Print

If you have not picked a model yet, start with Voicings — it links every model page and explains how the shared platform relates to each build. It's a good idea to have the electronics on order so that you have them when you're ready for the next stage.

The Relay body is printed in multiple parts and bonded together. The download bundle below is the released reference body used for Relay Lipstick today.

Questions while you work? Chat in the Discord thread →

Getting the print right is the foundation everything else sits on — a warped body or delaminated joint will cause problems that are hard to fix later. Sometimes, it's better to troubleshoot and reprint a piece instead of trying to force it all togehter later, but some parts are more critical than others.

Material

Print with PET-CF (carbon fiber filled) or PET-GF (glass fiber filled). These materials are dimensionally stable under string tension and temperature variation in ways that PLA and PETG are not.

The Body overview lists the filament with a purchase link. Two spools are required for a complete body, but there's no buffer; if any part of the print fails, you won't have enough material to finish.

What you're printing

• K7RHY Relay Flex Body.3mf — the main body structure. The core of the body that goes from the neck through to the bridge must be printed with fiber reinforced materials (PET-CF or PET-GF) for best sound and stability. You can print the rest with any material, but it's much simpler if you keep the material consistent throughout. The choices you make will have some impact on the tone of the guitar, but it's minor enough that you don't need to consider that aspect. The main issue is with shrinkage. Every material prints a little differently and experiences some level of shrinkage. When you use a single material throughout, the parts tend to shrink in ways that still allow them to fit together without modification. When you start mixing materials, you may need to do some sanding to get everything to fit together cleanly.
• K7RHY Relay Flex Cap.3mf — the front face that bonds to the body. Print in PET-CF or PET-GF. The way the model is cut, you should not mix materials here. Also, since the bridge is mounted through this layer, you need to use structural materials.
• K7RHY Relay Flex Accessories.3mf — small parts (pickup rings and similar). These parts aren't structural, so you can print them with whatever filament you like. This might be a good opportunity to inject some color into your build.

Body and Cap bond together into a single structure in the Bonding step. Print both before moving on. You can bond the body before finishing the cap, but you must not bond the cap components together without the body. I've designed the cap to have some room for adjustment so that it will fit the body even if the body has undergone some minor dimensional shifts. If you fuse the cap without the body, then you won't be able to fine tune it to fit the body.

Print time

With one printer, expect the printing to take about a week. Slower speeds improve layer adhesion with filled materials, so do not chase speed at the expense of quality here.

Orientation and layer direction

Orientation matters more than it looks like it should. The neck pocket and bridge mount areas need to be printed so that layer lines run perpendicular to the primary stress direction — this reduces the chance of delamination under string tension. The .3mf files include pre-set orientations; do not rotate the parts unless you are trying to solve a problem with your machine.

Bed adhesion

PET-CF sticks well to textured PEI sheets or smooth high temperature engineering sheets. The print profile in the model files have finely tuned settings to maximize your chances of success. The most likely cause of failure is warping that causes the model to lift at the edges. If they fail in this way, it'll happen 1-2 hours into the print. Wacth for this and abandon the print if the edges start pulling up. Use a clean plate and glue for the best results. A advanced adhesive isn't required. I use a light coat of hairspray.

After printing

Let all parts cool on the bed before removing them. This minimizes warping that will help the parts fit togehter once printed.

Print settings

If you're not able to use the provided print profiles, here's what you need to know to set up your own prints. These settings come from the released Bambu Studio profiles in the .3mf files. I sliced them for a Bambu Lab P1S with a 0.4 mm nozzle on a High Temp Plate, using a 0.20 mm profile.

Use these as the important targets, not as a promise that every slicer will expose the settings with the same names:

• Layer height: 0.20 mm
• First layer height: 0.20 mm
• Line width: 0.42 mm
• First layer line width: 0.50 mm
• Outer wall line width: 0.42 mm
• Inner wall line width: 0.45 mm
• Top shell thickness: 2.0 mm
• Bottom shell thickness: 2.0 mm
• Fill multiline: 3
• Bed temperature: 90°C
• First layer speed: 50 mm/s
• Brim gap: 0.05 mm for Body and Cap; 0.10 mm for Accessories

If you're using Bambu Studio or OrcaSlicer, enable Auto circle contour-hole compensation (enable_circle_compensation) for the Body and Cap. This is still experimental, but it has helped the dowel and screw-hole fit in my prints. The released Body and Cap files have it enabled; Accessories do not depend on it.

Structural Body Component Settings

The Body file has six plates. The first two plates are the structural core of the instrument and intentionally use stronger settings than the rest of the Body file:

• Plate 1: Top Core — 8 wall loops, 30% infill
• Plate 2: Middle Core — 8 wall loops, 30% infill

For the remaining Body plates, use:

• Wall loops: 6
• Sparse infill: 15%
• Infill pattern: gyroid
• Fill multiline: 3
• Supports: enabled, tree auto, build plate only
• Brim: outer only, 10 mm

Do not reduce the first two Body plates to the general body settings. Those two plates carry the main neck-to-bridge load path, so the extra walls and infill matter more there than they do on the cosmetic body sections.

Cosmetic Body Component Settings

The less-loaded Body sections can use the general Body settings above: 6 wall loops, 15% gyroid infill, tree auto supports from the build plate only, and a 10 mm outer brim. These pieces still benefit from PET-CF or PET-GF for dimensional consistency, but they are less sensitive than the Top Core and Middle Core.

Cap Settings

The Cap bonds to the Body and carries the bridge load through the front face, so treat it as structural:

• Wall loops: 8
• Sparse infill: 20%
• Infill pattern: gyroid
• Fill multiline: 3
• Supports: enabled, tree auto
• Brim: outer only, 10 mm

Keep Auto circle contour-hole compensation enabled for the Cap as well. It is especially useful anywhere the model depends on holes or circular openings fitting without post-processing.

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