Traditional Bow Press Heater Instructions
These heat strips are made from a silicone based matting material making them very flexible and easy to keep clean. The durability of these units require keeping your forms and pressure strips free of any excess epoxy and kept very smooth and flat. These are designed to withstand 70- 80 pounds of pressure, but all surfaces must be very smooth and free of debris or the heaters may be damaged.
Most bow forms are made from various types of plywood, and the surface of the forms themselves are covered with a smooth liner
Like Formica, fiberglass, or thin aluminum strips. With the constant use of epoxy during the assembly process bowyers call the “Lay up”, it is very important to use some form of bond breaker or wax on your forms to help keep your forms clean.
Here is a drawing showing the correct procedure for using your heat strips in a form. Note the pressure strips covering the heaters. This material is typically a thin spring steel, or aluminum. Hard plastics can be used that are rated for high temp, but they typically do not last as long as metal. These pressure strips must be kept perfectly clean and waxed with every use.
The width of the pressure strip should be as close as possible to the heat strip, and the same width as your glass you are using. You’ll note that I’m showing a Formica strip between the air hose and the heat strip here. This is to insulate and protect the heater under pressure. The insulation material used can be a wood lamination also.
IMPORTANT: Any portion of these heaters that extend outside the form need to be insulated from touching each other, and supported in a somewhat straight in line. DO NOT let these hang unsupported and un insulated. A common practice is to use scrap wood laminations above and below both heaters, and between them using masking tape, or I’ve even seen simple clothes pins used.
It’s very important the ends of your form is rounded over so there are no sharp edges that can cause a pinch point. See drawing below
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Note: Any damage done to these heaters in the form of pinching, creasing, denting, or folding, will not be covered under warrantee.