Improved DIY Hydrostatic Head tester for fabric.
3"diam x 5" ABS pipe
2 - 3" test plugs
2 - 1/8" barb x 1/4" NPT fittings
1 - 1/2" barb x 1/2" NPT fitting
1- hose clamp
1/8" ID tubing
Gauge and inflation bulb from blood pressure cuff
The middle fitting is even with the water level of the test vessel. The gauge was checked against another gauge and both were checked against a column of water. The following table shows the calibration results.
There is a learning curve and a bit of art in deciding when a test is 'over'. Water bubbles appear around the perimeter of the circle long before bubbles appear in the 'field'. Sometimes a tiny bubble will appear but not grow in size. Do you count it? With head increasing 10mm per second, looking away, waiting for a 'real' bubble, or other indecision can make a difference in the test results. In any case, for comparative tests of your own materials this works well.
HH numbers for the following pictures are for that specific test, not an average of multiple tests.
First bubbles, silnylon seconds at approximately 400 mm H20
First bubbles, same silnylon seconds flipped over at approximately 300 mm H20
First bubbles, silnylon seconds, approximately at 270 mm H20
First bubbles, silnylon seconds roll end bought 2004, 'back' side at approximately 570 mm H20
First bubbles, same silnylon seconds roll end bought 2004, 'front' side at approximately 1010 mm H20
same test, silnylon seconds roll end bought 2004, 'front' side at approximately 1240 mm H20
same test, silnylon seconds roll end bought 2004, 'front' side at approximately 1760 mm H20
Left, silnylon seconds roll end bought 2004, 'front' side at approximately 1950 mm H20
Right, silnylon seconds at approximately 450 mm H20