Parallel Coils Question

[Glytch]

I've recently been building in my ECR head and loving it. I'm using 28g Kanthal and trying various options (spaced, micro, parallel etc).

After some practice I can make a decent looking 4 wrap parallel coil that reads at 0.64 ohms. Ramp up is good and seems to glow nice and evenly on the dry burn.

However the coils looks beautiful on the jig and when I install it. However as soon as I dry fire it (by pulsing at around 15 watts) on my mod the coil spreads out and loses its shape.

Is this normal? How can I prevent it? Does it matter?

Thanks!

 

[Stephen]

Try using a set of ceramic tweezers while pulsing, by lightly gripping the coil at both ends. This should ensure it holds its shape.

If you only have standard tweezers pulse it first and then squeeze with the tweezers.

 

[Andre]

Try very, very short dry burns initially, not lighting up the coil at all. Then strum the coil with something metal and/or snooker the mandrel through the coil. Twice or three times should be enough. Then slowly increase the burn time until the coil starts to burn evenly. Then do the tweezer thing if required.

 

[stevie g]

That's weird because I've never had that happen to me. What wire?.

 

[Caveman]

Odd.. I've made paracoils with 24 - 28g Kanthal and SS and never had this happen to me at all. If anything mine tend to bind up and pull together a bit more after applying heat, not fall apart though. Might have to get yourself a ceramic tweazer and see if that helps.

 

[zadiac]

Yeah, that wire seems dodgy.

 

[Ernest]

Could also be that there is slack in one or both coil legs. Wrap them tight, make sure both wires are caught and clamped down tightly in the posts. Build close to the posts and pull the coil legs tight when positioning.

 

[Glytch]

Thanks guys. I have a feeling @Ernest may be on to something. There are no posts because it's a rebuildable coil head and not an RTA/RDA. The legs are only held in place by a rubber grommet and the metal pin. I'll try what @Andre suggested and try dry firing it more "gently" next time.

 

[Jan]

Just a question. What do you mean by parallel coil? Reason why I am asking is the Ohm reading is a bit high for a parallel coil with 28ga wire....

 

[Glytch]

Just a question. What do you mean by parallel coil? Reason why I am asking is the Ohm reading is a bit high for a parallel coil with 28ga wire....

The leg length on the ECR head is about 10mm per leg. I assume this is the reason for the higher than normal resistance. Coil calculator for 4 wraps, 2.5 ID and 20mm total leg length works out to around 0.6

 

[Yiannaki]

It must have something to do with how tightly wrapped the coils are.

One needs to pull all the slack out of the leads to make sure it sits nicely and doesn't deform.

Sent from my SM-N920C using Tapatalk

 

[Andre]

Thanks guys. I have a feeling @Ernest may be on to something. There are no posts because it's a rebuildable coil head and not an RTA/RDA. The legs are only held in place by a rubber grommet and the metal pin. I'll try what @Andre suggested and try dry firing it more "gently" next time.

Yeah, I think you are correct. I only do single contact coils on the ECR and even so I sometimes have to insert the mandrel, take out the metal pin, grab the two tails with a pair of pliers and tighten for those last wraps to form properly again. Personally, I would not even try a parallel coil in there, but then my coil building skills are very rudimentary.

 

[kev mac]

It must have something to do with how tightly wrapped the coils are.

One needs to pull all the slack out of the leads to make sure it sits nicely and doesn't deform.

Sent from my SM-N920C using Tapatalk

Nice looking coils

 

[Glytch]

It must have something to do with how tightly wrapped the coils are.

One needs to pull all the slack out of the leads to make sure it sits nicely and doesn't deform.

Sent from my SM-N920C using Tapatalk

Pull out the slack when? And how? I do one or two more wraps and then pull the one end until I have the correct number of wraps. Then I pull both ends down together to tighten it up.

 

[Glytch]

Yeah, I think you are correct. I only do single contact coils on the ECR and even so I sometimes have to insert the mandrel, take out the metal pin, grab the two tails with a pair of pliers and tighten for those last wraps to form properly again. Personally, I would not even try a parallel coil in there, but then my coil building skills are very rudimentary.

Thanks I'll try that while the coil is in the head. I'm doing parallel coils to get sub-ohm. With Kanthal it's like three wraps to get below 1 ohm which doesn't leave you much surface area.

 

[Andre]

Thanks I'll try that while the coil is in the head. I'm doing parallel coils to get sub-ohm. With Kanthal it's like three wraps to get below 1 ohm which doesn't leave you much surface area.

I would rather try a thicker gauge Kanthal - maybe 26 g. I presume you have a regulated mod. If so, no reason to go very low in resistance as you have all the power you need on tap. I use 27 g in there, going for around 0.8 to 1.0 ohm. Much easier to build with thicker gauge wire.

 

[Glytch]

Yeah. I'm realising that Kanthal 28g wasn't the best choice for a first time wire. I should've gone with 26g or NiChrome or SS. Oh well.

 

[Andre]

Yeah. I'm realising that Kanthal 28g wasn't the best choice for a first time wire. I should've gone with 26g or NiChrome or SS. Oh well.

Maybe try twisted. Should be easier to install on the ECR. Thickness might make it difficult to get that insulator and metal pin in though.

 

[Glytch]

Maybe try twisted. Should be easier to install on the ECR. Thickness might make it difficult to get that insulator and metal pin in though.

Thanks. I'll try that. The pin and grommet seem pretty accommodating. I'll give it a try. I like the lower ohm's because the ramp up time is shorter. The parallel (albeit skew) at 0.64 ohms is working nicely though. I'm sure I'll improve with time.

Thanks for the input everyone.

 

[Yiannaki]

Pull out the slack when? And how? I do one or two more wraps and then pull the one end until I have the correct number of wraps. Then I pull both ends down together to tighten it up.

When installing the coil is when you need to pull the slack out/ensure you keep the tension around the mandrel.

Maybe you can share a pic of your build so we can also see how the atty you're building on looks.

28 still works fine with para wraps. The only advantage with 26 is that it is far more forgiving.

Sent from my SM-N920C using Tapatalk

 

[Andre]

When installing the coil is when you need to pull the slack out/ensure you keep the tension around the mandrel.

Maybe you can share a pic of your build so we can also see how the atty you're building on looks.

28 still works fine with para wraps. The only advantage with 26 is that it is far more forgiving.

Sent from my SM-N920C using Tapatalk

It is not an atty. The Melo ECR head, which make it a bit more difficult to keep the tension.