Tubbyengineer
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- Aug 20, 2013
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There have been lots of posts and threads on building coils but very few on wicks - so here's one...
A wick relies on some simple physical priciples to work, so it's worth knowing about them as it will probably help to improve your wicking skills - or at least eliminate the more obvious mistakes.
The main misconception seems to be that it's the wicks fibres that move juice, so more fibres means better wicking. Wicks actually rely on Capillary action.
From Wikipedia:
Capillary action (sometimes capillarity, capillary motion, or wicking) is the ability of a liquid to flow in narrow spaces without the assistance of, and in opposition to, external forces like gravity. The effect can be seen in the drawing up of liquids between the hairs of a paint-brush, in a thin tube, in porous materials such as paper, in some non-porous materials such as liquefied carbon fiber, or in a cell. It occurs because of intermolecular forces between the liquid and surrounding solid surfaces. If the diameter of the tube is sufficiently small, then the combination of surface tension (which is caused by cohesion within the liquid) and adhesive forces between the liquid and container act to lift the liquid. In short, the capillary action is due to the pressure of cohesion and adhesion which cause the liquid to work against gravity.
If you cram too much wicking material into a coil you reduce or eliminate the spaces between the fibres, this results in the capillary action being drastically reduced or removed altogether - It's the reason you can squeeze cotton wool dry so easily. Sharp bends in a wick are another cause of this, at the bend the fibres become pressed so close together that the juice can no longer travel along the fibres and the bend becomes a barrier - rather like a kink in a hose.
From this it can be seen that the ideal wick should
1, Only lightly contact the inner surface of the coil.
2, Have the fibres of the wick be loose enough to promote capillary action - but not so far apart that capillary action doesn't occur - providing you
haven't "Rolled" or "Crimped" your cotton this should follow on from point 1 more or less automatically.
3, Not have sharp bends or compressed areas.
A well made wick will swell to 2 or 3 times it's dry diameter, if it doesn't even when wetted, then the fibres are too compressed and need to be "fluffed up" before you use them.
I hope these facts are helpful in helping you acheive the perfect wick...
A wick relies on some simple physical priciples to work, so it's worth knowing about them as it will probably help to improve your wicking skills - or at least eliminate the more obvious mistakes.
The main misconception seems to be that it's the wicks fibres that move juice, so more fibres means better wicking. Wicks actually rely on Capillary action.
From Wikipedia:
Capillary action (sometimes capillarity, capillary motion, or wicking) is the ability of a liquid to flow in narrow spaces without the assistance of, and in opposition to, external forces like gravity. The effect can be seen in the drawing up of liquids between the hairs of a paint-brush, in a thin tube, in porous materials such as paper, in some non-porous materials such as liquefied carbon fiber, or in a cell. It occurs because of intermolecular forces between the liquid and surrounding solid surfaces. If the diameter of the tube is sufficiently small, then the combination of surface tension (which is caused by cohesion within the liquid) and adhesive forces between the liquid and container act to lift the liquid. In short, the capillary action is due to the pressure of cohesion and adhesion which cause the liquid to work against gravity.
If you cram too much wicking material into a coil you reduce or eliminate the spaces between the fibres, this results in the capillary action being drastically reduced or removed altogether - It's the reason you can squeeze cotton wool dry so easily. Sharp bends in a wick are another cause of this, at the bend the fibres become pressed so close together that the juice can no longer travel along the fibres and the bend becomes a barrier - rather like a kink in a hose.
From this it can be seen that the ideal wick should
1, Only lightly contact the inner surface of the coil.
2, Have the fibres of the wick be loose enough to promote capillary action - but not so far apart that capillary action doesn't occur - providing you
haven't "Rolled" or "Crimped" your cotton this should follow on from point 1 more or less automatically.
3, Not have sharp bends or compressed areas.
A well made wick will swell to 2 or 3 times it's dry diameter, if it doesn't even when wetted, then the fibres are too compressed and need to be "fluffed up" before you use them.
I hope these facts are helpful in helping you acheive the perfect wick...
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