This is probably affordable:
How to Unwarp a Phonograph Record - At Your Own Risk
by Chuck Miller
There are so many Zen koans of thought in the world...
"What is the sound of one hand clapping?"
"If a tree falls in the forest and nobody is around to hear it, did it make a sound?"
"Who put the bomp in the bomp-pa-bomp-pa-bomp?"
And of course, for record collectors, the most mysterious question of them all -
"I've got a record with a warp in it. How do I un-warp the record?"
In a Utopian world (no, not a world where God is Todd Rundgren), all records that were pressed to be flat would remain flat for the duration of time. Unfortunately, sometimes records develop warps. Records can suffer from heat warps, which occurs when a record is exposed to prolonged sunlight or stored near a radiator or furnace. Records can also develop compression warps, when they are stored improperly and the vinyl is actually bowed or bent over time. Warping is an equal-opportunity problem; it affects shellac 78's, vinyl LP's and styrene 45's with equal malevolence.
Sometimes a collector can compensate for a slight warp by simply adjust the tracking and anti-skate on their turntable tonearm. The larger and more pronounced the warp, however, the more likely the needle will not track properly and the sound will be affected. Sometimes, instead of the peaceful gradual glide from record edge to runout groove, a warp can cause the tonearm to jerk and swing and bob and weave and bounce and (sometimes) leap from the groove. No warped record should ever be considered of a higher grade than Good. And, of course, the more severe the warp, the lower the collectible value.
But what do you do if, for example, your copy of Mike Oldfield's Tubular Bells has developed a warp, and you want to un-warp the record? What if it was that pressing of the Delfonics' "Didn't I Blow Your Mind (This Time)" that was you and your girlfriend's favorite song? What if it was an old 78 of Rosemary Clooney singing "Come On-a My House" and you wanted to fix it so that it would play on your restored Victrola 78?
You may want to save this column. I asked many different people about their own un-warping techniques, and the success and failures of each. I also bounced around the Internet, and found more than a few homemade un-warping formulas.
Before you break out that Rolling Stones "I Wanna Be Your Man" 45 with the slide edge warp and start any of these techniques, read these suggestions carefully, and understand that (a) not every technique will work for every type of record; (b) un-warping a record is a very tricky process and requires a lot of skill, patience and perseverance; © you need to practice these techniques with records to which you have NO emotional attachment (now where are my wife's Christopher Cross records?). And many of these un-warping methods have varying degrees of success and failure; and there is no guarantee that even if you do get the record flat, the grooves will not acquire a hiss or a mistrack upon play. Neither myself nor Goldmine nor Krause Publications is responsible for any damage caused by an attempt to un-warp a record - in other words, if your Roy Orbison 45 gets damaged, don't come crying to me.The "Oven Baking" method
(has been known to work on shellac 78's and thick vinyl LP's)
Many people swear that they can unwarp a record by using an oven. For this recipe, you need two 14-inch square sheets of tempered glass and an oven. According to Greg Weaver, begin by preheating your oven to 150 degrees.
Clean your record and rinse with distilled water, to make sure there is no dust, dirt or other residue in the grooves. Place the record between the two sheets of tempered glass, then place in your oven. Wait 12 minutes. Carefully take your glass-and-record sandwich out of the oven and place on a cooling rack for 30 minutes. Then gently remove the glass and inspect the record. It should have returned to its original flatness. Oven temperatures and cooking times may vary; you may have to add an extra two or three minutes in the oven to achieve the desired results.The "Solar Baking" method
(works best on shellac 78's).
This method was discovered at the Roadhouse website, a popular local for Ebay music buyers and sellers. The formula requires two 14-inch pieces of 3/8" thick glass, two large pieces of approx. 3/16" "place mat/craft" vinyl/foam, one quality album sleeve, five pieces of cork and common household glue.
Trace the outline of a 12" vinyl LP on the craft foam (make two of them, one for top and one for bottom). Cut out the center on each craft foam sheet, so that only the vinyl grooves are covered by the mats. Use common household glue to attach five (5) pieces of cork on the bottom piece of glass to avoid any clanking when setting it down, plus it makes it easy to pick back up.
Clean the LP and place it inside a protective sleeve, such as a Discwasher VIP sleeve. Then place the record and sleeve between the craft foam mats, and place all that between the two sheets of glass. Take outside on a sunny day and let sit for 10 to 15 minutes (sun times may vary whether you live in Houston or in Seattle). Bring the glass-and-record sandwich inside and let it cool for a day. Then inspect.The "Hot Towel" method
(may work better on 45's).
For this you need a thick towel and heavy books. Place the towel in the dryer for a full cycle (no need to use static sheets). Once the dryer cycle is finished, take the towel out, place it on your table. Lay a record flat on one end of the towel, cover the other side of the record with the rest of the towel. Place heavy books on top. Inspect after 30 minutes.The "Heat and Bath" method
I came across this one by using the Google Internet search engine.
This one is interesting. Once again, you place your records between two plates of tempered glass and bake in the oven. While your record is baking, go to your bathroom and fill your tub with cold water, at least four inches deep. After your record has baked for twelve minutes or so, take the glass-and-vinyl sandwich out of the oven, carry it to your bathroom and submerge the entire mixture into the cold tub water. After a few seconds, you should be able to remove a flat record from your tub. Make sure you have used tempered glass when cooking and submerging; some types of glass will fracture after going from extreme heat to extreme cold.The "Scientific Procedure" method
(may work with pressure warps and heat warps)
Some enterprising young students at this webpage actually designed a science project on unwarping records. Their tools included the requisite glass sheets and the solar method of flattening the records, as well as an aquarium thermometer that was applied to one of the glass sheets to monitor the interior temperature. "First the thermometer was applied on the glass in hope that later in the test we can get an estimate of the temperature of the glass itself. Then the glass was wiped clean to make sure no dust or debris could get embedded onto the record. Only water dampened paper towels were used to clean the glass. We didn't want to risk using a glass cleaner in case it contained any chemicals that may harm the vinyl."
They then placed a record between the two pieces of glass and set the apparatus outdoors on a table. "The first thing that was checked was the actual outside temperature. After a couple of minutes the thermometer settled in right around 86 degrees. From this point on, it was just a matter of letting time pass and checking for changes. We decided to check the record every 5 minutes. This was done by lifting up the top piece of glass and tapping around the surface of the record. If this caused the record to "see-saw" we knew the warp was still present. Written notes and mental notes were made of each record so that any changes could be gauged."
Eventually they noticed the record did start to flatten, but after 60 minutes they brought the disc inside ("We decided to limit the test to 60 minutes, due to the fact that some records contain Styrene in their vinyl composition, which makes the record more susceptible to damage by ultra-violet rays. As well as any record being exposed to direct sunlight for any lengthy amount of time can't be good for it.")
Some of the other un-warping formulae I've come across involve hand-held hair dryers, microwaves, wrapping in a towel and flattening it with a steam iron - but no matter what method you use to flatten a record, be aware that the following can happen:
You could cause other heat warps or ripples, where the concentric groove would no longer allow the needle to track properly;
You could melt dirt and debris directly into the grooves if the record is not cleaned ahead of time;
You could actually flatten the grooves, making the record unplayable.
But what can you do if your record is just too warped to play - or even repair? There are two suggestions. One is to place a listing in the "Goldmine Want Lists" section of this magazine, letting readers know you want to buy a new copy of your currently warped record.
Or, you can get really creative with your warped record. Take a 12" album and apply heat to the grooves. As the record softens, pull up on the edges until you have a bowl. Plug the record's center hole with a cork or tape. After enough practice, you've created a decorative potato chip bowl - a perfect party favor for Grammy night. And who said those arts and crafts classes in school would never pay off? Just think - an M&M bowl made from an Eminem 12" record.http://members.aol.com/clctrmania/cm-unwarp.html