Coating Wire

Question:

I enjoy reading your column every month. We have a proprietary flux coating which we dip apply to soldering rods. A customer of ours has now requested that we provide him with 10 or 25 pound coils. The wire is 98%/2% Zinc/aluminum alloy and has a diameter of .0625 inch. Coating the coil is beyond our capability. Would you happen to know of anyone who might be able to handle this type of application for us? We would supply both the wire coils and the coating. G. L.

Answer:

Using a wire tower is the best way to coat coils of wire. Although not as simple as dipping, the operation is not too complicated. For the record, I’ll describe a typical wire tower. As opposed to a coil coating line, which is horizontal, a wire tower is vertical. The footprint is small, but it is three or four stories high. Cleaned wire is pulled from a pay-out reel, over a sheave, and then vertically through a trough (yes, there is a hole in the bottom of the trough) containing the coating material. To control film thickness, the wire passes through a die mounted above the trough. After coating, the wire passes through a high-temperature vertical oven, over a sheave at the top and down through a cooling zone, onto a take-up reel. Product quality will be increased. The coating thickness will be uniform, since there is no “wedge effect” as with dipped coatings. Because the coating material trough is small, the amount of coating material exposed will be greatly reduced.

Once you see a wire tower in operation, you’ll wonder how you did without one. If you have sufficient product output, you may want to install one in your plant. Otherwise, find someone who owns one. Magnet wire producers, have wire towers. Some electrical equipment manufacturers also have them. Perhaps you can get one of them to coat your soldering rods on a toll basis.