saw this home made tool on this video: https://www.youtube.com/watch?v=cAXM1Gyt93g&t=358s go to around the 3:30 mark and I tried to copy his idea.
Here are some pics-
Not pretty but I think it will work. I had the 4x4 in the shed so went with it, but I think with tinkering one could go for a smaller base. You 3D guys could make something out of this idea I’m sure.
I’ve been pinning each end to a piece of cardboard, spraying one side, then flipping it over to paint the other side.
I never thought about that. wow. thanks for the nice ideas.
That is a great idea. I too have pinned tracks to cardboard in the past, which does not get into every nook and cranny.
The you tuber is the person who invented it! I’m already thinking of a updated version.
A system that works like a real tank would be great.
Have one small drum as the drive sprocket, attached to a motor. Have a second small drum attached to a tension spring as the idler. Connect the motor to a sewing machine type foot pedal.
Slip the tracks over both drums. Allow the tension spring on the idler to remove all slack. Press the foot pedal to slowly turn the drive sprocket. Hold your airbrush in one place and paint the tracks as they go by.
Make sure the drive sprocket is at the top and the tracks spin towards you so that if you press the foot pedal too hard and a link breaks, the whole run lashes out and smacks you in the face. The TikTok video makes itself.
I hope that you try this! 
That’s your job. I just make recommendations.
Sounds like my wife …
Ha ha!
When it comes to model building, if I make a recommendation, it is a pretty good idea to do the exact opposite of whatever I suggest.
I’ll keep that in mind!
