#Drawdown bar how to

So if you have a gap clearance of 6 mils, the theoretical wet film thickness will be approximately 3 mils. As a rule of thumb, the Theoretical Wet Film Thickness of a bar is roughly 50% less than the gap clearance listed for the bar. ASTM D823 contains more information on this subject. Variables such as gap clearance, coating viscosity, percent solids, solvents used, drawdown speed, surface energy and substrate absorptiveness all influence wet film and dry film thickness. Actual wet film thickness can be 40% to 90% less than the gap, and dry film thickness can vary even more. There are many variables in the drawdown process. It is important to remember that the wet film thickness and dry film thickness of your drawdown will be less than the gap clearance of your applicator. A good tool for this is the Gardco Microm Film Applicator an adjustable thickness applicator that can be used to create varying film thicknesses with very high precision. This can be accomplished by experimenting with various film thicknesses until you determine which film thickness yields the optimal desired product performance. The first step in determining which drawdown bar to use is to determine the optimal film thickness for your application. One of the reasons that high quality and precision Drawdown Bars, (also known as Bird Type Applicators and Doctor Blades) are used in making drawdowns is to ensure that a consistent film thickness is achieved, since most coating properties are thickness dependent. MIL P-13341.Ĭolor, gloss, opacity, pigment dispersion, wettability, dry weight, drying time, scrub resistance, pigment and dye uniformity, clarity, adhesion, and a host of other properties are measured on the completed drawdowns. They are also specified in many standards, including ASTM D823, ASTM D3258 Federal Specifications TT-P-29, TT-E-50BA, PD-220A FTMS 141a JAN JAN-P-630, JAN-P-700 and Military Spec.

#Drawdown bar how to

Some of these non-all-over covering measures are printing measures.Home > Products > Application > How to Select Proper Drawdown Barĭrawdowns are used in standard tests in many industries, including paints, inks, adhesives, paper, electronics, pharma, food, packaging, and a host of others.

A further thought for 'non-all-over' coatings is that control is required regarding where the covering is to be applied. A significant thought for most covering measures is that the covering is to be applied at a controlled thickness, and various cycles are being used to accomplish this control, going from a straightforward brush for painting a divider, to some extravagant apparatus applying coatings in the hardware business. In different cases, for example semiconductor gadget creation (where the substrate is a wafer), the covering adds a totally new property, like an attractive reaction or electrical conductivity, and structures a fundamental piece of the completed item. Paints and veneers are coatings that for the most part have double employments of ensuring the substrate and being enlivening, albeit a few specialists paints are just for improvement, and the paint on huge modern lines is for forestalling erosion and recognizable proof for example blue for measure water, red for putting out fires control and so forth Practical coatings might be applied to change the surface properties of the substrate, like attachment, wettability, erosion obstruction, or wear resistance. The motivation behind applying the covering might be brightening, useful, or both. Draw Down Barcoater With Pad A covering is a covering that is applied to the outer layer of an article, ordinarily alluded to as the substrate.