Helpful Techie Stuff
So as we lay awake at night contemplating the behaviours of varying tank sizes and shapes it may be helpful to consider a couple of known scientific aspects of liquids and gases.
First, gases (air included) are compressible and expandable. This includes air in vacuum ( low pressure) environments. In our case the air in our tanks is in a constant state of vacuum but the amount of vacuum (in/hg) varies slightly dependent upon whether a bubble of air has just risen to the top of the tank or not. Slightly more vacuum (causing less juice flow) if it has been a while since one has risen; slightly less vacuum (causing more juice flow) if one has just risen. The overall level of vacuum is controlled (regulated) by wicking density and juice viscosity (thickness). The vacuum applied to the top of the fluid in our tanks is the same in/hg per sq.in. of surface area regardless of diameter and has no greater or lesser effect on juice flow based on diameter of the tank.
Liquids are non compressible or expandable by positive or vacuum pressure changes. The downward force provided by liquids is a result of gravitational forces acting upon the mass of the fluid. Fluid in a column will provide a downward force proportional to it's mass and height. Not it's diameter. In the case of water: water in a column will provide a downward force of .43psi (pounds per square inch) per foot of height. It doesn't matter if the column is 1/2" diameter or 100 ft. diameter; it will remain the same.
So if diameter has no impact on juice flow based on physics then one may wonder why I included diameter in my earlier post where I stated that "I like tanks with a greater dia/height ratio? When we fill our tanks we stop at the point that the juice could run down the airtube. This leaves a small amount of air in the tank. That's a good thing because without some air up there above the fluid our tanks would stop flowing juice altogether. Why? Because without air there is no vacuum; just a solid column of non expandable fluid. An air bubble would never rise. In fact the more air we have in the tank vs. juice the more consistent vacuum we have because each air bubble that rises adds a smaller percentage of air to the overall air in the tank. This translates to more consistent juice flow. Because bdc clearos have shorter air tubes (taller wickheads) you will always have ample air above the juice after refill. Even more so with larger diameter tanks.
The following is my understanding of the dynamics controlling juice flow in tanks.
The low pressure air (vacuum) above the juice is regulated by a valve (the wick) and the viscosity (thickness) of the juice and remains fairly constant throughout the tank level. However, this low pressure air also acts an air spring and the spring tension (ability to resist expansion) of this air spring is controlled by the amount of air vs. juice in the tank. Greater volumes of air are easier to expand than smaller volumes. The level of vacuum AND this air spring tension is what dictates how much draw effort is required to pull juice from the tank. So as the ratio of air vs. juice increases so does our abilty to overcome the normalized vacuum by stretching the air spring with normal draw effort. This is why as tank juice level drops we can experience flooding at or near the bottom of the tank if not wicked heavy enough. As it is, this is the condition that I wick for, the bottom of the tank, not the top.
Summary of sorts:
The looser you wick; the lower the vacuum (because air can more easily migrate through the wick and into the tank) and allows more juice flow.
The thinner the juice; the lower the vacuum (because air can more easily migrate through the wick and into the tank) and allows more juice flow.
The more air vs. juice in the tank; the less vacuum change per risen air bubble occurs allowing for greater consistency in juice flow.
The more air vs. juice in the tank the easier it is to pull juice from the tank with a given draw effort because the "air spring" weakens.
Vacuum levels in the tank do not change much with changes in fluid levels of tank.
Wicking density should be adequate to stave off flooding at or near empty tank levels.
With a lesser air vs. juice condition of a full or near full tank you can experience dry hits or burny taste because the air spring is quite strong and resists our efforts to draw juice from the tank. A quick short reverse puff into the device will enable a bubble to rise into the tank and releave the high vacuum condition. Juice will then start flowing into the wick more easily. Once the tank reaches a lower level reverse puffs are usually not needed.
Hope this helps.
Sometimes after refilling my kanger BCC's I experience a reduced juice flow causing less than cloudy vapes. Even dry hitting at times. Don't know if reverse puffing has been written on before so I'm not claiming I thought of this.
The process: If you experience dry hits or a slight burny taste when the tank is full to 3/4 full, and your voltage/wattage it set to your known workable level, your wick is under-juiced. A quick reverse puff will force an air bubble to rise through the juice to the top of the tank thereby reducing the vacuum that's limiting juice flow. One quick reverse puff is usually all that's required each time you detect an under-juiced condition but sometimes when the tank is very full a couple are needed. Carefull though, too many reverse puffs in a row will flood the coil.
Hope this helps
Note: If you haven't already; read part 1 first.
Lets start by defining a few words in laymans terms.
Adhesion: bonding together of unlike substances (molecules in our case)
Fused: or fusing: joining together of like substances in the molten or near molten state.
Alumina: Aluminum oxide: the non-conductive and heat resistance coating formed on resistance wire when we heat our coils.
Covalent bond: the molecular alignment of atoms within alumina which hold it together as a material.
Diffusion: the phenomena by which alumina is formed. 2 aluminum atoms on/near the surface of the wire react with 3 oxygen ions in the air (or juice) when heated and a new compound is formed eg. A2O3 ( alumina).
So lets start with alumina development. Aluminum is highly reactive. That is, it's much more willing to give up its atoms (diffuse them) than the chromium or iron in our wire. Alumina formation is parabolic. Having very fast formation at first then slowing as the aluminum atoms become less available at the surface of the wire. Alumina formation only occurs where oxygen ions and aluminum atoms are present. That is, primarily at the surface of the wire where the aluminum atoms are readily available. Alumina has very high adhesion to the surface of the wire where it is formed. Alumina which was previously formed is pushed outward by new alumina formation at the alumina/wire surface interface forming new covalent bonding.
So when we fire our new microcoils and alumina is formed between adjacent (neighboring) winds two things happen very very quickly. A super high strength dialectric (high resistance) layer is formed and the coils are physically pushed apart disallowing the "fusing" together of the metals in the wire. And because the alumina is formed primarily at the alumina/wire surface interface where reactive aluminum atoms are most abundant but very little at the outermost surfaces of the alumina crystals you will not likely see any significant covalent bonding between the alumina of adjacent winds.
Sintering however is a common method for bonding covalent materials like alumina. Only problem is before we could reach the sintering temp for alumina (2000°f plus) our coils would likely be destroyed from excessive heat.
So imo adhesion, bonding or fusing together of adjacent winds is not happening. Test it for yourself as I did in part 1. If anyone still has doubts and would like to see part 3 just say so. I'd love to talk on grain boundary migration, electron/proton relationships and atomic orbit radii!!!
Just kidding.........or aaaam I? Lol
Hope this gives those of you with inquiring minds something to google!
Short answer: Only if contaminated with flavored juice. Many of you may have noticed that the winds of old gunky coils removed from tanks or drippers seem to be stuck together. Gently pulling on the legs reveals that they are indeed stuck together. Firmly adhered at that. But lesser so if the coil was recently dryburned. Raised my curiosity so I started some experiments a while ago.
Ran tests for adhesion on a dozen coils on a dripper where coils could be removed for testing without bending them. Some were pulsed only to achieving micro, some fired longer to achieve redish/yellow temps and some fired to bright yellow. Removed the coils after cooling and gently pulled on the legs. No aparent adhesion, sticking or fusing. All the winds(turns) just uniformly separated with similar effort for all 12 coils. (All 30awg).
Ran another test identical to the first but vaped them with unflavored 50/50 pg/vg 6mg nic base. Some for 1ml, some for 2ml etc and finally the last coil for 30ml. Same results as in the first test. No apparent adhesion, sticking or fusing together of the winds.
BUT WHY? It's a logical conclusion to believe they would. We're raising the coil temp (firing red/yellow) at or near the melting point (fusing temp) of the aluminum in the wire. And what about all those alumina crystals that are forming while the wires are touching? Surely they would grow together (adhere). Right? It's logical.
So I wonder. Could they still be adhering but at such a small level that I couldn't detect it? A possible conclusion without the scientific knowledge. But alas folks, it's not happening. The science prevents it from occuring.
For the answer why, and it will be slightly techie, see part 2.
View attachment 373459
1. It's nearly free
2. Easy to use if you have big hands and/or arthritis
3. Easy to count your turns because it's square instead of round. Count in quarter turns ie. 1,2,3-1. 1,2,3-2. 1,2,3-3 etc.
4. Provides better leverage because it's larger and has flat sides to grip.
5. Faster and more secure wire retainer than using your thumb or tape
6. No need to overwind then unwind starter coils because it winds the first turn at a perfect 90 degrees
7. Almost anyone can fabricate one with tools they already own.
8. Coils are wound directly from the wire spool.
9. Coils require no torching before install
1. Will only accommodate two mandrel sizes ie. one size on each end of tool
2. Probably won't look as pretty as a pin vise.
Super easy to make with a drill bit(mandrel), small #8 screw, cordless drill and a hacksaw if that's all you have. Even seen folks make one from 4-5" of broom handle.
Step 1: Grab a stick of wood about 3/4" square by 4-5" long (preferably hardwood).
Step 2: Shoot a drill bit (mandrel) into the end. Trick here is to drill out the hole except for the last 1/2"" of drilling depth.Then plunge the drill in the last 1/2" and loosen your drill chuck off the bit. That way the bit stays secure.
Step 3: Drill a .125" pilot hole for the #8 retainer screw but make sure it is offset from the center of the tool (as shown in pic) so it doesn't crash into your mandrel.
Step 4: follow instructions below for winding coils.
DIRECTIONS FOR USE:
This DIY winder is designed to wind coils directly from a wire spool with no preheating, torching or annealing. It can be used with loose wire if you wrap the wire around your hand (ouch!) or hold it with pliers, vise grips or a vise.
1. Pull 2" of wire from spool. Place end of wire along side of and under (not around) the retainer screw head. Allow wire end to extend just past screw head. Not too far or you'll get poked! Tighten screw firmly to trap wire end.
2. Pull 6-8" wire from spool in the direction of mandrel. Now anchor "spool hand" against your side securely. "Spool hand" should remain in the anchored position during entire wrapping session.
3. Grasp tool in other hand "tool hand" and with tool parallel to wire begin tensioning wire from retainer screw, over end of tool and along side of mandrel.
4. To begin winding coil rotate tool perpendicular to wire from spool while holding tension. Then turn tool a 1/4 turn at a time, re-gripping tool as needed, while holding tension against "spool hand".
5. When winding is complete gently lay tool down and snip wire from spool.
6. To remove and straighten "retained leg" loosen screw. Place thumb on end of tool to hold leg, slide wire out from beneath screw and bend leg straight.
7. Slide your perfect coil off mandrel.
SCREW WIND MOD: For those who would like to wind spaced coils on a screw:
Step 1: drill proper tap size pilot hole for desired screw size into end of winder.
Step 2: thread a nut onto the screw all the way up to the head of the screw.
Step 3: thread screw with nut on it into pilot hole at least 3/8" deep. No need to tap thread the hole as wood is soft enough to thread by only using the screw.
Step 4: cut the head of the screw off leaving the desired length of threads protruding from the tool. Use heavy side cutters or linemans pliers to cut screw. Attempting to saw the screw off will probably bend it.
Step 5: with a file angled at 45° gently file the end of the screw with a motion from the tool handle to the screw end to remove burrs and distortion caused by cutting off the screw head. Filing in any other direction can ruin the threading.
Step 6: unscrew the nut to the end of the screw to check for remaining burrs or distortion. Once the nut can removed and rethreaded without resistance you're ready to rock!
Separate names with a comma.