PVA help

[DRIPrinter 0]

Hello!

Im having some difficulties printing with PVA, specifically using it as a support when printing PLA. I keep my spool in a locked ziploc bag with two small bags of silica gel:

I tried a small test print only out of PVA before trying dual PVA/PLA and it turned out all right:

However the print with PVA support looks very brittle and it seems as if the two materials aren't adhering to each other very well (to me at least):

 

With the dissolved PVA and the removed Brim it looks like this:

 

Any advice to improve the print quality? This is what it was supposed to look like (on Cura):

 

[kmanstudios 1,120]

That looks like it was hitting the humidity pretty fast. Just how humid is it there? I usually start to get strings like that when mine gets moist.

 

And, I am not sure that two little bags of gel are going to keep that dry if they are exposed to the air and absorb ambient humidity;

 

But, what were your settings? Can you give us a screen shot?

[DRIPrinter 0]

The settings are: 

 

As for the bags of gel, they stay in the ziploc. Are they still susceptible to absorbing too much moisture? If so, is there anything I can do about it?

The digital Hygrometer reads 56% (I don't really know how humid that is but you might).

Thank you very much for your help!

[kmanstudios 1,120]

OK, the humidity should not be an issue at your reported percentage.

 

However, your settings are for the PLA. Please click on the tab for Extruder 2 at the top and let us see what you have.

 

When you do, it may be wise to look at the whole set of parameters for this by going to support settings in Preferences->Settings and unhide the whole shebang. For instance, you have a lot of support on the sides that is not needed. But you cannot change that unless you can see 'horizontal expansion' on the menu for support.

 

Also, when you started to print, did it pop or sizzle or smoke? Did you try to go to the 'move' command for the second extruder on the printer and see if it was moving ok and feeding a nice smooth PVA string?

[Brulti 177]

56% humidity might be a bit too much. I remember being told, when I had troubles with PVA, to keep it under 55% humidity.

 

The silica gel packs are good for transport, but not for long term use, you should buy some, or something else, with more capacity to absorb ambient moisture when you print and for storing the roll of PVA.

[kmanstudios 1,120]

5 minutes ago, Brulti said:

you should buy some, or something else, with more capacity to absorb ambient moisture when you print and for storing the roll of PVA.

And, get the ones that are rechargeable. Otherwise, when they get full of moisture, you have to buy again.

[DRIPrinter 0]

Anything in particular you recommend?

[geert_2 558]

1 hour ago, kmanstudios said:

And, get the ones that are rechargeable. Otherwise, when they get full of moisture, you have to buy again.

 

I use silica gel from car shops: these are used to dry car interiors in winter and have a high capacity. Can be re-used after drying in a microwave oven, or conventional oven at low temp (70°C or so). When the blue dot changes to pink, it is saturated with moisture and needs reheating.

 

I store my filament (PLA, PET, NGEN) in big plastic boxes, with such a bag in each, to keep it fresh. But I do not have PVA; so I can't comment on that. I don't know if silica gel is powerful enough to dislodge water from already moist PVA, nylon or other filament, at room temp? Maybe you need to warm the filament (stay below softening temp!) in the presence of silica gel, to shake the moisture loose?

 

 

Edited July 18, 2018 by geert_2

[DRIPrinter 0]

And so just storing the PVA with a better desiccant should improve the print quality?

[kmanstudios 1,120]

Better desiccant, large amount and sealed properly....helps to keep PVA fresh. But the drying methods above are for making sure it can be rejuvenated when it does get too moist. It can get moist on the spool holder. That is why I use Polybox. Feeds the materials well as well as keeps it dry.

Edited July 18, 2018 by kmanstudios

[Brulti 177]

I store my spools in a big plastic box with a lid. It's not hermetically sealed, but it's closed. And I've one of those big desiccant packet made for absorbing moisture from the living room or a bedroom. It keeps humidity inside the box around 20-25%, and it did absorb the excess moisture from the roll of PVA, meaning I could use it and finish said roll later without troubles.