Zahn Cup, Ford Viscosity cup, Viscosity Measurement

W

wtsgems

Guest
I am playing in the deep side of the pool here so please feel free to jump in and currect any misconceptions.
So in looking around I have noticed that most replies to the question how thick the paint should be follows the line of comparison to milk whole or otherwise.
I was wondering though why there wasn't a more precise form of measuring thickness for airbrushing?
In the short time that I've been doing this it seems to me that it is a key factor in performance.
The Ford Viscosity cup is simple in concept its a cup with a small hole in the bottom, and by measuring how long it takes for a set amount of fluid to empty you can figure how thick it is.
I will admit the math baffles me but we don't necessarily need to worry about that. Instead use controls and set those measures as goals. So how long does it take whole milk to flow through, how long does it take 2% milk and so one.

got an idea and wanted to see what you folks thought about it and if it was even worth the effort
The idea or goal of this is to use a universal method of measuring the paint in such a manner that the measurements can be communicated and duplicated by another.
One of the hurdles is that for another person to duplicate a measure they would need the same type of measuring tool.
The other hurdle is scale most of the tools I've seen on the market are for automotive paints to big for what we want a lot of paint would be waisted.
There is a way to build an easy zahn cup that everyone can duplicate.
I am sure most of you has an empty Createx bottle the kind with the screw on snap lid, if you cut the little tab from the lid that fits into the hole on the screw on cap (see pic with knife) and push it into the hole in the cap you will find that it cuts the size down quite a bit use an old needle from one of your guns as a plug it doesn't need to be pushed in tight and now everyone has the same sized zahn cup.
It will need to be mounted so it can't be shaken and for it to be accurate you will need to make sure to minimize vibrations I.e running feet across the floor, loud thumping music and so on. Also remember temperature, cold paint will be thicker than warm paint. Water base and oil base will flow different also even at the same temperature and thickness.
Fill to the last thread in the cap pull the needle and time to the point that consistent flow stops,
I would suggest using something close to this format for notation
00:05.32@ 75°
Am I over thinking the issue?IMG_20130107_183700.jpgIMG_20130107_183425.jpgIMG_20130107_183316.jpg
 
Top