Print settings
Suggested slicer settings for the parts you download from Rocket Builder. The fits between the parts were tuned on a Bambu Lab P1S with these settings.
Set the seam to Random, not Aligned. An aligned seam stacks a small ridge down one side of every shoulder and socket, and that ridge is what makes the joints bind. With random seams the parts slide together as designed.
Settings
| Material | PLA or PLA+The masses and flight numbers assume PLA (1.24 g/cm³). PETG works but is a little heavier. |
|---|---|
| Nozzle and layers | 0.4 mm nozzle, 0.42 mm line width, 0.2 mm layers0.16 mm layers give a smoother motor-cap thread if it binds. |
| Seam position | Random (never Aligned)Bambu Studio and OrcaSlicer: Quality → Seam → Seam position. PrusaSlicer: Print Settings → Layers and perimeters → Seam position. Cura: Walls → Z Seam Alignment. |
| Walls | 2 walls (perimeters) at 0.42 mmThe tube walls and fins are 0.84 mm, exactly two lines, so they print as two clean walls with no gap fill. Top and bottom: 5 layers. |
| Infill | 20% gyroidOnly the thick bits have any: the tail, the motor cap, the nose tip. |
| Orientation | As downloadedEvery STL already rests on its print face. Don't rotate the parts. |
| Supports | NoneThe overhangs (launch-lug undersides, the cord strap, the nose's tie-bar recess, the small relief at each shoulder's root) are 45 degrees or bridged by design. |
| Bed adhesion | Clean PEI or glue stickA brim only on the rod standoff, which is tall and thin. |
| Elephant's foot | Your slicer's usual compensationThe shoulders already have a 0.5 mm chamfer at the bed edge. If a joint still binds, sand the lip off the bottom edge. |
If a joint is too tight or too loose
- Check the seam setting first: an aligned seam is the most common cause of a tight joint.
- Print the test-fit pieces (also under the Download button) before a whole rocket: short slices of the body joint, the nose and the motor-cap thread.
- In Advanced mode, Fits and joints lets you change the gap per side for the body joints and the nose. A few hundredths of a millimetre makes a clear difference.
- Body joints are glued (medium CA, adults only), so they're a snug push fit. The nose is not glued: it should slide in by hand, stay put upside down and come off with a firm pull, because the ejection charge has to push it off.
- Parts that come out slightly oval on every print point to the printer (belt tension) rather than the fit setting.
After printing
Sand any lip off the bottom edge of each shoulder, check every joint dry, then glue the body joints. Your download's build_notes.txt has the parachute, motors and launch field for your rocket. Fly by the NAR Model Rocket Safety Code.