How to Make a 3D-Printed LED Neon Sign: The Complete Guide

What you need

• A 3D printer. Any printer works, because a large sign is split into pieces that fit your bed. A 180 mm bed prints it too, just in more pieces.
• Filament. PLA is fine indoors. PETG is better if the sign will sit in a hot spot, such as a sunny window. White prints reflect more light inside the channel; black prints look like a dark frame around the glow.
• An LED neon strip (silicone “neon flex”) of the side-bend type, 12 V or 24 V. Buy it first, because its size decides the channel width. See LED neon strip sizes and fit.
• A power supply that matches the strip voltage, with some headroom. See how to wire and power an LED neon sign.
• Small parts: strip end caps or silicone sealant, wire connectors or a soldering iron with heat-shrink tubing, super glue or a plastic-friendly adhesive, and a way to mount the sign (screws and standoffs, foam tape or a clear acrylic backing).

Step 1: choose the strip before you design

Most neon strips sold for signs are a rectangle in cross-section. The most common size is 6 × 12 mm, and it is the default in the Neon Sign tool. The 6 mm side goes across the channel and the 12 mm side stands up out of it. Different brands vary by up to half a millimetre, so measure your own strip with calipers rather than trusting the label.

Choose a side-bend strip, the kind that bends flat like a ribbon lying on its side. A top-bend strip bends the other way and will not follow lettering. If you are unsure, order a short sample first; a one-metre piece is enough to test the fit.

Step 2: type the name and choose a font

Open the tool and type up to four lines. The font decides how the strip runs, so choose it with the strip in mind. A single-line script font gives one tube that follows the pen stroke, like handwriting, and can run a whole word as one continuous piece. An outline font gives two tubes, one around each edge of every letter, and uses more strip. The tool offers 21 fonts, six of them single-line, and you can upload your own. Single-line vs outline fonts explains the trade-offs.

In the layout view you can drag any letter to move it or overlap it. Set Drag moves to “One letter” to nudge a single letter, or “Rest of line” to open or close a gap and carry everything after it. Where outline letters overlap they share one neon line, shown in blue, so you do not waste strip or print two tubes on top of each other.

Step 3: set the size

You can set the size by width or by height. A name sign of 40 to 60 cm across is a good first project: big enough to look like a sign, small enough to print in an evening or two. The tool shows the finished size, the number of pieces and the length of neon you need, so you know how much strip to buy before you print anything.

As a worked example, the name “Sofia” in a single-line script at 600 mm letter width comes out at 610 × 355 mm printed, needs 2.46 m of neon and splits into 9 pieces on a 256 × 256 mm bed. Switch to the outline font Chewy and the same name needs far more strip, because every letter is outlined twice.

Step 4: pick the body style

The body is the printed part. Channel only, the default, is just the U-shaped channel that follows the neon: light, fast to print and meant to be mounted on acrylic or a wall. Back plate adds a thin plate in the shape of the letters, and Solid letters makes the letters full height. Choosing the body style compares them.

Step 5: tell it your strip and your printer

Under Neon strip, choose your strip size (or type the exact width and height) and set a fit clearance. The default is 0.40 mm, which makes a 6 mm strip sit in a 6.4 mm channel: snug enough to stay put, loose enough to push in. Under Printer & pieces, choose your printer or enter your bed size and margin, and leave Split to fit the printer on. The tool cuts the sign into numbered pieces, and with Hidden connectors on it adds a dovetail key in the floor of the channel at every joint; the strip covers it from the front and the wall hides it from the back.

Step 6: check the glow and download

Switch to the Glow view to see the sign lit on a dark wall and try the preview colours. The colour is only a preview; the printed sign is the colour of your filament and your strip. Then download the pieces. The ZIP contains one STL per numbered piece, an assembly guide picture that shows where each piece goes, a 1:1 SVG template and a README with your settings.

Step 7: print the pieces

Print each piece flat with the base on the bed. No supports are needed. A 0.4 mm nozzle and 0.2 mm layers are a good starting point, with the wall settings matched to the tool: a 1.6 mm channel wall is four perimeters at 0.4 mm. Use moderate infill; the base is only 2 mm thick, so a few top and bottom layers do the job. Print settings for neon sign channels goes through material, orientation and the usual problems.

Step 8: assemble the pieces

Lay the pieces out on a flat table following the assembly guide, then join them one at a time. The dovetail keys line the pieces up; a drop of super glue on each joint makes it permanent. Where the tool warns that a joint on a tight curve got no hidden connector, glue it directly and hold it flat until it sets. If you engraved the piece numbers, they are cut into the underside so they never show.

Step 9: fit the strip and wire it

Press the strip into the channel from one end, starting with a free end. Do not stretch it: bend it, and keep to the minimum bend radius in its datasheet. Where the strip runs out of a letter, cut it only at the marked cut points and seal the cut end with an end cap or silicone. Connect the strip to the power supply with the correct polarity. Wire and power an LED neon sign covers the supply size, connectors and safety.

Step 10: mount it

A channel-only sign is light, so mounting is simple: stick it to a clear acrylic sheet, fix it to the wall with standoffs, or hang it with wire. See mounting and finishing a 3D-printed neon sign for the options and for painting the channel white for a brighter glow.

Troubleshooting