This is Dan from D.M. Pipes.
I'm just taking a break from working on a new and improved prototype...
A note about the carbon monoxide. I've been trying to gather all the info I can about this, but the studies that have been done have no correlation to this design. It's well documented that hookahs produce carbon monoxide, and if used in an enclosed space, can be quite harmful. Hookah users have all sorts of rules about how to avoid carbon monoxide poisoning. Many of them involve not using "quick light" charcoal, and having adequate ventilation.
The chemical reaction here is Carbon + Oxygen = Carbon Dioxide. When not enough oxygen is present for complete combustion, Carbon Monoxide is formed instead. So, from what I understand, the available oxygen plays a very important role here.
Hookahs are usually using a coal that is at least half smothered, and have an ember that is far larger than the ones I am using. They also stay lit for hours at a time.
The charcoals in my design burns on the inside diameter of the bamboo tube, as fresh air is being pulled directly through the hole, the resulting ember is very bright and burns hot, suggesting a mostly complete burn. Also, these embers burn for no more than 5-10 minutes at a time at the length I intend to supply. So the accumulated carbon monoxide in the room will not be substantial, no more than a candle I am guessing.
So, while I am interested in further information about this, I am fairly confident that this design produces only small amounts of carbon monoxide. While this may be a health concern to some, and I cannot say if it is as healthful than a battery operated device, I believe it's still a healthier alternative to smoking.
For the last while I have been researching the materials that I would like to use. It seems likely that I will be using stainless steel for the herb chambers. The herb chambers will have a groove machined on the ID of one end, into which a stainless steel screen will be fitted. This screen will be replaceable. No screen lasts indefinitely, and being able to replace it is a good idea, especially since I will be using a fine-medium mesh screen. Solid perforated discs don't have enough airflow in my opinion, same for ceramic. When the chamber is in the case, the open end will be covered, so no herbs will fall out. When the chamber is loaded into the device, the open end is sealed by a screen inside the device. This makes it so you never have to tediously remove a tiny little screen while re-loading the chambers. The screens, both in the device, and in the chambers, are only removed for replacement. They can be replaced with fine-medium mesh screens supplied by me, OR, replaced with generic stainless pipe screens that can be cut to size with scissors.
The outside diameter of the herb chambers will be polished for increased corrosion resistance, and because it looks nice. I may also experiment with heat treating the steel to produce various shades of gold, brown, blue, and dark purple, which I think would look awesome. Though, this surface finish is less durable, so I may recommend a coating of beeswax or petroleum wax on the outside of these chambers every once in a while.
The tip of the device, that will hold the charcoal, and the herb chamber, will be of medium carbon steel, most likely 1144 Stressproof for its moderate hardness, high tensile strength, and excellent maintainability. I would like to polish the inside diameter, for a nice mating surface with the herb chamber inside. The outside, however, will be intentionally rusted with traditional Japanese techniques, to produce a surface finish much like very old brown/black iron. This surface finish is used extensively in the making of traditional iron/steel samurai sword hardware. The richness and organic feel to this surface is amazing.
The prongs I have yet to figure out, they may be inlaid into the steel, and made from brass or copper, to produce a beautiful contrast between the two materials. This sort of inlay is very time consuming however, and I may have to save it for more expensive custom models. For the basic model, I will most likely attach the prongs with tiny brass screws, or brazing/hard solder.
I may or may not do the whole "bolt action" loading system. I will most likely save that for more expensive pieces, and just have the device come apart in the middle for loading the chambers.
At first, I wanted to make the distance from the charcoal to the chamber adjustable, for fine heat control, but the mechanism to make that work are iffy, as far as long term functionality goes. The only reliable way to make this work is with threading, and I would like to avoid threads if I can, they limit the wall thickness of the pieces, and I don't think they match the aesthetic I am going for. Mortise and tenon fits are only good between dissimilar materials, which is why I will be using it only for the union between the wooden half of the device, and the steel tip.
So, I think I will not make the chamber adjustable, but rather, the charcoal itself. Heat will be controlled by how far you push the charcoal down into the prongs. Or, even pull the charcoal out far enough to create a gap between the butt end of the charcoal and the steel tip, allowing cooler air to rush in. It does seem as though there is an ideal distance however, with very tight tolerance, a few millimeters change in distance seems to make a large difference. I think that the only time adjustments will have to be made, is possibly when it's winter time, and the ambient air is much colder, maybe. The majority of temperature control is with your breath.
As for the case, it will hold 4-6 herb chambers, and about 8-10 charcoals. This design I have not quite figured out yet. I am torn between a simple wooden box, much like a chopstick box, and done in the very minimalistic japanese style, a tube case..that will hold the chambers just like that shaving cream can from jurassic park (SO COOL!), or a hard leather sheath for the vaporizer, with a matching hard leather disc shaped case for the chambers and charcoals.
So, Any thoughts on all this? I've been obsessed with designing this thing. The first time I used the rough prototype, I knew it was something special. I've been a pipe maker for more than 10 years... but I haven't touched my pipe since...
Loving all the discussion so far!