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Materials: Dissolvable Support Filament
Dissolvable filaments allow you to 3D print more complex objects, but you'll need a dual-extruder to use them:
- One extruder is devoted to your primary printing material (eg.
- The other is devoted to the dissolvable support material (eg.
PVA (Polyvinyl Alcohol) is primarily used as a support for
PLA. When placed in water, the
PVA will dissolve away leaving just the
PLA. It's not the easiest filament to work with, however.
By design, it absorbs moisture - so keep it wrapped up with some silica gel desiccant in a sealed bag when not in use.
Many brands also seem to be UV sensitive, as well as heat sensitive. Keep in a cool dry place out of direct sunlight.
Most modern slicers will allow you to specify which extruder (or Tool / print head) to use for various aspects of the print which should suffice for basic use of
PVA (eg. rafts, supports, etc). Remember that
PVA is more easily removable, so you might want to use tighter settings than usual for your supports to get the best print possible.
If you're looking to use
PVA in more advanced ways, for example creating "impossible designs" (like this), the general approach is to use the same process as you would when printing with two different
PLA filaments - usually that means having two models loaded in to your slicer, and selecting which extruder to use for each model.
Pro Tip: Start by printing a
PVAraft and just a couple of layers of your
PLAobject - and get that working first before worrying about other stuff, otherwise you will end up going round in circles.
PVAraft should stick to the bed, and be clean and tidy. The
PLAshould stick to the raft, and have a well defined outline and fill.
PVA extrusion is usually erratic in comparison to
PLA, it will likely take lots of experimentation to get it extruding reliably - don't give up! Try increasing extrusion rate, and/or decreasing print speed when printing the
PVA. If you increase the extrusion rate, remember to check and tune the retraction rates.
Part of the problem with the extrusion is that the
PVA won't be printing the whole time. If you've done multi-extruder printing before, this will be obvious - but for me using
PVA was the first legitimate reason to use multi-extruder printing; and it's not just the
PVA that will need tuning for correct extrusion - you'll need to tune your
PLA extrusion as well, particularly if it's not printing infill or ooze shields properly.
PVA often struggles to adhere to other surfaces, including
If you have a heated bed, use it - a temperature of 40-80°C should help, depending on which
PVAbrand you're using.
Alternatively, try using hairspray or glue (ideally
PVA-based) to make the bed stickier
PVAraft can solve lots of frustration while you're tuning your settings
PVAprint speed when printing supports usually helps too
Most brands are overly sensitive to ambient temperature. For best results, open your printer enclosure to let excess heat out. Conversely, don't get it too cold either - if your printer has a filament cooling fan, turn it off because if the printing
PVA cools too quick it becomes brittle and won't adhere to whatever it's being printed on.
Keep a close eye on the print. It's not just the
PVA settings you need to get right, but also the
PLA settings that work alongside them:
You will often find one or both extruders are oozing too much between tool changes; using an ooze shield should mostly mitigate this issue
Even with an ooze shield, you should still try and tune your tool change retraction rates to prevent the nozzles from drooling in the first place
On the first few prints it might help to have some long tweezers to hand so you can quickly pluck unwanted mess from the print area
PVA dissolves in water - but it's a bit messy and can take a while. Pull or cut away some of the excess
PVA first to reduce time and mess. Warmer water will make it dissolve a little quicker, especially if given a few stirs from time to time, but avoid using hot water that could cause the
PLA to warp.
Note: After dissolving the
PVA, the remaining
PLAobject will likely have some water in it, even if there's no noticeable holes.
PVA isn't great at bonding to
PLA. I personally found that a
PVA raft would easily detach and with some patience I could also remove all the supports without damaging my printed object. This way I can drastically reduce the amount of time taken to dissolve any remaining
HIPS (High Impact Polystyrene) is most commonly used with
ABS. When placed in a solution of
HIPS will dissolve away leaving just the
While it's easier to work with than
PVA, it can't be used with filaments that are affected by
D-limonene, such as
You can often avoid the need for overhang supports by making your overhangs incline at >45° angle - modern slicers and printers are usually able to handle those without the need for supports.
Some other filament types can be dissolved, but often require nasty chemicals - here's a summary of the methods I'm aware of:
PLApartly dissolves in
Ethyl Acetate, fully dissolves in
PEEKdissolves in conc.
Sulphuric Acid(note: using PEEK as a support material would be insane)
There are other ways to create 3D objects to consider - such as CNC milling machines, SLA printers, etc.