Mounting and Finishing a 3D-Printed Neon Sign

Mounting options

Clear acrylic backing

Stick the channel to a sheet of clear acrylic, usually cut to a rectangle around the sign or to its outline. It makes a channel-only sign look as if the light floats in front of the wall, and it keeps all the pieces flat and aligned. Clean the acrylic, peel the protective film and bond the channel with clear epoxy, a plastic-safe adhesive or double-sided tape. Then fix the acrylic to the wall with standoffs.

Standoffs

Standoffs are small metal barrels that hold a panel away from the wall. They are the usual way to mount an acrylic-backed sign and give a shadow on the wall behind it. Use wall anchors suited to your wall type and pre-drill through the acrylic with the right drill bit; acrylic cracks if it is drilled carelessly or screws are over-tightened.

Foam tape

A strong double-sided foam tape is fine for light signs on a smooth, clean, flat surface. Test a small piece first and press firmly. It is not a good idea for heavy signs, textured walls or surfaces that may be repainted.

Hanging

For a back-plate or solid-letter sign, hang it from two points with wire, chain or fishing line, so it cannot tilt. Fix the hanging points to the plate or to small loops printed on the sign, not to the strip. Hang from two points so the sign stays level.

Make the glow brighter: white inside

The colour of the channel affects the light. A white or very light interior reflects light that would otherwise be absorbed, so the strip looks brighter and more even. You can print the channel in white filament, or paint the inside of the channel with matte white paint before you fit the strip. For a dark frame look, print or paint the outside black and the inside white.

Sanding, filling and painting

1. Remove blemishes. Cut away any stringing and sand the cut edges and joints lightly with fine paper.
2. Fill the seams. Where pieces meet, a thin layer of filler or glue-and-dust paste fills any gap. Sand flush when it is dry.
3. Prime. A plastic primer helps paint stick to PLA and PETG.
4. Paint thin coats. Several thin coats look better than one thick coat. Keep paint out of the dovetails and off the floor of the channel where the strip sits.
5. Seal. A clear matte coat protects the paint; test on an offcut first.

Hide the power lead

• Run the cable behind the acrylic or along the underside of the base, and out near the bottom of the sign.
• Fix it with small clips so it cannot pull on the strip.
• Leave some slack at the sign, so that moving the sign does not strain the joints.
• Keep the supply in reach, ventilated, and not covered by the sign.

Tools and materials

• A clear acrylic sheet (3 mm is a common thickness), cut to size.
• Standoffs and matching screws, and wall anchors suited to your wall.
• Clear epoxy, plastic-safe super glue or strong double-sided tape.
• A drill, bits for acrylic and for your wall, a level and a pencil.
• Isopropyl alcohol and a clean cloth to degrease the surfaces.
• Cable clips and a few cable ties.

Step by step: acrylic backing on standoffs

1. Hold the finished sign on the acrylic and mark where it will sit; keep the cable exit clear of the edge.
2. Clean the acrylic and the back of the channel with isopropyl alcohol and let them dry.
3. Bond the channel to the acrylic in short sections, pressing each one flat, working from the centre outwards.
4. Let the adhesive cure fully before you move the panel.
5. Mark the hole positions on the wall with a level, drill and fit the wall anchors.
6. Drill the acrylic corners slowly with a bit made for acrylic, with a piece of wood behind it.
7. Fit the standoffs, hang the panel and tighten by hand, not hard.

Wall anchors by wall type

Troubleshooting

Where not to put it

PLA softens at the temperatures a closed car or a window in direct sun can reach. If the sign will be in a hot spot, print it in PETG. Indoor signs are the intended use; if you want one outdoors, you need a waterproof-rated strip and supply and a properly sealed installation, which is beyond a basic printed channel.