PETG, PLA and ABS  

RE: PETG, PLA and ABS

Plastic pop bottles.

Actually, they are PET.

And now for this bit, blatantly ripped off from a filament manufacturers site:

PET (Polyethylene terephthalate)

• Higher working temperature
• More rigid
• More brittle

If you are looking to get a print out that is rather rigid, PET 3D printer filament is the right material for this occasion. It has a slightly higher working temperature compared to PETG and is rigid, much like PLA. Although prints made with PET are hard, they are prone to be broken easily. So be aware if you know that your part is going to be subjected to a considerable amount of stress as the plastic would break rather abruptly, with not much sign of plastic deformation.

PETg (Polyethylene Terephthalate Glycol)

• Has glycol added (hence the “g”)
• Slightly more flexible
• Greater impact resistance
• Absorbs more moisture (Dehydrating PETg before use is a good idea)

PETg can simply be thought of as PET with glycol added. The addition of glycol allows the material to be slightly more flexible, but not as much as TPU or TPE. Having a little more flexibility allows parts to have a greater tolerance to impact compared to PET.  Be careful of how you store your PETG as the addition of glycol means that the material absorbs more moisture. Ensure that you keep your PETg 3D printer filament in an airtight environment or dehydrate it before use.

RE: PETG, PLA and ABS

Thank you very much. I was a little shocked when a recent, VERY labor intensive LARGE multiple piece build, MELTED in the sun when painting it... it was a really shi**y experience that I never want to repeat. So I don't mind shelling out more money for PETg.

RE: PETG, PLA and ABS

As a newcomer to the wonderful 3D printing world I am a little confused about filament moisture absorbency.

After various test prints I have now adopted PET-G as my 'go-to' material.  According to the above discussion it is liable to absorb moisture.   I store reels in sealed plastic boxes with Silica Gel packs.   

What I am unsure of is how quickly it will deteriorate when exposed to air.   If I'm printing it may sit on the machine for 12 hours or more.   

I realise that it depends on the local environment.   I use my printer in a garage which is probably quite damp.  UK weather conditions prevail.  Can anyone give me some idea about how long different filaments can be left exposed before I will run into problems.

RE: PETG, PLA and ABS

Posted by: @obie-c

Thank you very much. I was a little shocked when a recent, VERY labor intensive LARGE multiple piece build, MELTED in the sun when painting it... it was a really shi**y experience that I never want to repeat. So I don't mind shelling out more money for PETg.

Paint PETg and it'll melt in the sun, too; and so will ABS and a few others.

RE: PETG, PLA and ABS

As for water absorption: best to check with the filament manufacturer because ingredients vary.  But here's one: 0.13% in 24 hours.

https://devel.lulzbot.com/filament/Rigid_Ink/PETG%20DATA%20SHEET.pdf

RE: PETG, PLA and ABS

Posted by: @tim-m30

As for water absorption: best to check with the filament manufacturer because ingredients vary.  But here's one: 0.13% in 24 hours.

https://devel.lulzbot.com/filament/Rigid_Ink/PETG%20DATA%20SHEET.pdf

May I point out Tim's water absorption rate is for total immersion in water. Note: Don't store your PETG in water.

My question would be how PETG ages after printing. My impression is that it does not accumulate moisture; no idea if that is accurate.

RE: PETG, PLA and ABS

Posted by: @obie-c

Thank you very much. I was a little shocked when a recent, VERY labor intensive LARGE multiple piece build, MELTED in the sun when painting it... it was a really shi**y experience that I never want to repeat. So I don't mind shelling out more money for PETg.

Would be interesting to know the details. My objects never reach >60C while painting it. Maybe you've used some paints which dissolve PLA filament. This can happen with any kind of filament (except of some special chemical resistant ones). Or do you mean you left it in the sun during summer time.

I've printed a bigger object in PLA and it's hanging outside the house on the wall. So far it survived two years without any deformation.

RE: PETG, PLA and ABS

For outdoor things use ASA filament. However...supposely warps even worse than ABS... i don't have it so i can't tell for sure, but my seller told me so when he offered it to me.