A Homemade Intercept (tm) Alternative, with results shown.

Intercept (tm) products of corrosion control originated with inventions and patents at Lucent labs ( AT&T ) for packaging made of polymer bound reactive metals to "intercept" corrosive compounds such as sulfides and bind them chemically, thus removing them from circulation within the sealed plastic bag( U.S. Pat. No. 4,944,916) issued to Franey However, this reactive metal coating was semi-opaque and rather expensive ( and to me rather ugly). Then after exposure in the coin press, a patent was granted to bind the reactive component to paper and other cellulose products. Here is a patent that explains this process and which led to the introduction of intercept (tm) coin products.

http://www.freepatentsonline.com/6593007.html

This process is not forever. There is a set amount of reactive material in the cardboard used for albums and boxes, and once it is fully reacted, it can not be reactivated, and also there is little indication as to how much reactive power is still present. Just an estimate in number of years it could protect under normal conditions. If you live in a heavy industrialized area, it would be quite less.

A sacrificial anode is basically the low tech answer to the above product. The more active metal is more easily oxidized than the protected metal and corrodes first (hence the term "sacrificial"); it generally must react nearly completely before the less active metal will corrode, thus acting as a barrier against corrosion for the protected metal.

Since the post 1982 cents have a coating of pure copper, it could qualify for this purpose, especially if it was protecting copper containing coins that by having developed a patina would be less reactive than pure copper. But to make the copper sacrificial coin more attractive, it should be abraded and cleaned severely prior to use.

So here is how I approached this project. I took a damaged 2009 Lincoln cent and used acid dip and physical scrubbing with a scrub brush. I decided not to use a metal brush as the copper layer is thin. The coin looked like this :



and this


I put it into a SD plastic ( probably polypropylene) holder that I had drilled 4 holes. More small holes would be better, maybe try that also.
and inserted the coin.





After 10 days leaving it on the table, I have the following appearance.
left lid still closed, right: lid open.




and : reverse






Here is the before and after reverse photos together



The areas of toning, representing sacrificial reaction with environmental gases shows the amount that would have been available to react with the coins you were trying to protect.

If you use albums or zip locks these can be added to the bags, or even attached to the album covers. Several can be put into 2x2 boxes, safety deposit boxes, etc. to have added protection. It is easy to check them as to the tone, and replace them or just scrub and acidify them down again. Be sure to remove all cleaning chemicals and dry well. I don't want to confuse the issue, but I did rinse them in acetone, and allowed to air dry , before inserting into the holder to remove any surface water and contaminants.

I purchased 100 of the holders from an ebay dealer in HK, and they were here a week later for total of $18, including shipping. So a few cents for chemicals, 19 cents in parts, and a little labor.

Hope this helps, and the patent above is interesting reading.

Jim

 

Log in or Sign up to hide this ad.

Interesting concept Jim. I enjoyed the read....

 

This is good stuff and great information, I enjoyed it - I will add only this:

First let me say that I hardly understand all this science at all. I come form the learned in life camp, brutal and informative but not overly technical. I'm not without brains as I have one brother who graduated from MIT and the other who went to UT. My father before he passed did say I was the wisest (of the three) though and a comment I will never forget.

The subject of this anti-toning material is interesting but lacks a couple of things.

From what I have seen some coins tone and other do not. This is true of proofs, silver, clad and all else in between except gold. Ah you say but,,, - yes but it depends. Humidity, cardboard, air, sulver etc. Well we have humidity here as high as 110% and it's really something but what I always try to go by, (and this includes ever thread or responce on CoinTalk) is "what I see". By that is what I see walk into these shops here, what I see come into the show each month, what I see that people bring me, what I buy. The answer regarding toning "is some do and many don't" - so what is the reason, answer or safeguard as it relates to toning, ie: what is real, what is hype, what is needed or warrented???

When the "Intercept" stuff came out I thought at first, neat I should get some but never did and I am glad. Why, because my coins have remained perfect after 16 years. The only problem I have ever had storing mint state and proof coins (in regards to toning) is with a Dansco album for state quarters that I started (in 1999) and only them with the proofs esp. the proofs on the outer edge and the silver ones even more. Those did tone and tone quick. Why, because of the Album material, the silver coins, and the closeness to the edge (or more air availible) to them.
I sold that junk though long ago. All and any other proof silver or mint state coins (that I have had that long or longer) are perfect in 2x2's within 20 pocket pages in three ring binders in an open desk.

My point (and I know I'm taking the long way around the barn with this) is, "I think some coins will tone and some will not"!

This is why during the summer I talked and talked about the mystery regarding the new 2009 original composition Lincoln Cents toning so rapidly. The proofs were found to be toned when they got to customers doors and the mint set ones are not holding up any better. The mint has commented about this and glossed it over to some degree. But why do we open up bank wrapped rolls from the 1950's that are still gem BU red, or memorials the same, whether they cme from Florida, Tenn. or Alaska???
The answer is again, "some coins tone and some don't".

So if "some coins tone and some do not" will any of the anti-corrosion methods work in the long haul with any really tangible results and my answer again has to be, "some will and some will not"!

You see many times I think we fail to ask most important questions.
It's not will this material prevent toning as much as it should be "is this a coin that has the natural tendency to tone or not tone"? Intercept as not really been around long enought to satisfy the toning question and I suspect that folks who bought Intercept, (or other) anti-toning materials will be reluctant to admit if thier coins toned even in the anti-toning material thay bought.
Although I cannot prove it (I wish I could) I think whether a coin will tone or not and if we can prevent it, will come down to a coins planchet production, striking process, anealing, washes and dozens of other things out of our control to begin with. If that's the case we are fooling ourselves if we think we can prevent it in the first place.

To sum it up, (and I'm sure any reading this will be glad) if I really wanted to prevent toning I would work very hard first at learning which coins tone and what coins do not.

 

So what we got there is a toning accelerater !!

 

Good points!

No, the environmental molecules that would cause toning/corrosion, are not "attracted" to the sacrificial coin ( at least not until they get within the range of molecular attraction , which is basically on the molecular surface. But the movement of the molecules in any container or out, is due to "Brownian movement", a random movement whose speed is due to the temperature above absolute zero , and most coins are about 300 degrees C above absolute, so the movement is rather rapid. Molecules hit us all of the time, but of course we don't feel them due to their very small mass. However this does lead to diffusion , where molecules will move from an area of high concentration to an area of lower concentration , due to this random movement, until all are equal. So the "bad" molecules that hit a barrier such as a slab, flip, etc, can not pass through unless it hits a "seam" or opening that is not air tight. If such a molecule hits a normal coin surface with already some patina present, the chance it will molecularly react is much less than hitting the sacrificial coin with fresh surfaces where an reaction can occur and remove that molecule from reacting with the other coins. If a sacrificial surface is not present, the molecule will continue to bounce around forever, fueled by environmental heat until it does land on a reactive unbound site on one of your "protected" coins, and toning /corrosion increases on that coin.

Your concept of moving water by gravity doesn't apply as that movement is due to the effects of gravity, and not the effects of heat. At absolute zero, the molecules don't move, no coin would ever tone or corrode ( except for possibly the minor effects of subatomic particles, and I don't know if that even happens).

I wasn't proposing that this project was better than the commercial products ( except it provides an indicator of the level of activity in the contained area). After a few days, the faster reaction with the sacrificial copper will reduce the concentration of deleterious molecules in its vicinity and more of these deleterious gases will move from other areas ( good coins) by diffusion to try and establish an even level in the container. This is the same as with the commercial product. Both work with to the 2nd law of Thermodynamics ( Enthropy).

Jim

 

Ben,

I think you have a point in that "Some coins tend to tone and others don't". Some of that is certainly metallurgy ( the metal of the coin), some may be minting process, (such as different for proof coins, etc.),and distribution ( especially more modern coins), and probably the largest factor is environmental. If all were close to identical, I would expect similar but not always the same amount of toning or corrosive processes to occur.

Part of me believes that if I find a nice obverse variety coin in a search that when I flip it over, it will have a spot or corrosion. Flip over a 1908 IHC to see if it is an "S", it will be corroded if it is

Jim

 

Regardless of the ripping you got from the old timers....

This is an excellent idea. I don't have a holder like you have, I just toss a BU cent into my ziplocks to serve as a sacrificial material. The bottomline whether anyone thinks it works or not....what is it going to hurt? This is just a good, common-sense storage practice.

 

I have always found that people have a hard time with diffusion , thermodynamics, and gradients. When I had to explain that in the lungs, oxygen went into the blood, passing by carbon dioxide leaving the blood, (they could even bump into each other), it was contrary to most physical processes with which they were familiar. Your idea is easier. I liked the plastic enclosure as it did give me an indication of levels.

 

It's always difficult to explain science. Even scientists I work with don't often understand what I'm telling them. LOL

The enclosure is a fantastic idea, that will permit nearly the full surface area to be exposed. I might be cutting down my surface area too much by just tossing it into the bag.....now you got me thinking I need to use your idea. :smile

 

Great article, very interesting read Thanks!

 

The best way to settle a scientific question is by experiment, and the easiest experiments are the ones that have already been done for you.

Remember those bags of Morgans that sat around for years, and toned in the bag? According to what I read, the ones near the outside of the bag toned, and the ones near the center stayed white.

From first principles I would have expected that reactive gases would have spread like ink in water within minutes and reacted over years, meaning that whatever was most reactive with them would suck up the most of them. But if the Morgans in the center were spared, that means there was a filtering effect as the coins toward the outside nailed down contaminants before they could diffuse deeper into the bag.

 

Yes, your idea will work, but I do not think as well as you think it will. I do not think you will find copper that much more reactive so it will do a good job of preferentially removing the contaminants - most particularly with other coppers. However, a couple suggestions might help. I believe you will find zinc a lot more reactive than copper. That can be employed either by using pre-1982 cents (minor help) or, better, post-1982 cent cores. Other metals (iron comes to mind) might even be better. Another improvement would be to increase the reactive area of the sacrificial metal. Powder being best (but most dangerous). Elongated pennies, etc. would help.

 

Very interesting. I was wondering if this process would be a better product for counterfieters? Would this be a safe process to apply to coins you really want to keep? Sorry if I missed something here.

 

Zinc is indeed more reactive in general, but does it have the same affinity for sulfur?

 

Yikes,.,,,this is very deep stuff, and Im not sure I understand it all.
All I know is, and from what I think I got out of all this...if you dont want toning...remove the opportunity of environmental exposure and use airtights.

Oh yea, and through the process of diffusion or is it osmosis(the transfer of molecules back and forth through a semi-permable membrane-as per high school biology), there is nothing out there that will protect your coins 100%.
N'est-pas?

 

Since I approached this with the idea of an alternative to Intercept(tm) technology, and since I was sure Lucent technology had done various experiments in their original patents and decided to stock with copper, I would also.

Not quite sure of the counterfeiter connection though, unless there was some confusion on the role and treatment of the sacrificial cent used.

Osmosis is a special case of diffusion as you say through a selectively permeable membrane (biological or manufactured).

The sacrificial cent I showed in the original post continues, after about another 2 weeks, to show it is still working, with the exposed surfaces getting a slightly deeper tone, and no noticeable changes in surrounding coins. I am making a batch to go into the Safety Deposit box and safe, as all they can do is to help.

The process will not remove corrosion or toning, but it can help prevent it, or if you have toned coins you wish to keep in that specific condition and no more so, it can do that also, IMO. There are many comparison type of experiments that one could do: different metals, different holders, vs. real Intercept(tm), under water, etc., but I have no interest in that as I have what I wanted, so others may wish to proceed

Thanks for reading,
Jim

 

I have a TV set whose picture tube has been airtight for 23 years. You can stop gas diffusion, just not with normal coin storage materials.

 

I would be interested to actually know your full name, since you are in trade mark violation. Your theory is interesting, but would not necessarily work. I guess if you are trying to store cheap coins, that you can potentially sacrifice it is OK, but we have found that there actually is science behind our Intercept Technology(TM) and how it is applied and used. You can learn more about what we do at www.staticintercept.com or www.intercept-technology.com - the other issue that we do not have to deal with is galvanic coupling, which with a penny, now you are talking about mass. Good luck in your endeavors.