How do DVD's & CD's get Polished so Perfectly?

[Gurd99]

When you get them new blank media or pressed, what methods do they use to get them so glossy & perfect? There is not a single visible sratch on them usually.

I tried to restore some scratched media with automotive compound & polish & many discs keep having scratches left. I think because the material isn't hard enough.

Maybe they are using some super soft & fine polishing techniques.

[redwudz]

They aren't polished. They are molded that way. The liquid plastic is injected into the smooth metal mold, against the data die, then the formed disc is coated with a thin layer of reflective metal. Then that is coated by spraying more liquid plastic over the metal layer as the disc spins. Then the printing and logo is applied over that.

Or look here: https://www.youtube.com/watch?v=YZKD2aYLTWw

[pandy]

I tried to restore some scratched media with automotive compound & polish & many discs keep having scratches left. I think because the material isn't hard enough.

Well, proper technique is absolute must whit this approach and trust me doing proper polishing on cars is not easy and optical disc are even harder to well polished, even visually ok they may be still full of scratches that works in poor way from laser perspective - it is common problem - scatter.

[Gurd99]

I tried to restore some scratched media with automotive compound & polish & many discs keep having scratches left. I think because the material isn't hard enough.

Well, proper technique is absolute must whit this approach and trust me doing proper polishing on cars is not easy and optical disc are even harder to well polished, even visually ok they may be still full of scratches that works in poor way from laser perspective - it is common problem - scatter.

My experience even the most scratched up discs can easily be read by a good drive getting 100% accurate, if not just cutters & a cotton rag by hand gets them readable.
I think the discs don't polish up perfectly because the plastic is too soft & there are no abrasives that are designed for discs, I couldn't even scratch a BD hard coating with my polish. After all they are designed for car paints. I will try a rotary buff & D/A polisher on my discs to try get them flawless.

[Gurd99]

They aren't polished. They are molded that way. The liquid plastic is injected into the smooth metal mold, against the data die, then the formed disc is coated with a thin layer of reflective metal. Then that is coated by spraying more liquid plastic over the metal layer as the disc spins. Then the printing and logo is applied over that.

Or look here: https://www.youtube.com/watch?v=YZKD2aYLTWw

thanks. Should have know it would be some completely different process.

[Cornucopia]

I tried to restore some scratched media with automotive compound & polish & many discs keep having scratches left. I think because the material isn't hard enough.

Well, proper technique is absolute must whit this approach and trust me doing proper polishing on cars is not easy and optical disc are even harder to well polished, even visually ok they may be still full of scratches that works in poor way from laser perspective - it is common problem - scatter.

My experience even the most scratched up discs can easily be read by a good drive getting 100% accurate, if not just cutters & a cotton rag by hand gets them readable.
I think the discs don't polish up perfectly because the plastic is too soft & there are no abrasives that are designed for discs, I couldn't even scratch a BD hard coating with my polish. After all they are designed for car paints. I will try a rotary buff & D/A polisher on my discs to try get them flawless.

If you continue down this road, you may ruin the discs by making them SO scratched that they are permanently unreadable.

Scott

[cornemuse]

Before trying to 'polish' one, (when necessary) I will rinse disk then wash with dish soap, rinse with cold water, dry & try. (rip)
They (Frys, locally) sell compound for 'polishing' cds/dvds. Do the polish with strokes from center to outside (& vise-versa!). Its the scratches which follow the data 'track' that cause problems. Scratches across the tracks (across the grooves, in LP record terms) are not as big a problem.

Its suprising how much difference a simple washing will make sometimes.

-c-

(edit: the dish soap makes the water 'wetter'. it flows deeper into the scratch, you cannot completely dry off all the water. Water fills the scratch & a portion stays in the bottom of it, (for a while, it does eventually dry out, in an hour or so) Its like a temporary polishing)

[JVRaines]

Some folks polish with furniture wax to fill in scratches and restore the refractive index. If it works, it's probably safer to add material than to remove material. BTW, Blu-ray discs are coated with extra-hard plastic because the reflective layer is so close to the surface.

[lingyi]

My experience even the most scratched up discs can easily be read by a good drive getting 100% accurate, if not just cutters & a cotton rag by hand gets them readable.
I think the discs don't polish up perfectly because the plastic is too soft & there are no abrasives that are designed for discs, I couldn't even scratch a BD hard coating with my polish. After all they are designed for car paints. I will try a rotary buff & D/A polisher on my discs to try get them flawless.

There are special polishes for use with disc resurfacing machines ranging from $30 to hundreds of $$$. However, even the best polish and machine will never be able to polish the disc back to the original pressed shine. As redwudz stated, the bottom layer (of polycarbonate) is clear to begin with and pressed as part of the DVD/BD creation processed, it was never polished and you can't bring back the original shine of the original material.

[Gurd99]

I tried to restore some scratched media with automotive compound & polish & many discs keep having scratches left. I think because the material isn't hard enough.

Well, proper technique is absolute must whit this approach and trust me doing proper polishing on cars is not easy and optical disc are even harder to well polished, even visually ok they may be still full of scratches that works in poor way from laser perspective - it is common problem - scatter.

My experience even the most scratched up discs can easily be read by a good drive getting 100% accurate, if not just cutters & a cotton rag by hand gets them readable.
I think the discs don't polish up perfectly because the plastic is too soft & there are no abrasives that are designed for discs, I couldn't even scratch a BD hard coating with my polish. After all they are designed for car paints. I will try a rotary buff & D/A polisher on my discs to try get them flawless.

If you continue down this road, you may ruin the discs by making them SO scratched that they are permanently unreadable.

Scott

Not a chance, all this gets the scratches out, by hand just takes sooooo long. Some discs polish almost flawless, others just get more fine scratches in them from the polish process it self. Some store brought CD's 10+yrs that are flawless have many read errors probably from the inside media deteriorating.

[lordsmurf]

RTI DiscChek = professional disc resurfacer

This is the cheap model: http://www.amazon.com/RTI-DVD-DiscCheck-Resurfacing-Machine/dp/B001J5TH1S/ref=as_li_ss...1a6ab974f22a4e

Price go up to about $10k.

[Cornucopia]

Even when it might be possible to "resurface" a disc, what you would be doing is THINNING the layer. Think about that a moment: an optical disc expects the layer to be a certain thickness for its laser refraction sensors to work properly. Thinning that layer permanently shifts the refraction away from its optimum range.

Use hand soap & clean water and a chamois, with radial ("inner to outer") wiping. If a pass or 2 of that (or toothpaste, I've also heard) doesn't work, move on & get a new/different copy of the disc.

(when will they ever learn?)

Scott

[mikel]

lordsmurf,

I have worked with an RTI unit for the last 5yrs or so. (college Media Services Dept) And it is a great machine. It saved the dept many discs and $ .

I might suggest that a person might contact a local Library or College that has to maintain a large collection.