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rkayakr
(@rkayakr)
Trusted Member
After PETG prints PLA no longer sticks

I've had my MK3 for three weeks and it's worked well. I've used it about 8 hours a day with several brands and colors of PLA including luminescent. I have always prepped with isopropyl alcohol and had no problems. Recently I got some PETG and printed some updated parts. I used Windex to prep the surface for the PETG and again all worked well.
I then tried to go back to PLA and I can not get the PLA to stick. I double checked the settings and the bed and extruder temperatures are the same as I used before. Here is a log:

cleaned with isopropyl -> print came up
cleaned with isopropyl, extruded a bunch- extrudate looked good -> print came up
cleaned with isopropyl, brass brushed extruder -> print came up
cleaned with acetone -> print came up
cleaned with isopropyl -> print came up
cleaned with isopropyl -> print came up

Any ideas of what to do next?

Posted : 15/03/2018 2:57 am
x50arm
(@x50arm)
Estimable Member
Re: After PETG prints PLA no longer sticks

Try cleaning it good with dish soap and then wipe it down with alcohol when you put the plate back on the printer. Works good for me.

Posted : 15/03/2018 3:46 am
neil.e
(@neil-e)
Estimable Member
Re: After PETG prints PLA no longer sticks

Welcome to my hell 🙁 I washed with soap and water, did rubbing alcohol, etc. and the PLA just won't stick as well as it did before the PETG prints.

I might try running the plate through the dishwasher. At this point I have nothing to lose. Blah. Stupid PETG.

Posted : 15/03/2018 3:52 am
Kwaad2
(@kwaad2)
Honorable Member
Re: After PETG prints PLA no longer sticks

Did you print PETG on both sides? Just an idea if you haven't. Reading this post, I will *MARK* one side for PETG. I haven't ordered any PETG just yet, but I will be soon, plan on re-printing my extruder soon, as I am having MANY issues with flex-filament, and would *LOVE* to speed it up, but the default design is rather, full of fail.

Honestly with the price of filament/expendables, I would rule this print-bed as an expendable part... that is, if you could order more. I would *love* to get me a spare. (I will be ordering the powder-coated one as soon as it's available... and 4 spools of Prusa PETG. (the orange and black)

Hi, I'm Sean. I used to work on CNC machines.
I try to not make mistakes, but the decision is YOURS.
Please feel free to donate to my filament/maintance fund.

Posted : 15/03/2018 4:18 am
rufflez
(@rufflez)
Estimable Member
Re: After PETG prints PLA no longer sticks

how about non-acetone nail polish remover? That can break down PETG like acetone does for ABS. i havent had issues with acetone weekly and ipa before every print. if i dont use ipa, it wont stick. i also heat up the bed when i clean it.

Posted : 15/03/2018 4:38 am
reid.b
(@reid-b)
Reputable Member
Re: After PETG prints PLA no longer sticks

When I have this issue, I simply clean with Dish soap and hot water. I do NOT wipe it with alcohol afterwards. The PLA sticks great after this treatment.

If you continue to have issues, check your Z-height, and maybe crank your bed up another 5-10 degrees. I have found that PLA sticks better to a warmer bed, but won't stick well to a hotter bed if the nozzle temp is too high, so it can be a fine balance.

Posted : 15/03/2018 4:50 am
Kwaad2
(@kwaad2)
Honorable Member
Re: After PETG prints PLA no longer sticks

I cleaned my print bed 500 times with 92% IPA while doing something stupid. Sorry guys, no stories.

I actually just noticed my PLA test prints were NOT sticking very well.

I just cleaned the print bed a 3rd time with Windex. They are starting to stick better.

Try heating your heat bed to PLA temp, and clean the heat bed with Windex 3-4 times?

Hi, I'm Sean. I used to work on CNC machines.
I try to not make mistakes, but the decision is YOURS.
Please feel free to donate to my filament/maintance fund.

Posted : 15/03/2018 5:00 am
reid.b
(@reid-b)
Reputable Member
Re: After PETG prints PLA no longer sticks

IMHO, Windex leaves some kind of film that allows PETG to release a bit better, hence I never ever use windex prior to printing PLA. I guess if it works, but I wouldn't recommend it. The best thing for me has been scrubbing with dish soap and hot water. There are organics in PLA that alcohol or windex won't touch, but soap and water do.

Posted : 15/03/2018 5:29 am
Shoey
(@shoey)
Estimable Member
Re: After PETG prints PLA no longer sticks

If you asked Mr. Prusa, he would probably tell you to read the handbook 🙂 specifically Page 60....Ignore the amount of print time, it helps....

PEI rejuvenation
PEI can lose it's adhesive powers after a couple hundred hours. Wipe throughly with acetone when you see the models getting lose to restore the adhesion

Posted : 15/03/2018 5:43 am
Shoey
(@shoey)
Estimable Member
Re: After PETG prints PLA no longer sticks


If you asked Mr. Prusa, he would probably tell you to read the handbook 🙂 specifically Page 60....Ignore the amount of print time, it helps....

Windex leaves a film, makes it easier to remove PETG parts
isopropyl help cleans/removes oils left behind from parts/fingers
acetone when isopropyl doesn't work.

PEI rejuvenation
PEI can lose it's adhesive powers after a couple hundred hours. Wipe throughly with acetone when you see the models getting lose to restore the adhesion

Posted : 15/03/2018 5:46 am
ed
 ed
(@ed-3)
Reputable Member
Re: After PETG prints PLA no longer sticks


If you asked Mr. Prusa, he would probably tell you to read the handbook 🙂 specifically Page 60....Ignore the amount of print time, it helps....

PEI rejuvenation
PEI can lose it's adhesive powers after a couple hundred hours. Wipe throughly with acetone when you see the models getting lose to restore the adhesion

However the OP said...

cleaned with isopropyl -> print came up
cleaned with isopropyl, extruded a bunch- extrudate looked good -> print came up
cleaned with isopropyl, brass brushed extruder -> print came up
cleaned with acetone -> print came up
cleaned with isopropyl -> print came up
cleaned with isopropyl -> print came up

I was having the same issue and what worked best for me was to wash the sheet with Dawn and the rough side of a new dish sponge, note I didn't use a lot of pressure with the coarse side of the sponge, then I scrubbed hard with the sponge side rinsed and dried thoroughly with a clean towel. After that I put the sheet back on the bed and heated it to 100C for about 10 minutes and that helped immensely. I still get some corner lifting on large PETG prints that I can't seem to overcome though...

Posted : 15/03/2018 12:51 pm
rkayakr
(@rkayakr)
Trusted Member
Topic starter answered:
Re: After PETG prints PLA no longer sticks

Thanks all
I followed edward.c6's advice and washed the sheet with dish washing liquid and the rough side of a new dish sponge, then I scrubbed with the sponge side, rinsed, dried thoroughly with a clean towel and then heated the sheet to 100C for about 10 minutes. I then prepped the cool sheet with isopropyl and now PLA sticks again. 😀

Posted : 15/03/2018 3:15 pm
Cowwolfe
(@cowwolfe)
Active Member
Re: After PETG prints PLA no longer sticks

I had similar issue where PLA didn't stick after printing PETG.
I now clean my plate with Acetone before printing the PLA. When my PETG stops sticking after multiple prints, refreshing with Acetone also helps.

I believe this was in the MK3 manual. 🙂

Eric Z.

Posted : 16/03/2018 12:02 pm
jweaver
(@jweaver)
Honorable Member
Re: After PETG prints PLA no longer sticks

If this really is a problem, so surely the solution is obvious which is to use 1 side of the bed for PLA and the other for PETG?

Posted : 16/03/2018 12:05 pm
Area51
(@area51)
Member
Re: After PETG prints PLA no longer sticks


I cleaned my print bed 500 times with 92% IPA while doing something stupid. Sorry guys, no stories.

I actually just noticed my PLA test prints were NOT sticking very well.

I just cleaned the print bed a 3rd time with Windex. They are starting to stick better.

Try heating your heat bed to PLA temp, and clean the heat bed with Windex 3-4 times?

IPA (Isopropyl) works best when diluted with some water.
Only use Windex/Windows cleaner before printing PET and Flex to get the prints easier to remove.

If nothing else works, use a very fine water sand paper grit about 1000 or greater on the PEI surface.

Have a look at my models on Printables.com 😉

Posted : 16/03/2018 1:40 pm
Dewey79
(@dewey79)
Honorable Member
Re: After PETG prints PLA no longer sticks


[IPA (Isopropyl) works best when diluted with some water.
Only use Windex/Windows cleaner before printing PET and Flex to get the prints easier to remove.

If nothing else works, use a very fine water sand paper grit about 1000 or greater on the PEI surface.

I've heard a lot of people talking about using Windex for first layer adhesion. Now a days they have all kinds with the different colors and additives. Are we talking about the Blue color Windex? Does the other ingredience leave a film?

Posted : 16/03/2018 2:50 pm
rkayakr
(@rkayakr)
Trusted Member
Topic starter answered:
Re: After PETG prints PLA no longer sticks

The obvious solution to the problem only is obvious if you know there is a problem. Until I encountered it, I didn't know. I hadn't seen any reports here. I used both sides for PETG printing.

I used plan old blue Windex for the PETG and it worked well. I think the point is that it does leave a film so the PETG doesn't stick too well.

Posted : 16/03/2018 3:20 pm
m2tts
(@m2tts)
Trusted Member
Re: After PETG prints PLA no longer sticks

You could try the old standby of glass bed users ( we have two Ultimakers in our shop) of Aqua net or Rave hairspray. PLA just falls off the glass after ten minutes in the freezer; or you can pull it off if we're patient enough to let it cool to room temp. The hairspray is basically aresol PVA glue. We clean the glass with soap and water. For the steel sheet (though I haven't tried this yet) I'm sure the hair spray would work as a barrier between the bed and PETG. No freezer needed as the steel will bend.

Posted : 16/03/2018 9:57 pm
Martin Wolfe
(@martin-wolfe)
Reputable Member
Re: After PETG prints PLA no longer sticks

As Windex is not commonly available in the UK I substituted Windolene for my PETG prints and I have had no problems since I started using it. PETG prints come off with a flex of the steel sheet.

So basically I give the sheet a wipe down with 70% isopropyl alcohol then when that is done and dry I give a quick wipe down with windolene. Also have no problems when I switch back to PLA.

Martin

Martin Wolfe

Posted : 16/03/2018 10:45 pm
Area51
(@area51)
Member
Re: After PETG prints PLA no longer sticks



[IPA (Isopropyl) works best when diluted with some water.
Only use Windex/Windows cleaner before printing PET and Flex to get the prints easier to remove.

If nothing else works, use a very fine water sand paper grit about 1000 or greater on the PEI surface.

I've heard a lot of people talking about using Windex for first layer adhesion. Now a days they have all kinds with the different colors and additives. Are we talking about the Blue color Windex? Does the other ingredience leave a film?

I am not using Windex but an allergy friendly windows cleaner (the cheapest) - It works great. The main effect of the windows cleaner is to leave a thin soap film behind when drying. This gives the PETG a weaker bonding to the PEI surface.
Before using windows cleaner I used disk wash soap diluted in water - works equally well, but it is easier to have the windows cleaner spray on 😉

Have a look at my models on Printables.com 😉

Posted : 17/03/2018 1:33 am
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