Frame Materials

Question 1

What are the two types of plastic used for frames?

Answer 1

Thermoplastic
Thermosetting

Question 2

What temperature does cellulose acetate soften at?

Answer 2

57 degrees

Question 3

What are the characteristics of a cellulose acetate frame?

Answer 3

Fully reinforced sides
Can be the same colour (colour extruded), 2-tone (laminated) or see through (dyed)
Made from blocks of acetate sliced into sheets

Question 4

What is the flash point of cellulose nitrate?

Answer 4

70 degrees

Question 5

What are the disadvantages of cellulose nitrate?

Answer 5

Low flash point
Becomes brittle and yellows with age

Question 6

What are the characteristics of Optyl?

Answer 6

Made from epoxy resin - injection moulded around metal elements
15mm of sides reinforced or full reinforcement or metal sides
Lightweight
Hypoallergenic

Question 7

What temperature does Optyl soften at?

Answer 7

88 degrees

Question 8

What are the characteristics of SPX?

Answer 8

Co-polyamide
Injection molded and coloured
Sides always reinforced
Flexible
Lightweight
Hypoallergenic

Question 9

What temperature should SPX be adjusted at?

Answer 9

95 degrees

Question 10

What are the characteristics of Silicone-based rubber?

Answer 10

Highly durable
Soft and pliable
No hinges or metal elements
Lightweight
Solid colour
Can use additional strap

Question 11

How is gold added to a base metal on a frame?

Answer 11

Welding or plated via electrolysis

Question 12

What base metals are used for gold frames?

Answer 12

Nickel silver
Bronze

Question 13

What are the advantages of a gold frame?

Answer 13

Colour keeps well
Resistant to corrosion

Question 14

What are the characteristics of Nickel Silver?

Answer 14

Assembled by soldering
Fairly corrosion resistant
Easily adjusted
Flexible

Question 15

How can allergies to Nickel Silver be overcome?

Answer 15

Plastic Tips and bridges
Inert coatings

Question 16

What are the components of Nickel Silver?

Answer 16

20% Nickel
Mostly Copper
No Silver

Question 17

How is colour applied to Nickel Silver?

Answer 17

Electroplating or lacquering

Question 18

What are the characteristics of Stainless Steel?

Answer 18

Assembled by welding
Lightweight
Corrosion resistant
Rigid but flexible
Hypoallergenic (if pure)

Question 19

How is colour applied to Stainless Steel?

Answer 19

Electroplating

Question 20

What are the characteristics of Titanium?

Answer 20

Cut and pressed, then laser soldered
40% lighter than other metals
Flexible
Corrosion and abrasion resistant
Hypoallergenic

Question 21

What are the components of Titanium?

Answer 21

If pure: 98% titanium
If beta: 80% titanium, other metals (aluminium, iron, tin) and titanium alloys (nickel and cobalt)

Question 22

What are the characteristics of Memory metals?

Answer 22

Return to their original shape after extreme distortion

Question 23

What are memory metals made from?

Answer 23

Nickel-titanium
Can be other alloys but normally contain nickel or titanium

Question 24

What are some other more recent materials?

Answer 24

TR90 Nylon - lightweight, flexible, v durable, thermoplastic
Wood/Faux wood - good shock absorber
Recycled materials - e.g. acetate
3D printed - castor beans or polyamide, not fully biodegradable