TLUD question

[braddsn]

Hey fellas, for the last 3 years I have been cooking my charcoal in crucibles over an open fire. I live in the country, and run a sawmill so bonfires happen frequently. However, starting a bonfire isn't always convenient when I need a little charcoal. Thus, I started reading about TLUDS. I got the plans for the 5 gal TLUD, picked up all the parts, and built it in about 30 mins. I have several thousand bdft of cedar from the sawmill, so I cut up small pieces (approximately 1/4" thick, 3"x3" squares) and filled the TLUD. I used my torch and got the cedar burning, then put the top on. It was really neat the way it burned. HOWEVER, when I thought the burn was finished (I could see orange glow under can reflecting off of the ground), I took the top off, and there was literally almost nothing left! There was a very small amount of charcoal left in the bottom. I obviously cooked it for too long. So my question is simple... what is the 'rule of thumb' for when to shut it down? I saw where some guys use a strip of duct tape down the side of the bucket, but on my TLUD, that's not practical, because the bucket is very rusty and duct tape would never stick to it. For the guys who have done many cooks in a TLUD, how do you know exactly when to shut it down? It seems like there might be a very fine line between undercooked, and cooked away! Thanks!

[Merlin]

If you could just sand down a strip up the side so the tape will stick. I use masking paper tape. I cook 5 gal of pet bedding in about five to seven min. The tape will take a couple min to start charing and peeling off. On a bucket of solid cedar pieces I remember it took around 30 min. When the tape peels to within an inch of the bottom I stop the burn. You have to keep a watch on it. You should not have excessive flame or smoke out the Chimney. Any questions let know.

[starxplor]

I heard masking tape was better, and you can scrub a small strip to clean it up just enough. Once you run it a time or two with the tape, you will learn the timing of your cooker and not need it any more.

 

As for construction, burning too fast could happen if you have too many openings/too much total opening space in the bottom for air intake.

[MasterBlaster]

Another method is to place a piece of aluminum foil beneath the bucket and then stop the burn as soon as you see orange embers reflecting off the foil. It sounds like this is essentially how you chose when to stop, but the foil might help you see as soon as the burn reaches the bottom

[Boophoenix]

Brad, by nothing left I assume you ended up with ash.

 

The more likely culprit here is you're drafting to much air from the bottom. The TLUD needs to cook in an air deprived environment for our purposes almost. The air drawing threw the uncooked material has no effect. Once the flame consumes the oxygen the rest of the material doesn't ash over. In that design the TLUD will extinguish itself right at done. Then you close the top and bottom off to suffocate the remaining embers leaving you with charcoal.

 

Just like in a retort with lack of oxygen the wood will not ash over. Think about your open fires if you've ever turned the coals. If it's crazy hot then coals will just sit there and glow for a bit before the ash starters to appear on them. Spread them out where they can get good air flow and they'll ash over pretty quickly.

[OldMarine]

Try plugging a few of your bottom holes with foil tape. That's how I finally figured out how many holes I needed for a good batch. I then made my others using only that many holes.

[braddsn]

Thank you all for the replies. This gives me some things to try. The number of holes I drilled was based on another TLUD post that was written long ago, by Dag if I remember right. But, im pretty sure one of my problems is too much air. My metal bucket glows red through most of the burn, and I don't believe that is right. Back to the drawing board. I will post my progress. One more question: should the charcoal yield be the same from a TLUD as it would be in a crucible the same size?

[lloyd]

For me, more from a TLUD. It's quite difficult to get a retort JUST at the right temp, while a properly-tuned TLUD does it automagically.

 

Lloyd

[OldMarine]

For me, more from a TLUD. It's quite difficult to get a retort JUST at the right temp, while a properly-tuned TLUD does it automagically.

 

Lloyd

I was going to gig you on that last word but it suddenly seemed to be a needed word!

[Merlin]

Brad, I had exactly the same problem on my first attempt. Too much primary intake sir. Holes too large and too many. I just punched holes In a new bucket. Mine glowed red and had flames out the Chimney.

Don't know if you punched or drilled but someone noticed from a photo that I drilled the first one. If you drill it will leave burrs on the inside. These burrs.can eventually come off and into your charcoal and into your mill and you have a potential for a mill explosion. Use punch or large screwdriver. You will have as much charcoal left as you would a retort and it will be more consistent. It's totally the best way -no open fires, no fuel and it's faster especially with pet bedding.

[Boophoenix]

You answered it right there Brad. The glow indicates you are most certainly getting to much airflow. You should have very little heat toward the lower part. With sticks or cuts it will preforma little differently than most of us who've mainly cooked shavings. The flame should still slowly work it's way towards the inlet air and cooking the material as it does.

 

I've witnessed a cook of 6" plus material in TLUD the same rules apply when your flame starts to cut out you've burned of most of the volotilities, but you want some of those to remain. So long as it cooks you just about can't go wrong with under intake I wouldn't think. So I'd start there and increase inlet holes slightly on the next go around if ya need to. I used a small flat screw driver for mine which gave nice thin slits for inlet air.

 

Your yield will vary it's gone all directions from various reports of the different methods since I've been following cooking processes for a few years now.

 

If you can pictures are wonderful. They help,others who are considering a build. Plus I find them really neat to see what others are using and the reports from them. I've been planning some research into this for a while. Hopefully I can get it off the ground before to long.

[lloyd]

It's a good word, Patrick! It aptly applies to many processes I don't fully understand!

 

Lloyd

[Nessalco]

For me, more from a TLUD. It's quite difficult to get a retort JUST at the right temp, while a properly-tuned TLUD does it automagically.

 

Lloyd

My experience has been just the opposite. Cooking sumac I end up with 6-7% more yield using a retort.

 

Kevin

[starxplor]

Given 'proper' conditions in both cases, the TLUD would have lower yield because some of the input is used as the fuel, while the retort uses external fuel.

[lloyd]

If that were all that mattered, it might be true.

 

But a TLUD is quite efficient, burning mostly the wood gasses evolved, but VERY little of the fiber. It's the self-controlling aspect of the TLUD that makes its average yield larger than a retort's for most practitioners.

 

That, and this one other thing... you seem to imply that the external fuel is not part of the "losses".

 

SOMEBODY had to cut, stack, dry, and split all that fire fuel! <grin> And, I'll bet that the 'open fire' nature of the retort method consumes more fuel than does a TLUD.

 

Lloyd

Edited February 3, 2017 by lloyd

[MrB]

For what it's worth, it's a bit of semantics. If you compare whats in the retort, and whats in the TLUD, the retort "should" give a higher yield. But as Lloyd pointed out, if you count the fuel used to heat the retort, you get a different result. I for one have only tried a few experiments with the TLUD, and will retain my retort cooker. I have, rather arbitrarily, decided that the idea of less ash in the end product is pleasing to me, and the way i'm set up, it's pretty much without user input once lit in my retort. Sometimes i do feel silly for using store bought charcoal to make my own, charcoal, but it passes quickly.

B!

[Arthur]

Make your TLUD burner with less air -fewer/smaller holes it's easier to punch another hole than to close a hole off.

 

The fastest charcoal I've ever used was the reject material from an artist's charcoal cooking factory. All cooked in an electric kiln, all under 10mm dia and all broken too small for them to sell to art shops.

[braddsn]

Ok so, I ditched the old TLUD bucket (5 gal), and made a new one. I used half as many holes, and the holes were half the size. I have done 5 cooks in it so far. Now instead of flames shooting out of the stack, and the bucket glowing orange, it cooks slow and the fire is "tame". With the old bucket, the cook was done in 15 minutes. With this one, it takes about 45. It works GREAT! I am getting large yields now, I am digging it. I could beat myself for using retorts over a fire for the past 3 years. The biggest downside to the retorts is like Lloyd mentioned... it took quite a bit of labor and time to get a nice fire going, I always dreaded dragging everything out. I would have to cut slabs off of the sawmill, stack them, and get the fire going. This in itself would take an hour or more, then another 2-3 hours to cook. The TLUD is a flat 45 minutes and I am done, and I don't have to build a fire. It is every bit of 5 times more efficient. I just have 1 small problem, but it's barely worth mentioning. When I pull the charcoal out, there are still 2 or 3 chunks of cedar that are barely cooked. They are black around the edges, but are un-scathed otherwise.. still nice and red like when I put them in the bucket. For the cooks I have been doing in the new bucket, I am using a strip of masking tape down the side of the bucket. When the tape burns down to the bottom of the bucket, I give it another 5 mins or so, then dump the charcoal into a pot and put a lid on it.. airtight. I assume maybe I should start adding 5 minutes per cook in increments until I finally have a perfect batch, note the time, then cook every batch for that amount of time? Also, a fellow pyro mentioned to me that Yellow Poplar is as fast, if not faster than Eastern Red Cedar for charcoal... have any of you used Poplar? With my sawmill business, Cedar is much harder to come by than Poplar. I always have tons of Poplar laying around. Thanks for the guidance on the TLUD, I am loving it.

[Arthur]

If it's cooked to "soft and crumbly" it's well charcoaled. If it's still timber tough you can always cook it again next time.

[Boophoenix]

+1 Arthur

 

If it's cooking good don't mess with it. Grind a little with the noticeable uncooked pieces removed. This will waste some material unless ya don't mind drying it back out. Dampen the grinding like you are going to granulate a comp. any uncooked portions will show there true colors as the fines start to stick to each other. It may require a touch of binder.

 

The hint of uncooked gives the hint you are not over cooking possibly right near optimum volotilities is how I would consider it. Classifying after cookeding and t eying the dampening of only the +10 or +20 material will tell you a lot.

 

Did you let it burn out? That's a good indicator that it is done or very very close. If you have a void in your vent holes this may be where the uncooked portion is coming from. Sounds like you're really really close to the sweet spot.

 

The only negative I can think of to a TLUD is ya need fairly dry source material.

[JOPETES]

Ok so, I ditched the old TLUD bucket (5 gal), and made a new one. I used half as many holes, and the holes were half the size. I have done 5 cooks in it so far. Now instead of flames shooting out of the stack, and the bucket glowing orange, it cooks slow and the fire is "tame". With the old bucket, the cook was done in 15 minutes. With this one, it takes about 45. It works GREAT! I am getting large yields now, I am digging it. I could beat myself for using retorts over a fire for the past 3 years. The biggest downside to the retorts is like Lloyd mentioned... it took quite a bit of labor and time to get a nice fire going, I always dreaded dragging everything out. I would have to cut slabs off of the sawmill, stack them, and get the fire going. This in itself would take an hour or more, then another 2-3 hours to cook. The TLUD is a flat 45 minutes and I am done, and I don't have to build a fire. It is every bit of 5 times more efficient. I just have 1 small problem, but it's barely worth mentioning. When I pull the charcoal out, there are still 2 or 3 chunks of cedar that are barely cooked. They are black around the edges, but are un-scathed otherwise.. still nice and red like when I put them in the bucket. For the cooks I have been doing in the new bucket, I am using a strip of masking tape down the side of the bucket. When the tape burns down to the bottom of the bucket, I give it another 5 mins or so, then dump the charcoal into a pot and put a lid on it.. airtight. I assume maybe I should start adding 5 minutes per cook in increments until I finally have a perfect batch, note the time, then cook every batch for that amount of time? Also, a fellow pyro mentioned to me that Yellow Poplar is as fast, if not faster than Eastern Red Cedar for charcoal... have any of you used Poplar? With my sawmill business, Cedar is much harder to come by than Poplar. I always have tons of Poplar laying around. Thanks for the guidance on the TLUD, I am loving it.

Hi, friend Brad. Here in Spain most of the pyrotechnic factories use alamo charcoal or poplar which is the same for making elevation powder and final layer of priming in colored stars. Alamo charcoal is a light wood charcoal such as willow, raft, maple and others .., are trees of fast growing trees, that is why they provide a very fast and powerful black powder. I have used the commercial for pyrotechnic factories and I have also made it myself with alamos growing next to a river near my house, they are hybrid alamos, that is, a mixture of black alamo and American alamo. Always use thin and very dry branches to make vegetable charcoal. I can assure you that this type of carbon is phenomenal very similar to willow.

 

I want to see more videos of you from air shell tests.Sometimes the forum becomes boring, many words and conversations but little action, je, je ,,,, excuse me, I do not want to offend anyone of this forum.

 

Joseph

[OldMarine]

Pretty sure Alamo trees are what we call cottonwood trees here.

Jopetes, your input is always welcome!

[braddsn]

Thanks Jose! I will certainly give Poplar a try, as well as Cottonwood. I have both of those trees in my area. I have been rolling stars and getting ready to mass produce some shells. I have tested a few, but more tests will be in the near future. Here are a couple recent tests that I used to make sure I have 100% star ignition, and shell altitude. These are just 3" shells, I will have 4, 5, and 6 inch test videos soon.

 

Here are 2 peonies, red and green.

 

https://youtu.be/19_owFBl9LQ?t=2s

 

Edited February 6, 2017 by braddsn

[Wiley]

Beautiful! Can't wait to see the bigger shells!

 

PM sent.

[braddsn]

Thanks Wiley. Yeah I will have some color changing stars and more interesting stuff with the 4" and up shells. Videos coming soon.