I wouldn't read too much into the claimed efficiency of the Nernst lamp, yes they may well be twice as efficient as the early CARBON filament lamp, but these were horrendous with their luminous efficacy (lumens per watt (lm/W) ). I have read of "16 candle power of light from 40W" carbon lamp, what we are seeing banned now is allready more efficient than that.
Using the silicon carbide globar as a heater will pose two problems : its size and its price. Last year I had to replace one in the IR spectrometer and it costed over 300$ . The emitter in the SiC source is rather short , less then 10 mm so you would have to use more than one to heat the ceramics.
I made some assessments of the temperature necessary to start the Nernst Lamp and it seems that with the "peeler glower" one needs to heat it to over 500 degrees Celsius . The original glowers probably had a bit different composition and this allowed them to be started with a match instead of the blowtorch .
I will try to make the heaters by covering some nichrome wire coils with high-temperature ceramic glue . I have over 1kg of this stuff left from the renovation of the chimney.
*takes notes* hmm, interesting! I think it's safe to say we can rule out SiC heaters due to cost, and sourcing them would be a little troublesome anyhow. Nichrome wire seems to be the easiest material for most of us to source (dead toaster etc).
As for the glower, I can't help but think there is a common use somewhere for a thin rod of the ceramic - but what that is, I couldn't say. It may be worth a look at / for alternative devices... One possibility is to get some samples made to our required specs - depending on how many are interested, and if anyone wishes to produce a kit form, this may be cost effective for a "group buy". There are a few sources of thin ceramic rods with a simple google search.
http://www.earthwaterfire.com/alumina_rods.htmThis website looks promising, they produce Zirconia (Yttria stabilised) rods, can do custom sizing, and claim "No minimum order value" and "Priced by the inch"!
With incandescent lamps slowly disappearing from stores, the Nernst lamp is rapidly becoming a real viable alternative light source for steampunk projects - we may even be able to strike some kind of deal with the company (maybe they could be the "official" BG supplier?) in return for a favourable cost reduction...
Once we get the gremlins out of the process, this would be a good topic for the "How To" sub forum, maybe a sticky. Of course the honours of writing the tutorial should go to Mr. Consciousflesh.
SS
