I am fascinated by the ingenuity shown in the various “venting” solutions created by Bullet users. We do custom engineering of systems designed to filter chaff, smoke and odor from roasters in the 5 to 500 Kg range; seeing these many solutions makes me want to come up with a “canned solution” just for Bullet.
3 Likes
This thread has been super helpful trying to come up with the best venting solution. From my reading, it sounds like the 6" affinity fan has been the “best” option for a few people. They sell a bundle on amazon that comes with the fan, ducting, and a carbon filter, found here for reference. Question for clarification hopefully someone can answer:
- Is the carbon filter that affinity sells “necessary?” Or is the inline filter box adequate? @krame your setup looks like exactly what I would like to do, curious on your thoughts on the carbon filter vs. the inline filter box…
I’ve attached a drawing, I’m very visual, of what I view as a kind of “schematic” or whatever.
Did I miss something? Would you recommend adding another feature somewhere within the schematic?
Acknowledging the ping. Running around with kids right now, I’ll have a real reply when I can sit down later this evening.
1 Like
I use the same system but with the 4" version. I’ve found the inline filter box to work well. It’s certainly more economical as the carbon filters seem likely to clog more quickly and are much more expensive from my recollection. The box filters are also cheaper and easier to find from various sources/manufacturers.
1 Like
Ok cool, good to know, thank you.
Also, the order I’ve got it arranged in is Roaster, Filter Box, Fan. This prevents the fan from becoming quickly clogged up and losing performance.
1 Like
I just realized how dumb my schematic is for having the filter after the fan, haha.
Alrighty.
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.
1 Like
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 
I haven’t. If you have what I’m thinking of, it was only $8 more for the viviosun that had 12,000 plus reasonably positive reviews.
I tried running it without a fan but that was… suboptimal.
I like the way you thought that through. 
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.
4 Likes
This is begging for an oony pizza oven!