All about our frames
Ever wondered what the difference is between different types and materials that glasses frames are made of? Here's a bit of light reading on the subject...
Full rim frames
Full rim frames are the most robust and easiest frames for glasses. They are the easiest to fit lenses into and generally hold the lenses the best. Plastic and acetate frames are heated to expand them which is how the lenses are fitted, then when they cool the material contracts slightly and holds the lenses in for a snug fit.
For metal full rim frames the process is a little different. The frames have a tiny screw that holds the part of the frames that surrounds the lenses together. Usually just under the part where the arm joins the front piece of the glasses. This is unscrewed, the frames are opened up, the lenses fitted in, the screw replaced and hey presto! Anyone could do it.
Semi-rimless or half-rim
These are glasses that only have half of the frame surrounding the lens. To hold the lenses in properly, the lenses actually have a groove cut into them and a thin piece of nylon holds the lenses tightly against the rest of the frame. Semi-rimless glasses are not as robust as full rim frames and generally are a bit fiddlier to fit which can increase the cost of the glasses slightly.
OK so you want that really minimalistic look? Then rimless is just right for you. These are glasses that have no rim whatsoever. The bridge (the bit that goes around your nose) and the temples (arms) are joined to the frames with small bolts and nuts through holes that are drilled into the lens. These glasses are typically the most fragile and difficult to fit lenses into and are not recommended for environments where they may get knocked around a bit.
Now lets get on to the materials that glasses are made of. The question we are often asked is: "why are some glasses more expensive than others and yet they look so similar?" Here's why...
Plastic frames are the cheapest to produce. All plastic frames are injection moulded by a machine that heats the plastic until it's molten then squirts it into a precise mould which when the plastic has cooled again, bingo you've got a frame component produced - very cheaply. Thats the good side of plastic frames. The not-so-good side is that plastic frames have a tendency (compared to the similar material acetate) to lose shape over time. Its not so easy for getting beautiful colours into the frame unless its painted on and this creates the possibility of it flaking or wearing off eventually, but hey they're cheap!
Acetate is a nylon-based plastic that is strong, lightweight and flexible. It is also hypoallergenic. Acetate glasses have the largest range of transparency, rich colours and finishes as it can be produced by layering several colours or transparencies and laminating them together.
Acetate eyewear is then made by combining layers of plastic into large blocks, the individual parts are then cut from it. It is hand polished and finally assembled into a complete frame.
Because of the extra work involved, and also the extra colour possibilities, acetate is always used for more expensive eyewear brands. It retains its shape and colour for longer than plastic, but is more expensive.