RC Tank Warfare community hobby forum

Herr Dr. Professor wrote:I have been checking in on your Comet now and then. I am impressed by how clean the castings are--seemingly free of any of the striations I have seen on other castings. In fact, given that you even used a specific color suggests to me that you might be intending for the castings to be unpainted. Could that be so?

Can any of you 3D printing wizards watching this thread recommend a simple primer from which I might learn about the types of casting plastics and 3D printers? (Actually "simple primer" is redundant wording, for emphasis .)

Thank you for taking an interest in my project. As with any 3D printer, accurate set up and calibration is vital to the success of the prints. All 3D prints have striations, there visibility depends a number of factors including the size of the print nozzle and the layer height. In my case I am using a 0.4mm nozzle and each layer is 0.2mm high.
There are available numerous materials that can now be used on a home printer. The most common, and what I am using for most of this project, is PLA (Polylactic Acid). The tracks are printed in ABS, Lego brick material, and the tyres will be printed in TPU which has a rubbery property. Other materials available include Nylon, Pteg, PLA+, Light Weight PLA, and so on. A Google search will provide you with a vast array of materials.
To answer your comment on the colour of the tank, Originally I intended to leave it in the gray colour but now I am going to paint and weather it. I have never done this before so any hints and tips on this would be appreciated.
Finally, if you are thinking about getting a printer the the Ender series (other printers are available) of printers are a good starting point because there is a lot of support out there if you run into difficulties.

A friend of mine kindly printed out the rear sprockets and hubs on his Markforged Mk2 printer. This is a high end desk top printer. The material used is called Onyx which is a carbon fibre loaded nylon. The parts are light and very strong.
The 3 parts were glued together with thick CA and a piece of track was used to keep everything in line.

Fenders and the rear of the hull done. Onto the top cover. [attachment=1]

There are 12 handles and 4 light guards made from the filament. There are 2 formers that are printed and then used to form heated filament around them. I drilled a 2mm hole in the former to act as an anchor while the warmed filament was pulled around the former.

Thank you for the interesting information on 3D printing. I have seen others recommend the Ender printers.
I approve of you wanting to paint the model. Have you any experience painting models--not necessarily 3D printed, but any plastic models?

Herr Dr. Professor

About 40 years ago I used to make plastic kits. The painting on them was always dubious! I thought I had done a good job if I didn't get a fingerprint on the paint!
Painting has come along way since then so any advice would be greatly appreciated. I have a Badger 155 airbrush which up to now I have only used to spray water onto my tissue covered model aircraft.
I am thinking about doing a base coat using Vallejo UK Bronze Green surface primer. Any thoughts on this?

That's the hull done, now onto the wheels. The tyres will be printed in TPU which has a rubbery property. I am still waiting for this to arrive through the post. I have never printed this before so another new experience awaits.

TPU is quite easy to use, you don't need to heat the bed to get it to stick (in fact its best if you don't, otherwise it sticks a little too well!) Slow print speeds are a must tho, and a direct drive extruder is preferable.

Tiger6
Thanks for the tips. I have a direct extruder. The filament should arrive Monday so I will let you know how I get on with it.

Now that my house guests have all departed I might be able to get back to using my 3D printer. I also have some TPU, but haven't printed with it yet. You Comet prints are really nice though.