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CoffeeAir II Roaster Build
seedlings
I have been on a bumbling mission to build an air roaster (in the spirit of Sivetz or RoasterRob) for pennies on the dollar. My first attempt showed some promise, but I couldn't bring it all together. This time? Who knows.

GOALS
2# capacity - bonus if it can roast as little as 1/2 pound.
Built-in cooling
Vented to outdoors
Electric - yes, electric
Easy to load/unload
Quiet enough to hear cracks
Ability to view beans
Cheap, cheap, cheap
Easy, easy, easy

GUTS
Air pressure source: Aluminum Kirby vacuum motor ($10)
Manual Air Control: Harbor Freight Router Speed Control ($10)
Heat source: Two HG-751b Master Appliance heatgun elements (14.5A each) ($10/pair)
Auto Heat Control: Fuji PVX3 Temperature Controller, 50A SSR, K-type TC ($50)
Viewing Glass: Safety glass from Halogen shop lamp ($10)
Ventilation: Fasco fireplace squirrel cage fan 180cfm ($30)

DESIGN
Working on that

MATERIALS
Cement Board
Aluminum Flashing
High-Temp silicone

With all the guts in my possession, it's time to figure out a design. This is the very general idea:
i206.photobucket.com/albums/bb54/seedlings/13concept.jpg

One reason for the squarish design is to be able to mount a viewing glass, another reason is my noted lack of fabrication skills. I have yet to decide if the hopper will be removable for loading/unloading, or permanent with a load chute and unload chute. The sides will be made from cement board, the interior lined in aluminum flashing. Above the hopper will be the Fasco fan blowing the smoke/chaff outside.

My first concern is that the beans might 'need' a conductive hopper to help retain heat.

Now, to find spare time.
CHAD
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
jlyon10
Good Luck

Jim Lyon
Jim's Coffee Beans
 
JETROASTER
Looks like fun!
I'm in the vacuum business. If that motor doesn't give you the results you want, let me know.
You could well ventilate a closed system with just the one blower.
Looking forward to your updates, Scott
 
seedlings

Quote

freshbeans wrote:
Looks like fun!
I'm in the vacuum business. If that motor doesn't give you the results you want, let me know.
You could well ventilate a closed system with just the one blower.
Looking forward to your updates, Scott


There may not be a complete seal between the top of the hopper and the bottom of the ventilation contraption, which may make the 1 blower not possible. BUT, thanks for bringing that up now since I can design it in.

CHAD
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
seedlings
I'd like to employ something like this to unload the beans. What do you think about the weight of 2# of beans and the pressure in the hopper? There won't necessarily be much weight from the beans, but probably need a lot of weight to hold the door closed during operation because of the pressure.

i206.photobucket.com/albums/bb54/seedlings/13loadunloadx.jpg

CHAD
Edited by seedlings on 04/30/2010 1:43 PM
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
JETROASTER
If I may pry a bit... what sort of tools do you have at your disposal?
Re-purposing some common items will require less raw fabrication.
I have a design logic in mind that has already worked.
(with propane) -Scott
 
seedlings

Quote

freshbeans wrote:
If I may pry a bit... what sort of tools do you have at your disposal?
Re-purposing some common items will require less raw fabrication.
I have a design logic in mind that has already worked.
(with propane) -Scott


Just the very basics... jigsaw, circular saw, drill, manual rivet gun, screwdrivers, pliers. No table saw, no drill press, no lathe, no welder.

CHAD
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
Unta

Quote

seedlings wrote:
I'd like to employ something like this to unload the beans. What do you think about the weight of 2# of beans and the pressure in the hopper? There won't necessarily be much weight from the beans, but probably need a lot of weight to hold the door closed during operation because of the pressure.




I think a latch would be successfull.At that point the weight of the roasted beans would be a benefit opening the door after the latch is released.
Edited by Unta on 05/01/2010 6:42 AM
Sean Harrington
educate.
 
Unta
heres my take..The hinge would have to be worked out and so would the latch.The section between the perf plat and the VC could be smaller, depending on the size of the elements. OH and for scale the pyrex tube is 15" tall, neglected to annotate height. ;) VC motor not to scale!
A link to a larger version of thebelow picture.
http://www.facebo...1576066216
Unta attached the following image:
ultra_bright_2lb_roaster_compressed.jpg

Edited by Unta on 05/01/2010 8:33 AM
Sean Harrington
educate.
 
JETROASTER
Release door; Hinge at bottom, opens inward.
As the door is pressed inward, existing airflow (from perf plate)assists in evacuating the RC up and over your door.
During roasting, bean weight assists in keeping door shut.

Tools: A dremel will be money well spent.
Looks like fun! Scott
 
Unta
it would have to be a pretty small door to open inward..I think you would also have some trapped beans. unless im not understadning. Pictures are worth a thousand words..smile
Sean Harrington
educate.
 
seedlings
Oh yeah, I do have a dremel.

I understand what you're saying Scott, but thought about "trapping beans" like Sean said. Sivetz uses a 'guillotine' sliding damper and most beans dump out, then they use a tool to scrape the rest out. (clip courtesy of opus).


I also thought about rotating the door open/closed - maybe with a channel to keep it closed tight.

CHAD
Edited by seedlings on 05/01/2010 12:54 PM
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
JETROASTER
Size and shape are an issue. It has to be shaped to act as an airfoil.
I skipped the dump door thing... seems more trouble than its worth. I did use vacuum evacuation in years ago.
Currently use a 5lb. pump and dump. (removable RC)
Roast it, cool it , dump it ,reload it.
At 2 lbs, it's worth considering . Scott
 
seedlings
If the roaster has a removable hopper, then it will be difficult to ventilate properly. I'd like to have the roaster fixed, with a chaff cyclone, vented outdoors, and probably partial recirculation. With all that it makes the hopper tough to move in/out... unless it slides straight in the front... hmmm... Then I'll probably drop it and break the glass.

Lots of variables.

Thanks for the input everyone, it helps to have different angles of thought.

Scott, could you post some pictures of your roaster (in a dedicated thread)?
CHAD
Edited by seedlings on 05/01/2010 1:04 PM
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
Unta

Quote

seedlings wrote:
Oh yeah, I do have a dremel.

I understand what you're saying Scott, but thought about "trapping beans" like Sean said. Sivetz uses a 'guillotine' sliding damper and most beans dump out, then they use a tool to scrape the rest out. (clip courtesy of opus).


I also thought about rotating the door open/closed - maybe with a channel to keep it closed tight.

CHAD



Blast gate might work also,though i was thinking that it might be harder to build then the hinge..
Sean Harrington
educate.
 
JETROASTER
I'll get crackin' on some photos. -Scott
 
endlesscycles
The bubble bed design might be best for recirculated heat, as the temp can be lower.

btw: just launch the beans out. You know that will work. This can be done.
-Marshall Hance
Asheville, NC
 
Koffee Kosmo
Did you have a look at the post I put up
http://forum.home...post_20826

Have a play with the interactive section for a Fluid Bed roaster
Keep adding beans and see the reaction

KK
Edited by Koffee Kosmo on 05/01/2010 6:58 PM
I home roast and I like it. Designer of the KKTO
Roaster Build information
https://homeroast...ad_id=1142

https://docs.goog...lide=id.i0
Blog - http://koffeekosm...gspot.com/

Bezzera Strega, Mazzer Robur Grinder, Pullman Tamper Convex,
(KKTO) Turbo Oven Home Roaster.
 
seedlings
KK, that's a great presentation. We had a long thread some time back talking about probat's bowl roaster, and that presentation came up. I have yet to taste a drum roast that I preferred to an air roast, but I'm willing to be impressed.

CHAD
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
seedlings
Found out today that our scrap yard doesn't sell scrap any more... But I bought a length of 4" square steel tubing from a local metal fabricator, then enlisted a coworker (who thinks cutting and welding is fun to do in his spare time) and gave him some general instructions to what I wanted. I'll be excited to see what he comes up with.

CHAD
Edited by seedlings on 05/03/2010 2:12 PM
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
seedlings
Here are a few pictures... I had to get the square peg (heat tube) to fit the round hole (blower outlet).

i206.photobucket.com/albums/bb54/seedlings/13coffeeairii51.jpg
i206.photobucket.com/albums/bb54/seedlings/13coffeiarii52.jpg
i206.photobucket.com/albums/bb54/seedlings/13coffeeairii53.jpg
i206.photobucket.com/albums/bb54/seedlings/13coffeeairii54.jpg
i206.photobucket.com/albums/bb54/seedlings/13coffeeairii55.jpg

The elements will fit in this tube, and each element came with 2 sheets of mica:
i206.photobucket.com/albums/bb54/seedlings/13coffeeairii56.jpg

I'm waiting to get the hopper back from a coworker doing some welding. Once the hopper is here, I will jigsaw puzzle some contraption together to join the heat tube to the hopper.

CHAD
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
JETROASTER
Hi Chad,
This looks like a fun one. If that Kirby is old enough to have a metal fan, it could handle a small amount of recirc.
Most of those also had a high speed option built into the safety switch(front of fan housing).
Looking forward to your progress. Scott
 
seedlings

Quote

freshbeans wrote:
Hi Chad,
This looks like a fun one. If that Kirby is old enough to have a metal fan, it could handle a small amount of recirc.
Most of those also had a high speed option built into the safety switch(front of fan housing).
Looking forward to your progress. Scott


My previous attempt included recirculation, but I didn't have enough electric heat. I hoped to roast 2 pounds with 1800W element + recirculation. After reading more, I think my air-to-nichrome heat transfer was grossly inefficient. I did keep the recirc temps around 200F and the kirby just kept going. It really is a beast. There's even a heatslinger between the motor and the fan.

http://forum.home...post_10094

CHAD
Edited by seedlings on 05/05/2010 10:44 AM
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
JETROASTER
Yup, that's good ol' fashioned American quality.
Rebuilding all these vacuum motors is just part of the daily grind for me. If you need parts, drop a line. Scott
 
bvwelch
CHAD - way to go! we're watching this project closely! I love the idea of using cement board too.

Possibly stupid idea-- connect a hose or some such to move the noisy motor further away from the entire setup?
 
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