Detailed Step-by-step Instructions
Just follow a few simple steps
Peel off the backing of the Capatch making sure to leave it attached to the Capatch. You will later use this attachment to remove the Capatch from the roll.
The blue, green, brown or red squares show where glue patches are located. Place the square at the top of the Capatch against the roll. Take the bottom square or the backing and stretch the Capatch downwards and place the bottom square against the roll, ensuring that it is properly attached without any wrinkles in the plastic foil and without trapping air between the foil and the roll.
Take the doctor blade and put the index finger on the arrow of the doctor blade. Keep the angle of your doctor blade roughly 45 degrees to the roll at all times while doctoring.
Start below the marked arrow on the Capatch, squeeze the indicator fluid from the capsule along the scale printed on the Capatch, moving in a slow tempo but with a firm press from the index finger (not the thumb) on the doctor blade. A slow tempo is needed to allow the indicator fluid to penetrate the cells bit by bit. Repeat this many times until there is no more visible movement of indicator fluid. Then use the left or right side, meaning moving the doctor blade arrow to the left or to the right of the arrow on the capsule, to squeeze the rest of the indicator fluid out of the capsule; this is typically at least 10 percent of the fluid, although it may not be easily visible in the capsule. Be aware that a layer of indicator fluid accumulates between the roll and the Capatch foil which is not in the cells, therefore repeat sharp doctoring on the rolls to make sure that ALL the indicator fluid has been pushed from the capsule and between the foil and the roll into the cells of the roll. Remember that the Capatch is calibrated on 100% of the indicator fluid leaving the capsule. Be aware that there is only a very little drop of indicator fluid in the capsule and if you leave 10 percent of the little drop of indicator fluid behind in the capsule AND you leave 10 percent behind between the foil and the roll, the reading will result in a 20 percent error with the volume 20 percent too large.
WARNING: Avoid these mistakes:
1) You must place the doctor blade at 45 degrees against the roll. A common error is to hold the doctor blade at a shallower angle. If you make this error, more liquid goes over the cells rather than into the cells, and the result may show up to 10% less volume than the real volume. To get accurate results, all the cells under the spot must be 100% filled. So, while using Capatch, either turn the roll so that you always have your plastic doctor blade at a 45 degree angle to the roll, or tilt the blade as you proceed around the roll keeping the angle at 45 degrees to the roll at the point of contact.
2) Do not move the plastic doctor blade too rapidly across the surface of the roll; liquid may not get enough time to fill up the cells under the spot. The liquid should fill up the cells closest to the capsule first, then progressively the cells further away, and so on. This happens when you use repeated sharp steady movements over short distances, moving progressively upwards, to wash out the liquid from the capsule and fill the cells as you go. Do not use long or fast forward strokes from the capsule to the end of the Capatch. If you make this error, Capatch will indicate up to 10% less volume of the roll then the real volume
3) Make sure that no liquid remains in the capsule. You must wash out the capsule with firm short movements until you see no further change in the capsule. Any volume of liquid remaining in the capsule will cause Capatch to indicate more volume of the roll then the real volume. Experience shows that this error can be as large as 10%. A small volume of liquid remaining in the capsule might be difficult to see. Continue doctoring until there is no further change or movement in the capsule.
4) You must press the doctor blade firmly onto the Capatch. The liquid layer between the Capatch and the roll must be pressed into the cells. The best way is to put your index finger on the plastic doctor blade at the end where it makes contact with the roll, and repeat the forward movements frequently until you see no liquid movement anymore between the Capatch and the roll at the place where you have been doctoring. Continue these firm motions from the beginning of the Capatch spot until the end. Always start at the arrow on Capatch below the capsule. If you do not press firmly enough, up to 10% of the liquid may remain between the roll and Capatch, and Capatch will indicate more volume of the roll then the real volume.
These recommendations are important. Make sure to watch the instruction movie on this website and observe the motions demonstrated.
Read the result.
Does the width of the stain have some effect on the volume measurement?
Due to the properties of the indicator fluid, the width of the stain has no significant effect on the measurements and on the tolerance of plus or minus 10 percent. Several tests have proven this. The speed of the plastic doctor blade does have effect on the measurement results. Faster blade motion forward causes the stain to elongate somewhat, and less cell volume will be indicated.
Immediately remove the Capatch by tugging gently on the backing.
Always clean the roll directly after making a measurement. It might occur that you see traces of non-permanent glue on the roll. We advise you to use, ethyl acetate, isopropyl alcohol (IPA) or equivalent to clean the roll.