Questions & Answers – Sprays & Solutions

How do Wei T’o® Sprays and Solutions Stabilize Paper?


Wei T’o® Sprays and Solutions stabilize paper by neutralizing the acids that cause deterioration and preventing re-acidification in the future. These acids cause 80 to 95 percent of all paper deterioration. One treatment with Wei T’o® will protect paper at least 100 to 200 years by:

Neutralizing the existing acidity.

Impregnating an alkaline reserve to prevent future acid attack.

Protecting against oxidative attacks.

Sanitizing the paper.

Preventing the brown stains caused by fungi attack.


Where are Wei T’o® Solutions Used?

Wei T’o® Solutions were first used by conservators to protect museum artifacts in 1968. For thirty years, professional conservators have been protecting unique documents like three of the twenty-one remaining copies of the U.S. Declaration of Independence, George Washington’s letter accepting the First Presidency of the United States, many Currier and Ives hand colored prints, three Audubon four volume Elephant Editions of Birds of America, posters and watercolors by Toulouse-Lautrec, the Constitutions of the State of Oklahoma and Wyoming, watercolors by Francisco Goya, etc. Wei T’o® products have also been used to preserve collectibles such as comic books, stamps, postcards, mounted black and white photographs, and memorabilia such letters home from Confederate and Union soldiers, insurance certificates of sailing vessels, and newspaper clippings of birth and marriage announcements.

The products of Wei T’o® are used by ordinary people to preserve and protect items against aging while their unique value is becoming known and before professional preservation treatment is needed. Rare and valuable books, records, and works of art should be examined and treated by professional conservators in private or archive, library, and museum conservation laboratories.



When Should Wei T’o® Solutions Be Used?

Protection with Wei T’o® should occur as quickly as possible after the decision is made for long term preservation. Our goal is to keep the paper strong and maintain its ability to resist color changes and damage from handling. Most of the visible aging that will occur (before the paper is too weak to be handled) takes place before embrittlement and yellowing occurs.

Urgency does not mean that weak and discolored documents do not deserve treatment. Rather, it means that deacidification protects against continued deterioration and Wei T’o® wants its clients and their property to receive the greatest possible benefit.

The results of a Wei T’o® treatment are an alkaline paper with, in almost all cases, greatly improved stability and no visual changes. Treated papers have more body and a slightly stronger feel. The protection value of the Wei T’o® alkaline reserve of one percent cannot be easily measured. For example, what will the knowledge of our achievements and activities contribute to stabilizing, invigorating, and enriching the lives of our Great, Great Grandchildren.

In terms of pH, each of the papers that you believe our society will need in 2050 should be deacidified if it has a pH below 7.0. The absolutely essential or high use papers with a pH below 8.0 also deserve protection now.

Wei T’o® products damage far fewer papers or inks than any other deacidification method! An occasional bleeding or staining problem can be avoided by selecting the correct product and application technique as explained below. Please contact Wei T’o® with suggestions or tips that you would like shared with other Wei T’o® users.



How Can Wei T’o® Solutions Be Applied?

Wei T’o® Solutions are applied by brushing, dipping (immersion), or spraying. Suitable brushes, dip tanks, and spraying equipment may be ordered from Wei T’o® Association or its distributors.


How Is “Brushing” Done?

Wei T’o® Solutions (Wei T’o No. 2 (Dipping Formula) and Good News No. 125 are recommended) can be painted onto the leaves of books, documents, and works of art on paper with a brush. This useful technique involves a minimum of expenditure for equipment and will protect the paper against deterioration. The brush should have soft bristles, e.g., sheep’s hair, which are mechanically clumped or sewn to the handle. The Wei T’o® Solution container should have high sides to minimize evaporation loss and maximize the time before moisture from air causes the solution to precipitate.

A uniform brush application is difficult because the quantity of liquid flowing from the brush diminishes as the stroke proceeds. Brush stroke patterns may show up 50 to 100 years from now because weakly treated paper with lower alkaline reserve may deteriorate at a faster rate than the paper containing an adequate reserve. This possibility can be protected against by leaving instructions for the pH to be checked every fifty years. Retreatment is recommended when the pH drops to 7.0 for ordinary documents; to 8.0 for unique articles.

The brush should be held lightly and minimum pressure exerted to avoid friction from bristles abrading or transferring the printed or painted image. Treatment should, if practical, always take place from the back unprinted side, e.g., verso, of the object being treated.



How Is “Dipping” Done?

Dipping is labor efficient application technique, particularly when objects of a similar size need to be treated, e.g., archival records, and when no special attention must be given to each article. Very little training is necessary, and folded leaves or four page pamphlets can be treated. Dipping is a suitable technique for the leaves of unbound books and many works of art.

Two persons using a Wei T’o® Dipping Tank (costing $245.00) can protect several hundred documents per hour. Alternatively, a home-made Dip Tank (described below) may be used. The procedure is simple:

– Check the documents, etc. for suitability for deacidification, e.g., effects of solvents or pH change.

– Pour a small quantity of Wei T’o® Solution No. 2 Dipping Formula (New: No. 125) into the dip tank to a minimum depth of 1/2″ to 3/4″.

– Slide the document carefully, quickly, and evenly through the Solution, producing a thorough wetness in one pass.

– Tip the document back and forth until (to produce an even wetness) the Solution is evenly distributed.

– Lay the treated document on a flat support, e.g., cheese cloth stretched over a wooded frame, so drying can occur from both sides. Alternately, the document can be hung to complete drying.

– More Wei T’o® Solution must be added as it is used to maintain the 1/2″ to 3/4″ minimum working depth.

– After use, the Dip Tank may be cleaned by wiping with a paper towel wetted with anhydrous alcohol. Any white residue may be dissolved with white vinegar; but if so, the Tank must be wiped subsequently using baking soda water and again with anhydrous alcohol to insure dryness.

– Any cloudy or opalescent Solution should be discarded when formed because it is contaminated due to absorption of moisture from air. Used Solution should be discarded or kept, if clear, in a separate container – but never poured back into a partially full Wei T’o® bottle.

– Storage life can be extended, after opening Wei T’o® Solution, by quickly wiping the bottle cap and bottle top with a dry paper towel. The cap should be screwed snugly onto the bottle and the gap between the cap and bottle sealed with four to six layers of vinyl electrical tape.

– Thin gloves, preferably made with nitrile rubber, should be worn to protect skin from drying and cracking when more than a few documents are treated. Fisher Scientific is a good source.

– To make your own Dip Tank, begin by cutting a mailing tube into troughs. One 4″ diameter tube will make three dip tanks. Then line the trough with aluminum foil. Fold up the ends to close. Place the container inside a six to eight inch high cardboard box to reduce evaporation and block sides to avoid rolling and spilling. Replace the aluminum foil after each use. Make the dipping container 1″ to 2″ longer than documents treated. More details are available from “Making and Using a Deacidification Dip Tank for Wei T’o® Solutions.”


How Is “Spraying” Done?

Spraying is both the safest and the fastest manual deacidification technique. The technique ranges from use of convenience methods like aerosol spray cans to sophisticated spray booths suitable for either mass production and museum quality protection of irreplaceable treasures. The two best procedures involve spraying with aerosol cans or with airless spraying equipment. A third procedure using compressed air guns continues to be useful, but is less efficient than the first two methods.



How Is “Aerosol Spraying” Done?

Wei T’o® aerosol spray cans are the best choice as an occasionally used, effective, and convenient sprayer. The additional costs of aerosol can components and manufacture and handling are balanced by the convenience and savings in set-up and take-down time. Conservators, though Wei T’o® spray have an extraordinary chemical tool, uniquely designed for preserving paper, available for use. The Wei T’o® pamphlet, “Hints for Better Spraying”, available on request, expands the following directions for spraying:


– Inspect the document and prepare it for treatment, e.g., test it for sensitive inks, remove dust, and place it upright on a spray board.

– Tilt spray can actuator holding the spray can approximately six inches from the document, so the spray impacts at a right angle.

– Start spraying off the paper to clear the nozzle before wetting object.

– Wet the document thoroughly and evenly spraying from side to side in an overlapping pattern.

– Lay the document flat to complete drying if a suction spray rack is not used.

– If the document cockles, complete drying between sheets of dry blotting paper under moderate pressure.

– After spraying is completed, remove the spray actuator and shake it to keep the valve stem dry to prevent the gradual build-up of a blocking residue. If the actuator blocks, soak it in white vinegar to clear.


How Is “Airless Spraying” Done?

Airless spraying retains the convenience of aerosol spraying while substantially reducing the application time, labor, and raw material costs. A capital investment is required for an especially designed spray booth and associated equipment. This equipment is justified for large projects and especially valuable items.


The total equipment for the Wei T’o® “Soft Spray” System is relatively inexpensive (approximately $4,115, ready for use including Gun with variable tips, Suction Spray Booth, and Solutions), “Soft Spray” can be envisioned as a giant aerosol spray can. The preparation for use consists of connecting components and opening valves. End of day clean up consists of flushing the cylinder valve, material hose, and spray gun with a special carbonated rinse solution (provided with System).



How Is “Compressed Air Spraying” Done?

Spray application using clean, dry compressed air was the application method originally developed by Wei T’o®. Many thousands of unique documents, books, maps, and works of art have been protected through spraying by compressed air. Aerosol cans and airless spraying, through convenience and improved efficiency, have largely replaced compressed air spraying. The technique for use of compressed air systems is as follows:

Apply the Wei T’o® Solution with a low air pressure, perhaps 20 to 25 pounds per square inch. Wei T’o® found a Binks-Bellows Spray Gun No. 630 with top cup the best choice. Apply the wettest spray from the backside of the document. The solution will penetrate the paper and dry in a short time; within seconds if a suction pressure is used to aid drying and penetration.

The advantages of spraying include: treated papers show no observable signs of having been deacidified; no bleeding or feathering even under microscopic examination; and the chance of damage occurring during treatment is minimized.


Which Wei T’o® Spray or Solution Should be Used?

The three formulations: Wei T’o® Numbers 2, 3, and 4 (New 115 and 125) are available in bottles and cylinders for application by brushing, dipping, and airless or compressed air spraying. Wei T’o® Spray Numbers 10, 11, and 12 (New 111 and 121) are available in easy-to-use aerosol cans for instant spraying convenience.

Answering the following two questions will guide the user to a proper selection:

1) What method of application is desired?

Choose Solutions 2, 3, or 4 (New 115 or 125) for brushing, dipping, and compressed air or airless spraying. Request Wei T’o® to supply the more stable Wei T’o® No. 2 (dipping formula) (New 125) when brushing or dipping.

Choose Spray Nos. 10, 11, and 12 (New 111 or 121) for aerosol spraying.

2) What effect will the solution have on papers and inks?

Choose Nos. 2 or 10 (New 115 or 111)for virtually no ability to dissolve soluble components in papers and ink. For example, very few ball-point inks are affected.

Choose Nos. 3 or 11 (New 125 or 121) for improved penetrating power and minimum vapor hazard, with the trade off of dissolving a few more inks.

Choose Nos. 4 or 12 (New 125 or 121) for penetration of thick papers and boards. This formula must be used only on very stable inks. Note: All new Wei T’o® products have lower vapor hazards and affect very few inks.


How Safe Are Wei T’o® Sprays and Solutions?

All traditional Wei T’o® sprays and solutions are nonpoisonous, nonflammable, and nonexplosive. New products are nonpoisonous and flammable; their flammability is similar to that of hairsprays, adhesives, and fixatives. They should be used in well ventilated areas with the concentration of solvent vapors in work room air kept within OSHA limits. The solvent vapors of all Wei T’o® Solutions and Sprays are less hazardous than the vapors from rubbing alcohol. Material Safety Data Sheets are available on request from Wei T’o® Associates or may be downloaded from this web page.


What Equipment Does Wei T’o® Provide For Use With Its Products?

Wei T’o® manufactures table top spray booths and dip tanks for use with its aerosol spray cans and solutions. These items make efficient treatment techniques available to one person, as well as to larger conservation laboratories.

Custom designed equipment ranging from large spray booths to mass deacidification units for deacidifying many books per cycle can be provided on a turnkey or other mutually acceptable basis. Such equipment has been supplied and is proven in operation. Planning for continuous belt, archival document, spray booth has been prepared.

Several magnesium bicarbonate aqueous deacidification solution makers producing up to five gallons of first-rate solution every twenty minutes are in operation.


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