How best to eliminate LP warps

I think the premise behind flattening the LP by heat and pressure is the hope that the LP WILL return to its original flat shape, that the stretching represented by a warp, if it is indeed stretching, will be eliminated by a corresponding shrinkage. I must say I don't quite understand your argument that warps can never be "repaired".  Anyway, when you play a warp, the warp itself does represent a longer distance between points A and B on the adjacent flat surfaces on the LP, as you say, and because the turntable motor maintains a constant angular velocity in the plane of the platter, the velocity of the stylus in the angular direction will increase momentarily between the flat points A and B, as it has to climb and descend a hill.  That ought to cause a pitch change.  Possibly, because this distortion occurs amidst musical passages, which are complex both in pitch and timing, perhaps that is why we may not hear a problem.  The video that Mijostyn put up here on this forum, when we were discussing tonearm design clearly does show that if the LP is encoding a pure tone, e.g., 1000Hz in the case of the video about the ARXA turntable and its wonderfulness, you CAN hear the warp.

@tablejockey 

What’s surprising is how resilient the LP is.

 

Amazing the LP grooves maintain integrity with all the deformation(is that even a word?) going on.

No it is actually not, a wrapped record is stretched but all is depending on how bad the warp is.

The diameter of the grove to the other it is not changed but it is a longer path from for example a stylus at a point the shortest path is the other side of a Hill is a straight line trough it as if it were flat.. but instead the stylus need to travel all the way upp the hill/wrap and down again to the other side.

So the stylus is traveling a LONGER DISTANCE than what it should have been doing when/if the record were flat. But the diameter is still the same.

OK then we have a STRETCHED and longer track then when it were flat (speed variation).

So when we flat out that material the extra length is not shrinking or get shorter back to its original size. The record will again get a new shape..

It will get flat but the additional length in combination that the material has no memory to get back to a previous shape. Where will that extra grove length go?

It will go to the side when we force it by pressure on a flat surface it can not escape somewhere else when it will not shrink.. to the side there is no pressure. 😜

So now we got the extra length on a flat surface so were the warp were it has gone to the side instead and now the third shape we have is that the grove is not circular it is more egg shaped! And do you look att the canteliver/cartridge NOW from the front you will see it work much more side to side (left and right). 

So we have changed from that the cartridge going up and down with the warp to left and right instead.. that is why a wrapped record is in reversible damaged forever. The goal should be to get the record back to its first shape as it comes out from the record press and that goal can we never achieve. Yes we can get the record flat but what does that help us when the circumstances of the grooves are longer than it had when it left the record manufacturers pressing..

Note that of course this is most noticible and easier to see and experience the more warped the record is. And smaller warps you might not be able to notice this at all.. when it is on a much smaller scale.

What’s surprising is how resilient the LP is.

Amazing the LP grooves maintain integrity with all the deformation(is that even a word?) going on.

So you’ve recently examined each and every one of your 2000 LPs, and you know for sure that only 5 have a detectable warp?

I doubt it. Actually I too had that smug attitude toward the issue, until recently I detected moderate to severe warps in 2 or 3 LPs I do not want to discard. Which led me to start this thread. But oddly and amazingly both of the LPs that were most warped actually played pretty well, and I did not detect any obvious distortion while watching the stylus trace up and down over the warp. I do not agree with Mijostyn’s hypothesis that this is because we are used to speed aberrations in the vinyl medium. I really don’t know exactly how to explain it. The stylus did not take off into the air. The tonearms were respectively my Triplanar and a Dynavector DV 505. In both cases using high compliance cartridges, so that may have something to do with the traceability. 

Honestly, I have 2,000 records. A very few (5?) have a slight edge warp that doesn’t have much of an impact. The other three that were warped I threw away. 
 

Is there a source like Warped Records dot Com you guys are buying from?

@mijostyn

Interesting observation about eccentric spindle hole placement: how did you measure this to confirm the degree of displacement off center?

(BTW, while DGG may have misplaced their spindle hole, RCA LP's are just really bad!)

Thanks.

@jw944ts , you haven't lived until you've seen your tonearm take off:-)  Any warp that can be easily seen without the record spinning will cause a noticeable pitch change if you are use to digitally stable pitch on record playback. It appears to me that given smaller warps and eccentric spindle holes we are use to a certain degree of pitch variation and our brains ignore it. If you are use to really stable pitch the irregularities become, I would not say obvious but certainly noticeable. A couple of months ago I was listening to Polini play Chopin and the piano was wavering. Sure enough the spindle hole was way off, a DGG pressing. 

@mijostyn , though I have many LPs and many have some  minor degree of warping, I honestly have never heard an obvious audible effect....perhaps I am not a good listener, or it just that the areas of warpage have never coincided with a musical passage that would make the pitch variation apparent...and i have never had a LP whose warp was SO extreme that it caused skipping or mistracking....just my experience

@jw944ts, having vacuum clamping, minor warps are not a problem for me. The warps I need to flatten are the major ones and they are easy to hear. Many arms will be airborne off these warps. The Schroder will track just about anything and once you are use to extreme pitch stability these warps become obvious. Minor warping may not be so obvious. My problem is that when the warps get bad enough the vacuum can not grab a seal.

SO, who here that have excellent TT/arm/cartridge can actually say that when they play an average warped LP that they can actually HEAR manifestations of the warp?

@edcyn 

Such cheap shot without any explanation.

Sad. Whatever floats your boat I guess. Sad again.

@baylinor  -- All I can say is that you are truly a lad insane...

mijostyn:

Thinking about it more it might be better to centrally locate the glass plates in a box with cardboard spacers (cardboard box with a top) and then wrap the box with the heating blanket.

This way the heat would be more evenly distributed.

I assume that many here may have digital thermometers with long wire leads for oven/grill cooking which could be used to monitor temp.

As already mentioned, lower temperature and additional time would seem to be the way to go, especially with DIY methods.

When I tried the glass oven method the oven used would maintain heat @ around 135-140 degrees (not any lower).

Doing so made the edge warp worse on a Pearl issue the "The Last Castrato".

I purchased another copy on line and it has a similar edge warp.

I only wanted to listen to it out of curiosity, so left it @ that (could not listen to the first cut on either side, and on the baked LP the first 2 cuts).

DeKay

Hey all. I wrote quite a bit about this. As many long-timers here often say, do a search.

I just had a look at the Furutech unit. It is the same unit as the Orb with a different dress on!  The Orb is not sold here any more by license agreement. Lets see...$1150...$3270... nice racket. I'll follow @lewm to eBay.

@dekay , nice thinking. The trick is there can not be any temperature differential across the record or you will make warps. Will a heating blanket and glass panes work? Sounds like a nice experiment to me!  

If a research is done into using a Peripheral Ring, it soon becomes apparent that additional to the intended benefits of the increased inertia, the impact of the weight on the LP, and the reduction of the warped form around the rim, has shown, if the reports are accurate that new levels of quietness are achievable during the playback when the Peripheral Ring is present. 

Not all TT's can utilise a common design of a Peripheral Ring, so it is always best to check if the TT is compatible with the design being selected. One such design change could be the need for a shallower depth weight or a chamfered edge to a weight.

I’ll add my voice to those who recommend an outer ring. When I got one I sold my vinylflat right away.

It is far easier to use than any reflex clamp, and does the job better.

Moreover, by adding weight to the edge of your platter it will add flywheel effect and increase SQ for that reason alone. I use one with all records, warped or not.

@drbond thanks for the info on Mockingbird.  I saw an Orb listed here on Audigon recently, but it was almost the price of a new one, so I passed.  It did get snatched up pretty quickly.

Agree with those that mentioned using an outer ring.  If your table will accommodate one, that's a great way to go.  I had one with my VPI Classic 2 and it worked great.  

I don't think it would be a good idea to put one on my Sota Sapphire with it's suspended chassis, which is why being able to flatten my records is appealing.  I have the Sota clamp which works well, but doesn't do much for warps where the outer edge is bent upwards.

The vinyl disc is manufactured using a compression molding process. Theoretically it is a process that will induce the least amount of "molded in" stresses in a plastic part like a record disc. There are a variety of reasons why a vinyl disc made like this will warp. From the process itself, from discs not stored properly, etc. To remove the warp you need to apply a type of annealing process where you want move, or reposition, polymer chains. This can be done in an oven. You will need to set the temperature control to the desired temperature and apply a force. After time the disc should be flat. 

The glass transition temp of PVC is 83C so this is the target temp. You will need to be at or just above this temp to get the polymer chains to move. If you place the vinyl between two aluminum plates and place a weight of 1kg on top this should work.  Place a thermocouple in the oven and determine what setting is necessary to achieve 83C. It will take time to come up to temperature and then there will be a necessary dwell time to make the disc flat. The time can be determined through a little experimentation. And it will also depend on thickness of the vinyl disc. I did this before and it worked well.

OUTER RING

+1

OUTER RING. It will flatten out pretty much anything while you play it. Who cares what it looks like in the sleeve.

A must on my rig.

Good consensus when i wrote 50°C that were in the dial of the oven and don't need be the real temperature..

But yes time is on your side.

I have used the Vinyl Flat plates and heating bag on at least 20 LPs. I was very satisfied with the results. I have used on both vintage and new releases. If the device doesn’t completely remove the warp, it can reduce the warp to barely noticeable. 
 

I purchased the system to 1) Avoid dealing with LP returns, 2) flatten a number of already owned LPs. I am completely satisfied with the results. 
 

www.vinylflat.com

A Vinyl LP is Thermoformed and the composition of the material will react to heat and deform, as well as conditions that are applying force to a degree that can cause it to deform in shape.

Methods to correct a deform in shape can utilise both of the above influences, the use of Heat and Force are the common methods chosen. The not so common method chosen is Force only and relying on a ambient temperature as the heat source. 

Methods to flatten a Warped LP are around for a very long time, and were probably presented as a method from an era, when a LP that was deemed as a damaged and very easily replaceable due to the LP as a commodity being readily available,                the Flattening Devices in their earliest concepts were one of many other marketable product, offered as a ancillary device, most likely to be purchased by individuals with a desire to 'make do and mend'.

The times have changed and the Vinyl LP is not so readily available, and the need to 'make do and mend' is a genuine consideration. The LP as a commodity today is for certain Albums a thing of rarity. If such a rarity is to receive a corrective treatment, the rarity, put a new emphasis on the considerations that are required to ensure the correction is not detrimental to the LP in general.

The only real concern that should be in place, is whether the outcome of a Groove having deformed and them being deformed once more, to be returned to an earlier shape, will have incurred an unavoidable change to its form produced at the time of the pressing being new.     

A Thread on another Forum has covered this subject and has suggested a variety of methods using Polished Edge Glass Sheets as the press to supply the force.

The Methods are all reported on as being successful, but in my mind some are carrying more risk than others and there are not guarantees, one method using force applied heat can be replicated in another set up.  

One individual used the Glass Sheet Press with a added Weight only, and had reported that the LP was flattened within a month.

This as a method, in my mind is the method that presents the least risk for the LP, as there is not a force heated environment being created, where forced heat or point source heat is presenting an additional risk.

The time required using the Press/Force only method, could probably be decreased if the materials were placed into a smaller environment with an increased Temperature set with a range between 25 - 40 Degrees Celsius, with 40 as the maximum.

In my mind the temperature should be ambient and not created by forcing or applying heat directly to a press material that is being used, as this could create a point source for the heat, and the LP could be detrimentally impacted on as a result. 

A method to control the temperature to a chosen level of heat, could be achieved at e very cost effective outlay.

A Polystyrene Box used for Temperature Controlled Transportation, with a Herpetologist's Heat Mat placed inside will be a very suitable method.

A Heat Mat produces a uniform heat over the mats surface, so a hot spot is not radiated, creating an intensely heated zone, using the Heat Mat with a Thermostat  will be ideal for producing a very cost effective method for controlling the Box's evenly distributed Temperature with a low voltage heating device.

I had a unwanted experience once when using a Oven to be the source of heat. , When trying to make a form in a foam material, the Foam was placed and concealed,  between two heavy metal plates and the Fan Oven set to a low Temp'. The low Temp' was still able to create a Hot Spot, which caused the foam edge to deform to a non correctable condition.

I don't recommend using an Oven as a method for rare vinyl LP's, I don't see how a condition can be created that is reliable and consistent for all adopters of the method, unforeseen risks seem inevitable.

For the DIY Method and not using purpose produced devices, the Ambient Room Temp and Press with applied weight, with an allowance for the time needed to complete the reforming of the original shape, is looking like the best place to begin.

If a version of this method is then wanted which can potentially produce a decreased time requirement for the process. The method to produce a space with an increased ambient Temperature being present, seems to be the next method that has the least risk attached.          

I use two pizza stones. And put the record in-between. You can probably use glas also.

But use uven instead of sun. The sun is unregulated..

Then you have two factors to adjust. Time and temperature. Start with 40°C and if nothing is happening then bump up some degrees and try again. But probably you don't want to go beyond 50°C.

You don't want to flatten to much either because then you will get radial problems (the grove getting egg shaped. So it is better to have some warp left than "over do it" and get flat and egg shaped. The record that is warped is already destroyed for ever. When vinyl has been prolonged it will not go back to its original shape. Never! Yes it will get flat but the damage is done and it is a longer circumstance on the grove. When vinyl is NOT like a rubber band and goes back to its original shape. It is more as a pizza dough. You will learn that lesson is you have a very warped one and when you have flatten it out.)

When you get a feel of what temperature to use then the procedure is rather straight forward.

(The pizza stone has two disadvantages one is that it will contain moisture that will not be able to escape between the stones and record label can get destroyed. That is eliminated by drying out them in the oven. Next is they're going to scratch the record surface. You need a paper between record and stone or have a simple papper inner sleeve.)

I usually use more time than temperature and may do it over the night when temperature will destroy much faster the record than time.

Vinyl Flat and Groovy Pouch hasn't failed me yet.

Clearaudio outer ring. Wayne’s audio outer ring. Vpi outer ring. Add any center weight. 

Thanks, guys.  I think we've covered the waterfront when it comes to curing warps. Unless someone else has a treatment not already mentioned.  My preference is to reduce the magnitude of the warp before playing the defective LP.  I am less interested in clamps and vacuum hold down, in this instance.

As my brain continues to de-fog (thanks all you guys!), I now remember doing A-B comparisons between having the SOTA vacuum hold down on & off. Vacuum hold down gave me more weight and dynamics but I often preferred the lighter, airier sound of just letting the LP lie there on top of the platter. . Imaging was different between hold-down and non-hold-down but were equally satisfying. A screw-down clamp meantime, puts me halfway between with the best of both worlds. In any case, a screw-down clamp is the way I now almost always go.

lewm:

What about glass panes and an electric blanket @ moderate heat?

Tried the glass/oven procedure once and it made the "edge" warp worse.

DeKay

I tried a friend's Vinyl Flat, but could not make it work for me. Too impatient, I think.

What did work is something very like a vacuum hold-down, a 'reflex clamp', which consists of a small flat dome under the label and a clamp that exerts force from the spindle. Actually I used the dome and a 2-3 kg weight, which is no problem for my air bearing TT. This solution is discussed on DIYAUDIO, the DIY Linear Tonearm thread, Niffy's posts on page 143.

Works well for me, and even improves the sound of flat records!

I had not thought of this. But after a bit of research I would definitely go with the Furutech LP Flattener DF-2. Looks like a great solution. 

Orb from japan via eBay works for me if I decide to go that route. $1150. As noted, 100V is no problem at all. A proper step down transformer can be had for ~$50.

@lewm OK, well it works for me,, both sides, to a degree.... Like I said,, it does NOT eliminate the warp, however it does allow you to play the record, rather than trashing it it also reduces the amount of vertical movement of the tonearm. Try it.

Also, if you find it is only reducing the warp on one side, then try the clamp without the washer for other side, as other side may be bowed up at label. The washer is good or better for when one side is dished rather than bowed.

@mijostyn @lewm @big_greg 

Mockingbird no longer sells them.  I already investigated this:  they are only available from Japan as 100V. 

@big_greg , Great find Greg and less expensive! $1150.00 @;lewm Have a look at big_greg's link. I sent them an e-mail asking about availability.

Orb Disc Flattener at Acoustic Sounds recently back in stock. I couldn’t get a reply emailing Mockingbird.

The Orb units work.  My local record store has one and they have flattened a number of records for me with it.  I've been thinking about getting one.

Here's where to get them in the US - Record Flattener – Mockingbird Distribution LLC

@lewm

No, if you read the print, even on @mijostyn ’s link, it says "no longer available for purchase". . . I only found it available for sale in Japan. You can find it on ebay.

@mr_m

The previously sold $1900 Orb was the cheap one! The expensive one, that’s still available for purchase in the US in the Furutech DF-2 for $3275!

$1900 for a LP flattener from Music Direct? Ya got to be kidding...

edcyn baby, No vacuum hold down for me, on any of my 5 turntables. Once upon a time I did own a Star Sapphire Series III with vacuum, but no longer.

I had completely forgotten about the Vinyl Flat options, probably because warps were such a rare problem for me. Thanks for that. So far that and the Orb seem the best ways to go.

As to the Orb, they are available from a US Company; see Mijostyn’s post. 100V is no problem; just get a 120V to 100V stepdown transformer. They are cheap. I already own two of them, one for my Denon DP80 and one for my Kenwood L07D.

My brain is getting foggy but I'm ninety percent sure I once had a vacuum hold-down platter for my SOTA turntable. In any case, when it ceased to work and the thing's center bearing got noisy, I shipped the 'table to SOTA HQ and had them install a new standard platter. In any case, the hold-down did eliminate everything but severe edge warps.

As @petg60 and @drbond just said, The Vinyl Flat Record Flattener, $159.95 direct from Vinyl Flat. Accessory heating bag The Groovy Pouch $89.95. Both @slaw and I (and Mike Fremer, etc.) have found it to work very well.

Mild/"slow" warps can sometimes be eliminated by the use of a good reflex clamp, standard on the old VPI’s (1/4-20 threading). It’s best if the top of the spindle is threaded, and of course the clamp itself. BDR made a couple of great ones, one a 1-pc. the other a 2-pc. I believe there is a 2-pc. on USAM right now, priced at $150.

@lewm

I’ve looked into this, as I recently acquired alot of vinyl. Unfortunately, I’ve found that some of the Mint LP’s that I’ve bought tend to be warped, as they’ve never been opened in 60 years, but just lying around diagonally on someone’s shelf.
There are two real options at reasonable prices: I think the best would be the Orb DF-01A for about $1,200, but they’re only for sale in Japan, and only at 100V. So, I purchased a Vinyl Flat and Groovy Pouch combination for about $300. It took me quite a while to determine the best time and temperature settings for the Groovy Pouch (which is just an electric blanket with velcro that you wrap around the Vinyl Flat discs). They recommend the low settings for up to 9 hours, but I’ve found that the only thing that’s really worked for my warped LP’s is the high heat setting for 4 hours. . . From what I’ve heard, there’s been no discernable damage to the LP..

audioguy, I disagree that the method you mention works well, certainly not for both sides of the same LP, because warps in one direction that may be ameliorated would not be affected as much or at all, when you flip the LP. I do have a SOTA reflex clamp, so I could give it a try for at least some of my warped LPs.

I just found the Orb too.  Much less expensive than the Furutech, but still not exactly cheap.  Anyway, that seems to be the best device currently available.

Why not on direct sunlight between the 2 glasses?

The device you are looking is called Vinyl Flat Record Flattener from vinylflat.com.

You can place a thin felt washer on the spindle prior to placing the record on the platter. Then, using a record clamp, such as the one from the Record Dr., gently clamp down the record until the warp is diminished. 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 negative effects from what warp may remain. This is generally how the more expensive Mitchell record clamp works.

Hey Lew, This thing really works. I plan on getting one as records warped beyond a certain point are difficult to get a seal on vacuum. Given todays shipping standards warped records are inevitable.