Hello everyone,

I just wanted to share my experience with Sharpie fine tip pens. First off, I'm using the original laser cut gondola with bearings. In the middle I used 0.5" copper water pipe that I had laying around. I am able to use the clip on the actual pen itself to hold the pen onto the copper pipe.

Here's an example to what I'm talking about:

The picture above is one of the new model of Sharpie fine tip pens, the retractable one. Unfortunately this pen only draws for around 8 hours max. The quality is very nice, as well as the precision. I was disappointed that it only lasts about 8 hours, when the pens cost around $3 each. You can not refill them.

I did some research and found a review on the Sharpie pens. The retractable pen is the third generation of Sharpie pen. Unfortunately, because it's retractable, it has an ink cartridge half the size of the previous two models of Sharpie fine tip pens.

Here's a picture from the other review:

Retractable on the bottom, generation two in the middle, and the original Sharpie pen on the top.

There is an Office Max closing down near me and I stopped in to see what they had. They have 50% off on all supplies, so I picked up a bunch of pens for my drawing machine, along with samples of each generation of pen to test them out.

Generation I:

Generation II:

Generation III (retractable):

I have yet to actually do any drawings with the Gen I or Gen II pens. I did test the Gen II and they fit onto my copper pipe the same way as the Gen III. I'm happy that they have twice as much ink

I'll report back on how many hours a Gen II lasts once I get some more drawings done. I just wanted to share with others what pens I like and spark some discussion as to what you guys like.

Here's an image drawn with a Generation III retractable Sharpie fine tip pen. The pen ran out of ink near the end of the drawing and I had to swap in a new pen. The darkest lines are the new pen:

This drawing was around 18,000 commands and took around 4 hours to complete.

Link to Sharpie review outlining how much ink they contain:
http://officesupplygeek.com/pen-review/felt-or-plastic-tip/inside-your-sharpie-pen/

Cool drawing and review Bob. The little automatic capping mechanism inside the retractable pens are very neat indeed, lovely little piece of industrial design, but you can tell that there must be less ink inside, even just by the depth of the "click". I'm surprised the ink felt is so much narrower though - don't really see the reason for that.

You know it would be pretty trivial to rig a continuous inking system for a polargraph machine, if you could a liquid ink that matched, or could find a "blank" pen. Actually, could probably flush a pen somehow and refill it that way.

Morbo, i found Sharpies in the cheap stuff trays of "Hagebaumarkt" (big german chain). If you ever go there try to find some.