# Cleaning offset firebox



## mrau (Mar 17, 2010)

After going through two different electric smokers over the years I went old school finally and got an offset wood burner. Looking for input on something I might have figured out but I'm not sure.

I did a brisket in it, 2 beer can chicken and ribs. About 8 hours in with just the brisket going and with the same load of fuel added I was not seeing even close to the same rise in temperature. Here's what I think is going on. As the ash accumulates in the bottom of the firebox it starts absorbing more of the heat energy so less heat travels through the main chamber and up and out of the vertical warmer?

If that's the case, and it sure seems like it was (whole lotta ash at that point) what do you guys do about it? The smoker came with a firebox clean out tool, but I wasn't sure about cleaning the firebox out and restarting that far into the cook. Do you pick a point and just scrape all the ash out then reload?

Obviously not something I've dealt with using electric smokers in the past. I ended up with great finished meats (Ill take luck over good any day) but I was using a whole lot more fuel up during the last half of the process.


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## TIMBOv2 (Mar 18, 2010)

is your wood setting on grating? You need air flow for it to heat correctly, if wood and coals/ashes are just laying in the bottom it will effect your heat.


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## sotexhookset (Jun 4, 2011)

^^ This. Make sure you're wood/coals are on a grate. If its a small firebox and you have to remove built up ash on a very long smoke, tinfoil off the opening between the box and pit and gently shovel out.


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## CoastalOutfitters (Aug 20, 2004)

agree, you want your wood up off the floor of the pit box

a piece of catwalk grate works or angle iron or big reebar, but you want that off the floor................. elevated 2" if at all poss.

i never have pulled the ashes out of a pit while cooking, new one on me, it might be blocking your inbound airflow tho.



once you get thru with a cook let the pit cool, remove all ashes, rinse out the insides (no soap), and try to tilt it so it drains well with all the doors open until it is dry.

this does 3 things

gets all the salt out from your rubs and sop
gets the ash out which holds moisture and contains tannic acid , which will make the pit rust
helps beat down the funky mold that can grow all over everything


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## mrau (Mar 17, 2010)

Thanks for the replies. The firebox is oval, not square. But in center it's 16HX16LX18W. Those measurements might not make sense. In my goofy nomenclature the 16L is front/back and the 18W is left to right, looking at it from the front. 

It does have a grate in the bottom that sits 3" off the floor. That grate was fully covered with ash 5 hours in, so no airflow passing under it. By about 8 hours the lower damper opening was covering up. Coastal, I get what you're saying about how odd clearing out the ashes in the middle of the cook is. I've always used the electric smoker boxes and that even sounds odd to me. I'm just kind of spit balling on that. But once that grate is covered and I'm down to one damper hole temp control is very limited.

I was using charcoal for my primary fuel and mesquite chunks for smoke. For such a long total cook (18 hours) should I have just used wood entirely for fuel and gotten a lighter ash that wouldn't choke the fire box up? I know, stupid questions, but first timer on one of these.


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## Dick Hanks (Aug 16, 2007)

There are so many variables on this, I'm going to just make a couple of suggestions to try. I do believe that your problem is probably oxygen supply.

Once a fire is going/smoking, air from underneath isn't as important. Side air will work fine. Example: For the part of the winter that I'm in Minnesota, I have a fire in the enclosed fireplace every day. I have no fire grate in the fireplace. Just firebrick on the bottom. To start the fire, I need to crisscross split logs to get air circulation from underneath. After the fire has been going, the coals are on the bottom, and additional logs are just added onto the coals. There is no more under air, just side air.

A smoker will work somewhat on this same principal. I don't think that loss of air from under the grate was your problem. My guess is that the partial blockage at the air inlet was more of a problem, blocking the air flow into the chamber.

The question of using charcoal or not, may depend on what temp you are trying to maintain, and how even that temp needs to be. If you looked at the recent thread of CaptJack, you can see a device that he uses that holds sawdust or pellets and no charcoal is used. In that device, the wood just burns/smokes like a slow burning fuse as it moves along the trail of sawdust or pellets. This is for a cold smoke.

You can also just use wood chunks (no charcoal) to get more heat and smoke. The trick is to get the moisture content of the wood correct so it doesn't burn too hot with less smoke. Try having some chunks that have been soaked, and some that are dry handy. Start the fire with the small, dry chunks (propane torch to start) and then mix dry or soaked to achieve the combination of temp and smoke that you are looking for. You can also vary the size of the chunks to achieve additional control. The more that you do this, the easier that it will become.

Try to start the fire at the back of the smoke chamber so that you can keep adding toward the vent end. Don't get it so close to the vent that the ashes will block air flow. You are correct, Charcoal just makes too much ash IMHO.
Every smoker has it's own quirks. Maybe these ideas won't work in yours, but at least it may be worth trying. Good luck!


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## peckerwood (Jun 9, 2012)

All good advise here.My grate burned out,so I made a new one with 3''x1/4'' flat iron in a square u with 1 end open.I used 3/4'' rebar for the grates at maybe 3/4'' apart.With the open end at the door,I can put a trash can lid or box under the door,pull the grate out bringing all the ashes with it.Almost all.I think if you would get some real smoker wood that'll make coals instead od powder fine ashes,you'd be a lot happier and have no circulation problems.


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## CoastalOutfitters (Aug 20, 2004)

ok didn't know about the charcoal part, that is prob the reason behind all the ash.

change over to lump charcoal, or just use wood only.

If you have the room, might try building a ground fire and shovel coals into the pit


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## mrau (Mar 17, 2010)

CoastalOutfitters said:


> ok didn't know about the charcoal part, that is prob the reason behind all the ash.
> 
> change over to lump charcoal, or just use wood only.
> 
> If you have the room, might try building a ground fire and shovel coals into the pit


Thanks Coastal and everyone else. Definitely wood only next time. Gotta admit my former life using the electric set and forget smokers was easier, but I am so far enjoying the "real" smoker.


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## CavassoCruisin (Jun 21, 2006)

I have an offset with 24" diameter firebox 24" deep. I use a sharpshooter shovel and clean out the excess ash every couple or three hours - it's no big deal. You'll gain a lot more in efficency than you'll lose by having the door open two more minutes! A lot of times, if there are a lot of coals in the ash, I'll just dump them above the grate all the way to one side. It is crucial that your fire have proper air flow to maintain good heat and clean burning, with minimal or no visible smoke. Best of luck!


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## peckerwood (Jun 9, 2012)

When I'm cooking and the pit is drawing right,I won't touch the ashes in the firebox.If I through a piece of wood in too hard,there'll be a light layer of ash on the meat.


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