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Double Barrel Blending Roaster
Are you some wizard of metal bending? Magneto? Flipping awesome! My hat is off to you my friend!!!

Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
Nice work! Be careful, you'll be getting orders soon!

Hey, If I didn't want people to copy my roaster, or obtain inspiration from it, I wouldn't have posted so many pictures of it! I have 1/4" standoffs and the control box has a metal cover. The bottom and sides of the heater box are insulated with 1/4" ceramic felt and lined with aluminum flashing. I've had no control box heat issues in the four years I've been using it.

For my roaster I just vacuum out the chaff and drum each time since I also need to vacuum off the cooling tray and surrounding area.
Thats some really great work on those boxes! Not easy stuff to work with especially with a modded break
Honey badger 1k, Bunn LPG-2E, Technivorm, Cimbali Max Hybrid, Vibiemme Double Domo V3
Thanks Guys!

Considering the tools at my disposal, the results are fantastic.
For kicks, Here's my "modified" HF bending brake:

Test bends revealed 1/4" of flex on the hinged portion. So I welded on some 1" square stock to reinforce it. Shortly afterwards the "stock" handles bent + broke. More square stock was welded on as handles. Then the clamp down part started to flex, So 1/4 by 3" flat-bar was used in it's place. Next time...I'll just build my own.

Dan, I'm all about "open source" too.
At this stage things are moving slowly. I'll put in a two hour shift with very little to show for it.
The fit-and-finish stuff takes forever. It looks awesome though. Kind of a hybrid between qajariaq and Dan's roasters.

I'm currently working on the driveshaft coupler for the small drums. Something that can thermally isolate the motor, support the drum, reduce vibration, and self align - would be ideal. The shaft coupler will be made of solid aluminium round stock center bored, with set screws drilled and tapped for the motor and drum shafts.

Here's my experimental shaft coupler:

The high-temp rubber gasket material has all the right qualities. On a previous test adhering two bolts end-to-end, it required a lot of torque to break the bond. Much more torque than the small drums will ever encounter. I'll put it through a battery of tests tomorrow morning.
The shaft coupler took a beating. It should work fine.

Just finished installing some bronze bushings:

Decided to mount them inside the shell.

Did away with the third box that the drums mounted to. Now it's a more like the lid of a shoebox.. It overlaps the element box, which allows for better sealing of the air gaps. It's also sloped upwards at the front for more bean capacity in the drums.

I'm really happy with how it's coming together.
Very nice! You make me want to build another roaster! The sloping is a good idea. Mine isn't. After a while I put some blocks under the table. The sloping permits greater loading of the drum. The large snout limits the amount of beans they can hold.
Looking great!!
Honey badger 1k, Bunn LPG-2E, Technivorm, Cimbali Max Hybrid, Vibiemme Double Domo V3
I'm a sucker for shiny metal! Very nice. -Scott
This one is exciting!
No oil on my beans...
It's looking really nice. Which option did you choose for the drums?

Thanks a bunch! Glad you folks like it.

John - I went with the film canisters with the martini shaker lids:

1/4" square aluminium stock holds the halves together plus mixes the beans.

Here's a look inside the shell where the drums will mount:

After many iterations of wooden legs - I defaulted to 1" galv. angle rod:

Not very elegant - but its sturdy, and minimalist. That's the goal.
That's a fine roaster build! You are setting the bar very high for the rest of us yokels!
+ 1 on Dan's praise! This is exceptional and it really makes me want to unpack my roaster stuff and start building a new one. :@

1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
Thanks Guys.
I hope that somebody will take what I'm doing and make it better. Keep the cycle going.

Getting sleepy now, the photos can do most of the talking:

From here, things should come together quickly. I'll begin cannibalising parts from the old roaster tomorrow. That leaves me without a roaster. By all accounts, 2 pounds of beans should support my caffeine needs till it's done. Maybe 3.

You are moving along nicely! The three motors in a row are impressive. To me, it looks like your ceramic heating element holders are spaced too far apart. When the nichrome heats up it expands and becomes weak, so it slumps. If it touches the bottom plate it'll arc and burn out. Morelectric doesn't have the perfect ceramic holder. I made mine from their round bushings. I used stainless wire to connect two, one as a bushing for the heater, the other as a riser to create a standoff. You could insert a standoff between each of your corner holders. You might need two risers to match your heating element height.
Thanks Dan... maybe "Sensei Dan" is more appropriate. Your guidance is much appreciated.
I share the same concern about the droopy coil. I just ordered some ceramic rings. For now I I'll install a couple more standoffs between the longer runs. Which can be re-used with the rings once they arrive.

Next on the to-do list is the thermocouple probes. Originally I wanted to install one in a similar location to Dan's in the photo above. That location is great if the drums are all skinned the same. In my case the large drum is skinned in stainless mesh, and the small are nearly solid. For a given "E" temp - I think the temperature the beans experience will be significantly different when using the one drum vs the other. So two different locations for temperature readings are needed. The large drum can have a thermoprobe in the 3 or 9 o-clock position and set 1/2" away from it. The small ones should have a probe inside the drum near the top.

Here's the bent 1/4" OD aluminium thermoprobe for the small drum:

That should give a better reading of the "E" temp the beans are actually exposed to without being too close to the bean mass (relative). If it fails miserably at giving a good "E" reading it can be used as a bean temp probe instead.

I hope this doesn't cause too many problems for the PID controller. When using the large drum the response time will be faster than small ones. Hopefully not too much of a difference or there will be overshoot undershoot problems. Setting the damping factor somewhere in the middle should work. With the user (me) making adjustments to compensate.
Wired up the motors.

I put some beans in them and gave em a whirl:

The audio is especially loud. It sounds nothing like that in person, I only hear the beans tumbling in the drums.
Wonderful! Can't wait to hear if it actually works. :) You've solved the "melt the motor cable on the heater box while dumping" problem using those spring strain reliefs. One end of those coiled cables disconnects to permit switching to the large drum, right?

What I did on mine was install a stationary plug and socket for the motor power. When I tilt the drum power is disconnected. No cable at all.

That's not romex on the heater box is it!? While we can do whatever we want on homebuilt machines, romex is not rated for unprotected applications. I'd put in 1/2" conduit (you have the right size holes already) and stuff it with high temperature wire from MorElectric.
Just looking at this great machine with the fine craftsmanship has me thinking. We need to have a new roaster of the year competition. Great machine, now I want too see smoke coming out and some of the shine turn dark, think it will roast great.
All you need in life is ignorance and confidence, and then success is sure. Mark Twain
Wow Ringo. That's quite the compliment. Thanks.

Sensei Dan,


Wonderful! Can't wait to hear if it actually works. :)

Blasphemy! Have you no faith?

Here is a pic of the connections:

The motor wire connectors are Type N from RS. The female socket is for a panel mount, It had to be isolated from the shell with a rubber grommet to prevent grounding issues.

The heater wire is teflon coated 12ga with a silicone impregnated fibreglass sheath. Metal flex conduit will house it during final assembly.

The problem solving has been incredibly fun. It beats the normally mundane idle time thoughts.
Nah, I'm not blasphemous, just pragmatic. It's my preferred belief system. ;) I put my faith/proof in the pudding.

Aha! The wire only looks like romex, but is the real deal. I might have known you'd do it up right.
Gotcha Dan. I aim to please in both aesthetics and function.

Wired up all the innards. Then ran this little test:
Warning: Very Boring Video You will lose 10,000 brain cells guaranteed.

The test was a ramp from 300f to 450f. In reality 420f should be the stopping point.
That would be around the 4 min mark. I call that a success considering the only thing that's insulated/sealed/double-walled is the heater box. The rest has lots of air gaps.

Nearly there.

Aah, Ain't that cute! The 16 minute roast proves the concept.

That's gotta be the quickest big build ever at HR! Hey, you could have shown your face!

I would have started the the cooler fan earlier, then agitated while cooling. I like rapid cooling.

So, how much per unit!?
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