home made light bulbs?? anyone ever??

[tyler]

hello all
im a new member, and a small collector.
ive been fascinated by old school ighting for many years.
ive recently become obsesed with making my own lightbulbs, i was inspired to loo here for suppot after seeing james light bulb repair. im an artist and designer with some engineering knowledge. ive gotten as far as hand blowing the glass, have argon tanks, and a vaccuum pump. have tungsten wire. and have done some basic tests. ive been doing alot of research, but as you can imagine its not a popular hobby, its all very basic or way over my head. anyone out there that could give me some consult on some of the deeper questions, id very gladly pay for a professional or super knowledgeable persons consultancy. im also hand making plugs from ebony and strling silver (this was easy) the idea is basically designing a lamp with no lamp, a completely hand made reference to the basic light bulb and plug.
i want to permanently dim the bulb for a simple soft glow (with a resistor??) for maximum life. and also make t with some sort of refractory plug that can be removed and refitted after failure. im doing a limited edition of them more as functional art. my test have not been able to keep a glow for more than a few seconds, am i crazy or is this possible.
look forward to any help and thanks for the great site....its great!

im a designer and artist in new york, my web site is BDDW.com

thanks again
tyler hays

[James]

Hi Tyler,

First of all to make a decent lamp you need to make it sealed gas-tight.  Have you sealed metal wires through glass before?

Let me know if you work in borosilicate hard glass, or sodalime/lead soft glass and I would be happy to mail you a bunch of the special alloy wires you'll need to seal through the glass.

Then its a fairly simple matter to spot-weld or clamp a bit of tungsten wire onto the inner ends of these wires, seal it into a bulb, and pump it out to vacuum.  You'll probably get better results making a plain vacuum lamp, as soon as you introduce the argon you're likely to get problems unless you include special means to remove out all traces of oxygen and water vapour from the gas to much less than 1 part per million.

Best thing is to just play around and give it a go, and post a reply if you run into difficulties and I'll advise you what you might need to pay more attention to.

Best regards,

James.

[tyler]

james
you have no idea how much i appreciate this.
its been a long search. i know wood and furniture making if i can ever help you with anything ill be gladly indebted.

so here goes. my friend is blowing the glass, hes an artglass blower so im guessing this is not the borosilicate (isnt that scientific glass like the pyrex) i searched to find a scientific glass blower to do these as i would assume it would be better for the heat and look more real. for now i have the basic hand blown vase. if i need borosilicate, ill make this happen.

my plan has been to use the wieght of the argon/air difference and just continually blow argon into the chamber at the bottom letting it push the air out, and then drawing this into a vaccum. this is where im a bit confused. your saying that jsut a vaccumed chamber would work? i dont get how the regular air under vaccum would corrode any less than regular air? so ive been trying to do both, albeit naively.

i have not sealed wire through glass before
my plan was to draw a refractory plaster or something like that through a tube using the vaccume and then just shut the valve. if this didnt work iw would make a ceramic plug and then draw an epoxy through the tube to seal the whole thing. (ive been experiment with just rubber stoppers for now) if im simply drawing a vaccum to the chamber, if im understanding right, then this removes a step and would make the process much easier. though i havent done it the idea of drawing through a small tube vent and heating to twist and seal seems fairly straight forwrd with some practice. sealing the wire through the glass a bit less obviuos. im imagining that my vaccum press pump will pull a sufficient vaccum for this, is there a sensitive rang of pressure i need to be in?
ive also been trying to figure out the type of alloy wire you mention.
id planned on worst case, stealing out of a regular bulb. what is this wire? i was planning on a crimp for this.
do you think i should forgo the plaster sealing idea and seal with the glass? i would imagine this would be getting the bulb blown with a tube for the filiment and a tube for the vaccum. heat the tube aroud the wire and crimp closed, pull a vaccum and crimp it closed? sounds too easy but is this the basic idea?

i dont recall my tungsten thickness off hand
but i imagine this is pretty crucial, as well as the length of my filiment to the electrical resistance and wattage etc that is a bit over my head, i had planned on experimenting however the tungsten wire i bought was a bit expensive as i had to buy a couple hundred feet (not something i could find  easily except  from a manufacturer and i had to plead my case to get them to sell to me) so itll be tough to try a dozen thicknesses, as i reacall paying over a hundred bucks for the tungsten. Now ive got enough to make a thousand light bulbs.

and the last question would regard permannetly dimming, i would assume there is a resistor or single electrical component i could put in line to permanently dim the bulb and then hide this in the base of the bulb (which will have a cover) idea being the lamp is as entirely hand made as possible
and hand making a dimmer seems out of my reach, as opposed to hand making a switch.

sorry this is a bit long, ive been desperate to find someone to help me with this. ill be happy to come mow your lawn, pay, or whatever to pick your brain. minimum youll re3cieve one of the finished pieces.
i think theyll be pretty cool. the plugs alone like jewelry.


thanks in advance

tyler hays

[James]

Tyler,

Apologies for my delayed reply I have been working in China the last few weeks.

To get started, yes you can easily make a lamp from ordinary soda-lime glass, that is what ordinary lamps are made from.  It takes somewhat more skill though to be successful.  I guarantee the first 50 you make will crack in this glass until you get used to working it!  Pyrex has the advantage that probably the first one you make will hold together.

Have a think about which glass you will work with, let me know your mailing address (you can email me jameshooker@lamptech.co.uk) and I will send you a few dozen wires of the special kind used for sealing through glass.  For soft/ soda lime glass, the wires I will send are 0.4mm diameter 42% nickel-iron with a copper sheath, plated with sodium borate.  For hard / borosilicate / pyrex glass I will send you 1mm diameter tungsten lead wires that are pre-sleeved with a layer of special intermediate glass which will help them stick better to the glass of your bulb.

What you need to to first is take some glass tube about 10-15mm diameter and 300mm long, and form an 'olive' or slight bulge in it near the centre where its diameter increases to maybe 20mm or so.  Then cut one end off 25mm from the olive.

Next you must put the wires I will give you into the open end of the tube nearest the olive you just made.  The wires are long, you can wedge them in place by ramming a cork up the other end of the tube which will not be heated.  To seal the wires in you have to heat the glass and press it flat around them.  Cool it down very slowly over a period of 5 mins or so to prevent it cracking.

Next you can clamp or spot-weld your tungsten filament onto the lead wires.  Then take your bulb which should have an opening at one end of slightly smaller diameter than the olive in the glass stem tube.  You will need an exhaust tube attached to the top end of this bulb.

Fuse the open end of the glass bulb to the olive region of the previous assembly.  Use the flame to cut off the excess length of tube below the olive that is no longer required.

You are then left with a bulb with an exhaust tube on the top of it.  Connect this to a vacuum pump and pull the best vacuum you can get.  Heat the entire bulb as hot as you can get it or to the point where a piece of newspaper will charr when you touch it on the glass.  Also light the filament up slowly.  When its as thoroughly pumped out as you can get it, then you tip it off and seal under vacuum.  You can fill with argon if you desire, but only for a low voltage lamp.  If you're making one for 120V use you'll need at least 5% nitrogen in there as well for safety reasons to prevent it flashing over through the gas.  I would advise making a low voltage lamp, 12V or so.  For 120V you will never succeed in making a filament by hand that will work.  Machines which wind coils to a dimensional tolerance of less than a quarter of the mean wavelength of visible light are required for this task!

This is about the easiest way I think you could make a lamp by hand.  If its not easy to visualise let me know and I will try and do some diagrams.

If you also need tungsten filament wire let me know, I have a few hundred miles of it here in various sizes . . .  And also finished coils I can send if you don't want to get into the coiling business.

Best regards!

James.

[nixie]

James,

Thanks for all the information that you are providing (even though I'm not the one who asked).

I was wondering if you would mention how to obtain the wires needed to attach as electrodes.  Maybe someone could work up a FAQ for the site dealing with bulb construction, so that this information doesn't get buried somehow.

regards,

jon

[wabi]

Hi James,


i'm a new observer and wanted to say thank you  for
sharing your expertise.  you have answered many
questions that i had as well.
while you are at it, can you tell me(or anyone else as well)  - what is the
largest bulb and voltage that can be made, either by
hand or machine? and is it possible to have a bulb
that is rather flat & rectangular, say like a thin box ? or
is the shape of the bulb limited to roundness?
thank you in advance.
please let me know if i can be of any help to you. i'm
in Los Angeles and have some knowledge in photography.

syko