First layer won't stick — and first layer sticks too hard

Almost everyone who prints has had a print come loose in the first ten layers, and almost everyone fixes it by trial and error: more glue, more heat, lower the nozzle, change the plate. That sometimes works, but it doesn't tell you what to do next time. This article goes cause by cause, and separately covers the reverse problem few people name: parts that stick too hard.

What makes a first layer stick

A bead of plastic just out of the nozzle is soft. It sticks to the bed when three things happen at once: the nozzle squashes it flat so the plastic fills the texture of the surface, the surface is clean so no oil film sits in between, and the bed is warm enough that the bead doesn't set before the second layer lands on it. Those three conditions map to three different adjustments, and diagnosis is working out which one is missing.

Working against all three is shrinkage. Plastic shrinks as it cools, and the bigger the part, the bigger the total pull at its edges. That's why a small part sticks well on exactly the setup where a large part lifts at the edges: nothing changed but the area.

The order of diagnosis

1. 01

   Wipe the surface with IPA

   The cheapest step and the most often skipped. Prusa recommends isopropyl alcohol of 90 % or more for smooth PEI, and warm water with dish soap for stubborn grime, read 07/09/2026. 70 % medical alcohol removes dust but leaves water and the bottle's additives behind.

2. 02

   Don't touch where you're about to print

   Bambu Lab states in its build plate documentation that oil from skin on the surface reduces adhesion. Hold the plate by its edges, and if you do touch it, wipe again.

3. 03

   Adjust nozzle height, then print a test patch

   Print a thin one-layer square and look at it. The lines should touch into one continuous, slightly flattened surface with no gaps and no ridges. Gaps mean the nozzle is too high; ridges and burrs mean too low.

4. 04

   Set bed temperature by material and plate

   Don't look it up by plastic name. Look it up by plastic plus plate — the table below shows the same plastic with two different ranges on two different plates.

5. 05

   Reduce fan and speed on the first layer

   Most profiles already turn the fan off for the first layer; if you've edited it by hand, check. A slower first layer gives the plastic more contact time before it cools.

6. 06

   Add a brim when the part has small feet

   A brim buys adhesion area exactly where it's needed: at the edges, where shrinkage pulls hardest. For tall parts on narrow bases, it's often the only thing to add.

7. 07

   Only now, glue

   Glue is an intermediate layer with two opposite uses: more grip for difficult materials, or separation for materials that grip too hard. The section below says which is which.

Which plate for which material

A build plate isn't an inert sheet of metal. Its coating decides which materials stick, how hard, and how long the plate lasts. The table summarises the surface types commonly used in Vietnam.

Bed temperature belongs to a pair, not a material

This is the most common mistake when reading the label on a spool. Bambu Lab's table for its own materials and plates, read 07/09/2026, lists PLA at 35–45 °C on the Cool Plate but 45–65 °C on textured and smooth PEI. Same spool, two numbers 20 °C apart, and what decides it is the coating, not the polymer. See sources.

The reverse problem: sticking too hard

On smooth PEI, PETG is the classic example. It doesn't come loose — it sticks so hard that when removed, the part takes a piece of PEI with it. Prusa groups PETG, ABS, ASA, XT and CPE among materials whose grip on the smooth sheet can be excessive, and the recommended fix is a thin layer of glue — here glue doesn't bond, it separates, read 07/09/2026. See sources.

• —Wait for it to cool before removing. PEI releases parts when cool; Bambu Lab recommends waiting for the plate to reach 35 °C or below before flexing it.
• —Flex the plate, don't pry. Every deep scratch in the coating becomes a spot where the next part sticks harder than everywhere else.
• —Wide, thin parts can't be released by flexing. Flat panels, lithophanes, name plates — for these, wick alcohol into the edge of the contact and use a thin spatula.
• —Don't use acetone on textured plates. Prusa recommends acetone only for smooth PEI, about once a month; textured and powder-coated sheets get IPA only.

Elephant's foot: a flared first layer

When the bottom few layers bulge wider than the rest of the part, it has elephant's foot. The cause is plastic at the bottom staying soft while the weight above presses down — usually a bed that's too hot, a nozzle set too low, or both. It doesn't affect strength, but it ruins fit dimensions and stops the part standing flat.

Glue isn't there to make up for a dirty plate. It's the intermediate layer you choose once you know whether you need more grip or less.

Workshop conditions in a hot climate

• —Ceiling fans and air conditioning blowing at the printer. A crosswind over the bed cools the first layer unevenly and makes the part's edges shrink first. It's the most overlooked cause in air-conditioned offices.
• —Dust in a machine shop. Metal filings and grinding dust on a PEI sheet don't wipe off with a dry cloth. Bag the plate when the printer sits idle for long.
• —High humidity makes filament wet, and wet filament sticks badly. A bubbly extrusion has less real contact with the bed than it appears to — the drying routine is in how to dry filament.
• —Large heated beds take time. A large bed needs a long time to reach its set temperature; let it soak for a few extra minutes before starting rather than trusting the displayed number straight away.

When the fault isn't the plate

1. 01When the filament is wet. Popping extrusion and pitted lines never give an even first layer. Dry first, diagnose after.
2. 02When the bed isn't flat. If one corner sticks and the opposite one doesn't, that's bed geometry, not surface chemistry. Rerun auto-levelling, and check the plate isn't warped or sitting on a trapped bit of plastic.
3. 03When the nozzle is partly clogged. Less plastic than commanded makes the first line thin and broken — see the troubleshooting guide.
4. 04When the part lifts from shrinkage. Adhesion only delays it, it doesn't solve it. You need ambient heat, or a lower-shrink material — the substitution guide is the place to start.

Once the first layer is stable, most of the remaining effort goes into calibrating each spool rather than the plate — the order of calibrations is in calibrate your printer per spool.