervin]

Different type of wood and different heat makes these things in my stove too. A good hot fire using hickory makes a lot, a smaller fire with ash makes none. YMMV, but seems normal.

 

[peakbagger]

Clinkers and ash fusion is much more of an issue with coal especially coal boilers. I

 

[Tar12]

I get then occasionally as well...I burn good seasoned wood and hot fires.

 

[venator260]

I get a version of this in front of both of the "doghouse" air inlets in my stoves. I'm burning 90% ash, and its dirty. Was drug out of the woods during the spring, and ash seems to grow in wetter areas, so it was pretty muddy.

They're not very firm though. It will hold together on the shovel, but it can be broken apart fairly easily.