Cryogenic treatment of guitars warning

[salvarsan]

Hurray for you. You figured out how to use Google! Who's a big boy?

The problem is that you're just spouting numbers without assigning any relevance to them. I happen to KNOW that mild steel and iron are virtually unaffected by cryogenic treatment. I know this because I already learned it. Now it's your turn to go learn it.

I suggest Google scholar here for its broad accessibility. SciFinder was more apt, but its availability is limited and DOI links don't go over well here.

I put the search strings out there for people with genuine curiosity about the topic. You give neither figures nor references, nothing in fact, preferring instead to pontificate when you aren't indulging in contrarianism.

Where's your proof? Perhaps you could exert yourself, provide illumination instead of noise.

[Mike Sulzer]

I have a hard time believing that the magnetic properties would be changed in any significant way. I have an even harder time believing that anyone could hear it.

If anything is affected, why not the permeability or the resistivity? I think changes in the resistivity would be heard most easily because that would affect the Q of the resonant circuit.

Alnico has a fairly low permeability, and there is a chance that changes in it could be heard. (When the permeability gets up to about 10, further changes do not matter much since the magnetic circuit is open.)

[big_teee]

If anything is affected, why not the permeability or the resistivity? I think changes in the resistivity would be heard most easily because that would affect the Q of the resonant circuit.

Alnico has a fairly low permeability, and there is a chance that changes in it could be heard. (When the permeability gets up to about 10, further changes do not matter much since the magnetic circuit is open.)

If that is the case, wouldn't it change back once the magnet, and wire warmed back up to room temp?
When winding the pickups, the DCR is up and down, do to temp.
Once the temp is stable everything goes back to normal.
Sure the resistance would be different at -100f, opposed to +75f?

[salvarsan]

If that is the case, wouldn't it change back once the magnet, and wire warmed back up to room temp?

The cryogenic treatment makes permanent changes (barring additional hi-temp annealing and/or tempering) in the microstructure.

I doubt that anyone doing this to knives ever measures changes in magnetic permeability, looking instead for strength and toughness.

[Rick Turner]

Try measuring pickup DCR before and just after wax potting...big difference. When matching coils, I try to let them sit overnight so they're all at the same temperature in the morning.

And I still wonder why folks can accept heat treating but not cold treating as being at least worthy of investigation. It's only within our lifetimes (well, I'm an old-timer) that it's even been practical to cryo/cold treat consumer goods this way. I can understand that not all the facts are in yet, especially with cryo treating non-ferrous metals as well as polymers, but that's no reason for vehement objections based on old-school thinking.

I suspect that the changes in materials other than austenitic steel may be due to de-stressing in a manner that does not change the hardness or temper of these materials. There may also be improvements to surfaces as well which would improve corrosion resistance. Just a couple of hunches based on what I have done with cryo treatment.

BTW, take a look at the info regarding cryo treatment of copper electrodes used in EDM machining. There doesn't seem to be much controversy there.

And...yes, the changes from cryo treating are permanent, just as are hardening and tempering.

[Mike Sulzer]

Coils should be matched by turns, not resistance.

I do not see anyone rejecting cryo out of hand, just asking for reasonable verification. Of course people accept heat treating more easily; it has very well known results for reasonably well known theoretical reasons.

Try measuring pickup DCR before and just after wax potting...big difference. When matching coils, I try to let them sit overnight so they're all at the same temperature in the morning.

And I still wonder why folks can accept heat treating but not cold treating as being at least worthy of investigation. It's only within our lifetimes (well, I'm an old-timer) that it's even been practical to cryo/cold treat consumer goods this way. I can understand that not all the facts are in yet, especially with cryo treating non-ferrous metals as well as polymers, but that's no reason for vehement objections based on old-school thinking.

I suspect that the changes in materials other than austenitic steel may be due to de-stressing in a manner that does not change the hardness or temper of these materials. There may also be improvements to surfaces as well which would improve corrosion resistance. Just a couple of hunches based on what I have done with cryo treatment.

BTW, take a look at the info regarding cryo treatment of copper electrodes used in EDM machining. There doesn't seem to be much controversy there.

And...yes, the changes from cryo treating are permanent, just as are hardening and tempering.

[salvarsan]

Should we all chip in for LN2 to hasten these essential experiments? I suspect that limiting respiration prior to their completion would be very unwise...

No need for direct purchase of LN2. Cryo treatment from commercial firms seems to range $5-10 per pound on a ~1 week turnaround.

The current process is to spend a day cooling to LN2 temp, wait a day, then use a third day to cycle back to room temp to minimize shock from dimensional changes. Even so, things like guitar bindings and stretched magnet wire may not survive, to hear it told.

Other items: cold-rolled steel has lower coercivity (magnetic permanence) than hot-rolled steel. Cold rolling precipitates carbon from cementite in the iron. Cementite is an iron carbide (Fe₃C) whose presence in iron increases its coercivity. Comparing 1% carbon steel and 0.1% carbon soft steel coercivities gives us 600 vs 150 amp-turns/meter -- Soft steel doesn't hold an imposed magnetic field as well.

This means that small changes in the carbon/cementite balance can translate to large changes in coercivity. Makes you wonder which way the cryo treatment pushes the balance.

Every percent of carbon can potentially sequestre 14% of iron as cementite unless precipitated out by various mechanical and thermal methods.

[The Dude]

What I find amusing about this thread is that the discussion seems to be largely about whether or not any "atomic" changes are made via cryo treatment.
More importantly to me would be the question, "Are these changes (if any) of any significant sonic value? Is it possible to "build a better mouse trap?".

Personally, I prefer to keep my ice in my drink and my guitar at room temperature.

[Rick Turner]

I'm not the best equipped here to test a pickup, but I'll pay for the cryo treatment if someone would like to donate a couple of pickups and do the testing. Or if that's too much of an issue, I'll buy a couple of pickups from Seymour and send them to whomever here is best set up to do rigorous testing.

This seems to be a battle of opinions here. I'm as interested as many of you (and a lot more interested than some of you) in learning. The only way to learn is to do. I'd suggest a typical single coil with just copper and Alnico and a humbucker that has copper, Alnico, and steel in it. I'm willing to put up or shut up. Money talks and bullshit walks. I'll cover shipping and the treatment.

[Chuck H]

The cryogenic treatment makes permanent changes (barring additional hi-temp annealing and/or tempering) in the microstructure.

But the changes are only significant with respect to a very limited range of materials. Your statement, taken as written and without putting words into anyone's mouth, implies that everything is permanently altered in a significant way. And that isn't true.

I doubt that anyone doing this to knives ever measures changes in magnetic permeability, looking instead for strength and toughness.

Excellent point. You're right. I'd be happy to find that there are advantages to cryogenic treatment other what is known. Either no one has ever researched it (doubtful) or no one has ever procured positive results (likely).

But I humbly digress for two reasons. First, the information and studies I'm familiar with from my own research are no longer free.?. Absolutely every credible study I was able to find on line required either purchase of the document or purchase of a membership of some sort. Far more $$$ than I would have expected too. I might have sprung for five bucks or less. So, since I'm not willing to fork over the coin to prove my point I need to retract my insistence that others do so.

Second, The studies I read were over ten years old. So, of course, new discoveries may have been made in that time.

I will defend my position. Having been accused of making noise instead of offering information. Well... I am offering information. I already read about and learned something of it. I figured someone (me) who actually knows something about it should post and let everyone know they can stop freezing all their stuff. You're all welcome. I'm glad my previously garnered knowledge can help. Instead I'm met with fanaticism. People with more faith than brains. So the bottom line from my perspective is either prove me wrong, default to my position or choose to fly in the face of science and just "believe". And one more thing. salvarsan, I have something you don't. I'm willing to be wrong for the sake of learning the truth. Even embarrassed. Maybe just tell me why you know what you do about it, as I have done. If your information is more recent I would be delighted read updated news on the subject if you can provide it.

Alas, the only credible information I've been able to find is inaccessible and all other information is either vaguely worded or utterly lacking in science, Usually from someone trying to sell something.

[salvarsan]

This seems to be a battle of opinions here.

Ahem.
I'd like to think that my bullshit (cough!)...er, opinions are better informed by research.

I'm willing to put up or shut up. Money talks and bullshit walks. I'll cover shipping and the treatment.

Cheapskate version:

• Take six humbucker slugs and six A5 strat magnets and mark them uniquely.
• Wind a small coil into which you can slip the slugs and magnets easily.
• Using an ExTech LCR meter, test coil inductance for each piece.
• If possible, test magnets for field strength.
• Cryo treat them at 300Below, Nitrofreeze, or similar.
• Repeat test.

Increased inductance after cryo means higher permeability. Don't know what to expect with the magnets.

[big_teee]

Ahem.
I'd like to think that my bullshit (cough!)...er, opinions are better informed by research.Cheapskate version:

• Take six humbucker slugs and six A5 strat magnets and mark them uniquely.
• Wind a small coil into which you can slip the slugs and magnets easily.
• Using an ExTech LCR meter, test coil inductance for each piece.
• If possible, test magnets for field strength.
• Cryo treat them at 300Below, Nitrofreeze, or similar.
• Repeat test.

Increased inductance after cryo means higher permeability. Don't know what to expect with the magnets.

So what does this experiment cost, and how much time, and does the ride home effect the parts?

[Rick Turner]

I think doing entire pickups might be better as there would be something familiar to which to listen AND test "scientifically". I think we're interested in any potential change in the copper wire as well. So do the big, full pickup test, and if there are differences, then break it down into component pieces to find where those differences show up best. No need to cheap out on this. The pickups are going to cost less than a hundred bucks from Seymour. Big deal. Shipping may cost ten bucks. Big deal. The cryo treatment will probably be fifty bucks or so. Big deal. I'll cover it.

BTW, no change in copper alloys? :

Increase in MRR for EDM through cryogenic treatment

Chuck, this information isn't that hard to find unless you really don't want to find it, which seems to be the case here.

BTW, I'm not saying "cryo, gooood". I'm saying it may make a difference, and it's probably up to us to find out if it does, and if it does, is it good or bad?

In my experience, there seemed to be a difference in the banjo tone rings we did. There seemed to be a difference in the bronze wound strings (as well as plain steel) that we did. I'd love to go back and do FFT measurements now to see if that was placebo or real.

I'd also like to know if it does anything with pickups, and it seems to me that rather than digging in on a position about it one way or another, the intelligent thing to do is to test, and I'm offering to fund the test. Like I say, money talks, and... Chuck, you're welcome to put your money where your mouth is, too, rather than project highly selected, ten year old information onto this time, place, and inquiry.

[big_teee]

What kind of pickup do you need, I can make something!
T

[Rick Turner]

Here's an interesting one re. permeability of austenitic vs. martesitic stainless steel:

Carpenter Technical Articles - Magnetic Properties of Stainless Steels