that’s awesome
Sweet Marias does carry this.
I bought one from them in June of 2022.
The complete assembly.
I have the adapters modeled up and am getting ready to 3d print the adaptor that attaches to the trapezoid opening.
I will use tubing to go from the two tubes that are shown to the mini cyclone.
The only modifications will be to the extra chaff collector. There will be no modifications to the main part of the Bullet.
I will be able to remove that hackenstein chaff collector and put back the OEM chaff collector in seconds if I need to.
Things I don’t know yet:
If the 3d printed funnel adaptor will stand up to the heat.
If it doesn’t, I will print a 3d mold of the funnel adapter and then use a high temp epoxy to fill the cavity of the mold.
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i just ran my first test with some Natural beans from Columbia. I wanted to use a bean with high chaff output. I have roasted these beans many times before.
Here is a photo of the first real prototype:
I was pretty pleased with how everything fit together and thought that this was going to be a good solution.
It is not a good solution.
I ran a recipe that I had and added higher fan speeds as the roast progressed.
I was not expecting the results that I got.
Preheat was normal.
Charged at 375 IBTS.
I noticed that there was a lot of condensation in the tube and chaff collection jar even before I got to yellowing stage.
When I got to yellowing stage (331F), I was getting a lot of steam coming out of the fan exhaust.
I don’t remember ever seeing steam come out of my Bullet before. Smoke yes, but steam, No.
I kept bumping up the Fan speed and had my microphone in the tryer port so that I could hear fist crack.
First crack started about where I normally notice it: 393F
first crack went into rolling first crack in 30 seconds. Then second crack started and was louder than I have ever heard it before. At first, I thought that I was still in first crack. But when I checked the IBTS, I was already at 430F and a very robust roling second crack.
I dropped dark oily beans at 445F.
I tasted one, and it was not as bad as I was expecting it would be.
The funnel that I 3d printed didn’t hold up to the heat well and was starting to distort and soften.
Here is a photo of condensation in the tubing. Also you can see the jar lid that I printed that just clips in place when you press it down onto the jar.
I am thinking that maybe the steam excelerated the roasting process.
I think that I will patent this as a new process: instead of dry roasting, I will be steam roasting. (I am just kidding)
I will try another roast and start with the fan speed higher, But, I am not very hopeful at this point in time.
Edit: Very little chaff was collected in the chaff collector jar. None of the chaff escaped out of the fan exhaust.
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Thanks rtuttlejr,
My modification did not reduce the airflow to the back fan.
If anything, there is less restriction without the plastic chaff cover installed.
Regarding the condensation: I am leaning towards a lack of airflow and a venturi effect because of the reduction in the “duct” size forcing the water molecues to squeeze together and bond with each other and condense. The mini cyclone only has a 25mm (1 inch) inlet and outlet. Similar to a contrail made by a jet engine.
I’ve heard of condensation issues with the Bullet when people put an adapter on the exhaust that is sealed to the exhaust housing.
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Before seeing the condensation in this setup, I had never really paid attention to the amount of water we are removing from the beans.
With weight loss of 12 - 20 %, that is a significant amount of water.
In this case: 132g of weight loss = .over half a cup of water.
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You know, my guess is that the fan is simply not strong enough to cover the distance of the tube and still be efficient. If the fan were placed inside the cyclone collector, I think the story would be different. But that would bring a whole other set of problems. I don’t have much advice, except trying to place it on its side, so the tube going into the fan will be much shorter and not lose so much airflow covering all that intricate itinerary. Nothing else comes to mind. Good luck.
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I agree with @braca19452f9m I think the pressure drop from the tubes and the cyclone is too high to be overcome by the fan (which is a forward curved fan, not good for high pressures). There is a large pressure drop in a cyclone, so you might need more than twice the power of what the current setup can supply.
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It was an interesting experiment.
I have put this on the back shelf in my archives, but I doubt if I will ever come back to it.
I will post the new process when I get further along with it.
I am already working on a new solution and have run some tests. So far, It looks like this new process will work. I just need to run a couple of 1000g roasts consecutively to see if the 3d printed adapters can stand up to the heat.
The new process doesn’t require any permanent modifications to the Bullet with the exception of removing every other blade of the exhaust fan. Which I have already done and re-calibrated the fan. (After buying a back up fan from Sweet Marias)
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Hey @jimmybulletroaster ,
I noticed that you “liked” this thread. I was going to message you but you have your privacy turned on. (I don’t blame you for that)
Anyways: did you see my other thread about my Bullet cart mount?
Forgive me if you find this inappropriate. You seem to be interested in these hacks.
Let me know if you want me to delete this post.
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I love these hacks!
I haven’t done any yet, because I wanted to make sure my machine was functioning correctly and that I understood what to do and what NOT to do.
Perhaps I’ll mod soon. I am still waiting to hear back from tech support.
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I wanted to see if anyone has created any workarounds to get this working? I have purchase my cyclone, and I’m awaiting a better method. What about a different fan impeller geared for more power? Or a more powerful external fan controlled by the bullets PWM for the exhaust fan?
Hi Prehistoricperk,
I scrapped the mini cyclone idea and modifications and went with a DustTopper and a smaller shopvac with a speed controller.
It works very well. It is noisy when the shopvac is at full power. I normally don’t need to run it at full power.
There is a link to that thread in one of my posts above. I have everything mounted on a cart and I am only cleaning the DustTopper every other month. (maybe 50 roasts)
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Hello! Been roasting with R1V2 for a few years, with about 300 roasts on my machine. Lately I started my own online business selling the coffee I roast, so I roast about 20 pounds a week.
I have a question: Why even bother with something like this? If one is doing back to back roasts, why not just empty and/or vacuum out the filter and collector between roasts? That’s what I do, and I am done before the bullet is ready to be charged again, usually with a minute or so to spare.
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Okay, Central Kentucky Coffee,
The short answer is that I am lazy…
The longer answer is that I enjoy the engineering challenges.
Here is a link to my current setup:
I had installed a bullet camera in the filter compartment of my Bullet and tried different ways of trying to remove the chaff from the filter basket. The camera showed that the filter basket never completely released the chaff. That told me that the air flow through the Bullet was changing and my recipes couldn’t adapt to the reduced air flow. The new R2 is supposed to have flow meters to detect and adapt the airflow if it detects a reduction in airflow.
I tried different solutions: changing out the filter compartment at every roast. Sticking a vacuum up the exhaust for the filter compartment.
My current setup with the DustTopper cyclone allows me to run many roasts (months) without stopping to clean the Filter compartment or the stainless steel mesh Filter basket. I have removed the SS Filter Basket. The chaff bypasses the filter basket and goes into the DustTopper and gets trapped there.
On my opening Roast World Dashboard page. Roast World says that I have over 800 roasts and have roasted over 1,000 pounds of green beans.
Now when I do back to back roasts, after dropping the roasted beans at the end of my recipe, I just hit the “back to back” button and then start preheating for the next roast. I don’t have to stop and clean anything.
I roast a lot of Natural -high chaff- beans and can go for more than 50 roasts without stopping to clean my chaff collector bucket.
Like I said: I am lazy and have OCD. (Obsessive Coffee Disorder) lol
I could easily change over to roasting commercially, but the financial reward is not enough compared to my day job. Maybe when I retire…
A couple of friends and former neighbors have asked me to sell them some roasted coffee. I had already spoiled them by giving them leftover samples and experimental recipe results. I used to tell them to slap the inside of their elbow and say: “The first taste is free” lol
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OCD? I think there’s a lot of that going around!!! 
Me
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Your design with the shop vac is great, but I think the removing every other impellor blade is what i needed! I’ve been running without a filter and it kept getting clogged with chaff. @billc can you share the STL for your baffle? what did you print it in? I may get it cut by sendcutsend.
Here is the STL for the baffle:
https://community.roast.world/uploads/short-url/zbKiTYaaD1KLHcf506pLyUbenzO.stl
Edit: I just used PLA. but it does deform a little bit after time from the heat.
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I printed mine in PPA-CF, cause it was already loaded in my machine, if you get it done in metal, you might have to file a little bit to get it to fully fit the ribs. Mine needed a little work to fit properly.
@billc Love your work, I have done something similar, inspired by you. It’s fantastic.
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