PETG tends to stick to a 3D printer’s glass bed due to the strong bonding of the thermoplastic filament with the heated surface. You may feel a need to apply force or exert some pressure when using a spatula to scrape and remove PETG models, but that is not an ideal approach.
You can easily remove PETG from a glass bed by spraying the surface and model’s base with a bit of isopropyl alcohol mixed with water. You can also use a glass cleaner as a release agent.
You can use a few tactics before and some remedies after 3D printing with PETG on a glass bed. I recommend a combination of proactive & adaptive measures so that you are not always responding to a crisis. Read on as I explain how you can easily remove PETG from a glass bed.
Simple Ways To Easily Remove PETG From a Glass Bed
PETG is stronger than PLA and easier to work with than ABS. Unlike several 3D printer filaments or thermoplastics, PETG does not have significant first-layer adhesion problems. However, this advantage can also be a curse, as it clings hard to print beds.
Exerting brute force on a PETG model can damage the object, even if you target only the base. Also, you cannot apply much pressure with the spatula or scraper on the glass bed, as you may damage the surface. Thus, you need a few gentler and safer ways to remove PETG easily.
Use Isopropyl Alcohol Mixed With Water on a Warm Glass Bed
Isopropyl alcohol and water can soften the PETG a bit, helping it release from your glass print surface.
Here are the steps to remove PETG from a glass bed using isopropyl alcohol and water:
- Dilute some concentrated isopropyl alcohol with water or use 70% IPA.
- Wait around five minutes for the glass bed temperature to start dropping. Do not spray alcohol on a hot print bed.
- Spray or dribble the diluted IPA beside the PETG model’s base on the glass bed.
- Allow the alcohol to evaporate for a few seconds. You may hear a crackling noise.
- After around 10 to 20 seconds, gently pull or push the PETG model off the glass bed.
- You may need the spatula to gently scrape off any brims or skirts remaining on the bed.
- Clean the glass bed as you usually do when it is cool or at room temperature.
It is crucial to wait for the bed and print to cool just a bit before you try to remove the PETG with this method. Spraying anything that reduces the glass bed temperature leads to uneven cooling. Thus, you may inadvertently put the material under stress.
Still, do not let the glass bed cool down to room temperature. Allowing PETG more time to bond will make removing the print harder. You want to spray the alcohol when the bed temperature is about 10º C (18º F) cooler than when you printed your object.
Use a Release Agent To Remove a PETG Print From a Glass Bed
Release agent sounds like a fancy term, but you probably have something that will unstick your print from the bed lying around your house. Windex is one of the best, most affordable, and most commonplace release agents.
To use it:
- Allow the glass bed to start cooling as you would with the IPA remedy explained above.
- Apply the release agent around the model’s base.
- Try not to get it on your PETG model since it could become slimy.
How Do I Stop PETG From Sticking To a Glass Bed?
You can stop PETG from sticking to a glass bed too firmly by using a dissolvable bed adhesive, reducing the bed temperature, changing the heat settings for the filament, and increasing the z offset for such prints. You have to customize these proactive measures based on your situation.
Use Dissolvable Bed Adhesives When Printing With PETG
Some hobbyists use glue sticks, hairsprays, and other materials to prep their 3D printer beds and make the base layers stick better. However, an adhesive might also make print removal easier since it will provide a dissolvable layer between your print and the bed.
Glue, tape, and hairspray are incredibly efficient at sticking down and unsticking your PETG prints from the bed. In the case of tape, you can likely just peel your print right off the glass bed. Glue dissolves with a spritz of water, and hairspray loses its grip when you spray on some isopropyl alcohol.
Also, you can consider something like the Elmer’s Glue Sticks. (available on amazon.com) These glue sticks do not contain any toxins or acids. The water-washable glue is suitable for 3D printer glass beds, and it can make removing PETG models an effortless process.
Reduce the Glass Bed Temperature
PETG’s glass transition temperature is 176 °F (80 °C). The filament’s Vicat softening point or temperature is 185 °F (85 °C). Thus, you should not heat the 3D printer glass bed anywhere near those temperatures when using PETG.
Suppose your PETG print sticks too firmly on a glass bed at 167 °F (75 °C). In that case, reduce the glass bed temperature to 158 °F (70 °C). Keep lowering the temperature until the filament sticks but is still removable. A little trial & error is unavoidable because PETG filaments made by different companies are not identical.
Change the Print Temperature Settings for PETG
The necessary heat settings for printing with PETG filaments range from 428 °F (220 °C) to 482 °F (250 °C). To prevent the filament from gripping too much, you may reduce the manufacturer’s recommended printing temperature for the base or first layer. Then, raise the temperature again to finish off your print.
For example, you may use 428 °F (220 °C) for the first PETG layer on the glass bed. Increase this to 464 °F (240 °C) for the subsequent layers. Hopefully, this combination will prevent the PETG print’s base from sticking to the glass bed and resolve adhesion issues between successive layers.
Increase the Z Offset for PETG Prints
If your nozzle deposits that PETG too close to the glass bed and squishes it, it will stick so well that you won’t be able to remove your print.
Review the z offset for PETG prints on a glass bed to remedy this issue. You should not have the nozzle so close to the print bed that it deposits the PETG filament almost into the glass. Increase your 3D printer’s z offset slightly to raise the nozzle’s distance from the glass bed.
When you change the Z offset, you will probably need to review your slicer settings for a PETG print. Otherwise, you may have layer adhesion issues. One way to counter adhesion problems is increasing the hot end temperature for the layers other than the first or base.
Like all 3D printing thermoplastics, PETG calls for customization, and the bespoke settings will vary, depending on the printer model, filament quality, and slicer. Hopefully, the proactive tactics and remedies shared in this guide will make it easy for you to remove PETG from a glass bed.
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I started 3D printing since 2013 and have learned a lot since then. Because of this I want to share my knowledge of what I have learned in the past years with the community. Currently I own 2 Bambulab X1 Carbon, Prusa SL1S and a Prusa MK3S+. Hope you learn something from my blog after my years of experience in 3D printing.