Think this will clean up? Titus Tet

[Jay GT4]

I'd like everyone's opinion on this coin.  It's not mine but I keep coming back to it and wondering if it can be cleaned up and how good it would get.  It's an interesting Titus Tetradrachm which is heavily encrusted (or is it a Bi Tet?).  How would you proceed?  Carefully I'd imagine....

[casata137ec]

Yeah, I think it would...it would take spot lemon juice soaks (lemon juce on a toothpick applied to the red crust), and manual/mechanical reduction. It would be a longish process, but probably worth doing.  By the way, I say spot treatments due to the fact that the Alexandrian "silver" was much crappier than the silver tets from Antioch of the same era...loads of base metals that will react adversly to whole coin soaks. That would be a nice project coin that would take me two or three weeks of nightly work. I love coins like that! lol

Chris

[Jay GT4]

I was thinking the same thing Chris, this would be a long process but I think it would turn out great.  It appears to have full legible legends...

[Dino]

I think the reverse would clean up very nicely.  Looks like the edges are pretty corroded.  I think the obverse would clean up ok, but the surface looks to be pretty porous doesn't it?

[Jay GT4]

I think the reverse would clean up very nicely.  Looks like the edges are pretty corroded.  I think the obverse would clean up ok, but the surface looks to be pretty porous doesn't it?

Yeah but as Chris said these Tet's are pretty crude at the best of times.  It looks like it will be a pretty bold coin under there... legends look complete!

[casata137ec]

I say get it if it isnt too expensive! I think it will turn out great...but I have thought that before! lol


Chris

[CzarMike]

Judging by my own experiences and how the rest of the coin looks I think if you remove the red crud you will get a moonscape coin.

[Snegovik]

The red substance on the surface is Cu₂O. A billon coin placed in corrosive environment will get the copper part oxidized. Since the density of the oxide is lower than the density of metal copper, the oxide pops out and forms a layer on the surface. I had exactly the same problem with a Severus Alexander denarius that had such a thick red layer on the surface that was not recognizable at all. I cleaned it by soaking in 5% disodium EDTA. The result is below. I regret I did not take a picture before cleaning, but it was a lot worse than the tet in question.

[Dino]

Where does one get 5% disodium EDTA?

[renegade3220]

Only place I know is from a chemical company...

It is commonly used in chemistry and is used in biology labs as well. I know we use it for our DNA procedures.

I guess you can get it somewhere else...

It is used as a chelating agent. It basically traps metal ions and diminishes their activity. In DNA it chelates metal ions that will otherwise participate in the destruction of DNA.

[Dino]

How hazardous is it to handle it?

[renegade3220]

Here is anlink to a msds (material safety and data sheet) for it.

Stuff is pretty safe. Of course we wear safety equipment anyways...

The msds will give you all the information you need. Sometimes they make things sound worse than they really are.

http://www.jtbaker.com/msds/englishhtml/e0170.htm

This is just the first msds I clicked on. Some are better than oters.

[Snegovik]

Where does one get 5% disodium EDTA?

I get mine from Sigma Aldrich, catalog # E5134. Dissolve 5 g of powder in 100 ml of distilled water. The advantage of EDTA is that it removes only the oxidized metal.

[renegade3220]

from Sigma Aldrich, catalog # E5134. Dissolve 5 g of powder in 100 ml of distilled water. The advantage of EDTA is that it removes only the oxidized metal.

Dino:

Sigma Aldrich = chemical manufacturing company

Just so you know... 

[Jay GT4]

How much does something like that cost?

[Snegovik]

Around $30 for 100 gr from Sigma. Enough to clean a couple dozens of coins. You can find it much cheaper, e.g. http://www.opentip.com/Pet-Supplies/Edta-Disodium-Salt-Lb-p-596434.html
but I am not sure of quality.

[Gallia Albanensis]

Is "calcium disodium EDTA" the same thing as "disodium edta?"

I suppose I'm asking, do they just usually abbreviate the "calcium" away, or are there different types? A local store sells the calcium version.