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

I see Jazz guys’ point, if you assume that a warp represents a local stretching of the vinyl, such that there is excess material in the horizontal plane and this forces the warp to occur. Like pavement expansion on hot days. If we assume that that is the genesis of a warp, then it must also be true that the LP will have thinned out in the region of the warp in order to produce the aberration. I have never observed such a thing, and I have never stored any LP ever under conditions that could conceivably cause vinyl to “melt” and warp in that fashion. So this is my reasoning why I also doubt jazz guy’s thesis. But I don’t doubt he saw what he saw. Perhaps the occasional LP comes from its factory in that condition, the warp having been caused by uneven heating in the press. But don’t we assume that most warps occur while the LP is in our own hands, in our own house?

Dear @jw944ts  : "  if i understand your situation, you have a very  small percentage of your LP collection with warps that concern you, BUT , when played, you dont notice a mistracking or audible problem....may i ask why you why wish to attempt to remedy this?  If its not broken, dont fix it.. "

 

You are totally rigth an accurated.

 

This thread goes around 100 posts in a thread that after the jw posts has no sense. It's the classic op style and he has the rigth to do it. So go ahed.

 

Regards and enjoy the MUSIC NOT DISTORTIONS,

R.

Interesting post Lew.  I believe I have a similar situation.  With a number of records in my collection (possibly a majority?), if I watch for arm movement while playing a record I can note slight side to side or up and down movement.  But I do not hear distortion with many of them.

Considering warps, I agree with you and optimize, there are different types of warps which may be worth identifying.  The two I see most often are "dishing" where the entire outer portion of the record is raised (when viewing one side).  With that, a weight or clamp may be effective, but only when the cupped side of the record is facing downward.  No help at all when the cup faces upward.

The second type warp I've experienced I call the "potato chip".  The outer portion of the LP has undulations.  I've never tried a record ring but assume it may work if the undulations are not excessive.

Regarding hearing the warps, again I expect there are different types of experiences.  Anyone who is sensitive to azimuth may notice the cupping type when tracking outer portions of the LP.  The potato chip warp(s) may change tones, particularly on sustained notes with piano or voice.  Of course if the warp is severe enough then mis-tracking or even the stylus leaving the groove will be heard.

Unfortunately I don't have any answers to offer from my own experience.  I did obtain two 12x12 panes of glass to compress a warped record in the oven.  But then I read too many failures with that to be brave enough to try.

@pryso , very true about warps and dishing. I send the dished records back. It is almost impossible to seal the convex side.

In order to hear the warp easily you have to have some steady tones like a cord held on a piano. Sine wave test records really demonstrate the effect of warps and off center spindle holes. When a turntable compensates for everything except the offset spindle hole which there is no compensating for, with vacuum clamping and rock solid speed control there is a sensation of solidity which greatly adds to the illusion. I can not tell you if this is psychological or not as I have not performed that experiment. It seems to me to be quite obvious but, out brains are powerful items and you should never write them off.