Cracking/popping of PVA filament

[Tiger91 1]

Hello,

 

I have some older (3+ month) PVA that was recently opened.  When using it, I've noticed it has a tendency to "pop" when going through the extruder.  Not always, but when it does it can result in poor support.  Any idea how to mitigate this?  (as I mentioned, though a bit old it was in a sealed package and I'm in a very dry environment)

[KickahaOta 14]

Hissing and popping is a sign of PVA that's absorbed moisture, which can really affect the PVA's performance. Note that keeping PVA in a sealed bag (preferably with desiccant) will keep the PVA from absorbing moisture, but won't do anything to remove moisture that's already there.

 

If possible, your best bet is to dry it out at around 55C for a few hours. If you use an oven for this, it's important to use one with good temperature control, because higher heat can damage the filament further. If you have a printer with a heated built plate and an enclosure, that can work very well as a dryer. And once your PVA is dry, always put it away -- in a sealed bag, with a desiccant -- as soon as you're done with it.

[Brulti 177]

I found out that you can also solve this by putting the PVA in a plastic bag with some desiccant and wait a couple days for the desiccant to absorb all the moisture. Saved half a roll of PVA this way, whihc I was quite happy about given how expensive PVA is...

Edited June 19, 2018 by Brulti

[kmanstudios 1,120]

I suggest a drybox as it will keep it dry while in usage. Polybox or download and make from Thingiverse. I go through so much of that crap that I never have to store it. The polybox keeps it nice until I run out.

 

PVA will be the financial ruin of me... ?

 

[kaos 0]

Avoid using it where possible - try using another PLA or ABS as support if you don't have to dissolve in water and can break off easily. PVA has just been a pain for us, blocked cores, wasted time...  If absorbing moisture into PVA is such an issue why don't they sell in much smaller spools?

[kmanstudios 1,120]

1 hour ago, kaos said:

Avoid using it where possible - try using another PLA or ABS as support if you don't have to dissolve in water and can break off easily. PVA has just been a pain for us, blocked cores, wasted time...  If absorbing moisture into PVA is such an issue why don't they sell in much smaller spools?

They do. They sell 0.35 Kg spools.

 

Also, not everybody wants to print in ABS. If you want to print in ABS, assuming it is not spindly, then you could print with Breakaway material.

 

And, nothing is stopping people from implementing their own drying solutions. For instance, I use a polybox, and it has greatly improved my experience with PVA. Not problem free, but not really bad either.

 

[Brulti 177]

ABS as support is a bad idea in my opinion, because ABS is a chore to remove...

 

I use dryboxes for storage and printing, and it solved all my problems with PVA. And PVA is quite a nice support because you can put it for 20-30 mins in water, and it comes out easily when you're printing flat surfaces. Just finished one such prints for a customer and one little tugging was all I needed to remove big pieces of PVA from the flat surfaces of the print. You can't do that with ABS.

[kmanstudios 1,120]

2 hours ago, Brulti said:

ABS as support is a bad idea in my opinion, because ABS is a chore to remove...

I think it was meant for PLA to be the support since it is much weaker than the ABS and also more susceptible to heat and can become much weaker.