cleaning of artifacts

[chrisj]

Got a few delicate artifacts off a a wreck circa 1870 could be brass/copper but heavily encrusted in hard marine growth - anyone out there got any ideas on how to clean these pieces? Appreciate any info

 

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[Chagy]

Hello Chris,

welcome to our forum you may want to talk to Jason aka Scubafinder
he works in the Fishers consevation lab...I am sure he will be more than happy to give you some tips.....

Here is a spike found by Tom Gidus from ARRG aboard the "Conquistador"

Goo luck,

Chagy......

 

[ScubaFinder]

Hi Chris, I think i can help you out. First things first, DO NOT put the artifacts in any type of acid, many people may tell you that this is an acceptable cleaning method, but it is not. There is a chemical called Airagon that works well for removing oxidation, but to my knowledge you can only get it in 55 gallon drums, and it's quite expensive. The best all around method is electrolytic reduction. Basically a tank of distilled water and enough soda Ash to bring the pH up to about 12 to 16. (get the pH test kit from a pet store with aquarium supplies).

I usually use a 3-6 volt DC power supply rated at between 300 and 600 mA. Connect the positive side to your anode (stainless steel plate or bolt or whatever stainless you have) and the connect the negative to the artifact. It should bubble a little...not a lot. Generally you want it to look like smoke, as in lots of tiny bubbles. Voltage and amperage depend on the size of the item you are cleaning, coins use less that I mentioned above normally, but a large spike could take more. The process is basically to reomve the oxidation from the object, and more importanty to get the salt out. When the salt dries, it expands and will definitely damage most iron artifacts. Couperous metals like bronze fair better under the water, and sometimes can just be polished.

There is an entire forum here on cleaning artifacts, go over there and you should find some pics and diagrams of the setup. I'm at sea this week doing a magnetometer survey so I can't take any pics of mine right now.

Best of luck.

Jason

 

[ScubaDude]

One of the better online sources of info is from Texas A&M:
http://nautarch.tamu.edu/class/anth605/File0.htm

 

[rgecy]

Here is another good link.

Basic Methods of Conserving Underwater Archaeological Material Culture

https://www.denix.osd.mil/denix/Public/ES-Programs/Conservation/Underwater/archaeology.html

 

[privateer]

one of the best methods i have found for cleaning brass or copper items is phosphoric acid-same acid that is in your coke cans-just mix a little stronger-you do have to keep an eye on it tho-if you leave it in the bath too long it will turn green and you will have a hard time cleaning this off-for other methods go to mother of all maritime links and there you will find a sub category on the subject.

 

[PDJ]

Scubafinder,
Where do you find or what is a 3-6 volt DC power supply rated at between 300 and 600 mA?
PDJ

 

[Chagy]

Scubafinder,
Where do you find or what is a 3-6 volt DC power supply rated at between 300 and 600 mA?
PDJ

Radioshack

BestBuy

Circuit City

or just do a search in google and get it online

 

[Chagy]

Hello Conservator,

Thanks for sharing...

Chagy.....

 

[stevemc]

The power supplies are less than $10.00. I use sodium carbonate instead of sodium hydroxide, as it isnt so caustic, and is less dangerous to people. It works good. You are just wanting an electrolyte, not a corrosive, caustic liquid. To get sodium carbonate, buy washing soda in the clothes cleaning area, or bake baking soda - sodium bicarbonate, for a hour at 350 degrees in your oven.

 

[Salvor6]

Thanks Steve.

 

[chrisj]

Thanks for all the info - much appreciated