How best to eliminate LP warps


I own about 2500 LPs, and I like to think they're flat.  Furthermore, I espoused the view that warped LPs ought to be discarded.  But lately I have found 2 or 3 of my LPs that do have warps but sound too good and are too precious for the music recorded on them to throw away.  So I am in the market for ideas on how to remove warps.  I am aware that there was a device on the market that looked like a large waffle maker, to be used for warp removal.  I think Furutech made it, but I never see it advertised these days.  I am also aware of the DIY method of placing an LP between two glass plates and heating the ensemble.  The question there would be how hot and for how long?  Any suggestions are welcome, especially opinions on the efficacy of the Furutech.  Thanks.  Please no comments on vacuum hold down; I think it's a great idea but none of my five turntables has that feature.

lewm
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 I got more fussy about warped records when I doubled down on record cleaning methods and noticed how many records don't lay truly flat on the platter- using a Monks, rather than VPI, RCM. I used the Vinyl Flat for a little while, it could work, but time consuming and very few benchmarks for time and temp-- I used an early one with a Groovy Pouch™ and single temperature-- some people got orange peel from either overheating or over-torquing the nut or both.

I eventually bought an Orb- a Furutech branded DF-2. I'd say if I guesstimate duration of heat cycle correctly based on type and severity of warp and thickness of the record, I have a roughly 85% success rate, which I consider pretty high.

Some records, even when "de-warped" will not be playable--the groove takes a bend where the warp was, and flattening it does not put it back "on track"---

Why so many warped records? I buy a lot of used records, many from the early '70s- period of much change in jazz--and a real low point for vinyl in the States, as everybody knows. I found a seller with a stash of Nathan Davis records on Segue- bought several from him, sealed. Pressed on the thinnest vinyl imaginable- makes Dynaflex look like a truck tire. Did get these flat but I watch my linear arm hunting and wandering--the record is out of round. Which makes me pause when you consider how expensive cartridges are today.

Replace the record- maybe-- I've certainly bought more than one copy of some records in the quest for a better copy (condition, surface noise, etc.) Some of these records are not so easily replaceable. 

The machine has, for me, paid for itself. 

Oh, I remember asking an online seller to confirm a record was not warped. He wrote back saying "you'd have to be an idiot to sell a warped record on ___." Guess what? (It wasn't a hard to find record). 

Here are the general steps:

It will not totally get rid of the warp, but the severity of the warp will be greatly lessened and your LP will play with no discernable · Hey Lew, This thing really works.

 

  1. Get two large panes of glass that will fit in your oven.
  2. Preheat the oven to its lowest temperature setting.
  3. Put your vinyl & glass sandwich in the oven for 30 minutes.
  4. Turn the heat off.
  5. Let the record cool down to room temperature.
  6. Determine whether or not that fixed the warping.

Regard:

Go india

hmmmm, if materials behaved this way the second law of thermodynamics would be broken! I encourage you all to read about entropy and IRREVERSIBLE energy! It is a fundamental foundation of how the universe works. There is a real difference between science and science fiction, having a warped lp remain round after removing the warp is FICTION! Furthermore, on the flat edged lps using two pieces of glass in the oven WILL MAKE IT FLAT; no question, but all the groove tops have been flattened as well! You can all believe what you choose, a good start is a BS in ENGINEERING or PHYSICs! I am a retired nuclear chemical engineer who believes in the laws of nature that are explained through mathematical relationships.

I have a VPI turntable with a spindle weight and a periphery weight.  If any of my records are warped such as this combo doesn't sufficiently correct it....my sense of pitch isn't that good that I need to go further.