Why is this hardwood burning so dirty?

[niagara]

Hi folks.

I have an RSF Opel 3.

I have some 3/4" solid ash flooring that I've chopped into 18" long boards.
This is unfinished ash hardwood, no urethane or coating whatsoever, straight from the sawmill.

But I find it burns very dirty. the flames are kind of "orangey-black" and is really dirtying up the glass.
I can even see little wispy black "streamers" in the flames.

I expected the opposite, I thought this would be ideal wood, perfectly dry pure solid hardwood.

I notice too it burns very intense, I have to close down the air lever to about 50% on the Opel.

Any ideas? Could it be *too* dry?

 

[jatoxico]

Can you clean up the flame with more air? Some posters have described very dry wood out gassing all at once to the point that the gasses cannot be burnt completely by their secondary burn system.

 

[branchburner]

very dry wood out gassing all at once to the point that the gasses cannot be burnt completely

Exactly. I have experienced this w/ pallet scraps, and it's not just the dryness: it's the huge increase in exposed surface area that comes from smaller boards vs. larger splits. Way too much out-gassing when you load the stove w/ small stuff.

I'd suggest using the boards only as kindling for startups, or mixing just a few in with larger splits when reloading.

 

[niagara]

Thanks folks, that makes a lot of sense. I'll try those suggestions

 

[JayD]

I Just grab the old ones with the 3 4x4 oak runners on the bottom when I see them. I just can't pass them buy, But they are getting hard to come nowdays.

 

[Seanm]

Can you clean up the flame with more air? Some posters have described very dry wood out gassing all at once to the point that the gasses cannot be burnt completely by their secondary burn system.

Yes this has happened with me in the past with ridiculously dry pine but that was stored in a garage for 6 years. I haven't see it since thankfully.

I have some 3/4" solid ash flooring that I've chopped into 18" long boards.

could you pile them on top of each other so that less space is open for flames? Either that or do what others above has suggested and use it for kindling. Some here have been able to burn it ok with monitoring the heat output but I never played around with it to much, just turned it into kindling.

 

[niagara]

Can you clean up the flame with more air? Some posters have described very dry wood out gassing all at once to the point that the gasses cannot be burnt completely by their secondary burn system.

I was reluctant to turn up the air because it would seem to over-fire. I could hear a lot of "tick-tick-tick-ticks" and creaks and groans from the Opel from thermal expansion I guess.

This morning I'm using it as kindling and it's working fine

 

[Jags]

Size matters. Just like one 14" diameter chunk stuck in your stove would burn like crap...a bunch of small stuff is gonna burn like last nights burrito grande.

 

[jatoxico]

I was reluctant to turn up the air because it would seem to over-fire. I could hear a lot of "tick-tick-tick-ticks" and creaks and groans from the Opel from thermal expansion I guess.

This morning I'm using it as kindling and it's working fine

Good to hear you're getting some use out of the stuff. My question about the air was more oriented towards figuring out if the wood was treated w/o your knowledge. If extra air could clean up the burn then I would go w/ the outgassing. You were right to be concerned, a load of that stuff with the air opened prob would burn like Jag's burrito w/ extra chiles.

 

[Wood Duck]

I was reluctant to turn up the air because it would seem to over-fire. I could hear a lot of "tick-tick-tick-ticks" and creaks and groans from the Opel from thermal expansion I guess.

This morning I'm using it as kindling and it's working fine

With very dry, small hardwood you might not be able to burn anything more than a small load at once. Your stove is designed for dryish cordwood, not very dry small boards. Too bad, because it seems, at first glance, that dry hardwood flooring SHOULD be a perfect fuel for a wood stove.

 

[niagara]

No, the wood is not treated.

To avoid the "burrito burn" syndrome I'm stacking about 6 pieces to form a large block. This is working well. This increases the mass/surface area ratio as Seanm suggested. Thanks.

@Jags - actually, in my Opel I can burn 14" dia. chunks very well. No problem at all. Once there's a nice coal bed established.

I'm really loving the Opel 3, it works amazingly well. It's -12C here in Ontario and it's heating the whole house. I have another thread explaining how I setup a convection loop to bring the warm air upstairs.

 

[Jags]

@Jags - actually, in my Opel I can burn 14" dia. chunks very well. No problem at all. Once there's a nice coal bed established.

Actually - so can I. I just used it as an example of one extreme to another.