Using the thumbs of both hands to keep the rod from bowing or bending away from the sample, draw the rod down through the liquid pool spreading and metering the fluid across the sample sheet. Immediately grasp the ends of the Drawdown Rod.Using a spatula, place a small pool of coating liquid near the top of the sample sheet.Attach (or tape) a sample of the most suitable substrate to the glass surface of the Drawdown Plate.Drawdown rods enable the technician to perform these tests with a minimum of effort. Typical coating patterns before "flow-out"ĭrawdowns are an inexpensive method of making laboratory samples to determine coating thickness, substrate penetration, fluid compatibility, bond strength, etc. Gapped Rods are used for coatings up to 25 mils (.025") thick. While a gapped rod is less durable than a twin coat rod, it is usually less expensive. A smaller wire creates a smaller interruption in the coating flow enabling the coating to wet out more completely. By winding a smaller wire with spacing (see image) the cavity created is wide and shallow allowing heavy coatings to flow better. Gapped Rods: For higher viscosity coatings, gapped rods reduce clogging and eliminate lines. This results in taller raised striations which are affected more quickly by surface tension, and flatten out to a glass-like surface in a shorter time span. Twin-Coat Rods: Another advantage is that a two-wire rod, used instead of a conventional single-wire rod, will have more than twice as many "grooves" for a given coating thickness. The result is a modified groove between the wires that will produce wet coatings up to 11 mils (.011") thick.
A standard single-wire rod is over-wound with a second, smaller wire which follows the spiral of the base wire. Twin & Gapped Drawdown Rods - For those applications where heavier coatings are required, use these special drawdown rods with two wires. They are manufactured of ground and polished steel and the very finest of wires.Ĭustom Rods Listed Below - Email us or call for pricing 954.946.9454 Applicator Rods are available in any length, a variety of diameters and almost any wire size. The desired thickness can be repeated again and again with little loss of time and expense.
Accurate thickness of coating from fractions of a mil and up can be achieved with this coating method. The groove area is determined by the size of the wire, hence, the larger the wire, the larger the groove. The amount that has passed through flows out or congeals, leaving a smooth, uniform thickness on the substrate. This groove or space allows the right amount of coating to pass through. Theory and Principle - The coating thickness is governed by the area of the groove between the coils of wire as shown in the diagram. Every item is 100% inspected and individually packaged. During the manufacturing process, tight tolerances are held along with strict quality control. The diameters of the wires, in the wound form, regulates the thickness of the coating.
The diameters of the rods and wires vary in size depending on type of application. Drawdown Rods are round stainless steel bars tightly wound with stainless steel wire. *Ask for a quote with your specific requirments Wire-Wound Mayer Lab Rods and Custom Production Rods* Wire-wound Mayer Wet Film Applicator Rods Home > Products > Application > Wet Film App Rods
0 kommentar(er)
