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Coils
HeyJoe Online
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Post: #1
Coils
I made my first coil with Kanthal 0.28mm with 7 wraps at 2mm ID and it came out at 2.4 ohms on my MVP 20w when i was aiming for 1.4 ohms - I used Steam Engine. The coil housing is a recommissioned Kangertech one. Where has the extra resistance come from? Should the adjacent windings be touching or separate?
(This post was last modified: 10/01/17 01:32 PM by HeyJoe.)
10/01/17 01:31 PM
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koshamo Offline
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Post: #2
RE: Coils
Need to be touching mate. Assuming you have them spaced this will effectively halve your results to 1.4. I always tidy and squeeze together with ceramic tweezers when i first test fire.


Jumbo Jets / Luxe / RaptorTank / Havoc / v3 / v4 / v4.5 hybrids.
(This post was last modified: 10/01/17 01:39 PM by koshamo.)
10/01/17 01:34 PM
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HeyJoe (10/01/17)
HeyJoe Online
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Post: #3
RE: Coils
(10/01/17 01:34 PM)koshamo Wrote:  Need to be touching mate.

Ta. It works ok but the resistance is creeping up... 2.8 now.
10/01/17 01:38 PM
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nisam Online
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Post: #4
RE: Coils
Leg length will account for extra resistance, but not that much.

My initial thought was that you'd used 28awg, rather than 0.28mm dia, but that would lower resistance and only slightly.

Assuming everything's nice and neat, with the coil & legs well clear of the housing, I'm wondering if you definitely have Kanthal A1. Your wire will have a known resistance so maybe measure the resistance of a short length and check that the result is what it should be for the wire type.

(10/01/17 01:34 PM)koshamo Wrote:  Need to be touching mate. Assuming you have them spaced this will effectively halve your results to 1.4. I always tidy and squeeze together with ceramic tweezers when i first test fire.

Spacing would need to be huge to almost double the resistance. Huge enough to accommodate almost twice the required length of wire.
(This post was last modified: 10/01/17 01:45 PM by nisam.)
10/01/17 01:41 PM
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koshamo Offline
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Post: #5
RE: Coils
(10/01/17 01:38 PM)HeyJoe Wrote:  
(10/01/17 01:34 PM)koshamo Wrote:  Need to be touching mate.

Ta. It works ok but the resistance is creeping up... 2.8 now.

Strange...i use the same wire and coils around a 1.75mm bit in some of my drippers for about 1.3ohm. Not used a kangertech mate so maybe someone here can shed more light for you.


Jumbo Jets / Luxe / RaptorTank / Havoc / v3 / v4 / v4.5 hybrids.
10/01/17 01:44 PM
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nisam Online
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Post: #6
RE: Coils
(10/01/17 01:38 PM)HeyJoe Wrote:  
(10/01/17 01:34 PM)koshamo Wrote:  Need to be touching mate.

Ta. It works ok but the resistance is creeping up... 2.8 now.

Does your mod generally read close to stated resistance on pre-made coils?
10/01/17 01:44 PM
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HeyJoe Online
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Post: #7
RE: Coils
(10/01/17 01:41 PM)nisam Wrote:  Leg length will account for extra resistance, but not that much.

My initial thought was that you'd used 28awg, rather than 0.28mm dia, but that would lower resistance and only slightly.

Assuming everything's nice and neat, with the coil & legs well clear of the housing, I'm wondering if you definitely have Kanthal A1. Your wire will have a known resistance so maybe measure the resistance of a short length and check that the result is what it should be for the wire type.

(10/01/17 01:34 PM)koshamo Wrote:  Need to be touching mate. Assuming you have them spaced this will effectively halve your results to 1.4. I always tidy and squeeze together with ceramic tweezers when i first test fire.

Spacing would need to be huge to almost double the resistance. Huge enough to accommodate almost twice the required length of wire.

I will redo it and make sure it's not touching anywhere it shouldn't. I got it from the Crazy Wire Company. I suspect I'm making noob mistakes but I thought I'd ask to know where to look. thanks.

Koshamo: I can't fanny with a live coil until my tweezers come.
10/01/17 01:52 PM
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nisam Online
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Post: #8
RE: Coils
(10/01/17 01:52 PM)HeyJoe Wrote:  I will redo it and make sure it's not touching anywhere it shouldn't. I got it from the Crazy Wire Company. I suspect I'm making noob mistakes but I thought I'd ask to know where to look. thanks.

You can't do much damage with a poor coil on a regulated mod, but it's good practice to build neatly and carefully, which will also give a more effective coil.

I'd definitely check the resistance of a length of wire as it's quite possible the spool is incorrectly labelled.
10/01/17 01:58 PM
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anditweighsaton (10/01/17)
Strawb Offline
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Post: #9
RE: Coils
(10/01/17 01:52 PM)HeyJoe Wrote:  I can't fanny with a live coil until my tweezers come.

If you've got an ordinary pair of tweezers (as opposed to ceramic ones) available, fire the coil until it's red hot, release fire button and immediately squeeze coil together. Obviously DON'T fire while the tweezers are touching the coil.
10/01/17 02:14 PM
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HeyJoe (10/01/17)
HeyJoe Online
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Post: #10
RE: Coils
(10/01/17 01:58 PM)nisam Wrote:  
(10/01/17 01:52 PM)HeyJoe Wrote:  I will redo it and make sure it's not touching anywhere it shouldn't. I got it from the Crazy Wire Company. I suspect I'm making noob mistakes but I thought I'd ask to know where to look. thanks.

You can't do much damage with a poor coil on a regulated mod, but it's good practice to build neatly and carefully, which will also give a more effective coil.

I'd definitely check the resistance of a length of wire as it's quite possible the spool is incorrectly labelled.

How do you turn the coils and keep the the legs perfectly straight without kinking ad bending them whilst turning... mine wasn't very straight.

I'll check the resistance of a sample... how long should it be? Is it that length that Steam Engine shows and is that for an uncoiled piece? I know bugger all about this. Smiling
10/01/17 02:21 PM
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