White Lettering on Tires

I've never been a fan of painting the bodies on my cars, so painting the tires never even crossed my mind, at least until I saw fellow modelers do it on their cars.  It is practically expected nowadays.  For example, after I built and painted a re-re Tamiya Sand Scorcher and posted pictures of it on TamiyaClub in 2010, a couple members replied that I needed to paint the letters on the tires to make it look complete.  I agreed with them, but at the time I did not have a method for doing so that did not seem completely tedious or error-prone.  Threads have popped up every so often where someone asks how to paint the letters on tires.  The responses are usually limited to using white paint and a toothpick, or a pin or similar and just letting it flow into or onto each letter on the tire.  I always considered that method extremely tedious and time consuming.  It is a time honored method, but not one that I felt that I had the patience or skills for.  I guess I am not a true "modeler" in that sense.  I always imagined a drop of white paint splotched in between two letters because I put too much on the end of the toothpick and it dripped before it got to its final destination.  Or the paint would dry on the toothpick too quickly and wouldn't flow into the letters.  With these thoughts in my mind, I gave up before even trying anything.

But, a recent post on TamiyaClub (http://tamiyaclub.com) that described a white ink pen that can be used instead of toothpicks got me excited enough to give it a try.  The pen is made by Sakura, a company headquartered in Japan, and it's called the Gelly Roll(R) ink pen.  Their US website Gelly Roll(R) product page (http://www.sakuraofamerica.com/gelpen) doesn't even list white as an available color, but it does exist.  I located a supplier on the net and had a pack of three pens in my hands a few days later.

Three-pack of Sakura Gelly Roll pens with white ink

The pen is actually a ball point, which I'd never thought could be used for painting tires.  The ball is 0.8mm in size which is considered medium point and draws a 0.4mm line.  I did not see any fine point 0.6mm ball (0.3mm line) pens with white ink when I looked, but they may be available for finer lettering.

Close-up shot to show the 0.8mm ball point

Armed with this new tool, I decided to try painting the Sand Scorcher tires.

It took me around 10 minutes per tire.  It isn't easy keeping a steady hand for 30 characters per tire.  The way I did it was to basically draw each letter, allowing the ink to flow in between the outline ridges that make up each character.  I was really happy with the result at first, but then I noticed that the letters were not completely filled in after they dried.

The zero and second one digit are not filled in completely

I had not allowed enough ink to flow into each letter, thus capillary action and surface tension made the ink stay in the corners of the letters and away from the flat bottom, much like water sticks to the inside corners of plastic containers when you wash them.  I could go over the letters again, but since it is only noticable up close, I'm not going to attempt to fix these tires.  I'll simply modify my method for the next set.

Next up was the Tamiya Subaru Brat and its Sand Blaster 915s. 

Now these letters are much larger and wider than the ones on the Sand Scorcher.  I made sure to allow each letter to be filled with a pool of ink by lifting the ball of the pen away from the surface of the tire slightly while following the contours of the symbol.  This caused the ink in the pen to flow past the ball point and fill in the letter.  Now this was impressive!  The ink is nice and opaque and flows very well.  The ink dries within about 10 minutes.

Lastly, I did another set of Smoothee and Padlatrak tires from my Tamiya Grasshopper.

This time I made sure to allow each letter to fill in with ink, and the result is that there are no dark areas in the middle of each letter.  So the key is to allow enough ink into the letter to create a pool.

As for how durable the ink is, I have not tested it to find out.  A toothpick or fingernail will remove the ink on the raised edges of the letters, so I predict that the ink will come off if it is scratched or rubbed inside the letters themselves.  On paper, the ink is very resistant to chemicals and is quite difficult to remove.  Rubber, however, is a tough thing to write on.  But I am not looking for durability here.  My cars are runners, and I don't mind the normal scrapes and bruises that happen during normal running.  If the ink comes off, I can always touch it up again.

I'm very pleased with the results so far.  If you've been afraid to paint the letters in your tires, give the Sakura Gelly Roll(R) pen a try.