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Dan's Direct-Flame Roaster
Dan
No, you misread something. The beans ARE FALLING THROUGH THE FLAME. Have you watched the video? What I'm trying to do is duplicate the Whitmee roaster technique on a homeroaster scale and budget.

 
allenb
Got it. I went back and watched the video again. I mistakenly thought the torch was aiming at the right side of the drum which would require the beans to arc across to that side to be in the path of the flame.

I was too lazy to go back and review previous posts. Looks good. You're certified Whitmee authentic!ThumbsUp
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
Dan
LOL! I'll be sure to stamp my machine "Allen Certified" :)

On this test model, I have to manually position the flame each time a begin a roast. I've learned that the best position is to set it level with the center of the drum and about 1" to the left of center and parallel to the drum axis.

The next model will have a three-position horizontal board resting on the baseplate under the drum. It will swing left to right on a pivot. When the board is swung all the way to the right it will bring the flame into the proper position for roasting. When swung all the way to the left centrifugal blower comes into position for cooling. When centered, there is enough room between the burner and blower to load the drum.

I think I can cool quickly in the drum using a blower because the drum is sheet metal and doesn't hold much heat, the beans will tumble past the air flow, and the rear open end of the drum allows the heated exhaust air to escape easily.

I'm working out a novel dumping idea, too. A "metal-head" fabricator buddy of mine and his wife are staying the weekend (I like to think they come just to have my coffee!). We worked out a way to tilt the drum UP, and pour the beans out the BACK drum opening instead of the front.
Edited by Dan on 11/06/2011 7:33 AM
 
Beaner
I'd like to see your video Dan but when I try the link I get eror message:
"Windows Media Player encountered a problem while playing the file."


Oh and btw, a late thanks for answering my question a while back about the DC motors in poppers.
 
Dan
I'm video deficient. YouTube wouldn't upload/convert the movie file from my digital camera, so I just put it on my server. You might need another viewer, say QuickTime, to watch it. I don't know for sure.
 
Beaner
I installed Quicktime and now I can watch the video, thanks. Just FYI, I use this free video converter to convert the Quicktime format videos that my camera produces. I convert them to .wmv format so that Windows Moviemaker doesn't act nutty when I try to edit them.

It's easy to use and was suggested on a Moviemaker forum:

http://www.freema...converter/
 
Dan
Thanks! I looked for a converter, but wasn't satisfied with what I found. I'll definitely try that!
 
Dan
Just an little update, I'm buying the collecting parts for version 2.0 of this roaster. I've been sketching ideas and coming up with some novel additions that will make roasting easier. Some of these ideas I'll test on the roaster I have now.
 
mk1
I look forward to the new mods. Once you work out the kinks I can start on mine. I appreciate your prototyping. It usually takes me 3 models to get it right. Can you hurry up?

Mark
 
Dan
Mark, Thanks for the encouragement and vote of confidence! The biggest improvement will be direct drive. That sprocket drive is just TOO noisy. I can't hear the cracks until they get rolling, and by then it is too late. So, start sourcing a gearmotor, say 30 rpm and 50 foot-pounds. And, the next time you are in Sam's Club pick up two of those 13 quart mixing bowls, but don't cut the bottoms out just yet. I'll post some construction pictures.
 
coffeeroastersclub

Quote

Dan wrote:
Mark, Thanks for the encouragement and vote of confidence! The biggest improvement will be direct drive. That sprocket drive is just TOO noisy. I can't hear the cracks until they get rolling, and by then it is too late. So, start sourcing a gearmotor, say 30 rpm and 50 foot-pounds. And, the next time you are in Sam's Club pick up two of those 13 quart mixing bowls, but don't cut the bottoms out just yet. I'll post some construction pictures.


Dan, instead of your sprocket drive have you considered high temp silicone rubber wheel drive? Remove the chain and where you have the sprocket exchange that with a high temp silicone wheel, I kind of forget how you rest the other side of the rotating globe, but a free wheeling high temp silicone wheel there also should work. If you cannot find the high temp wheels it is likely pretty easy to bond some high temp silicone sheet to a regular small wheel.

Len
"If this is coffee, please bring me some tea but if this is tea, please bring me some coffee." ~Abraham Lincoln
 
Dan
Len, That's a great idea. Drum mixers work just like you say, but with four wheels. Actually, I use RTV silicone rubber at work and if I don't already have the right hardness and heat resistance, I could get enough for wheels in a free sample. It would be easy enough to mold it around a metal hub to dog down onto a powered shaft.

Right now, the drum is supported on three points. Two are the sprockets, the other is a bearing next to the handle on the rear.

I already have the gearmotor, so I think I'll move forward with a cantilever design. However, if I think the weight is too much for the bearings on the gearmotor, I'll make some idler support wheels from silicone. They should be perfectly quiet! Thanks for sharing!
 
mk1
Dan,
I 'll run a few of my ideas past you to see if I'm missing anything. My design comes from what I have laying around and what I know I can source easily. It's a little of a hybrid between yours and the antique Belgium cast iron roaster pictured earlier in your thread. My basic goal is to roast great coffee and try to make it repeatable. Ha Ha... I've read enough to know that's not easy.
Since I'm fairly new to this I'd like to control heat (probably manually) and see and log BT and ET and hopefully infer rate of rise. I haven't figured out where the ET probe should be and probably won't until I see internal conditions.
I'm thinking of your SS bowls perforated, (mindless repetition is my forte) also because they're cheap and they'll center the beans somewhat. Internal vanes as per your design. A door for loading and unloading would be required. Next I'll weld a piece of SS pipe, 1" or 2" L X 1.5" D, to the ends over the openings. Add a big SS washer or disc to support and capture the drum on/in plain bronze bearings. To the drive end weld a chain gear to connect with chain to gear motor. This also permits some latitude on gearmotor RPM. Through the drive end opening insert the burner pipe ( modified propane jet burner) and through the other end the probes sheathed in small diameter SS pipe. I would control heat with the gas regulator.
What am I missing?

Mark
 
Dan
Mark, If I'm understanding it correctly, your drum is supported by two, hollow shafts. That will work great. Like you say, it permits entry into the drum with stationary items like the burner and TC probes.

The trick will be dumping. When 2nd crack gets started, a load of 2.5 or 5 pounds will continue cracking due to exothermics even if your burner is off. So, you'll need a quick way to dump and cool.

Hint: Perforate your bowls before you weld them together. That way you can drill from the inside and the burr will be on the outside where it is more easily removed with a little grinding disc.
 
seedlings
Dan I truly appreciate your mechanical and fabrication insight.

CHAD
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
mk1
Dan,
Thanks, you're right. I think I'll need a door, centered, to dump and cool. The de-burring of SS drilled holes I have some experience with in making cheese molds from SS bain-maries. I use my dremel with a small spherical carbide burr. It's fast and easily maneuvered.

Mark
 
mk1
Well, I've got my mixing bowls and have some other materials on the way. Gentlemen, start your drill presses!

Mark
 
Dan
Len got me thinking of molding two bogies to support the drum while roasting. So, I made this mold (upper half of picture) and filled it with medium-hard high temperature RTV. The tires are 1.5" in diameter and 0.5" wide and have a molded-in annual groove to accept ball bearings.

claycritters.com/coffee/bollinger_flame_roaster/bogies_and_mold.jpg
Edited by Dan on 11/25/2011 4:25 PM
 
coffeeroastersclub

Quote

Dan wrote:
Len got me thinking of molding two bogies to support the drum while roasting. So, I made this mold (upper half of picture) and filled it with medium-hard high temperature RTV. The tires are 1.5" in diameter and 0.5" wide and have a molded-in annual groove to accept ball bearings.

claycritters.com/coffee/bollinger_flame_roaster/bogies_and_mold.jpg


Dan, all I can say is awesome. This is what I love about homeroasters.org. You get to see some real high quality work here.

Len
"If this is coffee, please bring me some tea but if this is tea, please bring me some coffee." ~Abraham Lincoln
 
jkoll42

Quote

Dan wrote:
Len got me thinking of molding two bogies to support the drum while roasting. So, I made this mold (upper half of picture) and filled it with medium-hard high temperature RTV. The tires are 1.5" in diameter and 0.5" wide and have a molded-in annual groove to accept ball bearings.

claycritters.com/coffee/bollinger_flame_roaster/bogies_and_mold.jpg


LOVE IT!!!
-Jon
Honey badger 1k, Bunn LPG-2E, Technivorm, Cimbali Max Hybrid, Vibiemme Double Domo V3
 
JETROASTER
Nice fab!! What kind of heat can it take? -Scott
 
Dan
Thanks for the kind words everyone! Making molds and using RTV is something I've done a lot of. This platinum-cured RTV rubber is Shore A hardness 54 with a service temperature of 650? F.
 
JETROASTER
So, this is a two or three part mixture? How secure is the grip on the outer race?
Looks like pretty handy stuff to have around. -Scott
 
Dan
Two part, mix resin with hardener 10:1. Mix well, then mix again. De-air in a vacuum chanber and pour into mold. I like to de-air the mold again to eliminate all the voids.

I made the diameter of the annular groove a few thousandths smaller than the outer race so that it compresses on the race and shouldn't slip. These are idlers, so there's no torque to deal with.

This is Silicones, Inc. P-50 resin. We use their P-90 for making rubber molds. It is softer and stretchier. RTVs run about $10 per pound. We buy 200 pounds at a time. For small quantities, see Smooth-On.com. They have all sorts of silicone RTV and urethane casting resins. Plus, tons of information on how to make molds and parts.
 
allenb
I'm very jealous of your access to fab resources!:@ And I'm sure I'm not alone. A lot of us dream of this or that part to come up with our dream roaster but have to make do with something off the gourmet kitchen shop shelf. Obviously that's fun as well. Looking forward to seeing the Mark II come together!

BTW, David (dja) also posted some great resources for DIY silicone gasket making (molds, casting etc). I'm hoping it wasn't just pm's he sent me. If it was, sorry for the incorrect intel.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
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