RDA New to RDA, build suggestions?

[jlwiseman]

Hey guys, I've been building on my subtank mini for a while now and have a pretty good understanding of the physics behind building. I use the steam engine pro app to give me an idea of how stuff will work before I waste the wire. I've found I prefer a heat flux of 225-300 depending on the juice. So ig I like a cool vape. Anyways, my local shop hooked me up with a cheap dripper when I bought my mod. I'll tell you what I have, what I did and you guys tell me where to go from here.

Mod: tesla 120w
Max voltage: 11v
Max watts: 120 w
Current limit: 24 a
Working resistance: 0.2-3.5ohm

He gave me a vaporking twister rda to play with. It's a 3 post rda, coil post holes aren't very big.

I built a dual coil setup with 22ga last night. 0.2ohm, 6 wraps each around a 3mm mandrel. I wasn't sure how to wick it properly so I just ran wick snuggly through the coils and tucked one tail under the coil, the other through the coil posts. I placed the coils to either side that way they can be easily aligned with the airflow holes. I'll post a pic later. Haven't had a whole lot of time to play with it, but it seemed pretty decent around 70-80w.

 

[State O' Flux]

Hey guys, I've been building on my subtank mini for a while now and have a pretty good understanding of the physics behind building. I use the steam engine pro app to give me an idea of how stuff will work before I waste the wire. I've found I prefer a heat flux of 225-300 depending on the juice. So ig I like a cool vape. Anyways, my local shop hooked me up with a cheap dripper when I bought my mod. I'll tell you what I have, what I did and you guys tell me where to go from here.

Mod: tesla 120w
Max voltage: 11v
Max watts: 120 w
Current limit: 24 a
Working resistance: 0.2-3.5ohm

He gave me a vaporking twister rda to play with. It's a 3 post rda, coil post holes aren't very big.

I built a dual coil setup with 22ga last night. 0.2ohm, 6 wraps each around a 3mm mandrel. I wasn't sure how to wick it properly so I just ran wick snuggly through the coils and tucked one tail under the coil, the other through the coil posts. I placed the coils to either side that way they can be easily aligned with the airflow holes. I'll post a pic later. Haven't had a whole lot of time to play with it, but it seemed pretty decent around 70-80w.

Assuming around a 10mm net (2.5mm per leg - makes a big difference when you get down to low sub-ohm) for coil legs, and based on your other data, I get a dual parallel 6 wrap to produce a matching .20Ω resistance.
At that resistance, wire gauge and wattage, with 80 watts of current, the HF is 220 mW/mm2, with a somewhat slow (but not terrible) HC at 95.5 mJ/K.

To obtain a better HC (at a lower wattage), you can go up a gauge or two with the same resistance... down side is you lose surface area. Up to 23 gauge and the HC drops, HF goes up and surface area goes down.

Kinda depends what is the most important... me I can tolerate a slow HC for surface area, so I'd either stick with the 22, or try 23 gauge... just to see if I prefer a 312 HF at your 80 watt setting. That or stick with what you have and go up on wattage.

The only thing in your post that you may want to concern yourself with is the comment: "I just ran wick snuggly through the coils". "Snugly" is one of those subjective words that to me, might indicate your wicks are too tight in their respective coils, producing a capillary restriction. A high HF may consume the wick-in-coil juice at a rate faster than the capillary action of the cotton can keep pace.

I tend to use the term "slight drag" when pulling dry wick through coil... which may be exactly what you have, but if it's really "snug" (your vaping style and the occasional burnt hit would be factors and indicators)... then you may want to reduce the wick density or fit-in-coil.

All in all... other than the last few comments, your build looks like a winner. That's it! ;-)

 

[jlwiseman]

Thank you sir, and yes. When I said snug, I just meant it didn't just slide right through with wiggle room

 

[State O' Flux]

Thank you sir, and yes. When I said snug, I just meant it didn't just slide right through with wiggle room

Funny how we can quantify nearly all build, power and performance values... but when it gets down to wick density and coil fit, we're stuck with such subjective terms as loose & tight, firmly and lightly compressed, snug, slight drag - and the most recent of funny descriptors... "wiggle room".

At least for now. ;-)

 

[jlwiseman]

Lol true... I'll be experimenting with wicking tonight

 

[jlwiseman]

Here's my current setup. I get a burnt hit occasionally when I take a long drag.

 

[State O' Flux]

It appears you've got it about 98% sorted out. All I can suggest is:

You might try either setting the coils lower, and/or at a diagonal... either way, closer to the juice well/juice level.

After a long draw (Oh goodie, another one of them fabulous subjective values... what constitutes a "long" draw? 10 seconds or more?) you may want to give it a minute or so to re-saturate the wick-in-coil.

All I got. Seems to be just a matter of dialing in the wick... and perhaps playing with the wick height and/or angle relative to the juice well.

As you seem pretty well versed in the details of SE - which is fan-freakin'-tastic by the way - it means more and more people are either sorting it out on their own, or have read and understood my SE User Guides.

If you've not either the former or latter of those categories... have a look at them when you get a chance. Second sigline below.

Cheers!

 

[Bad Ninja]

When I first started building coils and using cotton wicks I found this quote to be very accurate and helpful.

"99% of all cotton wick problems can be solved by using less cotton."
-some EFC member whose name I cannot recall.

 

[jlwiseman]

It appears you've got it about 98% sorted out. All I can suggest is:

You might try either setting the coils lower, and/or at a diagonal... either way, closer to the juice well/juice level.

After a long draw (Oh goodie, another one of them fabulous subjective values... what constitutes a "long" draw? 10 seconds or more?) you may want to give it a minute or so to re-saturate the wick-in-coil.

All I got. Seems to be just a matter of dialing in the wick... and perhaps playing with the wick height and/or angle relative to the juice well.

As you seem pretty well versed in the details of SE - which is fan-freakin'-tastic by the way - it means more and more people are either sorting it out on their own, or have read and understood my SE User Guides.

If you've not either the former or latter of those categories... have a look at them when you get a chance. Second sigline below.

Cheers!

I haven't actually read your blogs. Been meaning to, just haven't found the time. I just heard of steam engine and bought the app.kinda figured it out as I used it since I had a basic understanding of the terms. I just have to learn the art of wicking now.

 

[jlwiseman]

I built this today, and while I like the vape temp, heat up time and no burnt hits, it just doesn't give me the rda experience. My subtank mini does better on flavor and vapor.

Dual coil, 0.6ohm, 26ga, 10 wraps around a 2.5mm mandrel, coils sitting low into the juice well, just enough wick to slightly drag through the coil, trimmed with the edges of the rda base and tucked around/under the coil.

 

[jlwiseman]

Ok, it seems one wick goes dry a lot faster than the other and then it burns. Like even at 75w, I can start to taste it and burn my throat. Any ideas? More wick?

 

[jlwiseman]

Ok, I tried more cotton and a cherry vapes wide bore drip tip and now I love my dripper

 

[State O' Flux]

Ok, it seems one wick goes dry a lot faster than the other and then it burns. Like even at 75w, I can start to taste it and burn my throat. Any ideas? More wick?

Dual parallels... even if they appear to be identical can lag, one coil behind the other. Just a millimeter difference in a leg can do it. Some will go so far (and actually, this is pretty easy with a two-hole positive post) as to resistance test each coil independently.

Ok, I tried more cotton and a cherry vapes wide bore drip tip and now I love my dripper

When it magically all comes together, you gotta' say... Ta Da!

 

[jlwiseman]

Yep, and I bet I can't duplicate it next time lol