I am happy to present the "Steampunk Oriental Night Light - Nur-al-Andalus" as my latest object to you.
Like it is a typical for my creations parts I took all needed parts -even the used batteries- from the scrap!
This small lamp is placed at my nightstand and I love to watch the wonderful colours of this nearly wrecked CMH-Bulbs each night.
To give you a short impression, I created a small animation of this light by sending the signal C-Q-D (which means: "Come Quick, Danger!" at that victorian era Steampunks prefer) in Morse-Code!
And now let us start with some necessary explanations:
When I was looking for some wrecked incandescent light bulbs at my local hardware store, these black coolured tubes which I have never seen before came to my hand and I took them with me at home. After some minutes with google, it was clear that these tubes are called CMH-Light-bulbs. At home, I just tried to activate them with an electronic board for flash units of a single-use camera (see this instructable) and was absolutely surprised, that it worked best!!!
NOTE: All producers like GE, Philips and more others, write about a possible risk that a bulb could burst when it is running in its normal use. It is said that if this tube bursts, very hot (about 500°C) glass parts will be spread. So take care and do not wreck yourself. Better cover these bulbs with a protective glass shield.
My personal opinion and experience is that these bulbs are quite safe when they just glowing like I used to work with, especially when you use the very low power of these flash units. It seems to me, that it is nearly the same risk like working with neon gas filled bulbs or nixie tubes.
These nearly dead CMH bulbs (and also brand new ones) just start to glow and they do not heat up. I measured at different times these bulbs while glowing under here described conditions! and they showed just the same temperature as the surrounding air in the room. Conclusion: This construction works deeply under the operating temperature!
Literature talks about 6 exploded bulbs while highly running! in a number of 35 billions of produced bulbs! over a time of twenty years.
But it is your own decision and I please you one more time not to harm you, and to take care of your health!!!
Well, I went down to my workshop and started this project immediately.
I hope that enjoy the instructable and I thank you for reading, watching, following and hopefully for voting;-))
Yous Aeon Junophor
Step 1: Some More Detailed Explanation About CMH-Bulbs If Needed
If you are interested in more details I´ll try to give them here by citing them. If not, just jump to the next step!
In literature I found a lot of information about these voltaic-arc-lamps and I picked the most important facts for this project out.
About the construction of an arc tube:
Inside the fused quartz arc tube, two tungsten electrodes doped with thorium are sealed into each end and an AC voltage is applied to them through molybdenum foil seals fused in silica. It is the arc between the two electrodes where the light is actually created.
Besides mercury vapor, the lamp contains iodides or bromides of different metals. Iodine and bromine are of the halogen group of the periodic table, and so are termed "halides" when ionized. Scandium and sodium are also used in some types, with thallium, indium, and sodium in European Tri-Salt models. More recent types use dysprosium for high color temperature and tin for lower color temperature. Holmium and thulium are used in very high power movie lighting models. Gallium or lead are used in special high UV-A models for printing purposes. The mixture of the metals used defines the color of the lamp. Some types, for festive or theatrical effect, use almost pure iodides of thallium, for green lamps, and indium, for blue lamps. An alkali metal, (sodium or potassium), is almost always added to reduce the arc impedance, allowing the arc tube to be made sufficiently long and simple electrical ballasts to be used. A noble gas, usually argon, is cold filled into the arc tube at a pressure of about 2 kPa to facilitate starting of the discharge. Argon filled lamps are typically quite slow to start up, taking several minutes to reach full light intensity; xenon fill, as used in automotive headlamps, start up relatively faster.
The concept of adding metallic iodides for spectral modification (specifically: sodium - yellow, lithium - red, indium - blue, potassium and rubidium - deep red, and thallium - green) of a mercury arc discharge to create the first metal-halide lamp can be traced to patent US1025932 in 1912 by Charles Proteus Steinmetz, the "Wizard of General Electric".
In the mid-1980s a new type of metal-halide lamp was developed, which, instead of a quartz (fused silica) arc tube as used in mercury vapor lamps and previous metal-halide lamp designs, use a sintered alumina arc tube similar to those used in the high pressure sodium lamp. This development reduces the effects of ion creep that plagues fused silica arc tubes. During their life, sodium and other elements tends to migrate into the quartz tube, because of high UV radiation and gas ionization, resulting in depletion of light emitting material that causes cycling. The sintered alumina arc tube does not allow the ions to creep through, maintaining a more constant colour over the life of the lamp. These are usually referred as ceramic metal-halide lamps or CMH lamps.The amount of mercury used has lessened over years of progress.
About the outer bulb:
Most types are fitted with an outer glass bulb to protect the inner components and prevent heat loss. The outer bulb can also be used to block some or all of the UV light generated by the mercury vapor discharge, and can be composed of specially doped "UV stop" fused silica. Ultraviolet protection is commonly employed in single ended (single base) models and double ended models that provide illumination for nearby human use. The cover glass of the luminaire can be used to block the UV, and can also protect people or equipment if the lamp should fail by bursting.
Old HMI lamps
At the end of life, metal-halide lamps exhibit a phenomenon known as cycling. These lamps can be started at a relatively low voltage but as they heat up during operation (sic!), the internal gas pressure within the arc tube rises and more and more voltage is required to maintain the arc discharge. As a lamp gets older, the maintaining voltage for the arc eventually rises to exceed the voltage provided by the electrical ballast. As the lamp heats to this point, the arc fails and the lamp goes out. Eventually, with the arc extinguished, the lamp cools down again, the gas pressure in the arc tube is reduced, and the ballast once again causes the arc to strike. This causes the lamp to glow for a while and then goes out, repeatedly. In rare occurrences the lamp bursts at the end of its useful life.
Step 2: Results of Testing CMH-bulbs With Different Ages
Meanwhile I got several CMH-bulb of different ages from brand new to very old ones and tested them intensively.
In these picture you can see my results.
Step 3: Woodworking With the Box
An old cigar box was broken in the middle when I took it from the scrap. To use this box once again, I cut the broken part off with a jig saw and made it smaller.Some brass made clamps, fixed with small M4 brass made screws are used for decoration and keep the edges together (which is of course not necessary but sound good as explanation)...
In the middle of the box top I placed the cover of an old and of course totally damaged junction box made of bakelite. Therefore I cut a big hole with a fret saw, finished it with some sanding paper and glued the bakelite cap with epoxy-resin in.
The hole in the middle of this cap had been used to close the junction box with a huge bakelite screw which also misses and a piece of a recycled copper tube muffle now perfectly fits in. In this muffle I put the bulb holder made of copper which is explained intail next step.
Step 4: Metal Works
The glowing light of these old CMH-bulbs is not so bright and so I took a piece of copper tube which once had been cut in the middle, polished and lacquered it, so that the inner side now reflects the light. The Top crown is made of different parts from the scrap like cover nuts, washers, rubber, a bearing cage made laminated fabric as well as copper- and brass made rings of different sizes. All parts had been finally glued together with epoxy resin and super glue.
As you can see at the pictures, long screws were needed to tighten the new box. Therefore I used these special screws which I already developed in this Flickering Bulb project. In combination with the "crowned" bulb holder and the bakelite cap it came to my mind that this lamp now looks like it is inspired from elements of the moorish architecture and I tried to work out this idea best.
The levers of the switches were also covered with brass.
Step 5: Electronic Equipment and Assembling All Parts
Another old junction box, made of bakelite had been used before as a tester for these CMH-tubes and there I took out all the electronic parts for this lamp an added one more switch and a 470k ohms potentiometer.
It is also possible to run the flash unit with 3.0 Volts instead of 1.5 Volts without ans problems. The "higher" voltage supply with 3.0 Volts of the circuit let the glowing of the CMH-Bulbs shine brighter or even is necessary to ignite the glowing.
While testing different aged CMH-bulbs, the idea came to my mind to add one small amber coloured LED to enlighten them additionally from the bottom, when their own glowing light is too weak.
So one can choose to switch on the LED too and with the potentiometer it is possible to regulate this LED-light.
This LED is integrated in the screw terminal for the CMH-tube an fixed with melting glue. In this case I chose two separate battery holders but you can also supply all electronic parts with one holder and 3 Volts. (This I show you in the following project)
This is an entry in the
Trash to Treasure