Stinch's Shipwreck Artifact Preservation Guide

When using acids, never pour water into acid, always acid into water. Wear aprons, full face protection for splatters, and gloves. Acetone is described in some of the preservation processes. It is extremely flammable and must be handled with care.  Never heat conservation wax directly over an open flame as it is flammable.  I melt the wax in a pot which placed in heated water. Acryloid B-72 is a synthetic thermal plastic resin that does not embrittle or discolor over time. This adhesive is readily removable with solvents.

The formula for the Tannic Acid solution can be found here.  I've also provided some information and suppliers of materials for conservation methods which are referenced below. 

The key ingredient for successful artifact preservation is PATIENCE. Take the time to do it right. Keep artifacts wet until ready for preservation process. Get all the chemicals required ahead of time. Never store chemicals in old food containers. Children may confuse the containers for food. If possible, practice on a smaller, less significant artifact of similar material and underwater exposure. I frequently practice with junk (wood, brass, copper, etc) that I find in salt water. That way when that irreplacable artifact is found, you will have some experience in selecting the best preservation method.

Please check local and federal laws before touching or removing artifacts from shipwrecks. Many are protected by law.

Artifact preservation is not an exact science. The methods outlined here are for your guidance, therefore I can not be held responsible if these methods don't work out for you. There is always a risk of further damage to your artifact.

Bone and Ivory

 

Calcium is dissolved from these artifacts when they are submerged for long periods of time, leaving them porous and brittle. Extreme care must be used when cleaning these types of artifacts.

Remove concretions from the surface with the use of soft toothbrushes, tooth picks and metal picks.

Rinse the item in fresh water.

Soak in 2% Ammonium Citrate solution. If this not available use vinegar. Watch the item carefully during this process as damage or destruction may occur.

Repeat this rinse/soak cycle until the item is free of rust stains.

Soak the object in 100% ethyl alcohol or acetone for a month, with weekly bath changes.

Mix a 20% solution of polyvinyl acetate with acetone. Soak for a week. When dry, this coating will help hold the bone together.

Dissolve concretions by submerging the artifact in a 10% Muriatic Acid solution. The muriatic acid can be purchased at major hardware centers or pool supply shops.

Make sure acid solution is used in open air away from interior spaces, items such as cars, and isolated from children and animals. The fumes are both toxic and corrosive. Usually a cover can be used prevent the fumes from escaping the container.

The artifact must be completely submerged in the muriatic acid solution to prevent a permanent line from forming at the point where the object protrudes from the acid solution. This line is almost impossible to remove.

Do not allow the artifact to soak for longer than necessary. Soaking time may be only one hour or as long as one to two days with frequent fresh water rinses. Check the object frequently for progress.

Soak the artifact in a fresh water and baking soda solution to neutralize any remaining acid. This should be done for one to six months with weekly solution changes to remove any clorides from the original salt water exposure and the muriatic acid bath.

If the artifact is not soaked in fresh water long enough, a green power known as 'Bronze Disease' will leach out. This may occur months or years after the item has been cleaned. It can be difficult to stop at this point. Prevention is the best solution.

(Compiling Data)

These techniques should be used for glass which has been in sea water for more than a hundred years, although they are effective for any rust stained glass.

Some consideration could be given to leaving barnacles on the glass to give it an authentic nautical look. If you choose this, then skip the Ammonium Citrate wash.

Carefully remove most concretions with a metal pick.

Soak in 5% Ammonium Citrate solution for 24 hours to remove remaining concretions and rust stains. If Ammonium Citrate is not available use vinegar.

Wash the artifact in cold distilled water. Repeat Ammonium Citrate wash if rust stains are still visible.

Allow the glass to air dry.

Submerge in alcohol for seven days to remove all water.

Soak for 24 hours in a 10% Acryloid B-72 solution in acetone.

Using a soft toothbrush, brush off excess Acryloid B-72 with acetone.

Boil lead in distilled water to extract the salt.

Let the lead cool down.

Brush any debris off with a soft toothbrush.

Rinse in a 0.1% solution of sulfuric acid.

Rinse again in distilled water.

Let it air dry.

Dip in heated conservation wax.

Store out of the sun in an acid free environment.

Carefully remove concretions using metal and/or wood picks and toothbrushes.

Alternate baths of 2%-5% solution of Ammonium Citrate and distilled water, until concretions are soft.

Using picks and toothbrushes again, carefully remove any concretions.

Allow leather to soak for 24 hours in room temperature distilled water.

Stuff nylon or wooden blocks into areas which require support, if necessary. Shoes are a good example of a leather artifact that requires support.

Submerge the item in a 30% solution of Polyethylene glygol (PEG) for two weeks.

Rinse excess PEG with warm water.

Use a freeze dryer (not your freezer) if available or allow artifact to air dry away from any sun and heat sources. While still damp, wipe a leather softener and conditioner on the artifact.

The leather should be conditioned frequently after the initial treatment has been completed.

Paper should be soaked in distilled water for a couple of days to dissolve any salt. The use of a nylon screen under the paper will help reduce damage from tearing during treatment.

Some people suggest using PEG for the treatment of paper, but I've had bad luck with it. Careful consideration must be given to any writing or printing on the paper before using PEG. I recovered a section of a navigational chart from the U.853, after soaking in fresh water, used PEG. The next morning I was horrified to find the once bright red grid lines were now pink.

If you are not using PEG, soak the paper in a 2-3% solution of clorox to kill any bacteria. Soak for an hour.

Remove the paper from the screen and place between wax paper. Keep flattened between glass and wax paper to prevent curling during drying. Change out the wax paper each day until dry. Usually one or two days is enough.

If you plan on displaying the paper, mount paper behind ultraviolet resistant plexi-glass to prevent the yellowing of the paper. Storage in an dry dark acid free environment will also help preserve the paper.

For small pieces, plastic enclosed stamp mounts such as Showgard can be used. These are acid free and available from any stamp and coin dealer.

Method 1 - Electrolyic Reduction

Carefully remove any concretions with soft toothbrushes, wooden picks and metal dental picks. Pewter is a soft metal and will scratch if the surface of the artifact is reached using metal picks.

Submerge the artifact in a 2% solution of Sodium Carbonate (baking soda) at approximately 3 amps for two to three days.

Remove from solution and manually clean with toothbrushes and wooden picks.

Soak in distilled water for two to three days.

Air dry item for 24 hours.

Dip the artifact in melted conservation wax for 15 seconds.

Using metal tongs, remove the item and shake off any excess wax.

Pewter plates can be rolled on acid-free paper while the wax is hot to produce a smooth surface.

Method 2

(Compiling Data)

Method 1 - Electrolyic Reduction

For silver items which are bad corroded, electrolysis may be required.

Place the item in a 2%-3% solution of Sodium Carbonate (baking soda).

Maintain a charge of 2 amps for two to three days as required. Check the item frequently.

Soak the item in boiling distilled water. If the item is small like a pendant, then three or four cycles of heating and cooling with fresh water changes in between may be required. Larger items may require up to eight or ten cycles.

Rinse in a 1% solution of Formic Acid.

Rinse the item again in distilled water.

Method 2

(Compiling Data)

Method 1 - Electrolyic Reduction
The Canadian Conservation Institute page describing the electrolyic treatment of a cannon can be found here.

Submerge the artifact in a 2% solution of Sodium Carbonate (baking soda) at approximately 3 amps for two to three days.

Manually clean the item during this electrolysis process using small brushes, metal and wooden picks. A Dremel tool could be used if done carefully.

When the artifact is clean of all concretions, submerge in boiling distilled water for about an hour. Allow to cool. Replace water with fresh distilled water and repeat the wash cycle at least three times. Larger objects like portholes may require ten to fifteen cycles of a hot water wash.

If possible, test for the presence of salt in the final wash solution (2-4 ppm) to determine if washing is complete. An Orion ion analyzer is expensive, but effective. I was fortunate for a time to use an analyzer developed for the Navy in the desalination of sea water. I found that three to ten wash cycles were usually enough.

Allow the object to dry thoroughly.

Dip or brush the object completely with a Tannic Acid solution and let it air dry. Repeat with four coats. Wear waterproof gloves when handling the Tannic Acid solution, it will stain your skin black.

If possible, attach wire to the artifact and dip in melted conservation wax for 30 seconds. This will prevent mosture from attacking the metal. The wax also provides a self-seal coating in the event it is scratched.

Using metal tongs or wire, lift the item from the wax and shake off any excess wax.

Method 2

(Compiling Data)

Wood must be kept wet after removal from the environment. If it is allowed to dry it will shrink and split. Let wood soak for one to twelve months in fresh water, depending of the size of the artifact.

Hard woods can handle a mild solution (5%) of Muriatic Acid. Make sure no steel or iron is attached, as muriatic acid will destroy these items.

If muriatic acid is used, soak again in fresh water. It will help remove the acid smell.

In order to preserve water logged wood, steps must be taken to replace the water in the wood cells with an compound. Polyethylene glygol (PEG) is the best choice. It forces the water out of the wood cells and forms a molecular structure throughout the wood artifact. When drying after this treatment, the most shrinkage is about 10%. PEG is available in liquid and powder form with different weights, 4000 MW is the best choice, but 3500 MW is readily available. I paid $30.00 for a gallon of PEG 4000, your price may vary. If you are using power, make sure distilled water is used for mixing. This will ensure no impurities get into the mixture.

Soak the wood in a covered container. I soaked wood handles from a seven spoke ships wheel in PEG 4000 for about a year. After air drying, they fit back on the spoke ends like a glove. The handles are about six inches long, one inch thick with a half-inch hole down the center. Very large objects may take two to twenty years, as in the case of the sixteenth-century warship Mary Rose.

When the object has soaked for about half of the expected time, remove the cover to allow some water to evaporate. This will increase the concentration of PEG over time, thus increasing the structural strength of the finished object. Don't let the PEG dry out too much. Of course, keep the open container away from pets, children, and dirt.

When the treatment has completed, rinse the object in warm water to remove excess PEG reside.

The wooden object can be sanded and coated with linseed oil or left in its natural state.