3D printed exhaust port


#9

Annealed PLA here, works great after the annealing process. Wasn’t as hard or complicated as it sounds, and now its very heat resistant :slight_smile:


#10

It is funny how roasting coffee got me back into 3D printing. Anyway, got 10 roasts, almost 11 pounds of coffee through my adapter and although it is a little dirty, it has help up nicely. If anyone needs, always here to print for you guys and save a couple bucks!


#11

What we sometimes do is to line the inside with aluminum foil. This makes for an extra layer of protection and you can rip out the foil and replace it when it gets too dirty.


#12

The reason I didn’t want to use ASA and actually any other plastic is the low heat tolerance.
ASA technical data recommends a maximum service temp of only 95C (203F) and we all know the Bullet reaches much higher temps than this.

What irks me about this adapter part is the No Support from Aillio in getting this part printed.
The last email I received from them they actually stated they have never printed it! Go figure!
You would think that they would be on top of this, being the manufacturer and all. I have spent hours researching this part and material to use for the actual printing. The last chemical engineer I spoke with said you will be pushing the limits of any plastic at Bullet temps. I will find out how Heat Resistant Resin works, stay tuned!

Good for you that you are able to make ASA material work for your roasting, I can’t chance smoke escaping from the exhaust in my roasting situation.


#13

No doubt, no plastic will be able to hold up forever under those conditions. From everything I read ASA was able to hold form just past ABS at ~105C. Regardless, so far so good. With the model in hand, I can print one when needed. next one may be Nylon or PC. Have to see what I have in my filament bins. Still unsure why a $3k roaster doesn’t come with a $10 part, but whatevs. Best thing to do is to print a part and make a mold and cast it. Honestly, I may just do that for the next one.

keep us posted on your findings as well!


#14

There is plenty of plastics in the Bullet, also where it is in contact with the exhaust air. I agree that ABS is not the best material but it is widely available for 3D printers and relatively easy to print. If you want to try others such as nylon go ahead. SLA printers now also offer high temperature materials…
As I mentioned above you can line the inside with aluminum foil for added protection.

I don’t know who you wrote with but Aillio has printed plenty of 3D adapters so we know it works - but I don’t think we have ever printed one in metal.


#15

Many plastics can easily withstand these high temperatures. Modern cars makes extensive use of high temperature plastics on the engine etc.

The reason the bullet does not ship with the adapter is that each mold for a different size of adapter would cost in excess of 10000 USD, and we would need to invest in 3 just to satisfy a few different sizes of exhaust pipes.
Also, we think it is better to not have a direct connection to the exhaust pipe, and prefer a hood type just above the exhaust as this will not influence the airflow as much as a directly mounted exhaust pipe.


#16

On my next roast I will try to remember to take the temp of the exhaust port area. I’m sure it is very hot, but has no affect on the adapter I referenced earlier from Shapeways.

I chose them, because they stated their material was nylon, and I did not have to send them any specs or files. They already had them…and the price was right. I’ve seen no change in the looks or performance of their adapter after 78 roasts (except some bean dust). I use a 3 foot flexible pipe extended up under the hood of the kitchen exhaust fan and have had no smoke issues.


#17

Knowing the exact exhaust port temps during roasting would be good to know. I assume it would be similar to the drum temp and during my initial drum seasoning roasts the temps exceeded 450F according to the digital read out. The exhaust port must definitely hold up at these temps as a lot of smoke is generated at these temps and my nylon one did not filling my shop full of smoke. I would rather not go through that again and hopefully the heat resistant resin adapter I’m having printed will eliminate the problem.


#18

The technical data of the heat resistance of materials used in 3D printing does not support the temps created by the Bullet. Molded plastic parts are different.
My apologies, it was not your company that had never printed an exhaust adapter, it was one of your major distributors.


#19


Blue line is exhaust air temp measured near the bean chute lid, so nowhere near the drum temperature. This is during roasting and might be different during pre-heating and cooling.


#20

I printed a Stainless\Bronze exhaust adaptor for $183 USD through Scupteo. Received a fairly high number of recommendations and quotes from a variety of vendors, this was by far the most reasonable. There was a little shrinkage in the part when printed due to the Bronze sintering process. Might suggest a edited version of the adapter for better fit, starting with 1 mm increase in size. I Have some tape designed to masking and use in oven related temperatures I will be using to obtain a airtight fit on the model I had printed.


#21

13 roasts in and the ASA adapter while dirty, still looks as it did when i printed it. No smoke leakage at all when I roast. Would love a metal or molded adapter but the price is too much. If the 3D printed one ever goes, I will just print another.

keep us posted on the HT resin!


#22

3M manufactures a Fire Block Sealant FB136 tested up to 750C. It comes in a standard caulking tube. Nashuatape.com manufactures a stretch and seal self-fusing tape tested to 500F. I purchased both at Home Depot and I plan on using them to seal my exhaust port adapter.


#23

Thank you for the ideas, I will keep these in mind. The tape I was thinking of using would wrap around the square side of the adapter to make sure it naturally gets a positive seal onto the roaster ‘pipe’. The same method would be used to provide a tight fit into the exhaust tubing that vents outside. Want to use rigid pipe versus flex tubing for future venting/ filtering idea.

Anyway, the tape is very thin and stable to 400 C. I have a bunch left over from a project I was working on. It’s pricy stuff…not sure I would use this if it wasn’t laying around. It’s called Kapton. Here is a Wiki all about it https://en.wikipedia.org/wiki/Kapton


#24

I used this around the outside square of the exhaust adaptor to snug up the fit.

https://www.amazon.com/gp/product/B00HWROO7E/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1


#25

Hello all Has anyone measured how hot the exhaust gets for a average medium to Dark roast? I just printed my from abs plastic.


#26

I haven’t measured the temps, but my ABS adapter had a very short life. I’ve gone to a DIY hood setup with an exhaust fan, at the advice of Aillio. (I think it was Jacob, but I don’t recall for sure.)


#27

I’m kinda surprised by all the people that have had problems with 3D printed adapters using ABS. I used Proto Pasta’s CF (carbon fiber) PLA and it’s been on my Bullet now pretty much since I got it, no problems. I’m running a straight up 4" vent that drafts well, maybe that’s the difference?


#28

I used ABS…no problems. Annealed though…