Adjusting Plastic Frames:

Most plastic frames will need to be heated before you can perform any adjustments. Be sure you have an ordinary zyl frame before heating it. If in doubt about a new frame, call the manufacturer and ask about adjustment procedures before heating it. All types of plastic frames must be adjusted on a material-by-material basis. You can ruin a frame in seconds by applying heat to the wrong material. Heat can, and will, damage frames and frame finishes.

You may also look at the websites for larger frame manufacturers. Many of them will provide adjustment techniques and even repair ideas for each individual frame.

Note: Unfortunately, there is no sure way to know what an old frame is made of. So when faced with an old frame of unknown material, use heat with caution. Some older materials will react in odd ways when exposed to heat.

• Carbon: Cannot be adjusted.
• Cellulose propionate: Is a cold insert frame.
• Polyamides (Nylon): Temples can be adjusted using heat like zyl. Frame front should not be heated.
• Rubber: Cannot be adjusted unless it has wire core. If it has wire core, adjust by hand.
• Optyl: If you are sure you have an Optyl frame, you will need to heat it to 200 to 300 degrees Fahrenheit to get it to return to its original shape as it cools. I would be cautious when reusing a patient’s own frame made from Optyl.
• Polycarbonate: Cannot be adjusted.
• Zyl: Heat in conventional heat source until softening or movement is felt. Hold in place until cool.
• Kevlar: Cannot be adjusted.

To adjust a plastic frame, two types of heating elements can be used: the “salt pan,” which now contains heated glass beads, and the more modern hot air blower. You may just have to learn with what is available to you.

Preference and experience determine which method is used. Older opticians will often use glass bead pans and newer ones will use hot air. Glass bead pans heat plastic to a point where it can be reshaped or adjusted. Experienced users will know just how long to hold the part under the beads to soften it. They will often shape the beads into a small peak and heat specific areas of a frame to perform minute adjustments. The beads can damage some modern frame materials and overheating of parts seems to be more prevalent in bead pans than in hot air blowers. Beads come in two sizes: fine, which is about the texture of sugar and large, which are about the size of “BBs,” so you may find a preference for one size or the other. Beads do need to be changed periodically to reduce sticking and hot spots.

Beads are the easiest method to heat the chassis end on plastic frames to realign the temples after inserting a high minus lens.

Hot air blowers (basically hair dryers) are another source of heat used to soften plastic frames. Since hot air blowers are becoming far more prevalent, it may be best to learn to work with hot air instead of a saltpan. Fine adjustments are slightly more difficult to make using hot air. But, hot air is far less messy, eliminating the problem of little glass beads rolling around the counter, jamming spring hinges and sticking to frames.

When using heat to perform adjustments, it is best to hold the frame in the heat source in the position you desire (stressed) until you feel it begin to bend. The moment you feel it begin to move, remove it from the heat source and hold it in place until it cools, or run it under cold water to cool the frame. Practice makes perfect! When you become familiar with how quickly your warmer heats up you may want to use a “count” method for adjustments. For instance, I knew that when using the warmer in the office where I worked, that lens insertion in a zyl frame required a count to fifteen to work perfectly.

Unless you are a blacksmith there is no reason to heat metal parts before bending them.

Just Do It!

Regardless of material, one of the keys to making adjustments well is adopting a “just do it” attitude. Experience is important, but so is willingness to bend a frame. Some adjustments require bends of several millimeters, and need quite a bit of force to accomplish. Get your hands on some old frames (buy them at flea markets and ask friends for old frames), and then practice, practice, practice.