How to restore your prized treasure

Thanks are due to Debbie Logan in the US who I believe produced the original text.

Artefact Restoration

  • Recognising artefacts can be difficult.
  • Be sure to respect any laws & etiquette concerning artefact removal from wrecks.

I Initial protection

Store all artefacts in fresh water after surfacing. If fresh water is not available, salt water will do. If no buckets are available, wrap items in plastic, towels, etc. so they don't dry out. As soon as possible soak in fresh water. Hint: toilet tanks are ideal for small artefacts, as the constant flush of new water removes salt.

II BRASS/BRONZE/LEAD/TIN

Tends to collect coral, barnacles, and a green patina.

1. Barnacle/Coral Encrustation

A. Remove with slow muriatic acid bath. Handle with care. 20% 50% acid solution. Always add acid to water/ not water to acid. Prevent fumes from escaping by covering container, preferably with a glass cover. Make sure container is non corrodible.

B. Be sure that the artefact is completely covered in the bath. Otherwise a green line is created where the object protruded from the bath that is impossible to remove. Normal soaking time is 1 to 2 days.

2. "Bronze Disease"

Untreated brass/Bronze leaches out a green powder caused by sea salt reacting with chlorine from the acid. The acid results from natural corrosion as well as soaking. This can occur months after the object has been polished and finished. Once it has got to this stage it is difficult to cure. Prevention is the best protection:

A. Soak all bronze/Brass objects, whether acid dipped or not, in fresh water for at least one month. Exceptionally old or porous pieces need longer soaking times.

B. Change the water in which the objects are soaking at least once a week.

C. Dump a box of baking soda in the water with each change to further neutralise the remaining acid, natural or otherwise. The soda helps create an alkali base that prevents bronze disease.

D. Cure is a maybe, with a long soak in ethyl alcohol.

3. Finishing Bronze and Brass

A. Sand blasting with extra fine glass bead is OK for intermediate treatment.

B. Polish with fine steel wool, brillo pads, fine wire buffing wheel and lots of elbow grease.

C. For a high shine, finish with buffing compound and wheel.

D. For the "at sea" look; use a short soak in vinegar. (Not recommended on the best pieces)

E. Some like the look of a coat of acrylic spray.

III GOLD/SILVER/COPPER/PEWTER

1. Gold Gold doesn't collect growths. However it can be stained by contact with other metals. This stain can be removed by a light acid bath. Gold is very durable and impervious to corrosion. However it is a very soft metal that is sensitive to abrasion.

2. Silver Silver is subject to electrolysis which causes a mild electric current that turns atoms to ions that float away and leave pits in the surface of the metal. This causes permanent damage to the artefact.

A. Remove any marine growths with a mild acid bath, or better, a prolonged soaking in vinegar.

B. After removal from the bath, soak in fresh water for 2 weeks. Addition of baking soda neutralises any acid.

3. Copper Very soft and delicate metal, highly dissolvable in the sea. An acid bath is too corrosive, but vinegar is "safe".

A. After CAREFUL soaking in vinegar copper items may be lightly buffed with a polishing cloth. Be careful when polishing copper, as the metal is extremely soft.

4. Pewter Normally a stable metal, however, contact with iron causes electrolysis that results in pitting of the surface.

A. Soak in fresh water for at least one month. After soaking, chip off soft flakes of encrustation with a wooden object.

B. Polish with pewter polish and a soft cloth.

C. Can be sprayed with acrylic lacquer.

IV EARTHENWARE / CHINA / GLASS / PORCELAIN

All are impervious to marine encrustation damage. Save for etching that occurs from the "glue" that holds the marine organism to its surface.

1. Encrustations should be removed while wet and soft. Soaking in a water softener, such as calgon aids in their removal. Sometimes a nice effect can be obtained by preserving the growth on items such as old bottles. In this case, a coat of acrylic spray aids in the preservation of the "decorations."

2. Orange coloured stains created by rust can be removed with vinegar or a mild abrasive

3. All items can be dipped in an acid bath without harm, except for those decorated with gold leaf. Gold leaf is loosened in salt water.

4. To clean items decorated with gold leaf, a cotton swab dipped in vinegar can be carefully used around the leaf but don't touch the leaf! Its too delicate.

5. Porcelain needs at least a month's worth of fresh water soaking. If it is allowed to dry prior to treatment in fresh water salt will crystallise and harden into lumps, this cracks the glaze and is called "checking."

V IRON AND STEEL

Rusts more readily when taken out of the water due to the exposure to Oxygen in the air.

1. To prevent disintegration, soak in 5% Sodium Hydroxide. Fairly new items should be soaked for about two months, real antiques take about a year of soaking. A sturdy plastic container with a tight lid is best.

2. Iron and steel items can be galvanised in the following manner:.

A. Buy chunks of zinc perhaps at a scrap yard

B. Hold them over the lye bath containing your artefacts, and melt them with a blowtorch. As they hit the surface of the bath they will splatter.

C. When the bath has cooled, wearing rubber gloves to protect your skin, pack the zinc around the object so that it is completely covered. Leave for a couple of months, making sure that the object stays submerged.

D. Remove and let dry.

E. If desired, paint acrylic or rust proofing spray paint.

3. Large things, such as anchors, can be sand blasted and painted to preserve.

VI WOOD / LEATHER / PAPER

1. Wood

A. Will shrink considerably to less than normal size if allowed to dry. Keep wet and soak in fresh water for 1 to 6 months.

B. Can stand a muriatic acid bath if no metal is attached. This acid will destroy iron and steel.

C. For wood preservation the cell structure of the wood must be strengthened by being imbued with a chemical strengthener such as Acetone, Ethylene Glycol or Polyethylene Glycol (4,000MW). Soak at least 6 months. Ancient wood takes a lot longer. After soaking, rinse in fresh water. .

D. After treatment, the wood can be left natural or sanded and coated with linseed oil or varnished.

2. Leather and paper -

are treated using the above methods. Keep flattened between two pieces of glass to prevent curling. Soaking for about 1 2 months is sufficient.

VII BONE / IVORY

Are only partially organic (60% calcium compounds) extended submersion dissolves collagen and fats leaving them porous and brittle. Upon drying items are prone to shrinking, warping and cracking. Marine encrustations are also composed of calcium so any chemical that breaks them up will also dissolve the artefact.

1. Careful, observed soaking in vinegar or calgon MAY work to dissolve encrustations. Use caution though, so you don't destroy the artefact. Rinse thoroughly between soakings.

2. To prevent disintegration, soak in ethanol for one month with weekly bath changes. Upon removal, as soon as the surface dries, soak in a 10% solution of polyvinyl acetate. A polyurethane coating will help to prevent flaking and keep the object together.

VIII JEWELLERY

Can be taken to a jeweller for cleaning. Sometimes a small ultrasonic cleaner does the trick.

IX Glass

I found out that Muriatic works wonders. This product can be found a pool supply stores since it is used for restoring the water pH level.

 

For all artefact preservation, take the time to do it right the key is patience, patience , patience!

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This page was last updated on : 06 Sep 2011