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Cotton not lasting on my builds

Invisible Rasta

Member For 5 Years
Hello guys, i been using 7 wraps on 2.5mm of nicrome 80 30awg (around 1.60ohm)on my mtl tank and i hardly can get trought 5 ml of juice before i have to change the cotton and clean the resistance... its getting for me too time consuming . By the way i am vaping at 10wats
any suggestions?
 
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5150sick

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Hi :wave:
Someone had asked about this the other day.
This is the thread here.
 

JuicyLucy

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Sounds like your liquid has lots of sweetener in it.

That was my first thought also - a low-wattage MTL set up like that should last weeks, not tanks

Hello guys, i been using 7 wraps on 2.5mm of nicrome 80 30awg (around 1.60ohm)on my mtl tank and i hardly can get trought 5 ml of juice before i have to change the cotton and clean the resistance... its getting for me too time consuming . By the way i am vaping at 10wats
any suggestions?

It might help if you say why you have to rewick so quickly

If it is just discoloring the cotton, that is okay to vape away until the coil gets gunked or it starts to taste "off"

If your coil is gunking up quickly, most likely it is too much sweetener in the juice
 

Carambrda

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Could you post a pic of your coil build? There's just too many variables to be able to speculate on what you might have been experiencing IMO, like, what's the positioning of your coil vs the airflow characteristics of your atomizer, and how did you wick it up?
 

Invisible Rasta

Member For 5 Years
Well the problem is not the cotton cause when i remove it ,it usually is still of the color of the juice or a bit darker and not black as if it was burned. The thing is that the top of the coil is full of black crap that tastes as if it was burned. The liquid i mostly vape is Don Juan Reserve by King Crest but most of the liquids i use cause the same.
 

Vape Fan

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i been using 7 wraps on 2.5mm of nicrome 80 30awg (around 1.60ohm)on my mtl tank.... hardly can get trought 5 ml of juice before...the top of the coil is full of black crap that tastes as if it was burned.... the cotton usually is still of the color of the juice
Are you saying that after using less than 5ml juice the top of your NEW 7wrap N80 coil has crud, and the cotton looks good?
 
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Carambrda

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Well the problem is not the cotton cause when i remove it ,it usually is still of the color of the juice or a bit darker and not black as if it was burned. The thing is that the top of the coil is full of black crap that tastes as if it was burned. The liquid i mostly vape is Don Juan Reserve by King Crest but most of the liquids i use cause the same.
Sounds to me like the airflow is hitting only the bottom of the coil causing the top of the coil to overheat as a result. If that's your case, you need to reposition the coil such a way that the airflow in the area surrounding the coil becomes fairly similar to this visualization:

CylinderImage.jpg


In this educational experiment they added smoke to airflow so that the airflow becomes visible. So the pic shows how air is moving, from left to right, past a cylindrical object. On the downwind side of this object you can see that the flow is separated from the surface and remains steady.

If you change the air speed, say, by repositioning your coil a little bit closer toward the air hole, which is where the airflow is at its strongest, then the flow on the downwind side of the coil will also be different. The size of the coil also plays a part, as does the force that causes airflow to shoot into your atomizer via its air holes.

The key to understanding how specific parts of a coil's surface can be overheated is that air moving across a heated metal surface covered in boiling liquid is what accelerates transfer of heat energy between the liquid and air, while at the same time also it (indirectly) accelerates transfer of heat energy between the metal and liquid. In those specific locations where this effect is weakened as a result from the speed of air being insufficient in these same locations, the coil temperature won't stop rising, as heat is being carried away from there too slowly to make the temperature stop rising as a result from keep holding the fire button of your mod─at least until finally you release the button.
 

Invisible Rasta

Member For 5 Years
Are you saying that after using less than 5ml juice the top of your NEW 7wrap N80 coil has crud, and the cotton looks good?
yes exactly.. the cotton is in perfect conditions,but the top of the coil is full of junk after about 5ml ejuice. I forgot to add that the RTA i am using is a Yachtvape Pandora. I am super happy with this RTA as the flavour and the airlow it has for me is perfect but this is causing me a bit of problems
 

Carambrda

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i use the tightest options on the ring and under the coil. I think its 0.8 airflow
Have you tried changing it to 1.0? I think 10 watts might be already a bit too high with this type of coil, though, as 30g Ni80 at 7 wraps 2.5mm is not a lot of metal nor has a lot of surface area. So I wouldn't be at all suprised if lowering the wattage also in addition to increasing the airflow is the only way to fix your problem if you don't want to switch to a different coil build. You could try increasing the amount of metal and surface area by making a parallel coil. There exist various video tutorials on YouTube showing how to build one. (Most of these videos use a thicker wire size, but it's also possible to do it with 30g.) How many wraps you'll need it to be is going to depend on your own preference, you'd have to experiment, and try many different combinations of airflow setting AND wattage setting to find out which combination you like best, each time after you've installed a new coil if this new coil has different specs than your previous coil has.

There really are a whole lot of variables to explore. It'll take some time and effort to get them all to play nice with each other, to find the right combination that you prefer. Always start with a wattage setting that is a tad lower than how much you think it should be at. Bump it up one small step at a time so as to not burn your wick immediately from the get go. Especially if the airflow is tight, the cotton will easily get burned as a result from having too much heat energy that is getting spread out over too little metal surface.
 
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MyMagicMist

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Ultimately, I think a lot of anxiety can be pitched aside. Here's why. People coming into vaping need to be given an awareness regarding consumables.

What are consumables in vaping? I'll list a few below.
  • cotton/wick material
  • wire/coils/coil assemblies
  • batteries
Yes batteries can be recharged. That noted you still consume them to a point they are not usable. So yes they're consumable.

Another point to add to consumables is disposable vape products. They are at best a one use and done product.

So now, everyone can let go of all the anxiety. It's not worth having fits over. That same anxiety is not worth spreading around on any forums, vaping or otherwise. Point blank, consumables are consumables because they're meant to be used up.

You don't like that? Stop using consumable goods/services. Simple as that.

Thanks. :)
 
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fidola13

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Use rayon from Sally’s it lasts a very long time in my very sweet and thick juice. Can’t go wrong! Plus I’ve been on the same box for THREE YEARS!!!!! And I vape A LOT being home all day.

good luck and enjoy!!
 

VapeOn1960

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Good advice so far from others. I will ad that I have never used 30 ga wire... seems too thin to me. Try 28 ga. More details always helps (like what RTA) Position of the coil above the airflow (assuming air comes from under the coil) is important. I would also increase to 1mm airflow and open the outer ring a bit more. What about your vaping style? Long draws with very little time between draws? Avoid doing that. I also like rayon but it's harder to work with (make sure it's snug in the coil) Do you do a "dry burn" when you install a new coil? Before you put the wick in, go to a darker area and gently pulse the coil several times (just enough to get most of the coil to glow, then a bit longer so the entire coils glows... don't overdo this) This gives you a good reference of how many watts you should use (which can be a bit more than the dry burn) Mostly, you are looking for even glow... no "hot spots". If it's not even, learn to "rake"/"strum" the coil... it really helps.
 

nadalama

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It sounds to me like you have air restricted so much that you are having to draw really hard on the atomizer to get it to vape at all. It's a balancing act, getting an atomizer to work right. You have to balance air, juice, and heat. Your hard draw is pulling too much juice into the atty, and 10W is not enough heat to vaporize it.

Also, most folks around here are used to restricted DL or airy DL, so 5 ml of juice doesn't sound like a lot to them. However, it takes some time to go through 5 ml at 10W. So the problem you are describing may not be as abnormal as you think.

If your atomizer will allow it, I would slightly increase the amount of air coming through the atty, and increase your wattage to about 15-18, and take a wrap or two off that coil to get it closer to 1.2 or even 1 ohm. I think it will work better for you if you do those things.
 

VapeOn1960

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What @nadalama said... spot on. Airflow is so important. Even with MTL, I like "loose" airflow. Not just because I want more airflow, but I also feel it helps keep the coil working better. Suck a golf ball through a garden hose if you want (and I understand many people want this) but you will pay a price with not enough airflow for the coil. A little more air should help (especially under the coil... if you have different inserts use a bigger one) You can still adjust the flow with the outer ring. Sometimes (as mentioned) not enough watts can be an issue. Just doesn't fully vaporize the juice.Try a few more watts but take short draws. Hey... I even still have issues with rebuildable tanks. It's an ongoing learning curve but very rewarding when you get it right.
 

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