ark@rabbit.UUCP (Andrew Koenig) (04/11/84)
I bought a record last week that was so warped that my turntable would not track it. I therefore decided to try a technique I had read about for unwarping the record. Here it is: Obtain two pieces of 1/4 inch plate glass about 13 inches square. You need glass that's heavy enough to keep the record completely flat. Put the record between the glass sheets and put the whole sandwich in the oven. Turn the oven up to 150 degrees for about 10 minutes, then turn the oven off and open the door part way. Let the glass and the record cool to room temperature (about an hour). The record came out completely flat! Score one for the good guys!
chenr@tilt.UUCP (Raymond Chen ) (04/11/84)
<fix this please...> >>I bought a record last week that was so warped that my turntable >>would not track it. I therefore decided to try a technique I had >>read about for unwarping the record. Here it is: >> >>Obtain two pieces of 1/4 inch plate glass about 13 inches square. >>You need glass that's heavy enough to keep the record completely flat. >> >>Put the record between the glass sheets and put the whole sandwich >>in the oven. Turn the oven up to 150 degrees for about 10 minutes, >>then turn the oven off and open the door part way. Let the glass and >>the record cool to room temperature (about an hour). >> >>The record came out completely flat! Score one for the good guys! Yeah, but did the grooves? Think about it. You're heating the vinyl to at best, just above the point where it begins to lose its rigidity, then subjecting it to pressure. If it's enough to flatten the vinyl, think about what it must be doing to the grooves cut into the vinyl. Consider also the width of a groove and how little change it takes to turn a cymbal clank into a thud. You might not hear it on YOUR system, but I wouldn't recommend this method to everyone else... Yours for better sound... -- From the Random Fingers of -- Ray Chen {allegra | ihnp4 | mhuxi}!princeton!down!tilt!chenr "It's amazing what a thousand monkeys and a few typewriters can accomplish..."
saf@floyd.UUCP (Steve Falco) (04/11/84)
I suspect the reason you can get away with un-warping a record in this
way is that there are deliberate high spots on a record - at the edge,
and at the center label:
__ ________________ _______________
/ \------------------------------/ | | \------
| | |
\__/------------------------------\________________| |_______________/------
The pressure is on the high spots, so the grooves don't get flattened.
Some detail may be lost but that can actually clean up high frequency
problems in your system at a reasonable price. (:-}
Steve Falcomlh@abnjh.UUCP (M. L. Holt) (04/11/84)
Since the rim and center are thicker than the groove parts, I don't think the grooves are being deformed. Mike Holt abnjh!mlh
ark@rabbit.UUCP (Andrew Koenig) (04/11/84)
>>I bought a record last week that was so warped that my turntable >>would not track it. I therefore decided to try a technique I had >>read about for unwarping the record. Here it is: >> >>Obtain two pieces of 1/4 inch plate glass about 13 inches square. >>You need glass that's heavy enough to keep the record completely flat. >> >>Put the record between the glass sheets and put the whole sandwich >>in the oven. Turn the oven up to 150 degrees for about 10 minutes, >>then turn the oven off and open the door part way. Let the glass and >>the record cool to room temperature (about an hour). >> >>The record came out completely flat! Score one for the good guys! >Yeah, but did the grooves? Think about it. You're heating the >vinyl to at best, just above the point where it begins to lose its >rigidity, then subjecting it to pressure. If it's enough to flatten >the vinyl, think about what it must be doing to the grooves cut into >the vinyl. Consider also the width of a groove and how little change >it takes to turn a cymbal clank into a thud. > >You might not hear it on YOUR system, but I wouldn't recommend this >method to everyone else... The object of the game is to heat up the vinyl just enough that it will flow a tiny bit under pressure. It is true that this might affect the contours of the grooves somewhat, but I cannot imagine that it could possibly have as much of an effect as playing the record, which I understand heats up the vinyl a good deal. I also expect that the record isn't completely cool when it comes out of the mold. We aren't talking about much heat here!
north@down.UUCP (Professor X) (04/11/84)
"anything that works is better than anything that doesn't work." so what *if* the pressing deteriorates a little? (i'll have to try this idea to find out if it really does.) it's still better than tossing out a record that can't be exchanged for an unwarped one. the really silly, ridiculous thing about self-titled purists is how they forget the REAL REASON for buying wonderful equipment and recordings. it doesn't sound like they have very much fun, trying to listen for the steps in digital audio and all the little defects in their "systems" (everything is a SYSTEM). Stephen C North
bhj@rabbit.UUCP (bhj) (04/11/84)
The key is that pressure=force/area. Don't worry that much about the grooves if I were you.
fritzz@sdccsu3.UUCP (04/11/84)
>Put the record between the glass sheets and put the whole sandwich >in the oven. Turn the oven up to 150 degrees for about 10 minutes, >then turn the oven off and open the door part way. Let the glass and >the record cool to room temperature (about an hour). I bet this does wonders for groove shape. In particular, the top part of the groove would be deformed, possibly even creating a lip bending over the groove. Unless you enjoy distortion, I think exchanging the record where you bought it is a better solution. (If it was a used record, it won't matter anyway) -- fritzz the Zebra- "Gee, you look funny behind bars..."
kar@ritcv.UUCP (kar) (04/12/84)
When flattening a warped record in the manner described, certainly most of the
information in the grooves is preserved. This is better than having all of
the information in grooves that cannot be played, and a lot cheaper than
replacing the record. If you're persnickety enough to worry about it, then
you can afford to buy a new disk; I'm not (yet).
Ken Reek, Rochester Institute of Technology
{allegra,seismo}!rochester!ritcv!karron@brl-vgr.ARPA (Ron Natalie <ron>) (04/12/84)
"anything that works is better than anything that doesn't work." Nothing is better than Eternal Happiness. A Peanut Butter Sandwich is better than Nothing. Therfore, A Peanut Butter Sandwich is better than Eternal Hapiness.
wm@tekchips.UUCP (Wm Leler) (04/13/84)
I have often heard that the stylus at normal tracking exerts a pressure of greater than nine tons per square inch on the groove walls. This sounds reasonable given the small size of the stylus and the velocities at which it is being moved. Given this, along with since records are wider at the edges and middle than at the grooves (so that changers don't instantly destroy the record), I can't imagine how heating it up between glass to remove a warp could possibly hurt the music. Besides, would you rather throw the album away? wm
fish@ihu1g.UUCP (Bob Fishell) (04/13/84)
If you'd buy yourself a decent phono cartridge, you wouldn't have the
problem to begin with. I have a Shure V15-IV, with a little viscous
damped carbon fiber brush that both cleans and destatics the record and
acts like a shock absorber. It will track records that look like they
would derail a train, without using excessive stylus force. I have
it set at just under a gram (adjusting for the brush, of course).
The reproduction ability of the cartridge is excellent, too, and since
Shure Bros. brought out the V15-V, you can pick up a type IV at a good
price these days.
--
Bob Fishell
ihnp4!ihu1g!fish