Does anyone have any good settings for Inland PETG using painters tape on the bed?

[mbaram 0]

I just got my Ender 3 Pro a month ago as a hobby to start during quarantine. I decided to start printing face shields, but I wasn't able to get them to stick to the bed.
Now I want to use painters tape but I don't know any good settings, and I have a few questions:
1) First of all, does it have to be 3m blue tape?  

2) What's a good bed temp?  

3) Should I put the tape on top of the magnetic bed?

4) I read somewhere that an Ender 3 should never go above 240c nozzle temperature—is that true?  

5) And kind of an unrelated question: Are PETG fumes toxic?
Some details: I'm using Inland natural PETG and I have an Ender 3 ProX

[gr5 2,265]

All painters tape is fine but some painters tape sticks better to the print bed.  So if it sticks to the print but not the bed then you will wish you got the blue painters tape (sticks more than green) and 3M is pretty good.

 

I recommend getting as wide a tape as possible (easy to find on internet and cheaper than in paint stores) as it sticks better to the bed and also goes down faster as you will be tearing the tape often.

 

You must wash the tape with rubbing alcohol (aka IPA aka Isopropyl Alcohol).  The tape has a waxy surface that keeps anything from sticking to it (otherwise the tape wouldn't unwind).  You need to wash that off.  it's very easy - just one quick wipe with IPA is all it takes.  Other solvents may work - I don't know.

 

I've never tried PETG with blue tape so I don't know how well this will work but it works great with PLA.

 

Ultimaker recommends their "adhesion sheets" for PETG because PETG is more difficult than PLA to get it to stick to the bed.  Someone on the forum claimed they are Avery L7567.  I can attest that many materials stick unbelievably well to the adhesion sheets!

[gr5 2,265]

I just looked up the ender and it has a heated bed.  So do you really need blue tape?  You want to heat the PETG above it's softening temp.  PLA gets soft around 52C so we heat the bed to 60C.  PETG - I'm not sure - I think around 70C?

 

Here's what you do - heat the bed to 90C, put a towel over the bed.  Cut a short length of PETG filament - maybe 5cm.  Put it on the bed under the towel.  When the bed is at temp, pull out the filament and bend it 90 degrees.  Does it stay at this new angle?  If so then it is above the softening temp.  If not then it is below.  Keep adjusting the temp until you know the softening temp.  Then print with the bed about 10C warmer.

 

Why?  The reason parts come off the bed (and especially corners) is that as you print the upper layers they shrink and pull inwards on the part which puts a huge amount of upwards pulling on the corners of your part.  If the part is rounded then the force is spread out a bit.  That's one of the 2 reasons why brim helps also.  Anyway but if the part is above it's softening temp then the plastic acts more like clay (plasticine) and the part warps slightly (so small you can't see it - we are talking maybe 0.1mm) and the forces are relieved and also spread out through more of the part.

 

A heated bed also heats the air and reduces how much the part is shrinking before the print is finished.  Especially if you enclose the printer so the air can warm up a bit.

 

For PETG if the part is still coming loose it helps to add a layer of glue stick (PVA).

 

[gr5 2,265]

Regarding the 240C - I'm guessing there is some teflon in the print head of your printer.  Teflon degrades faster at 240C (say 20 hours of printing) versus 210C (say 200 hours).  But this is a inexpensive part that you should be replacing regularly anyway.

[DivingDuck 105]

I'm printing PETG at 235°C on glass with 81°C. Usually PETG will be printed between 230 to 250 (max). Normal PEFE tubes will as @gr5 mentioned degenerate faster at higher temps and should not heated up to 250°C because of toxic fumes, but these temps are usually not needed.

 

[gr5 2,265]

Don't worry too much about the fumes.  I recently boiled a large pot of water and the pot was teflon coated. After the water was gone we didn't notice and burned the hell out of that pot.  Gas stove on highest setting.  It stunk up the whole house but no one got sick or anything.

[DivingDuck 105]

Ha, you have "coated and disinfect" your self. Now you are save against all viruses too. 😉