Resistance alone doesn't determine ramp up time (how long it takes the coil to heat up) on a mech. There's 4 major factors...
1)Wire type/gauge (ie. 24 gauge kanthal has a higher resistance than 23 gauge and will heat up faster if you wrap a coil in each gauge with the same resistance respectively. also 24 gauge nicrome has a lower resistance than 24 gauge kanthal and their ramp up time's will be different respectively as well.)
2)The number of wraps in the coil (less wraps equals faster ramp up time but also equals a less sturdy coil, you have to find the balance. With lower gauges lik 22-26 you can use less wraps and still have a more sturdy coil because of the thickness/strength of the wire compared to like 28-29 that can be very flimsy with less than 5-6 wraps and 30+ where you really need a minimum of 6 for a good solid coil usually. This is in regards to using normal wire and not twisted or any other special alterations, the numbers can differ in those instances depending on how the wires are combined/twisted.)
3)The inner diameter of the coil (The larger the diameter of the coil the higher the resistance and slower the ramp up time than a smaller diameter coil with the same number of wraps because you're using more wire to make the coil. There are pro's and con's to wrapping a coil of any diameter. You can search the forum for more detail on this as well as there is many Youtube videos that touch on this subject.)
4)Wicking material. (Depending on if you use Silica, Ready X, cotton or rayon or hemp [and making sure you have the proper amount of these types of wicking material for the size of your coil as well or any other non silica or steel or ceramic based wick]. In the case of silica or ceramic or steel rope/mesh types of wick the wick itself is the proper amount and making your coil fit properly is key to good wicking.)
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@martinelias said...it is very possible you have a short as well as 26 gauge wire should ramp up faster than 24. is .65 your resistance for a dual coil build? because that can take a bit two warm up....if you wrap two .65 coils than when you install both of them your resistance should read around .32 and should heat up pretty quick. One of my favorite builds is a 26 gauge dual parallel .24 build which is basically a quad coil setup with 6 or 7 wraps around a 3.2mm drill bit and it ramps up fairly quick, but if I take one wrap away and make it .2 it heats right up quick. I would screw your atty into your ohm's reader, check and make sure your screws are tight. ..if your resistance is reading right and your screws are tight than I would take a toothpick and poke around your coils to make sure the resistance doesn't jump around when you poke at them. The toothpick isn't conductive so it won't change your resistance by touching the coils like you would if you touched them with something metal. If the resistance jumps around a lot just by poking them with the toothpick than your screws might have pinched your lead causing you a short. If everything there is good then I would look all your insulators over on the center pin and deck just to make sure everything looks good and isn't warn or torn or burnt, it never hurts to check them once in awhile. If you do all that and everything looks good then yeah I would try a new coil with one less wrap and see how that works for you.
Sometimes too when a lead get's pinched by a coil it can put a sliver of wire inside the post under everything and it's almost impossible to detect but it can mess with your resistance and conductivity.
I don't know how much all this helps but it's some good just to know info. Good luck and I hope you find the vape you're looking for.