So with my specific setup and needs, I found the 6" fan and filter box to be unnecessary and a financial burden.
I have a roasting “business” and I’ve roasted on the bullet weekly with few exceptions since July of 2022. Probably average 3kg (hence the quotes around “business”) with an outlier of a 50kg order for a business gift basket.
I found that it would be cheaper to just run the fan until it breaks than continually replace the filters.
I recently moved my roaster closer to a window, so my bullet to outside distance is maybe 3ft. I downsized to a 4" viviosun fan and have not had an issue*. I’ve been running the 4" fan for a couple of months now without a filter without a problem. But I also have a replacement fan ready to drop in.
YMMV.
*When I drop the beans I get a puff of smoke as the cooling tray fan briefly redirects the smoke back out of the vent intake. This did not happen with the 6" fan.
Awesome, interesting. Ill be about the same distance from a window ~3 ft. Good to know about the cost of the filters in the long run, that also seems like an issue of scale “down the road” as you do more roasts etc. I saw one post where someone place some kind of “filter” over the exhaust tube ingress, which looked a “good” economical solution. Thank you!
Did you try other fan types before settling on the 4" viviosun, other than it’s big brother? I am currently using a chinese cyclone fan (metal fabrication rather than plastics) and it has stood the test of time with and without filters). Canberra climate so not as hot as some but def colder than others
Since I’ve picked up a ton of advice from this thread I thought I’d pitch in with my slight additions.
I’m roasting indoors, I have two 4in. ducts picking up roaster exhaust - one is connected to a 4-6in. step-down that acts as a hood and the other is connected to a 3d printed adapter and then into the Aillio cooling tray. Those two ducts go into a 4in. Y that has a short run to another 4-6in. step down to an AC Infinity Filter box then a 6in AC Infinity fan and then another short run to a 4-6in. step down and out a wall mounted dryer vent. The roasting room is completely smoke free and I am cooling 600g of roasted beans in 2 minutes.
The biggest change I’ve come up with is a metal filter screen instead of the poly filter material. I have two layers of galvanized rodent screening material tack/ soldered together perpendicularly to create a fine enough, but stiff, mesh that holds all the chaff. This slots in front of some 1/4” mesh that I’ve bent around the fan.
I could probably do without this extra layer but I wanted to be able to vacuum out the chaff between roasts and there’s so much suction going both ways that I thought it better to have the thing the chaff was against be movable but not able to get angled into the fan, and cause all the chaff to get brought into the duct.
It’s not nearly as complex and it might sound and works great.
I vent the chaff Down and Out exhaust up and out use the number 2 setting on the inline exhaust duct fan then turn it up to 4 after first crack. The chaff is collected in a screen bucket outside.
Here is my setup and venting solution in the garage. When I roast, I simply open the garage just enough to let the hose go through and up onto a platform right outside the garage so the smoke can be dispelled into the air. The AC Infinity filter box with a MERV filter does a good job in filtering the smoke.
The 6” hose and 8” register are screwed into a spare 2 x 4 I had lying around so that they are fully suspended above the exhaust and there is an air gap. There is a Y-splitter with 6” and 4” connection; the 4” goes to the cooling fan with an air gap. In the future, I’d like to order the adapter for a direct connection, but it seems to work well now.
Hello there, this looks extremely impressive. Do you mind sharing where you bought all of the materials from? My setup wasn’t that good and I got smoke all over my area (I’m roasting indoors). Any help will be highly appreciated.
How’s this setup working for you after all this time?
I have the same setup in mind (actually ordered the Bror cart before I even saw this). But I’m wondering if 4" flexible duct would be sufficient instead of 6".
Hi there,
To be honest with you, I haven’t tried it yet as I just installed the 3d print exhaust and haven’t had the chance to do it yet. Probably tomorrow or the day after. Will let you know.
I see most of you, like me, use flexible ducting and some sort of inline fan. I am wondering, how do you clean the ducting, and how often? If you could please let me know or point me to another thread that discusses this that would be very helpful - particularly those of you who roast commercially with the Bullet.
No, the only downside is mobility. I suppose I could have added a telescopic piece here, which would have extended the reach a bit, but I didn’t think of that when I made it. However, the horisontal conduit swivels around the knee in the ceiling, in a 1-meter radius, so I can move the roaster to the middle of the roasting area if I want. The ceiling, by the way, is a semi-loft where I store the coffee bags, and on the upwards side of that, the duct switches to PVC, going up and then through a wall where the ventilation and filter sits on the opposite side. Very low noise, which is really nice.
Great setup, thanks for sharing, looks quite sturdy and I’m definitely going to look into replacing my current setup. I also have a pipe going from the cooling tray and joining a Y connector into the inline fan, so I need to see how to achieve that setup with solid pipes.
) at the end of the ducting is more visible…