NGC Slabs are Hermetically Sealed

[bsshog40]

I seen this as a question in the "Ask NGC" forum. NGC told how the slabs were sealed, just thought I would add what it actually means.

A hermetic seal is an airtight seal. For example, tin cans are hermetically sealed. The term is often used to describe electronic parts that are designed and intended to secure against the entry of microorganisms and to maintain the safety and quality of their contents. Applications include thermostats, optical devices, and switches. The food, chemical, and medical industries all have applications for the use of such "airtight" packaging, such as induction sealing, as well. High-end coffins, too, are often made to be "hermetically sealed" and must be of metal or of other material with metal lining, and constructed so that when closed and fastened the coffin is completely airtight. In some nuclear reactor designs, the reactor is housed in a hermetically sealed reactor vessel.

[MunkyMan95]

Thanks for the clartification. I didn't know 100% what hermetically sealed was. So, I need not worry about air getting in! YAY!

[RGT]

And I thought it just meant some guy named Herman was opperating the sealing machine.

[bsshog40]

And I thought it just meant some guy named Herman was opperating the sealing machine.

 

He's actually a hermit!

[ibyandsellsmith]

Sounds like a Viral infection to me.

[rons]

Johnny Carson always used a hermetically sealed mayonaise jar when he did his fortune telling bit as Carnac the Magnificent . It was and still is a hoot

see for yourself http://www.johnnycarson.com/carson/carnac_main.jsp#

[MarkFeld]

Thanks for the clartification. I didn't know 100% what hermetically sealed was. So, I need not worry about air getting in! YAY!

I am NOT under the impression that NGC's holders or those of other grading companies are air-tight. And, I AM under the belief that gasses can seep through holders and interact with the coins. If anyone has solid information/proof to the contrary, please let me know.

[thebeav]

I've got a customer that had a flood where his coins were. That water walked right in to those NGC slabs.....Hardly hermetic......

 

Paul

[Dcoin]

I'v heard the real hardcore coin doctors can tone coins right inside the holders. If that's true, then there would have to be a way into the case, even if its just a gas.

[bsshog40]

Thanks for the clartification. I didn't know 100% what hermetically sealed was. So, I need not worry about air getting in! YAY!

I am NOT under the impression that NGC's holders or those of other grading companies are air-tight. And, I AM under the belief that gasses can seep through holders and interact with the coins. If anyone has solid information/proof to the contrary, please let me know.

 

Just going by the slab question that NGC gave halfpint for his slab question.

[MAULEMALL]

Thanks for the clartification. I didn't know 100% what hermetically sealed was. So, I need not worry about air getting in! YAY!

I am NOT under the impression that NGC's holders or those of other grading companies are air-tight. And, I AM under the belief that gasses can seep through holders and interact with the coins. If anyone has solid information/proof to the contrary, please let me know.

 

Just going by the slab question that NGC gave halfpint for his slab question.

Pam Kesten said

The NGC holder was developed and laboratory tested for two years and is comprised of state of the art material. The holder is hermetically sealed to greatly assist in the long term preservation of your coins.

 

Our innovative holder design is also currently the most reliable means of safe storage for your coins. Using inert plastics and sulfur-free paper, it has been tested and proven to provide an effective barrier from corrosive gases and moisture.

[MarkFeld]

Thanks for the clartification. I didn't know 100% what hermetically sealed was. So, I need not worry about air getting in! YAY!

I am NOT under the impression that NGC's holders or those of other grading companies are air-tight. And, I AM under the belief that gasses can seep through holders and interact with the coins. If anyone has solid information/proof to the contrary, please let me know.

 

Just going by the slab question that NGC gave halfpint for his slab question.

Pam Kesten said

The NGC holder was developed and laboratory tested for two years and is comprised of state of the art material. The holder is hermetically sealed to greatly assist in the long term preservation of your coins.

 

Our innovative holder design is also currently the most reliable means of safe storage for your coins. Using inert plastics and sulfur-free paper, it has been tested and proven to provide an effective barrier from corrosive gases and moisture.

quote]The NGC holder was developed and laboratory tested for two years and is comprised of state of the art material. The holder is hermetically sealed to greatly assist in the long term preservation of your coins.

 

Our innovative holder design is also currently the most reliable means of safe storage for your coins. Using inert plastics and sulfur-free paper, it has been tested and proven to provide an effective barrier from corrosive gases and moisture. I'm trying to post this to the other thread:

 

"Hi Pam, I believe that the term "hermetically sealed" is generally equated with airtight. However, I have never heard that NGC (or other grading company's holders) holders are airtight. I have always been under the impression that they are not. And that is based, in part, upon tests that have supposedly been conducted and reported in the numismatic press. Can you check this with someone else at NGC and get back to us? Many thanks."

 

Edited to add: I actually found this on the NGC web site:

 

 

"After encapsulation, can the appearance of a coin change over time?

 

 

Yes. In independent testing, the NGC security holder has been proven as the most effective grading service holder on the market today in minimizing the effects of oxidation. Even so, the NGC holder is not 100% airtight and therefore oxidation, a normal process where air reacts with the surface of a coin, can continue after encapsulation. To further limit environmental hazards, we recommend storing your coins in a temperature-controlled, low humidity area such as a bank safety deposit box. Be sure to check with your bank for rules & regulations concerning the storage of these items." See here: FAQS ABOUT NGC GRADING SERVICES

 

 

 

[bsshog40]

Well I guess we'll see what we come up with. Thanks mark

[Oldtrader3]

It is my understanding that "hermetic" refers to later generations of NGC holders with a modified weld bead slab design and ultrasonic seal process. I do not think that NGC holders were not hermetically sealed until a couple years ago. Earlier generations do not seem to be hermetic.

[Keleum]

To Mark's point, one of the reasons glass jars are still used for food and medicines is because plastic is air permeable. So while the seal might be airtight, the material of the holder is air permeable.

 

From a college chemistry point of view, plastic seems awfully bad choice to conserve anything in. Your fighting organic chemistry. But for it's opacity and cost to manufacture, I guess.

 

If they'd even put the coin itself in a glass capsule, fill the capsule with Xenon/Argon, seal it and then put the capsule in a slab, then at least copper would have a fighting chance.

[Doogy]

I use NGC for my grading, and after they are slabbed they go directly into on of my Intercept Shield "track" boxes for storage. The track boxes accept both PCGS and NGC coins, and they are a great hi-tech way to keep your coins from going bad on you. (not to mention an inexpensive way, at just 12 bucks per box)

[Oldtrader3]

PET or PETG (which may be the slab polymers) are used for food and beverage packaging, including carbonated beverages. These plastics transfer gasses extremely slowly, even under the high pressures of carbonated beverages which can be over 100 PSI. The company that I worked for used them for barrier packaging for medical devices and IV solutions because the plastic did not transfer gasses.

[MarkFeld]

PET or PETG (which may be the slab polymers) are used for food and beverage packaging, including carbonated beverages. These plastics transfer gasses extremely slowly, even under the high pressures of carbonated beverages which can be over 100 PSI. The company that I worked for used them for barrier packaging for medical devices and IV solutions because the plastic did not transfer gasses.

Regardless of what materials are used in the slabs (and I don't claim to know what they are), I highly recommend Intercept Shield as a low cost, yet very important precaution.

[bsshog40]

Well it seems that NGC changed thier terminology for the way the slabs are sealed. They are sealed Sonically.

[MarkFeld]

Well it seems that NGC changed thier terminology for the way the slabs are sealed. They are sealed Sonically.

That's how I had always heard it before I saw the word "hermetically" used.

[bsshog40]

I have searched the web and I can't find one definition for this type of procedure.

[MAULEMALL]

I have searched the web and I can't find one definition for this type of procedure.

Click here

[bsshog40]

So I would presume this would be the method for sonic sealing slabs.

 

Ultra sonic: Ultrasonic welding uses an acoustic tool to transfer vibration energy through the plastic parts and into the weld area. The friction of the vibrating molecules generates heat, which melts and welds the plastic. When the plastic reaches a molten state, vibration stops. Apply pressure while the molten plastic solidifies. Use this system is to weld smaller manufactured parts together.

 

I wonder if this generates enough heat to cause immature toning to coins after a period of time? I know this was a topic that Mark had posted in regards to slab toning.

[Oldtrader3]

The heat of the ultrasonic horn is contacting and generating molecular excitation only in the area of the sealing bead and female seal groove of the other slab half. The heat is locally generated and does not raise the temperature of the rest of the slab or of the coin. The frequency rate (39KHz I believe) of the horn is engineered to excite a small area of plastic molecules only and does not have any effect on the coin alloy. Typically the seal excitation area under the horn is 1/16th of an inch wide or less and is located only under the periphery of the slab.

 

Sometimes I wish people would read more and speculate less about the effects of simple technologies.

[bsshog40]

 

Sometimes I wish people would read more and speculate less about the effects of simple technologies.

 

Well actually this post was to just refer to the type of sealing treament to slabs that were done by NGC. The first response was hermetically sealed which they re-stated as a mistake, that they were sonically sealed. I did try to find info about this but didn't find much. The effects of the coins in slabs were directed at Mark felds post for coins changing in slabs. Sometimes I wish people would read the entire post before making comments on thier speculations.

[LostDutchman-migration]

maybe we can run a test??? immerse a common coin in an NGC holder in water or something?? I have 1 or 2 I would be willing to use.

[MunkyMan95]

Go for it! Make sure to take pictures, and show us the results

[bsshog40]

I seen this as a question in the "Ask NGC" forum. NGC told how the slabs were sealed, just thought I would add what it actually means.

A hermetic seal is an airtight seal. For example, tin cans are hermetically sealed. The term is often used to describe electronic parts that are designed and intended to secure against the entry of microorganisms and to maintain the safety and quality of their contents. Applications include thermostats, optical devices, and switches. The food, chemical, and medical industries all have applications for the use of such "airtight" packaging, such as induction sealing, as well. High-end coffins, too, are often made to be "hermetically sealed" and must be of metal or of other material with metal lining, and constructed so that when closed and fastened the coffin is completely airtight. In some nuclear reactor designs, the reactor is housed in a hermetically sealed reactor vessel.

[Revenant]

The thing to remember is that nothing is ever really 100% perfectly airtight (or it is very unlikely to remain so). You can restrict the flow of air into and out of the container to almost nothing but it is almost impossible to stop it completely. Look at the US constitution. Millions of dollars are spent to preserve it, the latest technology! It's still breaking down; it's just happening at a slower rate because their state-of-the-art inert airtight containers aren't really keeping all the air out.

[MunkyMan95]

Well, air is everywhere. Actually, what I should say is, that there are gases everywhere. It would be near impossible to take (or keep) the air out of one place for any extended amount of time.