eSun 1.75mm PVA 3D Filament yello, PVA-175-Y, print temp 180º-230º C
Insignia (Best Buy) White PETG, print temp 240º-260º
I have a very nice Sacred Heart statuette model jesus_de_nazaret.3mf but it has some very fine detail that caused me problems removing supports in two prints (vertically oriented). I want to learn to use PVA so the Lord seemed like a good idea. At least it will recompense for my breaking off two of His fingers with the supports. To minimize time and filament, I put the figure on his back, rather than vertical. After removing the supports, the result is acceptable (all fingers present and accounted for) but texture is rough.
The PVA seemed to adhere to the plate (Textured PEI from box). But then it didn’t adhere to itself consistently. It had some stringing and maybe looked like bubbling? Attaching photos.
I’m assuming the bubbly look is not right. I am guessing the temp difference is a big problem. I had a stack of filament changes with this print and it would get ridiculously long adding a wait each time for the head to cool from PETG temp to PVA temp. Maybe I should have paid attention to that before the effort. But it was teaching me things so…
So should I only use PVA as supports for PLA, which has temperatures in the same range?
Also, the PVA got despooled and had to be respooled, a long process exposed to indoor humidity. Used nitrile gloves while handling. Any reason to suspect I ruined the filament with that handling?
PVA is only compatible with PLA. Anything else should be considered an experiment with an uncertain outcome.
PVA must be dried. That makes sense: The filament is water-soluble - that’s its purpose. Any humidity harms the filament.
The question now is what advice would be best for you: something that won’t be misunderstood but will still help? Reading the manual / checking out the wiki? There are lots of useful tips, like:
“In a normal indoor environment with about 55% RH, the freshly dried PVA filaments will get damp in about 1 to 3 hours to the extent that the printing quality will deteriorate.”
PVA Printing Guide:
If you want support material for other materials, such as PETG, you’ll need to buy the appropriate one. There are several support material to choose from:
PVA can work with PETG prints, but PLA supports on PETG work better.
It’s actually pretty common to use PLA supports for PETG prints and vice versa. They bond well enough for the print and separate easily afterward (and pretty cleanly in my experience).
Honestly though, I haven’t done either of these in a while. I’ve had enough success using the same material for the supports as the prints. I generally have clearances set to 0.2 mm and the top interface spacing set to 0. Using ‘concentric’ as the interface pattern also helps.
I take care of any remaining roughness in the piece by passing a blowtorch flame over the trouble spots; it’s really amazing how well this just ‘erases’ crazed plastic and other problems, just don’t burn yourself doing it. Heat resistant Kevlar gloves are great for this.
No, I have not. I think a normal (bic) lighter would probably be too hard to control and a torch lighter is too much of a point source. I think these get your hands too close to the flame for comfort and safety. The central part of the flame is just too hot and the useful part of the flame is just too small.
Alternatively, I have used a heat gun for this, but the cheap-o propane torch just works better.
Yes, lightly, the very outside, whispy edges (where the flame is coolest). The effect is almost immediate, especially with loose ‘hairs’ and crazed surfaces.
Also, it’s better to take multiple rapid passes instead of one slow one.
Umm: the quicker the better, watch out for thin sections. Try to avoid heating up the bulk of piece; you’re trying to go only skin deep with the least amount of heat that still affects the surface.
And again, be careful not to burn yourself, a heat resistant/Kevlar glove is great for this.
