Replace the wick :Is this idea worth me having a go at ?

[exogenesis]

Atomizer design, replace the wick : Is this idea worth me having a go at ?

The current design, i.e. a bundle of fibres, surrounded by a short heating wire coil.

Operational parameters (as I see it):
1) Takes such & such a time to heat up.
2) Gets to such & such a temperature, controlled by liquid ingress rate & current flowing (wire resistance, applied voltage)
3) So giving off vapour from heating the liquid (at/near the wick surface) at such & such a rate.

Operational failures (as I see it):
A) Creates burnt 'gunk' at/near the wick surface, under the coil wire
- after a while pushing the coil outward, straining it & even breaking it eventually.
- even with burn 'cleaning cycle' ashing the gunk, this can leave a gap between coil & wick.
B) Wick cleans-up far less readily than the wire itself, during a clean cycle.
C) Wick can degrade (esp. near ends) due to 'breaking up' with use / cleaning cycles -> loose fibre fragments floating about.
D) others I can't think of atm

If there was no glass-fibre/polymer fibre wick, something needs to replace it's function.

Looking at different metal wires that are available & non-toxic,
along with their melting-points & resistivity I made a table of wire lengths required
to be equivalent to the typical 35mm of 0.1mm diam. (1.4" by 0.004" diam.)
nichrome wire in current atomizers:

http://www.Exogenesis.co.uk/WIRE.xls

Bottom line is that a bundle of multi-strand long-length fine (0.025mm) tungsten wire
could heat like the existing design, act as the wick, but be more stable & easier to
clean & wouldn't be stretched/physically-broken due to hard gunking up (?).
So potentially lasting a lot longer.

Nichrome creates an deep insulating oxide surface in air, so does tungsten,
no other suitable metals do, afaik.
i.e. electrical shorting across a bundle of fine wires should not be a problem ?

Soldering tungsten wire requires silver solder ?,
or at least extremely good pre-tinning (using borax), for ordinary soft solder.

Bound to be some factors I've not thought of here (apart from cost).

Possibly far less fine wire than estimated here would be required,
since effective heating possibly actually only occurs to a certain depth in the existing wicks,
meaning the required heated-wire surface-area might be significantly less ?

More expensive & fiddly to make?, yes,
but actual cost might be less than the 'pure' (research) wire source that I found.

 

[surbitonPete]

Hi Exo ...am I understanding you correctly.....you are thinking of a bundle of wires doubling up as the heating element and the wick??

 

[exogenesis]

That's the idea.

Think it's been suggested before, but the practicalities are the thing.

 

[surbitonPete]

That's the idea.

Think it's been suggested before, but the practicalities are the thing.

I am glad you mentioned about nichrome wire producing a surface insulation...I had wondered how come some coils still work even though the coil rings all seem to be touching.

I must say you seem to have a pretty meticulous way of experimenting Exo and the idea sure seems to make a great deal of sense to me. If it can work you would certainly be the one to find out and I would sure be interested in your experiments if you do try it. The only thing is that with an idea like that ...if you do find it works it would need the manufacturers to adopt it.

 

[kinabaloo]

Sounds like a good idea.

Only possible downside I can think of at the moment is that such thin strands might burn out easily.

Well worth experimenting with.

 

[exogenesis]

Well, I might well invest in a spool of 0.025mm tungsten wire then.

If it works (any bets?) & has a significantly longer life,
then it's not impossible some manufacturer could take it up.

Imagine a world with easy-clean, long-life atomisers - sigh


Hopefully the significantly higher melting point (than nichrome)
would help with combatting burn-out, might even be more tolerent.

 

[surbitonPete]

Well, I might well invest in a spool of 0.025mm tungsten wire then.

If it works (any bets?) & has a significantly longer life,
then it's not impossible some manufacturer could take it up.

Imagine a world with easy-clean, long-life atomisers - sigh


Hopefully the significantly higher melting point (than nichrome)
would help with combatting burn-out, might even be more tolerent.

Yes in my opinion atomizers should either cost 5 pence each so that I can keep throwing them away without thinking a thing about it....or else be made to have far more reliability than they already have. Throwing away 6 or 7 pounds every few days is something that I do think a lot about.

 

[kinabaloo]

I doubt burn out is through evaporation; could be changes in the alloy making it more brittle though - so I guess you stll win the point Most likely though is mechanical stress, particularly from deposit buildup; between filaments might be as bad as under the coil, especially as the filaments will be thinner.

Might be a bit easier to clean, but doubt there'll be much in it.

Expect the unexpected. Bound to be some complications, but should work.

It's a very neat idea, even if it doesn't achieve much

 

[kinabaloo]

Yes in my opinion atomizers should either cost 5 pence each so that I can keep throwing them away without thinking a thing about it....or else be made to have far more reliability than they already have. Throwing away 6 or 7 pounds every few days is something that I do think a lot about.

Pete - the problem is really the juice (deposit), not the atty.

 

[surbitonPete]

Pete - the problem is really the juice (deposit), not the atty.

quite true kinaba.......hey another thought that went through my head was could a coil somehow be made to 'vibrate' at a very high frequency or something and in a sense possibly shake the gunk to pieces so it could be washed out?

 

[kinabaloo]

That's what ultrasonic claening baths aim to do. Well, sort of (but by vibrating a surrunding liquid).

While home-use ones don't seem to work, the chemist guy seemed to get good results with his industrial scale lab one.

Applying AC to the coil could kill it just like DC if it tried to expand but could not because of a heavy deposit overcoat.

 

[exogenesis]

Expectation is the driving force,
hopefull I'll try & find out, one way or the other.

 

[exogenesis]

Actually before I go and blow £50 on a reel of fine tungsten wire.

Is there anyone with relevent knowledge / experience who's got any
reasons why this is a good or bad idea ?

 

[kinabaloo]

It's a lot of money Exo. Can you think of a place to scrounge a tiny bit to try ?

 

[Jim Davis]

Pete - the problem is really the juice (deposit), not the atty.

And it's hard as a rock. Most liquids wont break it down.

Does this sound too far fetched?
A tiny piece of dry ice. Put it on the coil with tweezers to contract the buildup. Then pour hot water over it. The extreme contraction, combined with the rapid expansion, may crystallize the solid gunk so it can be blown or washed off. the coil wire should survive.

 

[exogenesis]

Exo - 2 things.

1) Wonder if you could try this (even if you think it's crazy) - take a cleaned up coil and simply remove the inner wick; try without it. Seems to me a reasonably good chance that it will work well enough without it. After all, most of the juice that's vaporized lands on the coil when (after) it is heated and the target area would still be pretty large (it might actually be hard for a droplet to squueze through a gap in the coil).

2) I think it best not to buy the reel for now but try to think where it is used and find a scrap item to salvage some from. It's a lot of money and not much use for other things.

Pretty sure most of the liquid that's being vapourised is from the wick
surface, or near the surface rather than what lands directly on the wire.

I think the wire on it's own has almost certainly not enough surface area.

Found a much cheaper source, Wires.co.uk.
I got this lot for the same price as the single reel from the other supplier:

10mtrs 0.058mm Bare Tungsten Wire £12.50
10mtrs 0.1mm Bare Tungsten Wire £12.50
10 Metres 0.05mm Nickel Chrome Wire £10.00
4 Metres of 0.4mm SILVER SOLDER £5.20
Shipping £2.02
VAT £6.34
Total £48.56

I thinking maybe the 0.025mm wire would have been
too thin to handle anyway.

Compared to the usual atomizer 35mm of 0.1mm nichrome,
it works out the same current will be drawn for 0.058mm tungsten
with 3 strands of 675mm length (!)

May (or not) take 20x as long to heat up,
(what's the heat-up time of an atomizer coil?)
but it will have 33x the wire surface area,
which may well be enough to give a good vape....


Anyone got any tips for silver soldering, please ?

 

[kinabaloo]

Pretty sure most of the liquid that's being vapourised is from the wick
surface, or near the surface rather than what lands directly on the wire.

I think the wire on it's own has almost certainly not enough surface area.

Looking at it again, the col covers most of the area on a 901; I tink it would work reasonably well.

On the other hand, deposit will still likely form inside the coil, but take longer to cause diinished performance.

If the opportunity comes along you could give it a go (and same here, or anybody else).

Re: the tungsten - will this be one strand, or parallel strands?

 

[surbitonPete]

Hey guys ..... another day and my coil is still working like new with this quick dry burn idea.....Exo ....I am thinking that if you can make an atomizer where the wicking material is also the atomizing wire itself..... a quick burn method of cleaning the gunk off would probably work far better with that.

 

[kinabaloo]

Hi Pete - was getting worried as not seen you around today. Thought you might be back on the analogs and hiding

Good news

Still looking ungunked ?

 

[kinabaloo]

Beginning to think the coil insert is necessary for the initial vapor before reinforcent droplets arrive.

That zippo wick material looks interesting (http://www.e-cigarette-forum.com/forum/atomizer-mods/15020-wicking-material-2.html#post265964).