2.5

[Ephraim]

If 7 wraps around a 3mm gives me .35 wud 9 wraps around a 2.5 give me the same with more surface area. I hear people use 2.5 bits to get more surface area. Is that true?

 

[zephyr]

If 7 wraps around a 3mm gives me .35 wud 9 wraps around a 2.5 give me the same with more surface area. I hear people use 2.5 bits to get more surface area. Is that true?

The surface area would be the same...with the middle of the coil being farther from the wick ends

 

[zephyr]

Errr correction -

9 wraps at 2.5mm ID has a higher resistance than 7 wraps at 3mm ID, so yeah it would have more surface area because the wire itself is longer

They shouldn't be compared, really

 

[Letitia9]

It isn't that simple Ephraim. Personally I would just wrap the 2.5 9 wrap and give it a go out of curiosity.

 

[Ephraim]

The surface area would be the same...with the middle of the coil being farther from the wick ends

O well thats sucks cause just tried it. I did 8 wraps on a 2.5 and it ohmed out at .34. Ill see how it vapes. Im getting ready to wick it now.

 

[SteveS45]

A smaller diameter would be LESS surface area since it would be less wire with the same amount of wraps.

 

[Ephraim]

It isn't that simple Ephraim. Personally I would just wrap the 2.5 9 wrap and give it a go out of curiosity.

Do a lot of people use 2.5 vs. 3mm? Which is better?

 

[Ephraim]

A smaller diameter would be LESS surface area since it would be less wire with the same amount of wraps.

I added an extra wrap. 7 wraps of 3mm was .35 8 wraps on a 2.5 was .34. Not much difference at all.

 

[SteveS45]

I added an extra wrap. 7 wraps of 3mm was .35 8 wraps on a 2.5 was .34. Not much difference at all.

So actually still slightly less surface area because the lower resistance indicates less wire.

 

[Letitia9]

It's all about preference. I prefer 3mm, the size fits well without restricting my af too much and is easy to wick. MTL people generally use smaller id with thinner wire, more wraps for higher ohm. Higher wattage vapers will use thicker wire and tend to use larger id with fewer wraps. TC users have their preferences as well.

 

[zephyr]

Do a lot of people use 2.5 vs. 3mm? Which is better?

For me it depends on the size of the atomizer. My coils tend to me 3mm or 3.5mm diameter, and 4 to 6 wraps - my atomizers are "medium to large" I'd say, and I cut air down quite a bit

Like letitia said, there's quite a bit to it and experimenting helps find what you like