PETG fumes/irritation?

Hi all,

so I guess we're all familiar with the smell and possibly health risks of ABS, but has anyone noticed any problems while printing PETG? I haven't done a lot of printing with PETG, but I was running an 8 hour print yesterday and noticed some unpleasant burning in the airways and possibly some head-ache/grogginess. It might just have been coincidence, but I was curious if anyone else has noticed issues with PETG?

(To confuse matters a little, this was actually a dual extrusion print with PETG and ABS, so I guess the ABS may have been contributing).

I've done quite a few 20+ hour prints with PETG on PEI and I've not smelled anything. This has been with the Hatchbox PETG and the eSun PETG and neither have produced a smell as far as I could tell.

Thanks for the feedback. I've got another print running now with a different brand of PETG (filaments.ca natural) and I'm not noticing any problems. The print yesterday was with MG chemicals red, but for all I know it may have been something completely unrelated. I'll keep an eye out during future prints.

I haven't noticed any smells with PETG, however I do notice a white coating that appears on metal parts near the nozzle after printing a lot of PETG. I assume that it's to do with PETG fumes that are condensing on the cold metal parts.

Just registered for reply to this.

Yes PETG and other nylon filaments cause eye and respiratory tract irritation due to emitting high rates of caprolactam (which is a harmful volatile organic compound).

If you want to read more about adverse effects of over exposure to ultrafine particles and volatile organic compounds i strongly recommend to you to read this article: [pubs.acs.org]

Quote from the original article:

"Acute exposure to high concentrations of caprolactam is known to be “irritating to the eyes and the respiratory tract” and “may cause effects on the central nervous system”, according to the Centers for Disease Control and Prevention (CDC)"

Hi Kerembyl,

thanks for taking the time to post, and welcome to the forum. For whatever reason, that roll of red PETG was particularly bad for causing irritation. Since finishing and moving to a roll of black from the same manufacturer I haven't noticed anything like as much of a problem. I guess it's just another example of how much variation between different filaments exists.

I'm looking forward to getting my printer enclosed and adding a re-circulating filter at some point. That will hopefully reduce the issues for all the filaments.

I am quite sure that certain colour additives produce more odour and possibly more irritation. Black ABS produces much more odour than white or transparent.

Filtration for the printer, or the room or ventilation seems to be a very sound idea. In the end I settled on a large charcoal/hepa room filtration unit which runs on a timer during and 6 hours after a print. Seems to control odour, although whether its completely effective for particulates and volatiles is unsure.

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

I have not had any issues with yellow or black PETG. However, ABS gives me a headache. Nylon 230 maybe causing me some symptoms.

"I once had a headache at the same time as a print" is not conclusive evidence....

Neither is that paper. Caprolactam on wikipedia:

Quote
Wiki:
Caprolactam is an irritant and is mildly toxic, with an LD50 of 1.1 g/kg (rat, oral). In 1991, it was included on the list of hazardous air pollutants by the U.S. Clean Air Act of 1990. It was subsequently removed from the list in 1996.[4] In water, caprolactam hydrolyzes to aminocaproic acid, which is used medicinally.

As of 2016 caprolactam had the unusual status of being the only chemical in the International Agency for Research on Cancer's lowest hazard category, Group 4: "probably not carcinogenic to humans".[5]

Currently, there is no official permissible exposure limit set for workers handling caprolactam in the United States. The recommended exposure limit is set at 1 mg/m3 over an eight-hour work shift for caprolactam dusts and vapors. The short-term exposure limit is set at 3 mg/m3 for caprolactam dusts and vapors

The paper also makes very few real life comparisons, such as the emissions caused by everyday products. It instead uses a lot of estimates to assume how it will interact within an office.... I also highly doubt if enclosing, or using charcoal filters has any effect on ultra fine particles, and I don't think we have the ability to control them at the reprap level, unless you want to install a real ventilation system to funnel fumes out of the house.

I don't think charcoal filters do anything for particles but are very effective for volatiles. I think hepa filtration is effective for particles, despite the common misconception that a particle smaller than 0.3 um can pass through, this is actually just the least efficient particle sized filtered. Smaller and larger particles are filtered.

Its what is the best implementation, that is what we're talking about. Is it a filter inside the printer, a filter outside of the printer, a filter for the room, or a full external exhaust vent system? It would be useful if someone measured typical output of volatiles and particles emitted from a desktop 3d printer. I'm fairly sure it's less than we think it is, we just smell things like abs which are pungent at very low concentrations and worry about it. I have been thinking of trying a car air filter with charcoal/hepa inside my enclosed printer.

Perhaps a more relevant question is how many hours printing do you do, what total mass of material (10 printers will be more of a challenge than one), what material, do you spend time in the same room and how much. Is there any ventilation?

Edited 1 time(s). Last edit at 04/09/2017 08:24AM by DjDemonD.

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

A healthy dose of skepticism is always a good idea

From my point of view the issue is fairly straight forward; I don't like the smell from printing abs/nylon (and sometimes petg) and I'd like to reduce it if it's practical to do so. I'm going to enclose the printer anyway to improve thermal management, and once enclosed it's relatively easy to implement a recycling filter. Carbon+hepa filter modules are readily available for face-masks and while a couple of them in parallel won't be the most effective solution imaginable it's also unlikely they can make anything worse. It certainly seems worth trying.

Edit: my claim that hepa filters are readily available for face masks may be overstated, the typical rating is p100 and I'm not sure of the level of equivalence between hepa and p100. I cheaped out anyway and bought carbon-filters from ebay, and their particulate rating probably nothing special.

Edited 1 time(s). Last edit at 04/09/2017 09:05AM by JamesK.

Quote
DjDemonD
I don't think charcoal filters do anything for particles but are very effective for volatiles. I think hepa filtration is effective for particles, despite the common misconception that a particle smaller than 0.3 um can pass through, this is actually just the least efficient particle sized filtered. Smaller and larger particles are filtered.

Its what is the best implementation, that is what we're talking about. Is it a filter inside the printer, a filter outside of the printer, a filter for the room, or a full external exhaust vent system? It would be useful if someone measured typical output of volatiles and particles emitted from a desktop 3d printer. I'm fairly sure it's less than we think it is, we just smell things like abs which are pungent at very low concentrations and worry about it. I have been thinking of trying a car air filter with charcoal/hepa inside my enclosed printer.

Perhaps a more relevant question is how many hours printing do you do, what total mass of material (10 printers will be more of a challenge than one), what material, do you spend time in the same room and how much. Is there any ventilation?

I think total time is irrelevant, if they really do pose a risk then a single printer in a room with bad ventilation could be bad. I would just like to see an objective paper that doesn't scaremonger... Most papers just state that they do release volatile compounds and give little reference to that in a wider picture. Many households products let off all sorts of fumes and carcinogens that we don't worry about.

Ventilation is not an easy subject for reprap level printing. If you exhaust it away from your enclosure, you also take the heat with it. If you use a filter in the room, chances are you sit next to your desktop printer, meaning you are still breathing in volatiles before it gets to the filter (assuming the room filter is picking up these ultra fine particles). A filter in the printer may work, it keeps the heat in but then do we have to look at the proper disposal of the filters that are now concentrated sponges of whatever they have removed?

The best system I can think of and I tried it for a time was a recirculating air flow pulling air from the top of an enclosure, through charcoal and hepa filters and then returning it to the base of the enclosure. This keeps the enclosure temperature even and quite modest filters and low airflow are sufficient to remove any noticeable odour and surely some particulates. But no evidence to offer of its effectiveness.

---

Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

I just open a window and have a fan blowing to the outside. Does a pretty good job for me. I do get an odor when printing with the eSun brand PETG, but the fan takes care of most of the problem. But with the printer on the opposite side of the room to the window, it leaves some odor behind.

As for an objective paper on the problem? We don't want that. Then all the people selling these overprice air filters for your printer would loose their ability to scare you into paying outrageous prices for the same results you can get with a cheap air filter.

I'm all for cheap air filters I'd just like to know if they're effective and how best to use them.

---

Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

If I am smelling anything when I am printing PETG... something went drastically wrong and plastic is burning on the hot end. I normally can't smell anything at all. Even with PLA, it smells sweet... almost like oatmeal.

Edited 1 time(s). Last edit at 04/10/2017 07:01AM by rich1051414.

So far as an enclosure goes.... I had so many smell issues with ABS that I couldnt stand it anymore. I made a very large external enclosure for my Kossel. It worked well on small prints. I completetly enclosed the printer. My prints looked amazing since there was no air around to cool the prints too fast and it got nice and hot inside. However, this is also how I fried my RAMPS controller. It got a little too hot inside when I printed a very large print. The enclosure plus the heat from the heatbed made it way to hot for the RAMPS board to keep cool.

So my suggestion to you if you make an enclosure is cool your electronics while keeping your printing area relatively wind free.

Edited 1 time(s). Last edit at 04/10/2017 08:08AM by DRTak.

I have a externally venting setup that I like a lot. At the top of my enclosure I have an AC powered 120mm fan running into an aluminum flexible drier vent hose. From there it runs into a draft blocking coupler that is attached to an MDF board. The MDF board is cut to fit in the open window sill, and is only about 6" wide with weather stripping on the side.

Whenever I'm printing, I slide the window open, place the MDF board in the opening, then shut the window as tight as I can. The fumes flow out of the enclosure and out the window.

I mostly print PLA, occasionally PETG, but even with PLA, stick your nose up to the exhaust and you can smell the stinkiness coming out. I'd rather be safe than sorry, plus it will be nice when I eventually try ABS.