Tech tips for beginners
We use polylactic acid PLA plastic filament for printing these models (the color of the material does not matter if you are going to paint them). There are different specifications that may vary depending on the printer you use. Some newer models can use ABS to print as well. In any case, you should always ensure the bottom surface is touching the printing bed by performing calibration. You do not need to do it every time. You normally do it once, at the time you set up the hardware and the software.
You need to import the file to your 3D printer software. From within the software check to ensure the first layer of each element is sitting on the bed. Always avoid overhangs greater than 30 degrees! When printing is completed, use sand paper to clean up the model and remove any excess from the surface. You must realize that entry level 3D printing is not perfect and is not as precise as CNC. Perfect measurements need not deliver perfect printout. Manual fine tuning is often necessary! Also, the surface will not be as smooth as what you can find in manufactured ABS/nylon kits. If you expect something smooth you must do sanding yourself.
If your printer does not have bed heating, glue stick can be applied on the bed prior to printing. If it is not strong enough, add a think layer of liquid glue before the glue stick.
Still, when your model is large and tall, adhesion can be poor. What you may do is to enable build plate adhesion in Cura (which will print brims to increase the surface area that the print has with the build surface), then pause printing at around 20% progress and use tape to quickly secure the brims and resume.
When mounting electronics such as cooling fan and RC ESC, we often recommend the use of hot melt adhesive AKA hot glue. It is a form of thermoplastic adhesive that is packaged as a solid cylindrical stick. It can be applied with a continuous-duty heating element that melts the plastic glue. A cheap glue gun will do the job well.
The glue can solidify in less than a minute. It is pretty strong and durable. In fact it is removable with the use of a little bit of force.
20% fill rate is ideal primarily for a quick prototype for test fitting. If you want it to be durable, 50% fill is the minimum.
It can become tricky when dealing with screw holes. Entry level printers seldom get screw holes printed accurately, therefore when we designed our models we intentionally made the holes slightly larger.
If you feel that the screw or pin or whatever that passes through the hole is loose, wrap a thin layer of water seal tape around it.
When you design and print gears, keep in mind it is very uneasy to achieve 100% accuracy. In a gearbox, a slightly oversized gear can make things too tight and kill the motor. Our advice is that you should carefully consider the “thickness” – make the gear slightly thinner and shim using washers if found necessary. It is easier to shim to reduce play than to file plastic away for smoother rotation.