Choosing LED Strips for 3D-Printed Channel Letters
The LED strip decides how bright your letters are, how even they look and how much power they need. It also decides whether the strip fits at all, because a wide strip will not go into a narrow stroke. This guide compares the strip types, explains the numbers on a listing, shows how to fit the strip into a letter and how the LED Letters tool helps you check the fit.
SMD or COB
| SMD strip | COB strip | |
|---|---|---|
| Look | Visible dots of light | Continuous line of light |
| Even glow in shallow letters | Needs depth and a good lid | Smoothest result |
| Brightness | Varies with the chip and density | Often bright and uniform |
| Flexibility | Flexible | Flexible, usually a little stiffer |
| Cost | Lower | A little higher |
For shallow letters, or if you want the cleanest result, choose a COB strip. For deep letters, an ordinary SMD strip is fine and cheaper.
Voltage
Strips are 12 V or 24 V (some are 5 V). Choose the voltage to suit the power supply you want. Longer runs are easier at 24 V, because the voltage drops less along the strip. A supply must match the strip’s voltage. Read how to wire and power a sign for sizing the supply.
Width and fit
Strips come in widths such as 5, 8 or 10 mm. The wider the strip, the more light, and the more room it needs. The LED Letters tool flags areas that are too narrow for the strip you choose. If a stroke is too narrow, you can choose a narrower strip, a bolder font or a bigger size.
Brightness and colour
- Colour temperature: warm white (about 2700 to 3000 K) looks cosy; cool white (about 6000 K) looks crisp.
- Colour strips (red, pink, blue) are a good match for signs where the colour is part of the brand.
- RGB strips can change colour but need a controller and a matching supply.
- LEDs per metre: more LEDs in a metre means a smoother glow.
- Power per metre: a higher wattage per metre is brighter, but also draws more power and makes more heat.
Power, weight and cost estimates
In the tool, once you have chosen the strip, you see estimates of the power, the weight and the cost of the sign. Use the power estimate to choose a supply with about 20% headroom. The weight tells you what to expect when you hang the sign, and the cost helps you decide between strip types.
| Step | Example |
|---|---|
| Strip needed (from the tool) | 1.5 m for a set of letters |
| Strip rating | 10 W per metre (from the listing) |
| Load | 1.5 × 10 = 15 W |
| With 20% headroom | 18 W |
| Supply to buy | A supply rated at least 18 W; the next size up (24 W or more) is fine |
Fitting the strip inside a letter
- Clean the surface inside the letter before you stick the strip. Dust and finger grease ruin the adhesive.
- Follow the shape. Run the strip along the long axis of each stroke, bending it gently round the curves.
- Respect the bend radius. Do not bend the strip tighter than its datasheet allows; it can kink or the LEDs can fail.
- Cut only at the marks. For sharp corners, cut at a mark and join the pieces with a corner connector or short wires, rather than folding the strip.
- Leave the tail. Keep a few centimetres of strip or wire at the end of each letter for the connection.
Heat and ventilation
LED strips make heat, and a small enclosed letter holds it in. A strip running at its rated power in a sealed letter can become warm enough to soften PLA over time. Use a strip with a modest wattage per metre, run it at full brightness only if you need to, and leave a small vent or a thin gap at the back if the sign will be lit for many hours a day.
Buying checklist
- Voltage matches your supply (12 V or 24 V).
- Width fits the narrowest stroke you want to light.
- COB for shallow letters; SMD is fine for deep ones.
- Colour and colour temperature suit the sign.
- Cut marks and a cut spacing that suits your letters.
- Adhesive backing, or plan to glue it.
- A little extra length for mistakes and tails.
Questions people ask
What is the best strip for a shallow letter?
A COB strip, because it looks like a continuous line of light and hides the individual LEDs best.
Can I use a strip that is wider than the stroke?
No. The tool flags areas too narrow for the strip. Choose a narrower strip, a bolder font or a larger letter.
Do I need a controller?
Only for colour-changing strips or dimming. A single-colour strip can run straight from a matching supply.
Can I power several letters from one supply?
Yes, as long as the supply’s wattage covers the total of all the strips plus headroom, and the strips are wired in parallel from the same voltage.
Keep reading
How to Make 3D-Printed LED Channel Letters (Light-Up Letters)Design and print light-up channel letters: walls, depth, lid style, LED strip fit, wire holes, logo upload, and the STL, DXF and SVG files you get.Diffuser Lids and Even Glow for Light-Up LettersHow to avoid hot spots in 3D-printed light-up letters: lid colour and thickness, infill, depth, LED strip type and spacing, and the four lid styles of LED Letters.
How to Wire and Power an LED Neon Sign (Power Supply, Cutting, Connections)Choose the right power supply for an LED neon strip, work out the wattage from the strip length, cut and seal the strip, connect it safely and test it before you finish the sign.Written and checked by the Volucore team against the behaviour of our tools. Spotted a mistake or something out of date? Tell us and we will fix it.