Painting Circles with a Low-Speed Drill

[sequoiaranger]

I stumbled on this technique last night, when trying to think of how I was going to put a nice, even "ring" of color around my propeller spinner for my Jinpu-Kai. Unfortunately for us modelers, the human eye is VERY GOOD at noticing even the very slightest discrepancy in consistency of line or curve. (JMN's eyes are even better, but then again, they aren't really human.)

My electric drill/screwdriver has a very low-speed setting, more or less infinitely variable with thumb pressure, so I hit on an idea--put the propeller on a shaft, stick the shaft in the drill, and rotate the prop slowly while holding a paintbrush to it as it turns. It **SHOULD** make a finely-defined, super straight line with even edges.

It worked! Of course, you have to "balance" the shaft so that the prop rotates without wobbling, and have to be VERY CAREFUL how much thumb pressure you put on the trigger of the drill in order to keep the revolutions low and consistent. I got my drill down to about one revolution per second.

I used a Q-tip for a shaft, whittled down a bit then put the propeller onto the shaft with mere finger pressure (a little white glue might have helped, but was unnecessary). I put the electric drill drill-bit up and held it between my thighs like a vice. I used one hand to activate the drill, and the other to dip the paintbrush in the paint, and then CAREFULLY and slowly lower the paintbrush onto the slowly-rotating spinner and hold it there for a few seconds. Voila, as the French say! I didn't think of it at the time (but now do) to hold my thighs near a stable object so I could rest my painting hand on something. The less "moving parts" the better. I had to hold my painting hand VERY STEADY in mid-air, but it worked (example below).

This technique can also be used for painting wheels, tailhook stripes, or any other rotary-symmetrical items.

[Jeffry Fontaine]

Walther Doering came up with a similar idea over on modellversium.de by suggesting that you can use a dead muffin fan from a computer or other electronics device as a finger powered turntable to paint wheels.  I suppose it would also work for propellers with the added benefit that you don't have to have one hand on the switch so you can use both hands to work the part that needs to be painted. 

[BlackOps]

I have to admit, that is a very straight line. 

[sequoiaranger]

>...suggesting that you can use a dead muffin fan from a computer or other electronics device as a finger powered turntable to paint wheels.<

I don't know where the appellation "dead muffin fan" comes from, but those computer fans are almost frictionless and, as you say, can become a small turntable powered by a finger that has enough angular momentum to keep spinning awhile while one holds a paintbrush to an item.   Great idea.

[Jeffry Fontaine]

Craig,

The description "Muffin Fan" is usually associated with the cooling fans such as the one in the link due to the small size, some not much larger than a muffin.  Dead Muffin Fan was my way of saying burnt out or broken fan.  But there may be other descriptive terms applied for this small cooling fan that I am unaware of. 

Personally, Muffin Fan is a unique enough name to really help remember what the thing is.