Problems with PetG

[Alibert]

Just make sure that you start your oven with low temperature and gradually increase it. Use the fan if your oven has one. I was too enthusiastic and the reels (the ABS filament itself only barely) melted and blobbed all over the filament. It was one gungked-together mess.

Also, PETG is a modified version of PET and has somewhat different characteristics. My expeirence so far is that some reels of PETG arrive perfect, others give steam bubbles and need serious drying before being useable. The post on Makergeeks indicates that even a number of filament manufacturers are unaware of the need to pre-dry the resin before extruding to filament.

Having said that, I have also had reels of ABS and PLA come in with the same problem. It seems to be more or less random and I think depends on the state the raw plastics were in before the manufacturer made filament out of them. As most of the filement is produced by a legion of relatively small companies in the USA, Europe, China and elsewhere, quality control on the resin/pellets going into the manufacturing process is difficult to say the least. Also, it is a smallish batch process due to the many colors etc. The final packaging (plastic wrap, bag of dessicant) tells you nothing about what state the raw pellets were in before the filament was made, so even a new perfectly packaged reel can still be moist and give poor prints right out of the packet.

Having means to dry filament is in my opinion a requirement in order to handle this, or you need to be sure of your supplier right down to the actual purchase, storage and handling of the batches of raw pellets,as well as postprocessing and storage of the reels. I do not expect to get that kind of assurance from any supplier.

A lot of people bash on so-called 'cheap' filament and claim you should buy only expensive quality. I have had mostly excellent experience with 'cheap' chinese filament and the same but also some very, very poor ones with USA/EU manufactured 'quality' filaments.

I found that the sizing accuracy of chinese producers (and all others) is excellent, only some batches are not dry enough and giving ghasly prints due to excessive steam bubbles. I have had ABS from one chinese supplier of mine being mostly perfect (5 colors), but the black one was too moist and needed vacuum drying before being as good as the others (near perfect).

So, investing in a vacuum oven does cost money, but with it you can make 'cheap' (chinese) filament near perfect (and a number of the expensive USA/EU ones too as my Formfutura trial demonstrated), so it will pay back for itself in the end. As someone who goes through several kilo's per week, that ROI is within a year just on basis of the price difference per reel, not counting throwing away whole reels which won't print

As Brisbane is very humid at times, you will have a permanent problem with all your filament (PETG, ABS and PLA alike) attracting moisture. So my advice is to get a good means of drying it, and pay good attention to air-tight storage.

Happy printing!