Stump Clone - Need some suggestions

TravisT · Posted: May 25 2008 Post subject: Stump Clone - Need some suggestions

Hey guys, I built my stumps clone a couple months back and done about 5 or 6 cooks on it. I'm having a couple of problems and need some advice. First off is the heat. I can't get it very hot (3/4 to wide open will get me right around 225�). Should I increase the size of the area where the coals are actively burning, or increase the size of the opening to the cook chamber (or both)? What size does Stump make his "firebox" and how big is the opening from the firebox to the cook chamber?

Right now, I'm using some woven fiberglass seals that I got from McMaster Carr (sp?) and they work pretty well. The problem is that I just got some 3m spray adhesive to adhere them to the smoker. Time and heat causes them to fall off pretty quick. Is there a better solution to mounting them, or a better solution altogether? Some of those silicon teardrop style seals look pretty nice, but I'm not exactly sure how they would be attached to the smoker. Thanks for any advice you can give.

TravisT
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Robert & Keri C · Posted: May 25 2008 Post subject:

Travis,

I built a clone also. My charcoal chute is 6 x 8 x 3/8 wall. My opening into the cook chamber is 3 " above the grate and I used a piece of 4 x 6 x 3/8 w so I have a 3 1/4 x 5 1/4 opening for heat and smoke. My exhaust is 4" and it is top dead center . I can do 375-400 without any problems.

STUMP USES A 5 X 5 OR A 6X6 CHARCOAL CHUTE AND USES A 3 X 5 opening into the chamber.

I used 5/8 wood stove gasket for my seals and then used red hi temp silicone to hold it in place. I have been cooking on mine for almost a year.

What size is your chute, your smoke box entry and your exhaust?

Robert C
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Robert & Keri C
Under construction-GF Stump Clone using a 1965 Montgomery Wards deep freeze
2 well-worn WSM's
1 Home Built XL GF Stump clone w/Roc's Stoker
3 Cookshack FEC100's
1 Good One P30 (on loan)
1 Vermont Casting gas grill

TravisT · Posted: May 25 2008 Post subject:

I'm cooking right now, and I don't remember right off hand so I'll have to get back to you on exact measurements. I know that my exhaust is 4" also right in the middle (no baffle). I also know that my grate is not very far below the opening to the chamber, so I think my problem is that I don't have enough charcoal burning at any one time. If I remember right my chute is 6x8 and it opens up to an 8x8 chamber if I'm not mistaken. The opening is probably about 2x5 or 2x6" but I'll have to check this as well.

The entire smoker is built with 1/8" steel and 2" square tubing. I think I have 3 full sheets of 1/8" and 3 or 4 lengths of tubing in the whole build. It is pretty much immobile right now, even with the wheels that are on it!

I'll post more about the dimensions tomorrow sometime when I'm done cooking. Thanks and any more suggestions are welcomed.

TravisT
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Harry Nutczak · Posted: May 25 2008 Post subject:

Stump uses "Tadpole" shaped gasket material, It has a flap of extra material hanging off the round part, it is designed to be pinched between 2 pieces of metal to hold it in place, adhesive is not used.

I'll try to explain this better, The thin part of the gasket gets sandwiched between the actual door, and a plate that is screwed to the inside of the door.

I just replaced my firebox door gasket a week ago, I had to remove the inner panel of the door, set the new gasket material and screw the metal plate back in place and also ran the screws through the gasket, I also trimmed the gasket at the 90-degree bends so it does not bunch up at that location.

Stump also use a 2" diameter intake, they are triple the cost of a 1.5" valve, that could be your issue too.
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TravisT · Posted: May 25 2008 Post subject:

I understand what you are saying about the gasket - any ideas where I could find something similar to what you are using?

I had no idea that stump uses a 2" valve - I thought all along it was 1.5"??? Are all models the same??
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Harry Nutczak · Posted: May 25 2008 Post subject:

I think Northern tool or Mcmaster-carr carries tadpole gasket material.

I think they all use a 2" valve,

To explain how much of a difference that 1/2" can make, if I do not remove my stoker adapter (it reduces inside diameter of the valve so the fan fits tight) I have trouble getting my stumps up to 250 degrees in free draft config.

I remove the adapter and it will reach temp.
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Just remember that the toes you may step on during your climb to the top will also be attached to the a$$es you'll be forced to kiss on your way back down!

Bedlam BBQ · Posted: May 27 2008 Post subject:

TravisT · Posted: Jul 13 2008 Post subject:

Sorry it took so long to post this info... new baby = no time for anything.

The dimensions of my burn chamber are about 6-1/2 high x 11-1/2 wide x 6-1/2 deep. The opening to the cook chamber is 6-1/2 x 2". If there are any suggestions on what size this should be, that would be great. I need to remove that side of the smoker anyway to do a couple repairs. If I have to make changes to the size of the burn box, I guess then would be the time to do it. It's not going to be the easiest job, but I'll get it.
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TravisT · Posted: Nov 05 2008 Post subject:

I finally got around to cutting in to the clone. Here is what I'm working with. I need some suggestions as I need to get this thing back together by Thanksgiving, and starting Monday, I'll be out of town for two weeks.

I'm looking into getting a 2" ball valve which I think will help. My intake from the burn box into the cooking chamber is about 2" high and the bottom of that hole is level with the top of the grate the charcoal sits on. This gives me about 2" (give or take) of charcoal burning at any one time. I think I need to increase this by either moving the intake to the cooking chamber up (not easy), or by moving the cooking grate down (very easy). I feel that this, in addition to the larger intake should get my temps up a good bit.

Any suggestions/comments?
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Bedlam BBQ · Posted: Nov 06 2008 Post subject:

I think you are on the right track with moving the charcoal grate down thereby increasing the amount of burning lump.

The opening into my cook chamber is 3" above the top of the grate and I have a 3" x 5" opening into the cook chamber. Oxygen is only able to get up a couple of inches above the top of the opening, so that basically gives me roughly 8" tall of burning lump -- and my chute is 8" x 8".

The deminsions you gave for your "burn chamber" is really the ash box (nothing really burns below the grate -- that is just where the ashes fall). The burning area is from the grate up (to as high as oxygen can get into the chute). What is the size of your chute? It looks like you tapered the lower part out wider -- that's good, that should prevent bridges.

But lowering your charcoal grate down in the ash box, just be careful that you are still above the opening from the ball valve. If the opening from the ball valve is above the grate, you won't be getting full burning of the lump and won't get all of the heat from it either.

Keep us posted.
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Steve

Stumper clone with Stoker
Bedlam BBQ
Competition Team

TravisT · Posted: Nov 06 2008 Post subject:

SStory,

Thanks for the reply. The burn chamber I gave dimensions on is actually the burn chamber an not the ash box, but they were estimates. The actual burn chamber (the tapered portion of the chute) are 7"x11"x6" (lxwxh). Also, this area is only tapered on 3 sides. This is at the bottom of the tapered section of the chute, and measured to the top of where the grate is now. Now I realize that this entire area is not burning due to the low placement of the "window".

Now obviously due to the space constraints of working inside of this, the easiest solution would be to move the grate down and call it a day. How much do you think I should move it down to achieve better temps? I am building a new firebox door out of 2" tubing (as opposed to the 1" I'm using now) and adding two 2" pieces of flatbar (1/2" thick) inside to prevent warping of the door. I can move the intake down if I need to.

I'm afraid my ash box will be on the small side if I go more than a couple of inches down. As you can see in the pics, I have about 6" in height from the bottom of the current grate to the bottom of the ash box.

I'm planning to go pick up the tubing I need tomorrow or friday so I can get this back together this weekend. Any help would be great!

Thanks,

Travis
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TravisT · Posted: Nov 06 2008 Post subject:

SStory,

I meant to ask this also. How does your clone do without the stoker using the dimensions you listed above for your burn box? That would give me a good comparison.
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Big Tom · Posted: Nov 06 2008 Post subject:

I would suggest to drop the fire grate about 1" to 1-1/2" and see how that changes the temp range. It should not be to difficult to relocate if that doesn't do the trick for you. Has a plate been removed for the photos on back of the burn chamber just above the grate? If so when you lower the grate you might need to close that gap to contain the fire when opening the firebox door.

The ash accumulation will be dependant upon the fuel source. If you are using some quality hardwood lump the ash will be minimal + what might be generated from wood chunks for smoke. If using briquettes the ash will accumulate faster and could possibly have to be dumped during a cook (not a major task with good gloves and vice grips).
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Big Tom
Pigs-R-Us Cooking Team
Owensboro, KY / Corinth, MS

TravisT · Posted: Nov 06 2008 Post subject:

you are correct, there is a piece of metal that was cut out opposite the "window" in the burn box just above the grate. This side of the burn box angled out towards the side of the cooker and welded directly to the outside panel of the cooker. This resulted in the side of the cooker above the ash box to get very hot. I'm planning on modifying this to have a 1-2" gap here that will be insulated, and hopefully that will allow this beast to hold paint without burning it off. The side will extend down to the top of the grate.

I hope your suggestions work out. I was hoping this would be the advice I got from you guys, but expected much worse. We'll see how it works out.
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Bedlam BBQ · Posted: Nov 07 2008 Post subject:

TravisT · Posted: Nov 07 2008 Post subject:

I've heard a lot of good things about the stokers for sure. I'd definitely like to get one eventually. That seems like a long time to get the smoker going, even with the stoker. How are you lighting the lump? I typically use a chimney full of burning lump before filling the chute, and maybe I'm off on this, but it doesn't seem to take more than about 1/2 and hour or so to get up to temps.

How hot can you get yours cooking without the stoker? Are you using a 2" valve? Do you have pics/dimensions for yours in a post somewhere?
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Bedlam BBQ · Posted: Nov 07 2008 Post subject:

Travis - I start mine up by just putting a weedburner through the ashbox and light the lump from under the grate. I let that go for about 5 minutes (usually about how long it takes me to get the Stoker all set up). Then I pull the weedburner out and let the Stoker fan bring me up to temp. I use Royal Oak lump and put fist-sized chunks of wood in the chute with the lump.

I can't say how hot I've taken it without the Stoker because I've never tried. But I have taken it to 375 several times to cook pizzas in there. I don't really want to take it much higher so I don't cook all of the seasoning off.

My cook chamber is 24"w x 26"d x 48"h. I have a 1-1/2" ball valve.

Here's a link to an album of pics of my smoker -- you can see how it has evolved from first being mounted on pneumatic casters, then being moved to a small trailer (too small though), then the rebuild after the burn out, then the move to a larger trailer and finally the addition of the roof (I haven't gotten this part completely finished yet). I'll also be adding a platform that will fold down. With this being mounted on a trailer, it makes it pretty tall and hard to get to the two top shelves.

http://adobe.kodakgallery.com/Slideshow.jsp?mode=fromshare&Uc=jq5n3av.5710eilv&Uy=3e7vhu&Ux=0
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Steve

Stumper clone with Stoker
Bedlam BBQ
Competition Team

TravisT · Posted: Nov 07 2008 Post subject:

Thanks a bunch for the pictures. From the pictures, it looks like you increased the size of your burn box also?? I wish I would have increased the size of the window to the cooking chamber, but hopefully I can make what I have work. I'll be off to pick up the steel I need in a little while, so hopefully I can button her back up this weekend.

What type of insulation did you use? I was planning to order some high heat insulation, but then ended up using regular household fiberglass insulation. So far it has held up real good - the only thing that burned was the paper. Thanks again for the pics - they really helped me out.
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Jet_deck · Posted: Nov 07 2008 Post subject:

Bedlam BBQ · Posted: Nov 08 2008 Post subject: