RDA First RDA coil build experience - you get what you pay for?

[OGNDY]

So recently I bought a mech mod and rda combo on eBay along with some Kanthal and cotton. The mod is a penny clone(?) and the RDA is a Tug Boat clone. The entire setup was only about $35. I watched all the relevant YouTube videos on coil making and set off to reproduce what I had learned. I built the coil using 26G wire on a 3mm post, 5 wraps clocking in @ 0.9 ohms. Attached to the mod with a purple Efest battery I was a bit disappointed at what I saw. It took about 2 seconds for the coil to start glowing and it only reached a dull orange. I wicked it up with some Cotton Bacon and juice and went to town. Very disappointing. I sucked on that thing till I almost passed out, but it was like breathing fresh mountain air and the "cloud" was wispy cirrus at best and flavor non-existent. Well, it's my first go and I probably need to practice more, right? Only my coil looked exactly like those I had seen in the tutorials.

I put it away for a few days, and when my sigelei Mini 30W arrived I decided to try my Tug Boat build out on it before scrapping the coil. Wonder of all wonders. The thing lit up instantly to white hot. From the inside out with no hot spots like the experts teach. And it chucks clouds like it's nobody's business at only 20W!

I double checked the penny mod to make sure all connections were tight, that the battery was fully charged. I don't see how anything I did can have caused the poor performance, so unless somebody tells me otherwise I'm gonna say the penny mod is junk. I'm fine with that; I'll just put it down to experience. There probably is reason why some mods cost $200 and some $20. (Duh?)

PS
I just put some Vape Wild Dandy Caramel Candy in it and only now do I realize what I've been missing! I'm so glad I didn't give up after my less than satisfying debut with FIN/Haus.

 

[kickflipsnnollies]

There's no good reason that a mod costs $200 compared to a $20 clone. You probably had a connection problem somewhere or your battery wouldn't keep up.

 

[Sir Pouncival]

Clean all the threading, the firing switch, and the 510 on the penny mod with a toothbrush and cleaner. If there is any dirt it will cause poor performance. This is also a good way to find out if there is anything causing a short. My first mod was a stingray clone and it worked ok right out of the box. Once I took it apart and gave it a good cleaning it hit hard. The voltage drop is now at .12 (I didn't get a voltage tester until later).

 

[OGNDY]

Well shame on me. I didn't realize just how much I could adjust the pin in the firing button. It still doesn't fire quite as fast and hard as the Sigelei, but at least it's useable now. I'll try a detail strip/clean tomorrow and report back. I freely admit my ignorance. I thought contact meant contact. Obviously not.

 

[OGNDY]

Just in case any of you guys are still with me, could the battery form factor be an issue? I.e. I'm using a flat top battery. Could it be that a button top would work better? I've taken the entire mod apart, cleaned every little crevice with a Q-tip and alcohol, adjusted all screws so all connections are super tight, yet still it's temperamental as hell. 2-3 seconds to heat up the coil and very low temp. I know it's not the coil itself because it fires like a champ on the Sigelei. Batteries are high quality, almost new and fresh off the charger.

Just to make sure I've identified all the adjustable parts of the mod that would affect connectivity, I have 3 parts:

1. A screw at the bottom of the top cap that screws into the .510 and makes contact with the atty.

2. A smaller screw that goes into the screw in 1. and adjusts in the opposite direction to make contact with the positive end of the battery, and

3. The screw in the firing switch that completes the circuit when pressed to make contact with the negative end of the battery.

I've adjusted all three of these screws to make sure everything is snug. There is no battery rattle, the travel in the firing switch is not overly long; it hits the bottom of the battery for sure and the is definitely solid contact in the .510 connector. Any suggestions?

<Dazed & Confused>

 

[Robert Dupre]

Your build is to high of resistance for a mech i dont do anything above .4 on my mech otherwise its heats to slowly. On a regulated mod the resistance doesn't matter because you can push the same amount of power with any resistance.

 

[Lessifer]

I'm not sure about the pins but 0.9 might be too high for 26g on a mech. If you had no voltage drop, with a fresh battery you'd be approaching 20w, BUT you do have voltage drop(it's inevitable) so more likely you're hitting about 15w. Test it, drop your sigelei to 15w and see if the performance is comparable.

 

[OGNDY]

Well that's something I can work with! Did not know that. I'll try to build something below 0.5 ohm and report back.

Thanks guys!

 

[Lessifer]

Well that's something I can work with! Did not know that. I'll try to build something below 0.5 ohm and report back.

Thanks guys!

I use 28g and 0.9ohm is about perfect for my mechs, but yeah, if you use thicker wire you need to go higher power, which on a mech means lower resistance. On your regulated mod you can just pump up the watts as needed.

For your mech build, try going smaller inner diameter, like maybe 2mm, with the same 5 wraps, should get you around 0.5

 

[HecticEnergy]

Steam-engine.org is a great tool for getting an idea of how your coils will respond. Check out the heat flux tool. It's a bit of a pain to adjust for a mech as your wattage varies with the ohms, so you need to continually update the box on the coil building page. They also have an extensive write up on it... Here's the short and sweet version: more mass (lower gauge) means lower resistance, but more wattage required to heat!


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[flog]

Coming from an electronics background, good conductivity means shiny metal contact surfaces. If all else fails, try scratching the metal where it contacts at the switch and battery. Nothing drastic, just rubbing a small flat head screwdriver over the points might help.

 

[NightSky]

Interested to see what happens when you come back with a 0.5 ohm build. Its likely that's the problem, but if it isn't I can try and help you figure it out.

 

[HecticEnergy]

Coming from an electronics background, good conductivity means shiny metal contact surfaces. If all else fails, try scratching the metal where it contacts at the switch and battery. Nothing drastic, just rubbing a small flat head screwdriver over the points might help.

Clean contacts are good. I've used nolox on my mods and batteries to improve conductivity, just got some deoxit gold, that's way less messy than the noalox


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[OGNDY]

I'm really glad I found this board. I'd be completely lost without you guys! I am absolutely clueless when it comes to electronics. Give me wood and tools and I can build you a deck or a shed any day, but I leave the electricals to the pros. I'm soaking up all your advice and promise to come back with an update.

I just discovered steam-engine and it looks very helpful. I appreciate all your help!

 

[NightSky]

I'm really glad I found this board. I'd be completely lost without you guys! I am absolutely clueless when it comes to electronics. Give me wood and tools and I can build you a deck or a shed any day, but I leave the electricals to the pros. I'm soaking up all your advice and promise to come back with an update.

I just discovered steam-engine and it looks very helpful. I appreciate all your help!

Really do keep us updated, post some cloud pics once you're done!

 

[OGNDY]

So using the calculator on steam-engine I built a dual-coil setup: 28G wire on a 2.3 mm post (it's what I had) that measured 0.48 ohm. Much better performance, but still leaving something to be desired IMO. I'm thinking maybe the sweet spot is even lower. Next I'll aim for 0.35. The Sigelei still blows it out of the water. Which (to me at leas) begs the question, why even bother with mech mods? Seems like yesterday's technology. With reasonably priced high-wattage regulated mods being ubiquitous that seems like the way to go. Just slap on your favorite atty/build, dial it in to your likings and puff away. The only reason I can think of would be if you want to go super low beyond what a regulated device will allow (<0.2), but some of the newer regulated mods let you bypass the circuitry and essentially use it as a mechanical device (but still with some protection?).

I like dripping attys and building coils, but I'm not sure about the value of mech mods at all (again, in my uneducated opinion).

 

[HecticEnergy]

So using the calculator on steam-engine I built a dual-coil setup: 28G wire on a 2.3 mm post (it's what I had) that measured 0.48 ohm. Much better performance, but still leaving something to be desired. I'm thinking maybe the sweet spot is even lower. Next I'll aim for 0.35. The Sigelei still blows it out of the water. Which (to me at leas) begs the question, why even bother with mech mods? Seems like yesterday's technology. With reasonably priced high-wattage regulated mods being ubiquitous that seems like the way to go. Just slap on your favorite atty/build, dial it in to your likings and puff away. The only reason I can think of would be if you want to go super low beyond what a regulated device will allow (<0.2), but some of the newer regulated mods let you bypass the circuitry and essentially use it as a mechanical device (but still with some protection?).

I like dripping attys and building coils, but I'm not sure about the value of mech mods at all.

Seems like most like mechs for form factor and durability. .4 with 28ga seems like it would be a super hot vape...
Regulated mods are great for constant vape and boosting or dropping power for your build.
There is no need to build below .2 with a high powered regulated mod. On a mech you build low for more wattage.


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[edyle]

So using the calculator on steam-engine I built a dual-coil setup: 28G wire on a 2.3 mm post (it's what I had) that measured 0.48 ohm. Much better performance, but still leaving something to be desired IMO. I'm thinking maybe the sweet spot is even lower. Next I'll aim for 0.35. The Sigelei still blows it out of the water. Which (to me at leas) begs the question, why even bother with mech mods? Seems like yesterday's technology. With reasonably priced high-wattage regulated mods being ubiquitous that seems like the way to go. Just slap on your favorite atty/build, dial it in to your likings and puff away. The only reason I can think of would be if you want to go super low beyond what a regulated device will allow (<0.2), but some of the newer regulated mods let you bypass the circuitry and essentially use it as a mechanical device (but still with some protection?).

I like dripping attys and building coils, but I'm not sure about the value of mech mods at all (again, in my uneducated opinion).

To check the sweet spot you need to look on the right side by the 'heat flux' on the steam engine calculator page.
red is hot; blue is cold, and green is good.
You'll need to work out the watts and input that number

high wattage regulated mods are still relatively new/common. That's why there are still many mech mods around; otoh, it always good to have a mech for backup.

 

[OGNDY]

To check the sweet spot you need to look on the right side by the 'heat flux' on the steam engine calculator page.
red is hot; blue is cold, and green is good.
You'll need to work out the watts and input that number

high wattage regulated mods are still relatively new/common. That's why there are still many mech mods around; otoh, it always good to have a mech for backup.

I had noticed the Heat flux box in the calculator, but wasn't sure what is was for. If I understand you correctly, the number that appears there isn't a function of your build, but a recommendation for how to set your device (obviously only works with regulated devices)?

 

[edyle]

I had noticed the Heat flux box in the calculator, but wasn't sure what is was for. If I understand you correctly, the number that appears there isn't a function of your build, but a recommendation for how to set your device (obviously only works with regulated devices)?

The number there that you can change is the wattage; I think by default they have it at 10 watts. "10 W"
After you put in the numbers everywhere else, if you have a vw regulated mod, you can change that 10 to some other number to see what wattage gives you a green result.

If you just have a mech then you have to calculate: watts = volts x volts / ohms
and put that number in.
So in post#16 above where you aim for 0.35 ohms
that's 4 x 4 / 0.35 = 45 watts