The Perfect First Layer: A Complete Guide to Bed Adhesion

Why the First Layer Matters

If the first layer fails, the print fails. Full stop. You can have perfect temperatures, tuned retraction, and a calibrated extruder — none of it matters if that first layer doesn't bond to the bed. The good news: once you understand the principles, getting a perfect first layer becomes repeatable.

The Three Variables

1. Distance (Z-Offset)

The nozzle needs to be close enough to squish the filament slightly onto the bed. Too close and you get an elephant's foot, clogged nozzle, or gouged bed. Too far and the filament doesn't adhere.

What perfect looks like: A flat line with slightly bulging edges. Not a round bead sitting on top, not paper-thin.

How to set it: Most printers have a Z-offset adjustment. Start with your auto-level or manual leveling, then print a single-layer test square. Adjust in 0.05mm increments. If lines don't touch, lower Z. If the surface is rough or transparent, raise Z.

2. Temperature

Hotend temperature affects how fluid the plastic is. Bed temperature affects adhesion strength. Different materials need different temperatures.

PLA: 200-210°C nozzle, 50-60°C bed. Lower bed temps (50°C) work well with good bed surfaces.

PETG: 230-245°C nozzle, 70-80°C bed. PETG likes a warmer bed for adhesion.

ABS/ASA: 240-260°C nozzle, 90-110°C bed. High bed temp crucial for warping prevention.

TPU: 220-240°C nozzle, 40-60°C bed. TPU sticks aggressively — sometimes too aggressively.

3. Bed Surface and Adhesion Aids

Different surfaces work better for different materials. The bed also needs to be clean.

PEI sheet: Works for almost everything. Textured PEI gives a nice finish on the bottom. Clean with isopropyl alcohol regularly.

Glue stick: Helps with PETG and ABS. Also makes parts easier to release once cool. Apply thin, let dry before printing.

Hairspray: Budget option. Works for PLA. Needs reapplication every few prints.

Blue tape: Old school. Works for PLA without a heated bed. Replace frequently.

BuildTak / similar: Textured surface that grips well. Can be too aggressive for PETG — apply glue stick as release agent.

The Leveling Process

Manual Leveling

Most budget printers use four corner screws and a piece of paper. The process: heat the bed to printing temperature, disable steppers, slide paper under nozzle at each corner, adjust until you feel slight resistance. Then do it again. And again. Then check the centre.

The paper method is crude but effective. Thinner paper (standard printer paper) works better than thick cardstock.

Auto-Leveling (BLTouch, Inductive, etc)

Auto-level probes measure the bed surface and create a mesh. The firmware compensates during printing. But: auto-level doesn't actually level the bed mechanically, and it doesn't set Z-offset.

You still need to: (1) roughly level the bed manually so the mesh isn't compensating for extreme tilt, and (2) set the Z-offset so the nozzle is at the right height when compensation is applied.

Software Mesh Leveling

Even with auto-level, run a mesh calibration periodically. Beds warp over time, and some surfaces aren't perfectly flat. A 16-point mesh catches most variation. 25-point or higher for larger beds.

Common Problems and Fixes

Lines not touching: Nozzle too high. Lower Z-offset in 0.05mm increments.

Elephant's foot: Nozzle too low or bed too hot. Raise Z-offset slightly. For stubborn cases, lower first layer bed temp by 5°C.

One corner lifting: Bed isn't level. Re-level manually. Check that your bed is flat — some cheap beds have a dip in the centre.

Print sticks too well: For PETG on PEI, apply glue stick as a release agent. Let the bed cool completely before removing — thermal contraction releases most parts naturally. Don't force it; you'll damage the surface.

Inconsistent adhesion across the bed: Run mesh calibration. Your bed might have high/low spots. Consider a glass bed for perfectly flat surface (though glass has its own adhesion quirks).

Advanced Tips

First layer speed: Slow it down. 20-30mm/s for the first layer gives the plastic time to bond. Some slicers have a separate first layer speed setting.

First layer height: A taller first layer (0.28mm instead of 0.2mm) is more forgiving of minor Z-offset errors. Some slicers allow this independently of layer height for the rest of the print.

First layer extrusion: Slightly over-extruding the first layer (105-110%) can improve adhesion. Don't go higher or you'll get elephant's foot.

Bed cleaning: Oils from your hands reduce adhesion. Touch the bed surface as little as possible. Clean with IPA before important prints.

Brims and rafts: For difficult geometries or materials that warp, a brim adds surface area. Rafts are a last resort — they're ugly and waste material — but sometimes necessary for materials that won't stick any other way.

Material-Specific Adhesion

PLA: Easiest. Clean bed, correct Z-offset, and it sticks. PEI or blue painters tape both work.

PETG: Stickier but needs a release agent on smooth PEI or glass. A thin glue stick layer works. Let the bed cool fully before removing.

ABS/ASA: Difficult. Needs high bed temp and enclosure. ABS slurry (ABS dissolved in acetone) on the bed helps. Use a brim for large parts.

Nylon: Very difficult. Garolite bed or PVA glue stick required. High bed temp (80-100°C). Dry filament absolutely essential.

TPU: Sticks aggressively to almost everything. Apply glue stick to PEI so you can get the print off. Print slow on the first layer (15-20mm/s).

The First Layer Test

Print a single-layer square about 50x50mm. Watch it print. Adjust Z-offset live if your printer allows baby-stepping. The perfect first layer looks like a solid sheet with no gaps between lines. You shouldn't be able to see the bed through it, and the surface should be smooth to the touch.

Quick Reference

Z-offset is the most important variable. A clean bed matters more than expensive surfaces. Temperature affects both adhesion and release. Slow down the first layer. Use a brim for tricky parts. Let the bed cool before removing prints.