PVA Filament: Not Always What It Seems

June 20, 2025 by Maya Posch 6 Comments

PVA filament with a core. (Credit: Lost In Tech)

PVA filament is an interesting filament type, for the reason that while it can be printed with any FDM printer, it supposedly readily dissolves in water, which is also the reason why PVA glue sticks are so popular when doing crafts and arts with young children. This property would make PVA filament ideal for printing supports if your printer can handle two different materials at the same time. So surely you can just pick any old PVA filament spool and get to printing, right? As [Lost in Tech] found out, this is not quite the case.

As an aside, watching PVA supports dissolve in water set to classical music (Bach’s Air from Orchestral Suite No. 3) is quite a pleasant vibe. After thus watching the various PVA prints dissolve for a while, we are left to analyze the results. The first interesting finding was that not every PVA filament dissolved the same way, or even fully.

The first gotcha is that PVA can stand for polyvinyl acetate (the glue stick) or polyvinyl alcohol (a thickener and stabilizer) , with the ‘PVA’ filament datasheets for each respective filament showing various combinations of both types of PVA. This results in wildly different properties per filament, both in terms of Shore hardness, their printability, as well as their ability to dissolve in water. Some of the filament types (Yousu, Reprapper) also have an outer layer and inner core for some reason.

Ultimately the message appears to be that ‘PVA’ filament requires a fair bit of research to have any chance of having a relatively trouble-free printing experience.

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Pulp-Molding: A Use For Cardboard Confetti

November 5, 2021 by Kristina Panos 21 Comments

We’re pretty sure that we don’t have to tell you how great cardboard is. You probably sing the praises yourself and use it for everything from a work surface protective layer to a prototype of your next amazing build. But if you still find yourself flush with cardboard even after all that, here’s one thing you can do with all those pieces that are too small to use for anything else– chuck them in an old blender, whip up some cardboard pulp, and press that gunk into some 3D-printed molds.

In addition to a step-by-step of the process, [flowalistik] offers a mold set of STL files for various useful items like a pencil holder, a box with a lid, a tray, and a coaster, as well as the Fusion 360 files in case you want to change them around. You might want to seal the coaster with something protective so that it doesn’t mold/disintegrate/bloom from condensation.

Each part consists of the walls, the wall clip that keeps them closed, but allows for de-molding and reuse, the bottom lid, and the top lid. All these prints need to be pretty high-res so that they can withstand the pressure of the clamp holding it all together. [flowalistik] recommends a layer height no larger than .03mm and a 20% infill.

The process of making the pulp itself is fairly simple, and the recipe only calls for water and some kind of binder. To start, remove all tape, coatings, staples, and anything else non-soluble from the cardboard. Cut it into bite-sized pieces your blender will enjoy, and add water and PVA glue or rice paste. Mix it up, remove the excess water by squeezing your pulp inside of a piece of cloth, and then use it to fill up your mold. You’ll want to press out the water as you go and fill it further, then finally apply the clamp. You can start de-molding parts on a schedule, starting with the clamp after about six hours. Once it’s fully dried in about two days, you can treat it like MDF and sand, cut, or even drill it. We think some of these would look pretty good with a coat of paint.

Need your objects to be more sturdy? Keep that printer warmed up — you can use prints to cast concrete, too.