How to Build a Screen Hold-down for an Exposure Unit

If you have built your own exposure unit, you have most likely discovered that holding a screen firmly against the glass and the film positive during the exposure process can be a problem.

Each screen burning session often becomes a trial and error process that produces inconsistent results. What you need is a device that will work effectively each and every time you burn a screen.

There is a simple solution to this problem.

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In the ASPA Screen Hold-Down "how-to" tutorial, we show how to make an effective, low cost screen hold-down that works perfectly each time you burn a screen.

Before we get into discussing the ASPA Screen Hold-down, here's a little background information on the purpose of the "screen hold-down." Some type of device is necessary to hold a emulsion coated (or capillary film coated) screen tightly against the film positive and exposure unit glass to create a stencil during the exposure process. Keeping the screen in tight contact with the film positive and exposure unit glass is absolutely essential to creating a good stencil. If the screen is not tight against the film positive and the glass, the result will be a stencil that is difficult (or impossible) to wash out and the edge definition of the stenciled image will be blurry. Your exposed screen will be unusable and you will have to burn another screen (after you have figured out how to resolve the hold-down problem).

Most commercial exposure units use a vacuum pump and rubber blanket arrangement to draw down the screen tight against the glass. A vacuum system is an effective hold-down solution but building one yourself is difficult and costly. Moreover, a rubber vacuum blanket will eventually wear out and will require replacement–another expense that must be considered.

The type of hold-down that we show you in the ASPA Screen Hold-Down tutorial works on a very simple principle–weight. By applying uniform weight distribution to the inside of the screen, you can achieve an effective hold-down solution that is essentially maintenance free and will last a lifetime. It will allow you burn screens faster than a vacuum system as there is no time lost waiting for a vacuum blanket to draw down over the screen. The ASPA Screen Hold-Down device consists of just (3) low cost, easy to obtain parts and can be can be assembled in just a few minutes. Our hold-down device was designed to work with ASPA's E-Z Expose exposure unit and it will work perfectly for other exposure units as well.

Want to learn how to make your own screen hold-down? Please visit ASPA Screen Hold-Down tutorial page. The plans are shown in a “how-to” PDF ebook feature format complete with assembly photos and details on where to obtain all of the necessary parts. It is available as a quick download so you can get started right away.

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