Externet Posted June 25, 2018 Posted June 25, 2018 (edited) A compact disc has pits on its surface to represent the data bits. Is the optical surface of a CD smooth as a mirror when new and blank, before anything is recorded/'burned' ? Am after a small, light, thin, durable mirror if I can cut off from a new CD Edited June 25, 2018 by Externet
studiot Posted June 25, 2018 Posted June 25, 2018 Industrially manufactured CDs have pits which are mechanically pressed into the plastic by a metal master. User recordable CDs don't have physical pits. They incorporate a chemical layer which undergoes a local chemical change when 'burned' with the laser writer. These have different optical properties and are equivalent to the pits, but can degrade over time or heat or high levels of illumination. You would have to experiment with a CD or piece of one to see if it is specular enough for your purposes.
Externet Posted June 25, 2018 Author Posted June 25, 2018 Thanks. Just shot a laser to a new, blank, recordable disc and the reflection is not a single beam... Suppose there is some formatting pits or tracks or something
Endy0816 Posted June 26, 2018 Posted June 26, 2018 Might be possible to diy. Aluminum, plastic and lacquer, maybe substituting resin for the last two.
25007 Posted June 9, 2020 Posted June 9, 2020 On 6/25/2018 at 1:10 PM, studiot said: Industrially manufactured CDs have pits which are mechanically pressed into the plastic by a metal master. User recordable CDs don't have physical pits. They incorporate a chemical layer which undergoes a local chemical change when 'burned' with the laser writer. These have different optical properties and are equivalent to the pits, but can degrade over time or heat or high levels of illumination. You would have to experiment with a CD or piece of one to see if it is specular enough for your purposes. What's a master?
MigL Posted June 9, 2020 Posted June 9, 2020 (edited) Master is the original from which copies are made. Along the same lines, you might have better luck with the internal platter of an old hard drive. They are very smooth and reflective, but extremely brittle ( possibly glass ), so cutting a small piece might be a problem. Edited June 9, 2020 by MigL
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