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Larry Cotton's 'wobble disc' heat gun build
Ploni
Top  #26 Print Post
Posted on 12/12/2021 4:24 AM
Good to get your opinion, Tim.

Thanks much.
Edited by Ploni on 12/12/2021 5:51 AM
 
allenb
Top  #27 Print Post
Posted on 12/12/2021 7:52 AM
If any chaff will be able to fall onto the glass cooktop surface, you will have lots of burning/smoking chaff as it drops onto it which will obviously taint the roast if not cause flames to reach the beans. A metal bottom between the glass and sifter screen will do the same once it gets up to any temperatures hot enough to roast.
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
Ploni
Top  #28 Print Post
Posted on 12/12/2021 11:20 AM
So what's the solution?

1. Vacuum attached to the bottom portion of the roaster?
2. Metal and/or metal mesh just above the glass to catch the chaff?
3. Set the roaster on legs with a 3–5 mm. gap above the glass and a blower to push the chaff off before it can burn?
4. Start drinking instant?
Edited by Ploni on 12/12/2021 11:35 AM
 
allenb
Top  #29 Print Post
Posted on 12/12/2021 12:20 PM
Well, unfortunately, there aren't many work arounds for any roaster design where chaff will fall down onto a radiant or electric tubular heat source. All viable designs where beans are agitated on a screen have those heat sources from side or top for this reason.

Trying to blow room temperature air across the heating surface will cool the environment temp too much.

Metal mesh just above the heating surface will still cause burning chaff plus blocking of radiant heat towards beans.

Instant can cause depression and indigestion. thumbdown
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
Ploni
Top  #30 Print Post
Posted on 12/12/2021 11:49 PM
What if the blower was intermittent?
 
allenb
Top  #31 Print Post
Posted on 12/13/2021 6:01 AM
That may work as long as it is only short pulses in duration. As you know, later in the roast, there is a time where chaff is pretty constant but it may be worth a try and may work.
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
renatoa
Top  #32 Print Post
Posted on 12/13/2021 6:54 AM
What about a curved (concave) perforated metal plate, allowing the heat pass, but lead/slide the chaff outside the heater surface?
 
allenb
Top  #33 Print Post
Posted on 12/13/2021 7:30 AM
Might be worth a try but would need to be a steep cone shape or chaff would most likely just lay on all surfaces of a concave dome and not slide down to the edge without giving the roaster repeated taps.
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
zamunda
Top  #34 Print Post
Posted on 12/13/2021 11:18 AM
Hello,

Actually, I am trying to implement something similar for my pop-corn roaster:
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Ploni
Top  #35 Print Post
Posted on 12/13/2021 12:59 PM
Thanks for all the input.

Gonna have to let all this ferment awhile.

Gonna also have to get creative because the three components of Larry's Wobble Roaster (sifter, heat gun, cordless screwdriver) are not to be found here and the cost of purchasing online with shipping and taxes is outrageous.

Maybe renatoa's remark is the way to go.

And, zamunda, your chaff trap is really working well!

If I incorporated zamunda's chaff-trap design, would I have to incorporate a blower as well . . . or would the naturally rising heat push the chaff up into such a trap?
Edited by Ploni on 12/14/2021 6:27 AM
 
zamunda
Top  #36 Print Post
Posted on 12/26/2021 9:12 AM

Quote

zamunda wrote:

Hello,

Actually, I am trying to implement something similar for my pop-corn roaster:


Based on the above, I built this simple chaff collector which turned out to be quite effective.

I found the parts in a local shop (run by ChineseGrin):
  1. kitchen sieve
  2. food tray for dogs/cats


The chimney I had built before from an old coffee flask which fitted perfectly in the roaster. I made hole in the tray by cutting a "star" in the center with a small disc cutter, then pushing back the remaining triangles gives me an opening where I could push in the chimney. It is important to turn the tray upside down to enable it to catch the chaff.
zamunda attached the following images:
img_3075s.jpg img_3074s.jpg img_3073s.jpg screen_shot_2021-12-26_at_091842.png 550x249.jpg
Edited by zamunda on 12/26/2021 9:29 AM
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renatoa
Top  #37 Print Post
Posted on 12/26/2021 10:13 AM
Nice job !
Even better, instead a single big hole, multiple narrower radial cuts would also impede some beans jumping out in the chaff tray.

An alternative to that bowl could be a Bundt pan, having hole already opened, so no cut job required.
And higher funnel results into bigger chaff catch volume. Grin
Edited by renatoa on 12/26/2021 10:19 AM
 
zamunda
Top  #38 Print Post
Posted on 12/26/2021 11:32 AM

Quote

renatoa wrote:
An alternative to that bowl could be a Bundt pan, having hole already opened, so no cut job required.
And higher funnel results into bigger chaff catch volume. Grin

That's a good idea! I'll look whether it is available here!
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renatoa
Top  #39 Print Post
Posted on 02/04/2022 4:15 AM
A new iteration, much more compact:



Time for a small cyclone attached, for a complete solution, what do you think Grin ?
 
zamunda
Top  #40 Print Post
Posted on 02/04/2022 8:58 AM

Quote

renatoa wrote:

A new iteration, much more compact:



Time for a small cyclone attached, for a complete solution, what do you think Grin ?


Thanks, Renatoa, this looks really nice!
Yes, a chaff collector would be a easy to add...
I will make a proof-of-concept as soon as I got time and let you know!

Thanks and regards!
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renatoa
Top  #41 Print Post
Posted on 02/04/2022 9:51 AM
Use this design for inspiration Grin

https://www.aliex...18825.html

Don't look UP ! ... at the price Grin
 
DRUMTC
Top  #42 Print Post
Posted on 05/13/2023 6:34 AM

Quote

CharcoalRoaster wrote:

cool

wobble disc very innovative
I think Larrys Wobble disc would be the perfect newbie starting place under $50 to integrate and very active feedback teaching the roast progression and decision making process. Even lends itself to a bean probe simply! Larry confided in my my M12 sifter video inspired him to start he took the sifter platform to the next level!

Matt

Edited by renatoa on 05/13/2023 8:41 AM
 
renatoa
Top  #43 Print Post
Posted on 05/13/2023 9:19 AM
Not sure I get it... Are you the author of M12 roaster ?
 
Piotrkurak
Top  #44 Print Post
Posted on 05/13/2023 9:21 AM
Comments: heat gun selection is a critical component. The big old fashioned red ones output enough hot air volume to exhaust all the chaff, most cheapo ones don't. Did see an appropriate 220v powered hair dryer in a B&B in Italy.

Dry process beans have the most chaff, typically erupting at 1st crack.

With the Ryobi drill on the beaters, I can get to 1lb in mine, weight is restricted by bean size and torque to agitate. Typical roast of 200+ grams is relatively effortless but messy

Not sure about $50 usd max, the 9" stainless sifter was $35 and the heat gun was $35 also. Wood scraps and tablesaw use was free
Edited by Piotrkurak on 05/13/2023 9:28 AM
 
renatoa
Top  #45 Print Post
Posted on 07/14/2023 3:03 AM
Updates...
 
Piotrkurak
Top  #46 Print Post
Posted on 07/14/2023 10:19 AM
Larry used to complain the stock sifter beaters did not agitate the beans properly. The demo on this wobble plate doesn't show a very active agitation. Could be there is more movement at the bottom of the pile that I can't observe

It is a more attractive, finished look than the old system
 
wbbh
Top  #47 Print Post
Posted on 07/15/2023 7:48 AM
The disk follows the curvature of the flour sifter screen so the beans are moving well. I made one using his earlier design of a simple paddle screwed to a shaft. The screws loosened and the paddle became angled, scraping closely to alternating sides of the screen and it works well roasting up to one pound of coffee.

This a short video of my roaster before I replaced the tinfoil extension with sheet metal.
Edited by renatoa on 07/15/2023 7:53 AM
 
renatoa
Top  #48 Print Post
Posted on 07/15/2023 8:17 AM
I dislike taller designs, so what do you think about other approach to inject the hot air:
what if the hotgun would be placed almost horizontal, just having the hot air conduct/nose raised under an angle that led to a hot air stream path tangential to inner walls of the roast chamber, thus forming a vortex...
Could this hot air pattern bring any roasting benefit, other than a shorter build ?
 
Spyderman24-7
Top  #49 Print Post
Posted on 07/16/2023 4:49 AM

Quote

Piotrkurak wrote:

Larry used to complain the stock sifter beaters did not agitate the beans properly. The demo on this wobble plate doesn't show a very active agitation. Could be there is more movement at the bottom of the pile that I can't observe

It is a more attractive, finished look than the old system


That clearly depends on the type of sifter used... I've tried various 8 cup designs and one in particular gives perfect sweeping agitation with no binding, etc. I've been using the same sifter type for over 7 yrs now and well over 1,000 batches with no issues to be honest. Have yet to see the need to bend/redesign the arms.

Wonder how long he has been using the 'funnel' for the heat gun as when I first built mine seeing all others having an open bottom the first thing that came to my mind was to use a metal canning funnel. That definitely helps prevent hot/cold spots from incoming wind no doubt and helps to evenly distribute the heat/airflow.
 
renatoa
Top  #50 Print Post
Posted on 07/16/2023 7:24 AM
A picture or link to that sifter/cup you praise ?
 
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