Q: Is hard rubber difficult to work?
A: Hard rubber can be cut, drilled, machined, and polished with ease, using standard tooling and equipment. It behaves much like a rather dense, grainless hardwood. Multicolor hard rubber is also like wood in its patterning, which can vary from piece to piece, as well as from layer to layer. A single piece may show a very different mix of colors depending on how far down it is turned.
Q: Is hard rubber compatible with other materials, such as celluloid?
A: Yes. From the mid-1920s on, celluloid was the dominant material for fountain pen manufacture, but nearly all celluloid (and later, cellulose acetate) pens had hard rubber sections, feeds, and inner caps, and many had hard rubber end plugs. Decades later, we can see that prolonged exposure to ink and rotting soft rubber ink sacs will discolor celluloid, but close contact with hard rubber does not. In fact, the best-preserved color on many vintage celluloid pens is found where a tightly-fitted hard rubber inner cap has protected the outer cap from staining from within.
Q: Is hard rubber stable?
A: Hard rubber is in many respects one of the most stable plastics, old or new. It does not shrink as it ages, nor does it outgas plasticizers. Exposure to bright light and especially UV may cause dulling and fading of the surface, but this does not affect the integrity of the object as a whole.
Rubber chemistry, including hard rubber chemistry, has not stood still over the past 150 years. Modern hard rubbers are significantly more resistant to light fading than their early 20th-century precursors.
A: Pipemakers typically turn and carve hard rubber rod stock nearly all the way to its center. Our current stock will sometimes show microscopic porosity if worked in this fashion -- something that never became apparent in other applications. We have adjusted our production methods and will soon be offering a special grade of ebonite rod stock specially formulated for pipemakers' use.
Q: How can fading of hard rubber be prevented or reversed?
A: Hard rubber items that have been stored in the dark are often found in like-new condition, even after 100 years or more. In the shorter term, avoidance of prolonged direct sunlight is advisable, as is display under unfiltered fluorescent or halogen lights. Note that the damage done by light to the surface of hard rubber may not be visible immediately; in many cases, it will be apparent only upon exposure of the surface to water (water will have no effect on pristine hard rubber, but will immediately fade hard rubber that has been light-burned). While wax will provide some protection against this sort of water-spotting, too thick a coating and one loses the feel of the material - which is, after all, one of the qualities so appreciated about hard rubber.
Polishing will restore a faded hard rubber object's original color. This does entail a loss of material from the surface, however - not usually of concern where the item is smooth, but an issue where there are imprints, chasing, or other surface ornamentation.
Q: Is hard rubber brittle?
A: When a piece of our newly-made hard rubber is dropped on a hard surface, it bounces. It's real natural rubber, after all! Older hard rubber could be quite tough, too, as long as it was black - colored hard rubber was another story, at least back then. Modern pigments now allow a much broader range of colors without any loss of resilience.
Q: What happens when hard rubber is heated?
A: Hard rubber will not melt or shrink when heated; instead, it will progressively lose its hardness as it gets hotter, becoming more like regular rubber. While in this state, it can be stretched or compressed, and if the tension or pressure is maintained as the material cools, the deformation can be "frozen" in place. Heat the object again, but in an unstressed state, and it will return to its original shape. Although overheating will scorch it, hard rubber is very heat-tolerant, with a broad working temperature range for heat-molding. For this reason, it was and remains an ideal material for fountain pen sections and feeds, and as a base for metal overlays.
Q: Doesn't hard rubber stink?
A: Hard rubber does have a distinct, sulfurous smell. The smell is quite apparent when a hard rubber article is freshly made, but largely fades away after a few weeks. Firmly rubbing the surface will bring out the smell, and is one of the classic methods of quickly identifying hard rubber. The smell of hard rubber is the strongest when it is being cut or machined, and when it is heated to softness.