How much weight is enough to damage vinyl?

[33audio]

You guys need to lighten up on the top-gun routine.

Your opinion based on your microscope?

You give yourselves too much credit.

Did I say red hot?

Did I say the tip melted the groove wall?

You really don't have the whole picture.

I don't think you even read what I wrote. You scanned it and jumped to conclusions.

When I first read the beginning of this thread I saw that some people had wear problems. I don't have a wear problem and loading of the groove wall really doesn't matter that much.

Aside from a worn tip what matters is dirt, especially deposits on the stylus. Dirt also wears the tip very quickly.

I wrote what I wrote for the original poster.

I gave my side of the issue. Again, I have no wear problems. I can't be totally wrong.

I really don't care about your delusions of accomplishment.

You simply don't know as much as you think you do.

Static electicity could easily melt vinyl. It could also generate a lot of heat in general.

I simply gave my understanding to whomever may have been interested. I don't care whether you approve or not.

[Ldg]

@audio33. Not intended as an affront, just posting an opposing opinion and setting out why. FWIW I do read your posts fully, and you did claim a red hot stylus is possible, amongst other points of contention about baked on vinyl, heating etc, about which I hold an opposing view, and have some evidence to back it that I'm happy and interested to discuss.

[missan]

It is my thinking regarding melting of the vinyl, that quite long before reaching a melting temperature, we must pass the glass transition.
To me it´s reasonable to think that when passing (if) this transition the vinyl will be severely and permanently damaged at the playing areas.

My own measurements have shown a glass transition temp of 65degC.
I strongly believe we are far from reaching this temp.

missan

[flavio81]

You give yourselves too much credit.
You really don't have the whole picture.
I really don't care about your delusions of accomplishment.
I don't care whether you approve or not.

Nice, very nice. Are you satisfied now?

Now please explain how "static could easily melt vinyl", as you wrote.

[flavio81]

Somebody should come up with information regarding the effects of temperature and time on vinyl. Under proper use the instantaneous melt/freeze principle should take effect.

There is no such thing. The vinyl grooves do not momentarily melt on playback. There is not enough energy for a significant temperature rise.

This has already been disproven & discussed on the forum:
http://www.vinylengine.com/phpBB2/viewtopic.php?t=22360

http://www.vinylengine.com/phpBB2/viewtopic.php?t=27421

The myth was created when G. Alexandrovich published a paper in which he "observed" that the vinyl "appeared to flow" under the stylus tip. No objective measurements!! It is 99.9% sure that he mistaken the expected elastic deformation of the vinyl for "melting".

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[1200y3]

There must be some truth to it when it comes to +5 gram styli. I had a .7 spherical that had the vinyl melted to the tip. It was a mono stylus with no vertical compliance, a GE VR 2.

I did some of my own damping improvements to the cantilever and the cartridge body, and have had no problems with record wear, so I assume the vinyl elasticity works in conjunction with the VTF and stylus size.

I wet play or lubricate my records though, and without a tape recording of the original surface noise, I can not be sure, but I may be hearing less HF degradation (good sign), with more surface ticks from wet play use (not good).

[Ldg]

There must be some truth to it when it comes to +5 gram styli.

Still not according to my calcs. There's plenty of headroom.

[timeltel]

33audio: Mark, allow me to misquote a forgotten authority from years ago: "Keep your stylus clean, deposits of vinyl can build up, sometimes to the extent of fracturing the stylus from stress". It is my amateur's understanding that friction, pressure and static all contribute to essentially "weld" vinyl residuals from the groove surface onto the stylus. Once allowed to start, an acceleration of the process results. Regardless of cause, it occurs.

Orlandoscapa, greetings. You ask if there is a definitive way to know how much is too much, and this has been well answered. I concern myself equally with "too little". said "use your ears". Accordingly, if you start somewhere in the higher range of recommended VTF for your cartridge and then slightly reduce it, listen and repeat this, you will eventually hear grain in the vocals and exaggerated brilliance in the highs. You may also have unexpected skipping. You now have too little VTF, you will damage your records. Raise VTF slightly and listen again. Don't hurry. Typically, but not always, low VTF will slightly emphasize hf's, greater VTF will have the same effect on the bass. The objective is to bring these into balance. Edgy mids or sssibilance (this is distortion) usually calls for a slight increase, if alignment is correct, that is. This is just a suggestion, but doing so should assure you that you're not tracking with too much VTF. Still, you should double check to confirm you're within the maunfacturors'. specs., they're rarely wrong. By the way, don't use your favorite lp when doing this.
Too little or too much VTF, dirty vinyl and an unmaintained stylus all contribute to record wear. Welcome to vinyl, your first post, aren't you glad you asked?

[Deccadong]

There's one scenario being missed here. You're called out of the room while an LP is playing, or worse still you completely forget you've got one playing. The stylus eventually arrives at the lead out groove and continues, ad infinitum, to circle around that same grove over and over again. As with the cave man's technique of rubbing two sticks together to start a fire, is it possible that a stylus circling over and over on the same narrow stretch can eventually heat up the vinyl? I have no idea - anyone care to comment?

[1200y3]

L dog:Possibly the old 78's that used a couple ounces?

I don't think the lead out groove will do anything but polish the tip and many reviewers do it for a 24 hour break in. Possibly different on a worn record, or a line contact. Let us not forget that fine lines still need proper set up or there will be more risk of damaging grooves. And the damage I got was from VTF too. It cut a new groove into the record, shaved it clean.

[flavio81]

Revisiting some of the posts!!

2. Flom, The deformation of plastics with hard, spherical indenters, J. of Audio Eng. Soc. 1959, p.122

Plastic deformation on vinyl occurs for a 0.005 cm stylus at 5 grams static
load.

0.005cm = 5 um (micrometers) =0.2 mil, far far smaller than the typical 18uM=0.7mil conical stylus, which is specified to be used at 5g or less.

So:

0.2 mil -> 5g

3. Walton, Gramophone record deformation, Wireless World 1961, July, p.353

Shows a graph with VTF vs stylus radius : plastic deformation is caused for spherical styli of 0.0003 inch at 2.1 gr deformation, 0.0004 inch 2.7 gr, 0.0005 inch 3.1 gr etc.

Converting to mils:
0.3mil -> 2.1gr
0.4mil -> 2.7gr
0.5mil -> 3.1gr (now this is an available size for conicals)

A first play at 9 grams had worn off 1.5 dB. For the same standard M3D cartridge at 9 gr a drop of 5 dB at 15 kHz occured, at 6 gr 2 dB, at 3 gr no drop , all drops indicated after 20 plays

Fortunately no one needs 9gr VTF these days!

5. Oakley, Inner groove distortion, Audio Magazine 1962, June, p.57

For 0.5 mil styli a VTF of more than 3 grams tends to erase high frequencies

More or less exactly what Walton (3) reported.

7. Walton, Stylus mass and reproduction distortion, Wireless World 1963, April p.171

Pictures of stereo grooves played with pickup at 2.7 gr VTF (stylus mass 3
mg). Permanent indent depth = half modulation depth. After 5 playings, little further deformation is visible. Low effective tip mass is advantageous.

My comment: Practically all good styli today are 1mg effective stylus mass or less.

8. Kogen, The elliptical stylus, Audio Magazine 1964, May, p.33

0.7 mil circular tip
slight change between 10-20 Khz at 3 gr after 100 plays

Sounds coherent with the other tests.

[flavio81]

I would not go over 3.5 grams for a .7 conical.

I wouldn't too.

Almost one year later, i am using 3.5gr on a .7 conical and enjoying it...

[flavio81]

So, revisiting the thread, i think that there is much more than just VTF regarding record wear. I think the importance of a low effective tip mass is paramount, if we want the stylus to always be in contact with the groove. Plus yes, the polishing of the surface surely has a lot to do, and i wouldn't be surprised if mirror polished conical tips such as the one in the Denon 103 do not do any kind of harm despite the heavy VTF.

I have many record sleeves from Deutsche Grammophon that say "Use 10g or less for a 1.0mil mono tip, use 5g or less for a stereo tip" (0.7? 0.5? -- i'll have to search for those sleeves). From the studies on the 50s and 60s cited by Klaus, those limits seem to be perfectly safe.

The bottom line is, assuming that the cartridge and stylus are of a decent quality, the real-life vinyl wear ought to be caused by dirt abrasion and mistracking caused by dirt accumulation in the stylus tip!!

In any case, for what is worth, i usually play the records wet with distilled water, which was estimated by ld to reduce friction in 30%. Not only it reduces friction, but it also help the stylus to glide dirt off -if there's any remaining-, instead of stomping over it.

(<--- Smug face here)

[flavio81]

3. Walton, Gramophone record deformation, Wireless World 1961, July, p.353

Shows a graph with VTF vs stylus radius : plastic deformation is caused for spherical styli of 0.0003 inch at 2.1 gr deformation, 0.0004 inch 2.7 gr, 0.0005 inch 3.1 gr etc.

Converting to mils:
0.3mil -> 2.1gr
0.4mil -> 2.7gr
0.5mil -> 3.1gr (now this is an available size for conicals)

From Namiki and Audio-Technica leaflets, contact area for a 0.5mil conical is 23-28um^2. Doing again the pressure calculations, for approx. 3.1gr

P= (0.031N) / (23e-11 m^2) = 134 MPa.

So if we believe Walton, the record he put under test had an approx 130MPa elastic deformation limit. 1961. Note that records in the late 70s were tangibly more "flexible" than 60s records.

So, for 134MPa and a 0.7mil stylus [33um^2 area] the limit would be:
F = (134 MPa) * (33e-11 m^2) = 0.044 N which is approximately 4.4grams VTF

So for a 0.7 mil stylus on a specific 1961 record, Walton would then advice not going over 4.4g VTF. Which is more or less consistent with the recommendations on record sleeves of the era, which said "5g or less".

Q. E. D.