My love/hate relationship with tungsten

[chefjoosie]

I've been trying a lot of different wires for temp control. I got some 30 gauge tungsten wire in to test. So far it's the best and worst wire I've used.

As far as building coils, it's a nightmare to work with. It's extremely springy. It takes me a good 15 minutes of fighting and torching to get a nice even coil.
Once the coil is made however, it is outstanding. It heats up and cools down really quickly, so there's no ramp up time, and the atomizer doesn't overheat when chain vaping. The flavor is noticeably better than an identical coil built with nickel or titanium. The coils also hold up very well over time. Easy to dry fire to clean and rewick.

Does anyone else have experience with tungsten? If so, do you have any tips on dealing with the springiness to make the coils easier to build?

 

[edyle]

I've been trying a lot of different wires for temp control. I got some 30 gauge tungsten wire in to test. So far it's the best and worst wire I've used.

As far as building coils, it's a nightmare to work with. It's extremely springy. It takes me a good 15 minutes of fighting and torching to get a nice even coil.
Once the coil is made however, it is outstanding. It heats up and cools down really quickly, so there's no ramp up time, and the atomizer doesn't overheat when chain vaping. The flavor is noticeably better than an identical coil built with nickel or titanium. The coils also hold up very well over time. Easy to dry fire to clean and rewick.

Does anyone else have experience with tungsten? If so, do you have any tips on dealing with the springiness to make the coils easier to build?

Do you have a coiler, like a simple kuro type?

 

[chefjoosie]

I have a kuro coiler set. The way I've been doing them is, I wrap them on the 2.0 with 2 extra wraps, they spring to about 2.5 when I stop turning and take the top piece off, then I stretch the coil out to space it, but it doesn't want to stretch evenly, so I end up pinching and torching it back to contact, then restretching till I get it.

I get the coils as close to the post width as possible or they deform when I screw them in.

 

[Nikea Tiber]

You might want to look into building tensioned coils. From what I know of it from a metalurgic standpoint, as well as your anecdote, tungsten is extremely tough, so it will be resistant to mechanical fatigue deforming it, much like titanium is.
I hated how ti would not conform accurately using a kuro, so I started making tensioned contact coils.
Hope it helps for tungsten. What is the approx resistance per mm of it? I'm always keen on trying new wire.

 

[edyle]

Yes tensioned coils.

Also, when using the coiler, afex one end, and when turning the coil part, try to keep it compressed to get a tensioned effect.

I guess if that doesn't work you can just use a smaller diameter than what you are aiming for and it will spring up to what you want.

 

[chefjoosie]

What is the approx resistance per mm of it? I'm always keen on trying new wire.

The 30 gauge I have comes out to .14 for 7 wraps a bit loose on a 2.5 mm mandrel, so 2.6mm. so .0019/mm.
Steam engine's number isn't even close on that one. They must have used an alloy with something resistive in it.
Also the tcr that is listed everywhere for tungsten(450) will torch cotton at 420. I run it at tcr 400 on devices that have variable tcr, or on titanium mode for others and it works well.

 

[Nikea Tiber]

Is that for a single coil?

 

[chefjoosie]

Is that for a single coil?

Yes .14 single coil, .07 dual

.0019 ohms per mm

 

[Nikea Tiber]

Sounds like a wire I'd like to try, given that it is 30 awg, even with tungsten's density the Watts/mass ratio has got to make for an extremely quick coil response time.
Does tungsten form a non-reactive oxide layer like kanthal, SS, ni80, and ti?

 

[chefjoosie]

The response time is the fastest I've seen. As far as oxides go,
I'm no expert, so others might know a lot more about this, but from what I understand, Heating the tungsten creates 2 oxides, WO3 and W2O3.

Contact coils work well. Ceramic tweezers are kind of a necessity. It's too springy to pinch the coil together unless it is glowing.

 

[sig-cmt]

Might as well go for the good stuff. I contacted Midwest Tungsten Service to see if their wire stock was fully annealed or if they could perform a full anneal for custom orders. Specifically their 0.020 (24g) and 0.025 (22g) options...

 

[chefjoosie]

Those might be too thick. 12 wraps of 30 gauge at 2.5mm comes out at .2 ohms. Might be hard to get especially a 22g coil over .05. It's hard to tell though, since the only ohms/length numbers that I've found are wildly inaccurate.

Please keep us updated though. Midwest seems like it'd be a great place to get quality product, but it's way out of my price range for experimenting.

 

[sig-cmt]

According to Midwest, their tungsten wire is heat treated to be as ductile as possible. Minimum lengths are also delivered on spools. I am still waiting on resistance specifications...

 

[sig-cmt]

Midwest Tungsten Service supplied the following graphical calculators...

 

[chefjoosie]

Midwest Tungsten Service supplied the following graphical calculators...

View attachment 536680

View attachment 536681

That's fantastic. So it looks like 22GA single coil and 24GA dual coil would both work without having to make enormous coils.