Create your own Dual Sided disks

[sunny_2]

I just pasted two cheap Accu DVD together, and now it works like a dual sided disk!!!

I have old panasonic A120 and did not have any problem playing on either side

I have created a small template that goes between inner ring up to first track to label these disks.

Great , why pay 9bucks when I can do it myself for a buck !!

[SLK001]

You run the risk of damaging your DVD player. The DVD spec specifies the thickness of the media, and the laser is set at a certain height above this specified thickness.

Consider yourself lucky you didn't damage / destroy anything.

($9?? You need to shop around more...)

[johneboy]

I just pasted two cheap Accu DVD together, and now it works like a dual sided disk!!!

I have old panasonic A120 and did not have any problem playing on either side

I have created a small template that goes between inner ring up to first track to label these disks.

Great , why pay 9bucks when I can do it myself for a buck !!

you know... i wondered why we dont see CD-Rs like this... seems like it would be simple enough..

i was actually thinking about shaving a bit off the top of 2 CDRs and supergluing them together... but never got around to it...

[vitualis]

You are joking right?

We don't see dual CD-Rs because of the physical limitations of the media. The data layer of a CD is in fact right under the top layer. The CD reading laser is designed to (and expects to) pass through the ?1.2mm of polycarbonate substrate before hitting the data layer.

As the thickness of a CD is about 1.2mm, you cannot put another data layer on the disc (e.g., other side) without INCREASING the thickness of the disc (and hence making non-compliant PHYSICALLY. The problem is that these extra thick discs may damage some equipment (e.g., slot drives) and may not sit properly in others (e.g., spindle type drives on notebooks).

The only way of making a dual sided CD-R that is IN SPEC would be to somehow change the refractive index of the polycarbonate substrate so that a 0.6mm layer would appear to the reading laser as 1.2mm. This is probably not a trivial thing to accomplish and as yet, no one has made a commercial product that does such a thing.

Now, as for shaving a bit off the top of a CD-R, that equals instant data destruction. As I've said before, the data layer is actually just under the top layer (often protected by no more than a lacquer layer).

Gluing together two discs is a bad idea also. Modern drives can spin discs (CDs especially) to incredible speeds (i.e., thousands of RPM). If the glue delaminates in the drive, you can damage your equipment, or worse, injury someone.

Regards.

[BJ_M]

you should have just let him try it :P

i had an old 1x (maybe it was 2x) burner that after time i used to put two disks in it to burn proper -- worked fine .. untill it died .. it was an old trick though that a few people used on die'ng burners ..

i wouldnt think of doing it now on the burners today though ..

[[_chef_]]

dual sided
NOT
dual layer...

[BJ_M]

]dual sided
NOT
dual layer...

no one mentioned dual layer

[wulf109]

What's the point of glueing disks together! How much time do you save by flipping a disk compared to changeing a disk?

[johneboy]

The CD reading laser is designed to (and expects to) pass through the ?1.2mm of polycarbonate substrate before hitting the data layer.

I didnt know this

Now, as for shaving a bit off the top of a CD-R, that equals instant data destruction. As I've said before, the data layer is actually just under the top layer (often protected by no more than a lacquer layer).

I actually meant the bottom..

There are things out that you can put your scratched CD/DVDs in that will essentially take a layer off the top (to remove the scratches)... so i figured i would try a couple AOL cds in one of these, and just spin it inside for about an hour or so... till it had worn it down to about half the thickness.. then see if it still read in my computer... however, i was unaware of laser expecting to go thru a certain layer of plastic before hitting the data layer

[BodyMaker]

We don't see dual CD-Rs because of the physical limitations of the media. The data layer of a CD is in fact right under the top layer. The CD reading laser is designed to (and expects to) pass through the ?1.2mm of polycarbonate substrate before hitting the data layer.

How do they make the double sided disks ?

I have lock stock and 2 smokin barrells and its 4.3 on one side and Wide screen on the other

[BJ_M]

We don't see dual CD-Rs because of the physical limitations of the media. The data layer of a CD is in fact right under the top layer. The CD reading laser is designed to (and expects to) pass through the ?1.2mm of polycarbonate substrate before hitting the data layer.

How do they make the double sided disks ?

I have lock stock and 2 smokin barrells and its 4.3 on one side and Wide screen on the other

thats a dvd - not a cd ..

i posted a HUGE post here a couple months ago how dvd were made ..

or read this http://www.usbyte.com/common/dvd.htm

[vitualis]

Exactly, DVD is a different kettle of fish when compared to your plain old CD. DVD supports both dual layered AND dual sided. A much more flexible physical format though making a dual layered recording medium is still fantasy.

Regards.

[[_chef_]]

BJ_M:

Yeah, sorry, wrong read.

[Nolonemo]

I thought you could buy dual-sided DVD blanks for burning?

See http://www.cwol.com/dvd-burners/dvd-r9.4g1xds-5.htm

Anyone done this?

[vitualis]

I thought you could buy dual-sided DVD blanks for burning?

See http://www.cwol.com/dvd-burners/dvd-r9.4g1xds-5.htm

Anyone done this?

Yes you can. These obviously are not to single side blanks pasted together though...

Regards.

[BJ_M]

at least one would hope so !! :P

[chazzie]

I just pasted two cheap Accu DVD together, and now it works like a dual sided disk!!!

I have old panasonic A120 and did not have any problem playing on either side

I have created a small template that goes between inner ring up to first track to label these disks.

Great , why pay 9bucks when I can do it myself for a buck !!

you know... i wondered why we dont see CD-Rs like this... seems like it would be simple enough..

i was actually thinking about shaving a bit off the top of 2 CDRs and supergluing them together... but never got around to it...

I glued two CD-R's together and played them in my old Yamaha CD-player, worked well, but the disk almost touched the top of the tray =)

[dcsos]

NOTE on how easy it is to destroy a CD:
I put a Sticky label (AVREY) on a CD and it was sorta off center enough
to worry me..So I tried to peel it up...
and VOILA the entire contents of the cd were on the reverse of my label in my hand..only the silvery edges of the DATA remained on the now clear transparent remainder of the disc
PLEASE don't try this AT HOME

[gmatov]

All,
This is a kinda goofy thread. Everyone is so serious in his response, that it is funny.
Point 1 would be can the device clamp down on a disk that is twice normal thickness. Probably.
Point 2 would be is the laser's optimum focal length correct?. That would depend on whether the point of registry is the TOP of the disk, or the bottom..
Most of my machines, the laser is attached to the bottom of the tray, so if it closes on the disk at all, the focal length should be right.
Another point would be, can you actually grt the thing up to speed without burning up the tiny little motor. You have twice the mass to spin up. And, since the CD Stomper type devices can't get s LABLE perfectly centered,now you have a disk, heavier, not perfectly centered. Catastrophy? Probably. Factory made disks have disintegrated in higher speed drives, without offcenter lables, stress alone being enough.
BUT, if you could glue 2 back to back, and if they would clamp properly , the focal length, aim point should be correct.

Vitualis,
If you can buy dual sided DVDs, flip-overs, what happened to our focal length, maximum thickness argument?
If a disk MUSTt be .062 in thickness to be in focal length, then a dual sided MUST be .125 thick to have the laser be able to focus on the phase change material, or the dye, or whatever.
And as to peeling off the working media, I am not sure I believe the reports of peeling off a lable and destroying a disk. I do not think any of my disks, dating to about 7 years ago, have a minute, leveling layer of "plastic" on top of the die-struck recording layer, which could be peeled off by removing a lable. It may be possible. Glues do become better with every problem encountered .
The best question,tho', was Wulf 109, " How much time do you save by flipping a dual sided over, compared to changing disks" ( On an aside, some of the damn boxes they come in make you think you're gonna snap them in half before they release. Someone is being payed to make a plastic company die, and they try to make them user-proof, snap 6 petals loose, one at a time.

[dcsos]

And as to peeling off the working media, I am not sure I believe the reports of peeling off a lable and destroying a disk

Well I urge you to believe it!

You're the one telling ME...I'm serious

You are correct in that regard

[gmatov]

DCsos,
I may have to beleive you, but, till I find one that the substrate is that close to the lable side, or printed side, I'l reserve judgement. IF you are peeling off .015 or thereabouts of polycarbonate with your lable, then I would have to give you credence. If you are peeling off a lable, and a thou or 2 of diestamped aluminum foil with it, then I think not. If there is a minimum thickness to a disk, there is also a min and a max to where the substrate can be located. We are not talking rocket science here, not as in shooting rocket ships out of space, but as in a thou or 2 is out of focus, hence, will not alter the substrate, no data transfer. ( No heating of the spot that should have been half a thou closer.)

[dcsos]

Well all I can say is when the label was peeled fully,
The CD was transparent and had only a tiny residue of silver foil around its outside perimeter. It was like those packing blanks they give you
i think IT WAS A MEMOREX 32x certified CD-R

Like an Idiot, I put the clear disc in the drive..
suffice to say it was reeboot time

[gmatov]

Hey, gotta beleive you, but that sure makes a shambles of the so called spec, doesn't it? If it has to be "so" thick and "so" far from the lens ( to be in focus ) then, either it was too thin, and able to have the reflective/burnable media in focus at the top strata of the disk, as a glued on layer of foil, or the thickness was off, so they had to glue the foil on at the top layer to be on focus. Either way, garbage. So, stick with the cheap stuff, after rebate, test, if no good, take it back, with UPC, so thay don't think you're trying to screw 'em

[dcsos]

I will be using
VERBATIM
TAIYO YUDEN(if i can find)
and
PHILLIPS or SONY
blanks from now on..
Thanks..
Hopefully none of these brands are thinning the layers

[dcsos]

I will be using
VERBATIM
TAIYO YUDEN(if i can find)
and
PHILLIPS or SONY
blanks from now on..
Thanks..
Hopefully none of these brands are thinning the layers

Took a few hrs to find the sucker (I kept it)
HERE is the cd whoose label peeled off..taking the recorded data along with it!

[vitualis]

Vitualis,
If you can buy dual sided DVDs, flip-overs, what happened to our focal length, maximum thickness argument?
If a disk MUSTt be .062 in thickness to be in focal length, then a dual sided MUST be .125 thick to have the laser be able to focus on the phase change material, or the dye, or whatever.

I believe I am covering this a second time on this thread.

There are differences between DVDs and CDs.

The DVD format is flexible and this is why you can have dual sided and dual layered discs. The optics of the DVD player are completely aware of the possibility of dual sided AND dual layered and can focus on the appropriate layer.

Regardless of the DVD disc type, the thickness of the disc is the same.

A dual sided DVD is NOT twice as thick as a single sided one.

However, the optics of a CD player do not expect (and hence cannot read) discs where the data layer aren't a certain distance from the bottom of the disc. You could make a CD that has a polycarbonate layer only half as thick but it wouldn't work on most if not all CD reading devices. As the data layer of a CD is just a smidge below the TOP surface of a CD, to make a double layered CD would require a disc essentially twice as thick.

There are maximum thickness tolerances. You would probably get it to work on most tray type drives, but it wouldn't sit properly on spindle type drives (e.g., try putting TWO CDs on the spindle, the second disc doesn't sit properly) and you are risking absolute disaster with a slot type drive.

Furthermore, if your glued together disc ever gets spun up to the high rotation rates of a modern drive, stand clear!

And as to peeling off the working media, I am not sure I believe the reports of peeling off a lable and destroying a disk. I do not think any of my disks, dating to about 7 years ago, have a minute, leveling layer of "plastic" on top of the die-struck recording layer, which could be peeled off by removing a lable. It may be possible. Glues do become better with every problem encountered .

You perhaps need to guess less and actually believe people's experiences (and learn how a CD is actually constructed!). A CD has only a laquer layer on top of the data. There is NO POLYCARBONTE LAYER ON TOP OF THE DATA LAYER. From top to bottom:

TOP
- Additional protective layer (optional)
- Lacquer layer
- Data layer (thin layer of aluminium or organic dye)
- Polycarbonate substrate
BOTTOM

Better CD-R discs have an additional protective coating while cheaper ones do not. You can well peal off the lacquer layer by trying to take off an attached sticky label and the lacquer layer will take the data layer with it.

For more on how a CD is made, I suggest reading the excellent CD FAQ and CD-R FAQ.

Regards.

[dcsos]

Thank you for the EDUCATED response..
NOW I UNDERSTAND

[Wightpants]

lol dcsos, you kept it as a souvenir
I love these kind of threads

[gmatov]

Vitualis,
Hell, I believe you. I thought this thread started out as a gag. It was funny.
As to the focal lengths, I didn't pay attention to the mention of "DVD" above, was still thinking CD, even if I wrote DVD somewhere. I have been to a page that was devoted to CD FAQs, looong page, and will return sometime.
For now, I have to assume the data layer of a DVD is centered in the polycarbonate, with a shorter focal length than a CD. And, correct me if I'm wrong, but aren't DVD ROMs dual lasered to be able to read both media?

Dcsos,
I guess you sure showed me, huh?
Actually, that's the first time I have seen that. Thanks for the pic.
Hey, if you want to destroy a disk to keep one from "data recovery" of incriminating evidence, don't try to snap it in half. I did, once, as much to see how tough they are, and wound up with a bunch of shards on the floor. It literally shattered.
Now I gotta go tear one apart to see if they're all like the one you posted.

[Cornucopia]

TRUE STORY:

Year and a half ago did a job for a client that required mini-CD's. They were wanting to rush so I couldn't order nice ones. Went to Staples and got a coupla packs of Memorex CD-3s.
Then my sales rep says they want labels. At that time I had no label template for minis, so I fudged with cutting down full-sized ones. Kinda halfway worked, but some would be slightly off center.

Made the discs, put the labels on. Sent them off.

Later, they want to get custom printed correctly-sized labels, so they send back the discs.
Without my knowing, sales rep and co-worker start taking off the old labels...

Looked just like what you showed in that picture.

Needles to say™, I had to start over from scratch with better stock.

Its better to learn the easy way (this forum) than the hard way.

Scott