What exactly is a CLINKER?

Cap · By: **Cap** On: Wed Mar 15, 2006 8:21 pm

My only guess is the ash when it retains the shape of the coal an is somewhat still intact after burning. Is this correct?

coalburner · By: **coalburner** On: Wed Mar 15, 2006 8:49 pm

Cap wrote:My only guess is the ash when it retains the shape of the coal an is somewhat still intact after burning. Is this correct?

It is when the ash melts together. Sometime they can block your air flow.
It depends on the minerals in your coal.

Richard S. · By: **Richard S.** On: Thu Mar 16, 2006 4:37 am

As mentioned above it's where it has melted together. You'll find this in any ash from a stoker to some degree, if it'sgood coal this will easily break apart. It's where it's excessive that it presents a problem. Some can form a large mass that is rock like and in a lot of cases will require you to shut the stove off to remove it. I've seen chunks from new customers where they were larger than softballs from a hand fired stove... Obviously something that is not going to go through the grate.

LsFarm · By: **LsFarm** On: Thu Mar 16, 2006 4:58 am

Take a look in my ash pan. I shoveled most of what you see out of the firebox because it was too big to fall through the grate. Some of the clinkers you see are baseball sized.

They look like assorted rocks bonded together.

Richard S. · By: **Richard S.** On: Thu Mar 16, 2006 8:16 am

NEPAForum Admin wrote:You'll find this in any ash from a stoker to some degree, if it'sgood coal this will easily break apart.

Just to clarify, you'll find very little of this. I'm not even sure if clinker is the appropiate term for what you'll find in a good load of coal. You'll find ash that is similar but easily crumble even under the slightest pressure.

The clinkers in the picture posted asbove you can probably hit with a bat and send it sailing. :wink:

coalburner · By: **coalburner** On: Thu Mar 16, 2006 3:45 pm

LsFarm wrote:Take a look in my ash pan. I shoveled most of what you see out of the firebox because it was too big to fall through the grate. Some of the clinkers you see are baseball sized.

They look like assorted rocks bonded together.

Those ash looks like they could pass for metorites.

When I was a kid growing up in NC my pops hand fired stoval coal stove burned lumps of coal as big as footballs. That coal left large ash rocks and poured black sute all over the place. When it would snow it would be speckeled with the stuff and the women in the nieghborhood could never leave laundry hanging out ovenight or it would be turned black by the flyash from all the coal stoves in the nieghbohood. Most people burned coal there in the 50's and early 60's . I think the cost was about $10 a ton back then, Not really cheap if you consider most folks made about $1.00 an hour back then..

Richard S. · By: **Richard S.** On: Thu Mar 16, 2006 5:22 pm

coalburner wrote:
Those ash looks like they could pass for metorites.

Having just seen a few meteorites onTV that is not a bad comparison.

LsFarm · By: **LsFarm** On: Thu Mar 16, 2006 5:33 pm

When I get back to Michigan this weekend, I'll try to post a close-up photo of a big clinker so you can see what it looks like close up.

The bagged anthracite coal I have burns down to a fine ash almost like talcum powder. You can see a thin layer of this ash in the pan near the bottom of the photo. If I were to burn only anthracite I would not fill my ashpan this full in three or four weeks. What you see here is from about five days of mostly Bituminous coal. My Bitum coal is very poor quality.

Greg L

Cap · By: **Cap** On: Thu Mar 16, 2006 7:23 pm

Greg--

Now that I have seen your ash pan full of ash & clinkers, I can recognize some smaller clinkers from time to time in my hand fired unit. Typically I may see some clinkers after a few really hot burns. But there is no good way to remove unless I reach in with gloves and move quick or kill the fire.

I have also noticed with the handfired unit, the first two days, I will have a real clean burn. But by day three, the coal fire turns to an ash like consistency below the top layer. At this point the fire just doesn't have the really clean looking apperance I like to see. But I guess there isn't much anything can be done about it but heat it up and refill the box.

LsFarm · By: **LsFarm** On: Sat Mar 18, 2006 5:52 pm

Here is a large but fragile clinker, it is about 16"x12" It covered the bottom of my firebox when I let the fire burn down without stirring it with a poker or hoe.

This clinker broke into three pieces when I picked it up. It is like a crunchy fiberglass. It looks like the sand and minerals contaminating the coal melted together, sort of like sand will melt down an make a glass-like lump in a fire.

Sometimes this is what I find in my firebox, other times I find more solid lumps and clumps that more resemble rocks.

Good coal just doesn't have the residue to melt together like this Bituminous I have.

Thankfully I've almost burnt through the pile of this stuff and I will purchase better quality coal for next season.

Greg L

blue83camaro · By: **blue83camaro** On: Mon Mar 20, 2006 2:46 am

I burn anthracite and get clinkers once and a while. I have never had one bigger than a baseball. I get more when burning hot because it is cold out. My understanding of it is the ash fuses together when the fire gets hot enough for the specific minerals to bond. If the coal contains more minerals then you will get more clinkers.

What exactly is a CLINKER?

What exactly is a CLINKER?

Re: What exactly is a CLINKER?