micro coil help

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Jazzi Mike

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You are using 28 gauge when you should be using 30 gauge. I guess you could try more wraps. Try 10-12 wraps. That seems pretty low though. For micro coils with that number of wraps, you should be getting closer to 1 ohm. Try wrapping again. What diameter is the thing you are wrapping the resistance wire around?
 

EddardinWinter

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Are you compressing the coil and torching it after wrapping? I ask because I use a 5/64, 28 gauge, 8 wraps and get 1.7 ohms all day long as long as the coils are tight against each other.

It sounds like some sort of short. Lack of compression (in my mind, at least) would result in higher ohms. The ohms the OP is reporting are quite low.
 

H. Hodges

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I'm using 28ga a1 kanthal and a 5/64 drill bit to make my coils . I've tried 8/9 and 9/10 wraps. Put it on my MVP and I get .4 to .8 ohms. What am I doing wrong

Here's some pics of my dual coil on an IGO-W. Each coil is 28g 1A Kanthal @ 15 wraps (14/15 coil) around a 2mm diameter drill bit. I annealed the wire prior to wrapping to stiffen the wire. I then made my wraps as tight as I could where they were visibly touching as I wrapped them. After wrapping the 15 wraps, I removed the coil and held it firmly (with the coil being compressed length wise like a compressed spring) with a pair of pliers and heated the coil until glowing red. I continued to hold the coil until it cooled. This created a very tight coil. Each 2mm inside diameter 14/15 coil ohm'ed at approximately 2.6 ohms and were almost identical to each other. After firing and cooling the coils, I placed them back on the drill bit and installed them into the RDA. I made sure that they were approximately the same distance from the posts and not touching the deck, post legs, or cap when installed and locked them down. If the coils touch anything besides the wicking material a short can occur and bad things can happen, including dropping your ohm readings! Once installed, I checked the ohm reading using my Vamo V3 and made sure all leads were tightly screwed in (which again creates a short and can drop your ohms). I then pulse fired the coils on my Vamo at 13 watts until the coils glowed red. I made sure the coils were starting to glow from the middle of the coil and out to the sides and that both coils were firing/glowing evenly. My dual coil set up is a 1.3ohm system and perfect for my Vamo or mech (I don't sub-ohm). I've been using it exclusively for about a month now and no problems! If the taste gets off (about every three to four days), I just remove the wick (I'm using cotton) and dry burn the coils. As others have noted above, there are three ways to increase the resistance (ohms) of your coils:

(1) Use more wire in a single strand coil. This can be accomplished in one of two ways:

(A) more wraps around an "X" diameter bit (5/64" in your case), this makes a very long coil. So, just make sure the ends don't
touch the inside of the cap (overhand your deck) when installed. Or:

(B) increase the inside diameter of the coil with the same amount of wraps (I'm using a 2mm bit to wrap mine). This makes
shorter coils, but wide diameter. Make sure the coil does not touch the deck, posts, or inside of the cap when installed.

(2) Use a higher gauge of wire for the same size of coil. The higher the number of the gauge (32g vs. 28g), the smaller the diameter of the wire is (28g is a larger diameter of wire than 32g), and higher the resistance. You can think of the wire as a pipe; the larger the the pipe, the more current (fluid or electrical) it will to flow (fluid volume or energy) with less resistance (friction) to the flow at the same rate of input (fluid pressure or battery potential (charge)).

Either using one of the ways (1A, 1B, 2) above, or any combination of theses (1A and 2, 1B and 2, 1A and 1B, or all 1A and 1B and 2) will increase the ohm's of the individual single strand coil.

If you are still not able to get the ohm reading to increase with a larger/longer coil or smaller diameter wire, then the problem might be in your RDA/RBA where is is shorting itself. Hope this helps. Here's the pics:
 

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Vaslovik

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I have 30ga but its flat so how many wraps of that

Oh, well you have ribbon wire, so no wonder you are having trouble. Get some round kanthal wire, works a lot better for micro-coils, and be sure you compress the coil (gently) and torch it until it glows real good, then let it cool. I use hemostats for this.
 
Are you using a stainless steel.wick? If so, your coil is probably shorting against the wick (even if it is well oxidized, little burs can still poke through and cause a short. Also, the oxidation layer can be scraped off by the SS wick when pushing and twisting it through the coil.

My method of choice now with my Aga-T2 is RIP Tripper's cotton coated SS wick method (he has a good video showing how to do this). Basically, you roll up and oxidize your wick, then rub the coil end against some loose cotton fibers and roll it around until you have a very thin layer of cotton that acts as an insulator between the wick and the coil.

For reference, my current T2 microcoil is a 1/8" 11/12 wrap 28g (round) kanthal which ohms out around 2.4.

Good luck
 
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