Dear ktnchemical

Have a look at:

http://en.wikipedia.org/wiki/Capillaryaction

or search the internet.

A great source of information, also for physics.

Success

Teus ■

Dear ktnChemical,

I did a google search for "wicking rate equation" and found some abstracts of journal article reprints that can be purchased online.

I don't know the equations but have some experience with qualitative aspects of wicking. The wicking rate can be a little tricky conceptually because as fluid rises in a capillary it slows down.

If you have a certain fluid and want compare the vertical wicking rates of two materials with different maximum wicking heights (that is, you ask "which material wicks faster") the answer on wich material wins a "vertical wicking race" will depend in part on the height at which you place the finish line of this race. This is a tortoise and hare phenomenon. In my experience, initially the material with the lower maximum height (bigger pore size) wicks faster, like a sprinter. However, that one "tires out" and slows down, and the material with the greater maximum wicking height (because it has a smaller pore size) eventually overtakes it, like a well-trained marathon runner. If you ask "who is faster, a sprinter or a marathon runner" the answer will depend on whether it is a long race or short race.

Conducting this "wicking race" experiment is tricky also. Water and many other solvents can be difficult to see as they wet out a vertical strip of material. A pigmented fluid can suffer from the porous material's acting as a filter and removing the color particles as the fluid rises. Watching the the color rise then can produce misleading results. A trick is to mark your porous material in increments with a water soluable ink marker (if your wetting fluid is water.) As the water rises the marks on the fabric will smear as the water passes them.

Please let me know if you are in need of porous materials.

Regards,

J Bernsley

Porvair Filtration Group ■