PVA Removal

[Tigerbeard 4]

A lot of people seem to have printing and storing problems with PVA. Fortunately I do not, it prints quite fine.

 

But I have the problem that I can not really get it off. Since I am printing small parts (>20mm) with corners, holes and edges, it sits in there.

I sumberged the parts in water for 2days. I added dishwashing detergent, I stirred it from time time time, I changed the water 2-3 times - all to no avail.

 

My observation is, that initially material dissoves rather quickly (1hr or so). But some time it stops. When I remove larger chunks once they come loose, I left them in the water to see what happens. Also there they did not fully dissolve. For all parts glibbery blobs remains, about 8-10mm thick.

So far I cleaned my parts with loads water (changing the water all the time) with manual scrubbing and using tools to get in the corners. Some parts I broke in the process, in some I just can not reach those areas, so a bit of residue remains.

I have not tried boiling it, though.

 

Are there any tricks to fully resolve the material without manual intervention? 

[Carla_Birch 116]

Hi @Tigerbeard

 

When i use PVA support i personally put into warm water around 30c (I use a heated ultra sonic cleaner) and after a few min i pull off the thick of the PVA and put in back in and use the ultra sonic cleaner itself with fresh clean water in in heated when its almost all gone to remove the final bits that like you say seem to blob up in places.

 

Some people use a fish tank with an heater and air bubble filter to keep the water moving and warm, so maybe something to look in to?

[SandervG 1,521]

Clean, warm water and water circulation help best. So it is recommended to replace the water after an hour or so to make sure it is clean again. PVA can saturate the water and it will loose its effectiveness. Regarding how warm, make sure to stay safely under the glass temperature to make sure the part you have printed doesn't deform. 30ºC should be a pretty safe temperature to use for PVA. 

[Tigerbeard 4]

2 hours ago, SandervG said:

glass temperature

What is that?

 

Thanks for your feedback.

 

@SandervG, your are saying "warm" water, so as your are from Ultimaker, do I take it that there is no specified optimal temperature in the material specs or from laboratory tests?

 

So I take from your replies, that there is no simple way got solve the glibbery leftover bits in the corners, holes and cavities without manual intervention.
 

It funny. The first consumer SLA guys came up with extra UV curing devices all customers needed to buy after a few years. Are we looking here for new devices to remove PVA support? I am a bit surprise by that issue. I just see all these images with meter over meter of shelfs full of Ultimaker printers printing in "Printing farms". Are behind those shelfs long tables where low-cost workers manually move containers with water over hours and then finish off the last corners of industrial parts with toothbrushes in order to remove the support? Obviously that no one would like to put up an image like that 😉

Seriously, this is quite a limitation of PVA that I find quite unexpected - your page just lists steps to remove "Breakaway". By saying nothing about a prodecure for PVA you create the (high) user expectation that it is just "throw in water and done". Needing something like 10-20l of warm water and regular manual intervention over hours plus final manual corner cleaning to remove the support from about some 30 grams of netto print is quite a procedure.

 

To be honest, I find that a bit disappointing. Maybe its because dual heads and thus the ability to print solvable support was the prime reason to get an Ulitmaker device in the first place. And that is when the device is realling doing a much better job in some areas than expected.

 

Now, I would not like to give up so soon. Would it be worth to experiment with aectone, oils, acids, lyes, vinegar, detergents like toilet cleaner, automotive brake cleaner, petroleum, isopropyl alcohol, etc, or has that all been tried?

 

 

Edited July 20, 2020 by Tigerbeard

[Carla_Birch 116]

Glass transition temperature is the temperature that a plastic goes from being rigid to becoming soft, For a filament like PLA that temperature is around 55-60c. So if breaking down PVA in warm water with PLA you need to make sure the water is below that tempure or you risk the part becoming soft and losing it's shape.

 

Warm and water thats not still really helps break down PVA faster, that's why people use fish tanks with heated water and air bubble bricks to keep the water moving.

[UlrichC-DE 114]

I would try to put the parts in a dishwasher after a long bath.

But maybe environmental concerns could keep me from doing so. 🤔

[Tigerbeard 4]

1 hour ago, UlrichC-DE said:

I would try to put the parts in a dishwasher after a long bath.

But maybe environmental concerns could keep me from doing so. 🤔

Good suggestion. That could show if the corners get cleaned out.

 

However, if the glibber does not fully dissove it may accumulate in the tubes of the device and in the long run block the dishwasher. I had that once with stickers on jelly glasses. Could be repaired but was not cheap.

 

2 hours ago, Carla_Birch said:

Warm and water thats not still really helps break down PVA faster, that's why people use fish tanks with heated water and air bubble bricks to keep the water moving.

Are you aware about what cleaning times we are talking about in a fish tank with warm water? Is it like 1hr or is it more like 10 or 20hrs?

[Smithy 1,146]

I use a cheap Sous Vide stick which heats and moves the water.

Takes also long but after a few hours or overnight the object was nearly free of PVA. I think the key is the temperature, in cold water it takes really long.

[Carla_Birch 116]

Warm and moving water will always break down PVA faster than cold still water. As for how long it’s still going take time to break down but how long goes by how much PVA you need to break down and how easy the water can get to it.

That’s why it’s a good idea to pull most the pva off the print after the pva as become soft after about 10min in the water.

[Tigerbeard 4]

I started to think about magnetic mixers, but I think the sous vide things have the advantage to be programmable. Sounds like the hassle free approach that I was looking for. Great Idea!

 

 

[Tigerbeard 4]

58 minutes ago, Carla_Birch said:

That’s why it’s a good idea to pull most the pva off the print after the pva as become soft after about 10min in the water.

You are right, I tried that that with some outside support structures before. After a couple of minutes in the water some of those could be snapped off.

Edited July 20, 2020 by Tigerbeard

[Smithy 1,146]

9 hours ago, Tigerbeard said:

I started to think about magnetic mixers, but I think the sous vide things have the advantage to be programmable. Sounds like the hassle free approach that I was looking for. Great Idea!

 

 

 

It has a lot of advantages, it is cheap if you buy one from a discounter, the stick don't need to be the best quality, doesn't matter. You can use any container you want, I use simple plastic box. And you can store both easily if you don't need them.

 

But I guess the ultra sonic cleaner,  as @Carla_Birch said, works even better, especially with small parts.  But you need one which is able to heat the water. I have one but haven't tried it yet. For my needs the Sous Vide sticks works great enough.

[SandervG 1,521]

18 hours ago, Tigerbeard said:

What is that?

 

Thanks for your feedback.

 

@SandervG, your are saying "warm" water, so as your are from Ultimaker, do I take [....] aectone, oils, acids, lyes, vinegar, detergents like toilet cleaner, automotive brake cleaner, petroleum, isopropyl alcohol, etc, or has that all been tried?

 

 

 

Not so fast 😉 Just because I didn't specify an exact temperature does not mean we're all in the dark here running around. A guide on how to dissolve PVA can be found via this link. PVA on its own is harmless, you are allowed to flush it down the sink. Make sure to check if the material you used for the build can withstand the temperatures of a dishwasher before you try something like that. I don't think we recommend using a dishwasher. 

 

If you can break away larger chunks of PVA and the warm water can circulate the PVA should be able to dissolve in a few hours. If you would throw in a large block of PVA without any help or circulation it could take up or over 24h. 

 

Although the removal of PVA can be done by regular tabwater without too much hassle (it takes longer if you use more PVA), I agree with you that there is room for an easier solution that would help you remove the PVA and you don't have to mess around with a bucket. 

[Tigerbeard 4]

Thanks for the link. I apologize, I have not seen that link you your page. 

 

From my tests I can not confirm that all will resolve over time, at least within 48hrs. But that was cold water only exchanged like 2x.

I will test 35°deg and I think for that reason the cheap sous vide approach best since its the only way I am aware of to control low temps and move the water without manual intervention.

 

[Smithy 1,146]

2 minutes ago, Tigerbeard said:

I will test 35°deg

With 35° you should be safe. If I remember correctly, I also set 35° on my SV stick.

[Tigerbeard 4]

Hi

I got my cheap Sous Vide stick and it is running for 1.5hrs with 35°deg now.

 

The results are very good so far. I plainly forgot to remove the PVA build material (about 50% of the part) and found that it really fully resoved. On the parts were alreay less remains of the PVA structure than I have before from 48hr submersing into water with several water exchanges. I just swapped out the water and I am going to see if it removed all of the PVA.

 

From what I can say now I think UM should include such a thing with their printers. At least the help pages should describe this option, because the trial and error approach with cold water is just fustrating and a waste of time.

 

 

 

Only drawback so far is the SousVide housing design. It sucked in some small parts inside its housing, because the water slits are too wide. This can be solved to open it an put in some fine metal mesh. Biggest problem is really to get about 10x10cm of that stuff in the first place. Maybe I harvest an old kitchen sieve.

 

 

 

[geert_2 558]

1 hour ago, Tigerbeard said:

Hi

I got my cheap Sous Vide stick and it is running for 1.5hrs with 35°deg now.

 

The results are very good so far. I plainly forgot to remove the PVA build material (about 50% of the part) and found that it really fully resoved. On the parts were alreay less remains of the PVA structure than I have before from 48hr submersing into water with several water exchanges. I just swapped out the water and I am going to see if it removed all of the PVA.

 

From what I can say now I think UM should include such a thing with their printers. At least the help pages should describe this option, because the trial and error approach with cold water is just fustrating and a waste of time.

 

 

 

Only drawback so far is the SousVide housing design. It sucked in some small parts inside its housing, because the water slits are too wide. This can be solved to open it an put in some fine metal mesh. Biggest problem is really to get about 10x10cm of that stuff in the first place. Maybe I harvest an old kitchen sieve.

 

 

 

 

A kitchen sieve sounds like a good idea: if you take a bigger one, and 3D-print a custom clamp for it, the sieving-area is wide enough so that small particles getting stuck to the sieve won't totally block it.

 

Mosquito-gauze (not sure of the name in English) for the windows might also work well. Easily available in brico-shops, and cheap; usually made of nylon here.