A question of smell

[joe]

OK, here is something that eludes me. I have 2 printers running the exact same roll of ABS (not at the same time).

My smaller printer with a cheap but super reliable MK8 direct drive extruder/Hotend sits at my desk and has almost no ABS smell while printing @235C. It's barely noticeable.

My second larger printer using a Prometheus hotend with bowden tube @235C smells of ABS so strongly it is sickening and has to be in another room.

I have verified with a temp probe that both hotends are the at 235c. It is the very same roll used on both machines. Other rolls of ABS act the same.

Anyone have any ideas? I have some large ABS prints to do on the bigger machine but my stomach can't even enter the room after 1/2 hour.

[Qdeathstar]

Hi. Nothing worse than a gassy printer. I had an issue similar to yours. What you need to do is get some beano drops and pour them down the bowden tube. The entire bottle. It's amazing how well it works.

[img]https://cdn.fsastore.com/ProductImages/large/10449.jpg[/img]

[barry99705]

Hi. Nothing worse than a gassy printer. I had an issue similar to yours. What you need to do is get some beano drops and pour them down the bowden tube. The entire bottle. It's amazing how well it works.

[img]https://cdn.fsastore.com/ProductImages/large/10449.jpg[/img]

Hahahahahaha!

Sorry Joe, but that was funny!

Are both nozzels clean? Could be one has crap on it slowly burning off.

[mhackney]

My hypothesis is the Prometheus stinks.

But really, the only thing that could cause a smell is melt temperature OR the length of the melt zone and it's ability to outgas to the atmosphere. I suspect that even though you measured the same temp, it probably isn't. What kind of probe are you using?

You could try elevating the temp by 10° on the small printer and see if it stinks or reduce the temp on the big one.

[joe]

My hypothesis is the Prometheus stinks.

But really, the only thing that could cause a smell is melt temperature OR the length of the melt zone and it's ability to outgas to the atmosphere. I suspect that even though you measured the same temp, it probably isn't. What kind of probe are you using?

You could try elevating the temp by 10° on the small printer and see if it stinks or reduce the temp on the big one.

I have systematically adjusted temperatures 5° at a time with no difference. I use a probe off my multi-meter for measuring the temp just at the opening to the nozzle. I think the Prometheus does stink!

Are both nozzels clean? Could be one has crap on it slowly burning off.

Yes, clean nozzles. The small printer actually had more debris.

Thanks for replies.

[Xenocrates]

Is it possible that there's junk stuck inside the Prometheus nozzle (Since it's so long), or that it's not sealing well against the filament or bowden tube? One assumes that the ABS smell comes primarily from heated ABS, so unless there's a serious difference of bed temperature (or airflow, which we try to reduce for ABS), the inside of the hotend is the best candidate, which since the Prometheus is sealed from the tip to the heatsink, being a single part, you would assume it would be less of a problem (unless somehow the airflow acts as a siphon feed for the smell, sorta like an airbrush). I might also check the grub screws on the heatsink, and add some loctite/teflon tape to see if the added sealing helps.

[mhackney]

Very interesting indeed. A new friend I visited recently in Calgary had a beautiful spool of amber PLA sitting on his shelf. I commented and he said "it sticks, it's yours if you want it" I jumped on it, I have a thing for translucent amber it seems. I brought it home and it prints beautifully and odorlessly!

[knabo]

Are the printers in the same room? Same airflow? printing ABS does create fumes but usually not so precisely directed that you smell it all the time.

The more important detail is about the print quality. If the print quality is good, then add some ventilation to remove fumes. If there are quality issues, then... well you know where I am going.