Subscribe
Share
Share
Embed
Petg First Layer Settings
Deep dives into 3D printing — filaments, settings, mechanisms, and the engineering behind prints that actually work.
# Transcript
**Generated:** 2026-05-29 11:57 UTC
**Source:** deepgram
**Niche:** forgefiles
**Episode:** ep_140_petg-first-layer-settings
---
Forge and file. Let's make something you've been lied to about the perfect first layer for PETG.
That beautiful smooth glass look everyone chases? It's actually the weakest way to print it.
If your PETG prints are lifting, warping, or not sticking to the bed, the problem isn't your
filament. It's your first layer settings. Today, we're tearing up the rule book and dialing in a
PETG first layer that's built for strength, not just for show. 2 months ago, I printed a batch of
phone mounts for a local car dealership.
40 units in PETG, had to be outdoor rated, UV stable, the whole deal. First run was a disaster.
Perfect looking first layers that look like glass, smooth, shiny, beautiful. And 12 of them cracked
at the mounting points within a week.
The problem wasn't the PETG, it was that I was treating it like fancy PLA. PETG has exploded in
popularity for functional parts, car phone mounts, outdoor equipment, mechanical assemblies, but
most guides still treat it like it's just tougher, PLA. As we move from prototyping to production,
getting this foundation right is the single biggest lever for improving your margins and customer
satisfaction. When a customer returns a broken mount, you don't just lose the sale, you lose the
relationship.
Here's what nobody tells you about PETG first layers. PLA loves a squished flat first layer for
maximum adhesion. PETG hates it. I learned this the hard way last spring.
Had a customer order for outdoor planters, beautiful design, thick walls, perfect for PETG. I dialed
in what I thought was the perfect first layer, 0.2 millimeters height, cranked the z offset down
until those lines were flatter than a pancake. Flow at 120%, then at 60 degrees. The result, nozzle
drag on every single print.
Stress marks running parallel to the print lines and warping that got worse as the print got taller.
See, p e t g is more viscous than PLA. It's stickier when molten. When you squish it down, you're
not creating better adhesion.
You're creating stress. Think about it like this. PLA flows like water. You can spread it thin and
it stays put.
PETG flows like honey. Try to spread honey too thin and it fights back. We're not laying down
toothpaste here. We're placing a well bead.
The visual difference is striking. A proper PETG first layer should show distinct rounded lines that
touch each other but aren't flattened. You should be able to run your fingernail across it and feel
the texture. That smooth glass look that's over squished p e t g that's been stressed into
submission.
It might look prettier, but it's weaker at the molecular level. Alright. Here's the exact protocol
that turned my p e t g game around. This isn't a suggestion.
It's what I run on every single PETG print now. Z offset first. Start higher than you think you
need. With PLA, I run my nausea at negative 0.1 millimeters from perfect level.
With PETG, I'm at positive 0.05. You should see distinct lines that touch but don't merge
completely. If you can see gaps, go lower. If the lines are completely flat, go higher.
Temperature. This is critical. I run 240 degrees on the nozzle for the first layer, then drop to 235
for the rest. Bed temperature, 80 degrees.
Not 75, not 85, 80. Here's why those numbers matter. PETG needs heat to flow properly, but too much
heat creates stringing. That first layer at 240 gives you flow without the mess.
The bed at 80 creates just enough tackiness without overheating the filament. Speed is non
negotiable. 25 millimeters per second for the first layer. I don't care if your printer can do 200.
Slow it down, and here's the setting most people miss. Fan speed off for the first 3 layers,
completely off, then ramp up to 40% maximum. P e t g needs time to bond with itself and the bed. Hit
it with cooling air too early and you get adhesion problems that look like bed leveling issues but
aren't.
Last week, I printed a batch of camera mounts with these settings. Perfect first layers on every
single 1. No warping, no lifting, no stress marks. And when I did the bend test, they flexed instead
of cracking.
Want a cheat sheet for these settings? We've built a free 1 page PDF for Forge files listeners. It
has the exact numbers we just talked about for PETG plus PLA, ABS, TPU and ASA. Grab it at
forgefiles.com/chichi.
Now here's something that's going to sound backwards. You need a glue stick for PETG, but not for
the reason you think. Most purists will tell you that if your bed is properly leveled and your
settings are dialed in, you shouldn't need adhesives on a textured PEI sheet. For PETG, they're
wrong.
But not because PETG doesn't stick well enough, because it sticks too well. 3 months ago, I printed
a custom bracket for a friend's motorcycle. Beautiful print, perfect tolerances, exactly what he
needed. When I went to remove it from the PEI sheet, it took a chunk of the surface coating with it.
$50 build plate ruined because PETG can form a chemical bond with PEI that's stronger than the
coating itself. The glue stick isn't adhesive. It's a release agent, a sacrificial layer between
your print and your expensive build surface. I use a basic purple Elmer's glue stick, not hairspray,
not fancy bed adhesives.
Just the same glue stick you used in elementary school, 1 light coat, spread evenly with a damp
paper towel. Here's the technique. Heat your bed to 80 degrees. Apply the glue stick in overlapping
strokes then take a slightly damp paper towel and smooth it out until it's barely visible.
The result, your PETG print sticks perfectly during printing then releases cleanly when the bed
cools down. No fighting with the part. No damage to your build surface. No stress marks from trying
to pry it loose and here's a bonus.
That thin glue layer actually helps with first layer consistency. It fills in tiny imperfections in
your bed surface that you can't even see. Think of it less as glue and more as the ultimate non
stick coating for your $50 build plate. Don't just listen to this.
Go test it right now. Take a simple 50 by 50 millimeter single layer test, print and run it twice.
First with your old PLA style settings. Z offset cranked down, moderate temperatures, cooling fan on
from layer 1, then run it again with our protocol.
Higher z offset, 240 degrees, fan off, glue stick prep. Peel them both off the bed when they're
done. Feel the difference in flexibility. Look at the surface texture with a magnifying glass if you
have 1.
That hands on comparison is the fastest way to make this click. The difference isn't subtle. 1 will
feel brittle and stressed. The other will have that tough flexible feel that makes PETG worth the
extra cost.
Share your results with us on the Forge Files discord. We wanna see your before and after shots. The
link is in the show notes. Family Flourish has great projects for making things with kids.
If you've got a printer at home, their ideas pair perfectly. If you're turning these perfected
prints into a business, you need to hear our sister show, the Print Farm Profitability Podcast. Next
week, we're breaking down how to set up a fail safe shipping station. Find it wherever you get your
podcasts.
That's all the time we have for this deep dive. Keep your nozzles hot and your margins high. This is
Forge Files signing off.