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PLA print on PVA glue solution - How to get it off the bed again?

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Maybe that's the reality week. After @Nicolinux had recently some challenges with a small print I'm a bit knocked-off by - well - actually a success.

So far I always printed PLA without any glue on the warm glass (60°C). With larger prints I got a tiny little bit of delamination at the edges despite using a brim.

For a large base area print I decided to use a PVA glue-water solution. It actually worked. No warping at all. The problem is: it still works. It's glued to the gold glass. Any attemp to remove the print failed so far. In the meantime I took the glass out of the printer and put it into warm water trying to dissolve. Maybe it works. I just don't want to damage the glass.

However, I wanted to ask the community if someone knows a better recipe for getting a PLA print of the bed when having used PVA glue solution.

One thing is clear: I took a bit too much of the glue solution (mixed it about 1:8). If I use the solution again, I'll take less.

Edited by Guest
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Cold, as cold as you can. That should break the crystal bond with the glue/glass. On my bad glass umo+ (one of three) I can use hairspray as much as I like. But on the other 2 umo+ bed if I use hairspray I can't remove the print unless I cold it down to 26C on one and the other bed I had to put it on the freezer since I did chip the glass once (without hairspray or anything).

I also used my air compressor to cold it down when it was around 35C and it did pop quite fast, but I don't like the amount of humidity it makes.

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Room temp didn't help. Hmmm... freezer. I'll try it next time. Got the print now off finally. Sucked it into water until I could dive under with a spatula from one side. Didn't feel very comfortable having all those stories of damages glass surfaces in mind. But the glass still looks ok - uff...

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Seems like you got it sorted and already had some nice input from other users...

I use PVA glue solution as well and have been a big endorser of it whenever the adhesion questions came up, so I thought I would chip in as well.

For solution strength I think 1:8 is way too much glue, as you said, put more water in... To my experience it will still work fine, even with something like 1:15.

I heat up the bed and apply a thin layer with a sponge, let water vaporize, and good to go.

Most smaller prints snaps right off once bed reaches room temp.

For large prints I will throw the entire warm glass plate and print into the freezer... Prints will usually have popped off by themselves when I come back later.

And yes... simply applying brute force violence to a stuck print (especially one that is still luke warm), WILL chip your glass plate... Ask me how I know :(

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Instead of using glue, you might try wiping the glass plate with salt water, prior to printing PLA. Gently keep wiping the plate with a moist tissue, until the water evaporates and leaves a thin mist of salt on the glass. This *greatly* improves bonding of PLA to heated glass. When hot (60°C), my prints bond rock-solid to the glass, I can't pull them off. But when cold after finishing, they come off without any force at all. But it does require a heated glass bed. For me, this works much better than printing on bare glass, or with glue. And you don't need to remove the glass from the printer anymore.

And salt is cheap too...  :-)

See my manual (PDF-file) with lots of pictures at:

https://www.uantwerpen.be/nl/personeel/geert-keteleer/manuals/

I hope this helps.

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Instead of using glue, you might try wiping the glass plate with salt water, prior to printing PLA. Gently keep wiping the plate with a moist tissue, until the water evaporates and leaves a thin mist of salt on the glass. This *greatly* improves bonding of PLA to heated glass. When hot (60°C), my prints bond rock-solid to the glass, I can't pull them off. But when cold after finishing, they come off without any force at all. But it does require a heated glass bed. For me, this works much better than printing on bare glass, or with glue. And you don't need to remove the glass from the printer anymore.

And salt is cheap too...  :-)

See my manual (PDF-file) with lots of pictures at:

https://www.uantwerpen.be/nl/personeel/geert-keteleer/manuals/

I hope this helps.

 

I do the same but with sugar, and the result is exactly the same. The heated bed at 45ºC and some water+sugar mix and it works great (I've even chipped the glass because one print was really stuck).

I think that any sticky ingredient, either salt or sugar, will work fine with PLA, and the most important thing, it's environmentally friendly.

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I do the same but with sugar, and the result is exactly the same. The heated bed at 45ºC and some water+sugar mix and it works great (I've even chipped the glass because one print was really stuck).

 

#geert_2 is claiming that with salt the item just pops off the bed when cooled down... so it sounds like salt maybe better than sugar ? I'm starting a test just now....

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Just did a test with bed at 65c, with refill pet  (which is what I happend to have in the printer atm) with a quickly drawn model with small contact area tentacles based on geerts design, but the comparison print on clean glass was already perfect without lifting corners :)I pulled the object off the bed at 60 celcius, just to feel how good it was attached. did this in both cases, it seemed to be a bit more attached with the salted glass, but it did not feel like a lot of difference, think I need to make a more challenging test object, and/or try with PLA. I'll do some more test, I like the salt bed idea a lot.

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Edited by Guest

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I do the same but with sugar, and the result is exactly the same. The heated bed at 45ºC and some water+sugar mix and it works great (I've even chipped the glass because one print was really stuck).

 

#geert_2 is claiming that with salt the item just pops off the bed when cooled down... so it sounds like salt maybe better than sugar ? I'm starting a test just now....

 

The example of the chipped glass was just an extreme example. :p

I print with the bed at 40-45ºC and the printed parts also pop off when the glass is cooled. It also depends on how many times I've already applied the "magical mix" to the glass, as the first time just after cleaning it is not very effective.

I will run some tests with salt in the future, but I guess that with PLA it may be enough with salt. I don't have any ABS to test with, but I feel like my mix is just as sticky as the hairspray people use on the heated bed glass in Spain (there's a very cheap and effective brand, although the room smells like an old lady).

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@flowalistik that's interesting, are you saying you also use the sugar mix with ABS? at what  bed temperature? (I usually use 95-100c)

 

No no no, I've never tried with ABS, but as it gets so stricky it may work. I always apply the mix when the bed is hot, if not the water doesn't evaporate and the surface of the glass is spotted (with water drops) and not a uniform sticky surface.

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Thanks for trying it with different materials and letting us know. I did not expect the salt method to work with other materials than PLA and PLA/PHA, so I am very interested in the results.

Thus it seems to work a little bit, but not that well?

On PLA indeed, when hot the bond is rock solid. When cold it pops off automatically. It has done so very consistently for over a year now, on about 1000 prints.

Concerning the sugar method: for now I have no need to, but if I ever want to print in ABS, and if the salt method would fail (as I expect), I will for sure try the sugar method next, because I like the idea.

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On 31-3-2016 at 10:18 PM, neotko said:

Cold, as cold as you can. That should break the crystal bond with the glue/glass. On my bad glass umo+ (one of three) I can use hairspray as much as I like. But on the other 2 umo+ bed if I use hairspray I can't remove the print unless I cold it down to 26C on one and the other bed I had to put it on the freezer since I did chip the glass once (without hairspray or anything).

I also used my air compressor to cold it down when it was around 35C and it did pop quite fast, but I don't like the amount of humidity it makes.

I can confirm the above. I had printed a large PLA object that stuck to the aluminum bed that I prepared with wood glue. The print did not want to come off. I know wood glue turns into a flexible film when heated to about 80-90C but of course that would destroy the PLA object as well. So, I tried the cooling in the freezer and with a little bit of effort it detached from the plate and the PLA object kept it's shape perfectly!

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On 5/5/2016 at 1:31 PM, eldrick said:

BTW, with glue or gluestick, soaking the plate will dissolve the glue and release the part, but it takes at least overnight.

????? I can usually get the most stubborn parts off the plate in an hour. Usually much less. I print with a PVA glue made from recycled PVA supports and never have this issue with PLA. I even use a PVA brim for most parts. Even when using a PLA brim to really anchor stubborn parts I can get the parts off with no issue. Many times, I can just peel off the part starting with the brim after it cools.

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