Technical drawing
Rapidographs are a type of pen used in technical drawing. Since 1953, the Rapidograph pen has been wildly popular among architects, engineers and draftsmen. Rapidographs make lines of even width and consistency.
Most professionals purchase a set of Rapidograph pens, with nibs of varying width. There are pens for thick lines, thin lines and just about every size in between; each size is denoted by a different-colored band. Rapidographs are famous for producing smaller lines, dots and other marks than most pens.
Rapidographs are fountain pens, so those using them must keep them clean and refill the ink periodically.
Picking the Right Ink
Clogging is a frequent problem with Rapidograph pens. If ink clogs the nib, the Rapidograph will not produce marks. Many draftsmen suggest using a different ink than the ink that comes with Rapidograph sets.
India ink is the type of ink most frequently used for drawing. Other popular options are the Rapidograph "Ultradraw 3085-F" and Mars-matic drawing ink.
Cleaning
Careful cleaning is essential to keeping Rapidographs in good working order. There are a number of commercial cleaning solutions available, like Rapido-Eze.
Some people clean their Rapidographs by soaking the pen tips in ultrasonic jewelry cleaners, as the fine vibrations loosen dried ink. Other suggestions involve using vinegar to soak the tips.
Storage
When not using the Rapidograph pen, keep it stored with the tip pointing up. Art supply dealers also suggest storing pens filled with ink in a jar of water that comes about halfway up the pen, with the top off. The water prevents the ink from quickly drying out. This only works for about a week, however.
Drawing
If the pen starts to clog while you're drawing, make a little side swipe on a separate piece of paper. This often removes light clogs and you can begin drawing again.
Avoid a heavy hand while drawing. More pressure will not affect the quality of the line, and may damage the nib or rip bits of paper from the page--which will clog up your nib as well.
Persistent Problems
If problems with your Rapidograph pen persist, consider contacting Koh-i-Noor, the company that manufactures them. Koh-i-Noor tends to stand by the quality of its product, and the company's representatives are often helpful.
