Build help needed - coils heating outside in, legs melting

[Mnemerah]

Hi everyone I just received an order from fasttech today with goblin and Cthulhu clones. I've done rda builds before (mad hatter and troll) so I anticipated a small learning curve but little trouble adapting to the tanks, though I am still pretty new to building.

However, every build I put in (coils made with magic stick) the coils want to heat from the outside in instead of inside out, and the legs are melting and breaking before the middle of the coil heats properly. I have never had this problem when making coils for my rdas. I have tried 24, 26, and 28g kanthal with multiple different numbers of wraps and I keep getting the same results.

To make matters worse, I'm pretty sure I fried my evic vt on the last build. It will no longer turn on. After waiting so long for this order to come in, needless to say, I am quite sad tonight.

If the trouble was just with one of the two I would assume I got a bad clone, but since I am having the same issue with both tanks I am thinking this is user error somehow. I am beside myself and don't want to fry another mod since after killing the evic I am down to a coolfire iv and an istick 30w. I start feeling antsy without a backup for my backup.

Could it be the coil winder? I am tempted to try winding a set by hand and testing those out, but as I said after frying the evic I'm feeling a little paranoid tonight. This is also the first time I've used a coil jig, I've been winding by hand around allen wrenches to date.

If anyone has any insight I would love to hear it. Thanks for checking this out everyone.

 

[roxynoodle]

What was the power setting on the mod? Melting kanthal isn't easy.

Try wrapping some new coils and maybe compress them with tweezers while still on the rod or bit to make them neater ahead of time. When you mount them, make sure they aren't touching posts or the airhole. Pulse them at a lower setting and after getting them lit up, give them a little squeeze with some tweezers. Be sure your finger is off the fire button if you aren't using ceramic tipped tweezers or you'll short.

If everything is going correctly, do a second resistance check with your chimney on before wicking to be sure a coil isn't touching the chimney.

I don't have a Goblin, but it is a tight deck, and easy to have a coil touching something it shouldn't. I do have a Cthulhu, but rebuilt yesterday, and didn't take photos. However, I have photos of other dual coil bases if you need to see one.

 

[DaveP]

Give us some more information. How many turns of 28ga? What's the diameter of the coil? What's the resistance of the coil? As Roxynoodle asked, what voltage are you starting at with your build? When I dry burn a new coil it tends to heat from the outside to the inside. Once I've dry burned a couple of times I use tweezers to compress the coil and it starts to heat from the inside after that. Have the tweezers ready and compress the coil for a couple of seconds as soon as you let go of the fire button. Then, dry burn it again. Twice is usually good.

I usually dry burn a 3mm 28ga coil at 4.2v to 4.5v. What ever it takes to heat it to a visible glow in 4 or 5 seconds is good. Once it's glowing for a second release the fire button and let it cool down, then burn it again. Don't hold the fire button down for more than it takes to glow, then release. Repeat it in short bursts rather than hold it and let it glow. The life of a coil depends on having a wet wick to sink the heat. The only reason you dry burn is to burn off contaminants and create an oxidation layer on the wire for insulation. At that point you can compress the coil, wick it, put it all together, and vape.

I usually wind 8 wraps on a 3mm rod for a 1.8 ohm coil. Are you sub ohming?

 

[Mnemerah]

Thanks for the replies! The builds were around 2 or 2.5 mm rods from the coil jig kit, and the number of wraps varied from 5-10. I tried 4 or 5 builds and the same thing happened each time, then I decided to give up for the night after killing the evic. Wattage was between 25 and 30. The advice is much appreciated and hopefully I can make these tanks work. I was really looking forward to trying something new. Gotta class starting so I'll check back later. Thanks again!

 

[ZombieJuice]

With 5-10 wraps on a 2.5 mm / 2 mm that would put you roughly around 0.8 to 1.8 (give or take a little). You DEFINITELY do not need 25-30 watts to dry burn your coil. Take it down to around 10-15 watts especially if your above 1 ohm. I usually pulse at 11 watts for my 1.2 ohm builds.

The first few fires you probably will notice your legs and outer wraps glowing like crazy. Go slow with your pulses and squeeze with tweezers in between fires. There is a PLETHORA of videos on YouTube that explain/demonstrate this procedure. RipTrippers build videos are awesome to get the "idea" across. Pbusardo is great too but his videos are a little longer.

There is also a trick where you lightly brush a flathead screwdriver over your coil a few times if you have uneven heating. Not sure of the science behind this but it does work, though not always needed.

Having a hard time understanding how you fried an Evic... Even with a short that mod has a lot of protection built in. I would contact manufacturer on that one. Got me scratching my head.

Sent from my Nexus 7 using Tapatalk

 

[ZombieJuice]

Watch this video about 5 min in you see the pulse and squeeze.





Here is the link for product support, select Evic VT and see what they have to say.

Technical Support - Joyetech


Sent from my Nexus 7 using Tapatalk

 

[Mnemerah]

Ok! I have watched some videos, and played around, and I now have a working build in my goblin RTA!

I ended up with 6 wraps of 26g kanthal around a 2mm jig. I wrapped by hand instead of using the coiler. The dual coil build is coming in at .35 ohms. It appears that I was definitely dry burning at way too high a wattage, though it's interesting that I never had this problem with the mad hatter. To date I've always dry burned at the same wattage I vape at. I will not continue this habit in the future.

The evic is a fallen soldier. Not the first in my vape life, and I suspect not the last. I took it back to the B&M I bought it from, and they are going to check on getting a refund from their supplier. Apparently about 60% of the evics they have sold have come back. Surprising, as I've heard very little about evic failures. Even if that doesn't pan out, I feel that it was broken through user error more than anything, so I'll take it as a lesson. Still a shame. Loved that mod. Felt so good in the hand.

Thanks for all the quick replies everyone. The world of vape is like Aslan's country. Every layer is larger and more complex than the one before it.