sub tank mini rba dry hits at high wattage
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Your wattage isn't high, heffe... in fact, if you use the Ohm's law formula or v² ÷ Ω = P (wattage)... it's low.
Although there is an unidentified wire gauge/wire strand count value that will have an effect on "heat flux" (coil radiant temperature in mW/mm2)... 0.4Ω resistance at 4.2 volts (the standard constant for a mech mod), will result in a discharge of 44 watts.
Where I'm going with this, is that your atomizer wicking isn't keeping up with your resistance. It may be the wick itself, the coil physical dimensions, the wire gauge... and/or the air flow distribution is biased towards drawing in outside air rather than pulling juice from the tank into the vaporization chamber.
The latter can be quickly determined by taking one or two open circuit, "primer draws" between closed circuit draws... if the dry hits go away, either reduce your fresh air inlet orifice, which will shift the bias of your draw vacuum towards the juice tank/vaporization chamber orifice, or look at ways to open the juice transfer/wick orifice, or... one if the most common wicking issues - reduce wick density and/or in-coil fit compression.
Although there is an unidentified wire gauge/wire strand count value that will have an effect on "heat flux" (coil radiant temperature in mW/mm2)... 0.4Ω resistance at 4.2 volts (the standard constant for a mech mod), will result in a discharge of 44 watts.
Where I'm going with this, is that your atomizer wicking isn't keeping up with your resistance. It may be the wick itself, the coil physical dimensions, the wire gauge... and/or the air flow distribution is biased towards drawing in outside air rather than pulling juice from the tank into the vaporization chamber.
The latter can be quickly determined by taking one or two open circuit, "primer draws" between closed circuit draws... if the dry hits go away, either reduce your fresh air inlet orifice, which will shift the bias of your draw vacuum towards the juice tank/vaporization chamber orifice, or look at ways to open the juice transfer/wick orifice, or... one if the most common wicking issues - reduce wick density and/or in-coil fit compression.
my wicking w/rayon, stock 0.5 coil
try this method.
thick going through the coil.
tails - cut short and on an angle and thinned slightly
formed to the post wall and juice channel kept clear
try this method.
thick going through the coil.
tails - cut short and on an angle and thinned slightly
formed to the post wall and juice channel kept clear
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Dry hits here too. New to world of RBA but not to extensive research. Wrapping 30 G around the little blue screwdriver that came with the Subtank Mini. A few wraps, give or take as I have just been trying to get my feet wet. Best I have come up with is 1.2 ohm, tested on multimeter. I think I must be going wrong with the wicking...too much, maybe too tight? Keep getting dry hits. A little discouraging but I figure this is part of being a newb. Any suggestions would be super helpful!
imo blue screwdriver to small, my last coils i used a ~3mm diameter, working real nice.
w/that size i made twisted pair 28g 1.0 ohm and single 28g 1.3 ohm, no dry hits
watch the vid for howto wick at about the 11.20 mark.
w/that size i made twisted pair 28g 1.0 ohm and single 28g 1.3 ohm, no dry hits
watch the vid for howto wick at about the 11.20 mark.
don't know if this'll get flamed or not but quite a few subtank mini owners on Facebook, including myself, have found that the taking of a drill bit, i used 5/64ths but i don't really think it matters, to the "collar', right above the juice holes, and abuve the threading, fixes dry hits every time. I did it about two weeks ago and the only dry hit i've had since then was when i didn't notice the tank getting empty. People ask if it causes leaking, and the answer is it does not. Others prefer to take a file to the juice channel instead, or to dremel out the base. For me, the drilling was super easy and I highly recommend it.
Thanks very much for the reply w/video. I will definitely check this out later and make some notes. Definitely an over the top notes everywhere kind of girl here. Waiting on some vape mail that includes 28 G Kanthal, I think this will get me closer to the resistance I am looking for. Hoping it will be sturdier, the 30 G seems a little flimsy. All the tips and info are greatly appreciated! I've learned so much from lots and lots of lurking on this forum for a few months.
I drilled a hole in the RBA side walls this morning similar in size to the other Sub-ohm coils/heads. I think the juice feed notches at the bottom (2 of them) are too small. (I saw that someone else did this modification and tried it) It's working OK so far at low watts, haven't bumped it up. I just feed the cotton through the coil and next to the drilled holes. The juice feeds the coil much more efficiently this way.
The holes are drilled above the notches. Needs to be between the threads. I just took a small punch and started the area to drill. Then put it in a vice with a piece of wood on each side and drilled a small pilot hole. Then took a larger bit and drilled it out to a larger size. (Need to go slow, let the drill do most of the work)
The dry hits really suck and leave such a bad taste, it almost makes you quit vaping for the day...
The holes are drilled above the notches. Needs to be between the threads. I just took a small punch and started the area to drill. Then put it in a vice with a piece of wood on each side and drilled a small pilot hole. Then took a larger bit and drilled it out to a larger size. (Need to go slow, let the drill do most of the work)
The dry hits really suck and leave such a bad taste, it almost makes you quit vaping for the day...
my wicking w/rayon, stock 0.5 coil
try this method.
thick going through the coil.
tails - cut short and on an angle and thinned slightly
formed to the post wall and juice channel kept clear
Bang on the money here, thats how I wick, especially for higher vg juice, I find you need a bit more cotton for 50/50 mixes as it floods the coil.....but as a general rule, this is some great advice here, if you follow this you shouldn't get any dry hits, make sure you leave a little channel by pushing the cotton back very slightly away from the juice holes too..
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