Terence;Originally Posted by Terence
The blades you see are sitting on the surface that rides on the support. You have things rotated 90 degrees in your mind. The surface contacting the support is polished mirror bright and is square, and that is part of the price problem. There can be no leaks around the edges or under the flat part. The corners that lead the direction of motion are chamfered to allow smooth movement without catching or grabbing. There are a lot of features not apparent in these photos. These are my 4th generation of blades.
The trailing edge of each blade is the movable plate which is raised up by a varying amound by means of the 4 screws, so when you are looking at the screws you are viewing the trailing edge of the blade.
The emulsion flows under that gap and is held at a constant laydown by that gap.
The 4" blade weights about 1 pound, or about 430 grams, the 8" blade is about twice as heavy. The end cap is heavy enough stainless to prevent any fluctuations. The 8" blade uses a heavier end cap than the 4" blade for just this reason. The weight is high to prevent wobble during coating. It is a high end stainless to prevent corrosion from the chemicals used.
BTW, a similar blade is used in the paint industry to evenly spread paint during tests. These blades are only 4" wide and are made of aluminum. The last time I queried the company these blades were $1200 each. I can no longer locate that web page. I guess they went out of business. At the time though, Kirk Keyes directed me to this additional use of this type of blade. I didn't go with one of these, as aluminum is not compatible with emulsions.