Does anyone have a 100% fool-proof method of getting a working coil?
Right I am no expert but I did learn some valuable lessons whilst doing the .15 Kanthal microcoils that may help you (went through nearly 1 meter of the stuff before I got two working coils). Basically if you get a hot spot on a .15 Kanthal coil when you first dry burn it, it will either:
a. Instantly and irretrievably distort the coil causing it to be written off or;
b. Instantly burn out.
So, after much trial and error I found that:
1. Make sure you are wrapping a fresh bit of wire. What I mean by this is if you are using a pack from stealth vape for instance that came wrapped around card, avoid the kinks that the card causes in your coil section at all costs.
2. Always burn the wire before you begin and don't be shy - get it white hot at least 3 times across the full length. This helps it keep its shape when its on the screwdriver.
3. When wrapping around the screwdriver don't hold it too hard because the wire will twist on the driver when you wrap - let it slip through your fingers as you wrap so it lays on the driver and does not twist. Its a fine line - you need to maintain the tension to form a tight coil but avoid the twist.
4. Slide the coils down the driver then tension the tails by pulling down (not too hard or the Kanthal will snap and you've chuffed it) and finally burn the coil again on the screwdriver to "set" the coil. It does not have to be purfect at this stage this is to get the tension right. Later you will push the coil together on the atty to finally form the microcoil. This is easier said than done seeing as we are unfortunately burdoned with just two hands. I tried all sorts of positions and ended up trapping the tails with my thumb against the side of my desk whilst supporting the driver then bringing the lighter to bear. Occasionally I knackered it at this stage by busting off the tails so burn lightly and do not pull too hard. Occasionally I burnt my fingers
5. Offer the screwdriver up to the atty and keep the coil on the driver until the tails are fixed.
6. Most importantly DO NOT LET THE TENSION GO FROM THE COIL UNTIL THE ENDS ARE FIXED IN THE ATTY. Hold the two tails close to the driver and insert it, then pinch it tight or better still twist around the retaining screws and fasten one at a time whilst maintaining the tension. When both are fixed you can let go and gently remove the driver.
7. If you are fixing with screwed posts, insert the tails so that the screw post tightens the tension around the driver - so as you turn clockwise the tail is pulled into the screw head clockwise. Do it the other way and you will loose tension and probably create a hot spot.
8. Use slightly longer tails than most tutorial vids show you so you have some flexibility when compressing the coils and don't bugger it up when you secure it.
That's about it really I hope that helps. I'm not saying this is 100% fool proof but that what I found anyway.
