Building a Homemade Atomizer

[aaa]

Have you considered kevlar as a wick material?

It has high fire-, mechanical- and electrical resistance, it does not react with chemicals, and is relatively cheap in sports shops (in such a small quantity). It is even used as a wick is some applications...

The idea would be this:
The shaft of a long (but thin) metal screw projecting into the cartridge could be fully covered by a kevlar string. The heating wire could then be wound over a part of the shaft (that is covered by kevlar). The whole thing might also get a "collar" (made of kevlar?), that guides surplus e-liquid to the shaft, rather than letting it flow through the atomiser.

As for heating wires: when I could not buy resistance wire with the required ohm/m value, I used to unwound some turns from wirewound resistors. I know it is a dirty workaround, but it may work...

I plan to revive some dead atomisers using these materials in my hollidays. I wish I succeed. Atomisers are expensive here, and die one after the other .

[aaa]

I have figured out a more simple "sandwich" design with kevlar, that I will try soon:
heating coil | <1cm kevlar disc | metal wires | cartridge filling material

- heating coil: is located inside the kevlar disc (i.e. the kevlar disc is pushed onto it)
- kevlar disc: is just made by cutting off less than a length of 10 mm from the end of a kevlar rope that can be bought in shops
- metal wires: these project into and "interconnect" the kevlar disc and the cartridge filling material, and hopefully convey the e-liquid between them

Here the kevlar disc would function as a wick that surrounds the heating coil. An atomiser of such a construction could probably be simple and easy to disassemble for cleaning, when necessary. It will hopefully work...

[Kate]

There is some discussion here about suitable materials for wicks for fire dancing equipment - Home of Poi lessons - How to make your own gear> Fire Poi> What to use as wick?

They seem to think that Kevlar degrades but glass fibre is more durable. I wouldn't like to try breathing fumes from degrading Kevlar.

Here's another discussion about wicks that you might be interested in - http://www.e-cigarette-forum.com/for...-atomizer.html

[aaa]

Thanks Kate, those are great links. I will read them through to find out at what temperature kevlar degrades.
Anyway, that degradation would not be a problem if it happened only over the working temperature of the heating coil or if it happened only on a long run (in which case the kevlar disk could be regularly replaced.)
I hope I will have time to do some experimentation at my workplace, since we are engaged in electrical safety testing, and have adequate equipment for temperature measurements and such.
Anyway, I think glass fibres should be avoided, as those are liable to break, and their small particles may be extremely dangerous when inhaled.

Edit:
Your first link provides this information: "KEVLAR ® begins to evaporate at 427degree Celsius (800 degree Fahrenheit). turns into a gas. "
So, kevlar may be OK, if the heating coil operates well below 400 degree Celsius. Experimentation can show if enough vapour can be produced under this temperature. I suppose the answer will be positive.

Edit2:
Propilene-glicol boiling point is 300 degree Celsius. Quite narrow working range for the heating coil: 300...400 degree Celsius. Besides, kevlar possibly emits gases in this temperature range, too

Edit3:
Other sources mention a boiling point between 170...190 degree celsius. That is much better. Kevlar may be more stable at that temperature.

[Kate]

I'm not sure about this but I read somewhere that our atomisers only heat to around 250 degrees C. That would make it safer to use Kevlar I guess.

[jarvis]

"I wouldn't like to try breathing fumes from degrading Kevlar."
You're already breathing it! It's what's inside the atomizer coil.

[Kate]

Originally Posted by Ludo

It is a heat-resistant aromatic polyamide fiber!

http://www.e-cigarette-forum.com/for...html#post43065

It might be Kevlar, it might not.

[jarvis]

It is a heat-resistant aromatic polyamide fiber!
I've read that Kevlar is just a trademarked name for this type of fiber. there's probably differences, nomex is another common polyamide fiber.

[aaa]

The main goal would be to make the heating coil more robust, so as to result in longer endurance.
I found that it is hardly achievable without increasing the heating current, if a common resistance wire is used for the heating coil. Those wires all have too high conductivity. Increasing the diameter of the wire to be more robust -> the length should be increased, too, to result in the same resistance -> consequently, the heated volume is also increased -> the current should be also increased to heat up the higher volume to the same temperature.

Because of this, common resistance wires might not be suitable for a more robust design, without increasing the heating current.

I found, however, that graphite heating foils have 300 times as high resistivity as metal alloys. So, a heating element made of graphite foil could be 300 times as robust (i.e. its cross-sectional area could be 12mm2 instead of the 0.04mm2 that is used presently.)
The problem is, that such graphite foils cannot be bought in shops. They can be ordered by appliance manufacturers, instead. So, it is up to the e-cig manufacturers to use them.

[kinabaloo]

aaa - how about getting some graphite foil out of an old device?

Or how about experimenting with the graphite found in pencils?