In conservation treatment, we always need to use materials that will be strong, long lasting, and is reversible should better treatment options become available in the future. For the Houston letter, the materials of primary concern are the mending paper that will be used to repair the letter, and the adhesive that will be used to attach the mending paper. Both of these must be prepared before we can begin to mend the letter.

We almost always use wheat starch paste for mending because it is strong, but can be reversed with water. To prepare the paste, we mix wheat starch powder with with deionized water and cook it. During the cooking process, we stir the paste constantly. As we heat and stir, the paste thickens, and becomes translucent. Once the paste reaches this stage, we remove it from the pan and allow it to cool.

While the paste is cooling, we can prepare the mending paper. Traditionally, we use handmade Japanese papers for mending, because they are lightweight, but have long, strong fibers that will adhere well to the letter. In a treatment of a document that is not as important as a letter from Sam Houston to Anna Raguet, the Japanese paper could be left as is, and just applied to the letter. However, the Japanese paper and the letter are dramatically different colors, and the mends will be ugly and obtrusive. Because this letter is important, and we are doing a complete treatment, we are going to tint the paper using acrylic paints so that it matches the color of the newly washed letter. This will make our mends practically invisible.

After the paper is chosen, we mix an approximate color from acrylic paints thinned with deionized water. Then we dip a small sample of the mending paper into the paint mixture and dry it with a hair dryer. Once we are sure the sample is completely dry, we can check the color match. Then we can adjust the color, and repeat the process until we have achieved a perfect match. Color matching requires a sharp eye and can be one of the most time-consuming parts of the conservation treatment.

Once we find the exact color that will disappear against the letter when it is mended, we dip large sheets of Japanese paper into the bath of color and allow them to dry. We always dye more tissue than we anticipate needing, in case we make any errors. Then we let the tissue air dry, preferably overnight, before starting the mending process.

While removing the silk and tape from the letter and adding an alkaline buffer has already helped prolong its life and improved its appearance, we still need to take one more step. Left unchecked, tears and holes tend to get larger even with careful use. If handled roughly, these tears and holes leave the document vulnerable to being ripped completely apart. To make sure that the letter can be handled safely, we will mend the tears and holes.

First, we must assemble all of the tools and materials needed. These include paste, deionized water, mending tissue, a straight edge and etching needle for cutting strips of the mending tissue, a brush for pasting out the tissue, tweezers, small squares of blotter and polyester web, and weights for drying. To avoid spilling water or paste on the letter as we work, we will keep all liquids in this pan which will contain any spills.

Only the smallest amount of paste is necessary for a mend to be applied to the letter. Used full strength, the paste would be far too strong for the document, and even encourage new breaks where it makes the mends stronger than the original letter. Because of this, we thin it with deionized water. First we work all the lumps out of the paste with a brush, and then add water gradually until it is a thin liquid.

Each mend must be custom sized to each specific tear in the letter. To start, we use an etching needle to score thin strips of the toned mending tissue. Scoring the strips, and then tearing them off using tweezers gives us strips that are straight and neat, but have soft fibers at the edge that will ease the visual transition from the mend to the document.

Once a few strips are torn, it’s time to mend. First we choose a tear to mend. Often it is easiest to work from the center of a document out, because you have more control over any distortion in the paper. We tear a strip of mending tissue to the right length, and put it on a square of blotter. Then we brush paste over the strip and wait a few seconds as the blotter absorbs as much of the moisture as possible. Water causes paper to expand and distort. Therefore, our goal is to introduce as little moisture into the letter as possible.

We position the strip onto the letter using tweezers, press it into place, blotting gently to removes more moisture. Then we allow the mend to dry under blotter and weights. When we remove the weights, we find that our thin mend with toned tissue is almost invisible to the naked eye. As one mend dries, another can be started, and the process continues until we have mended. It is a long and meticulous process, but well worth the added safety that the mends bring the document. It is important to remember that even this deceptively simple looking process must only be performed by a trained conservator. Otherwise damage to the document may result.

The holes made when Anna Raguet opened the letter present us with a dilemma. Mending them might add stability, but would destroy artifactual evidence. After consultation with the archivist for this collection we decided to leave the three large holes caused by opening the letter unfilled, as their artifactual value was more important than the increased durability that would be gained by repairing them. Therefore, we will only repair a few small holes.

We’ll repair the holes with a process called filling. Fills are a two step procedure. First, we make a patch of mending tissue for the back of the document. Placing the letter on a light table allows the hole to be clearly delineated on the light table. we can see the shape of the hole clearly through the letter and mending tissue. Then we cover the letter with a protective layer of polyester film. This film will keep the letter from being damaged as we use our etching needle to score an outline just slightly larger than the hole. The outlined tissue is then removed with tweezers, and any long fibers are trimmed. Then, we paste the patch out, just like we pasted out the small mending strips, and apply it to the back of the letter. Now we let the patch dry under weight.

Once the patch on the back of the document is dry, we cut a piece of slightly heavier mending tissue that will exactly fill the hole in the letter. As with the patch, we paste the fill out on blotter. Then we position it on the document so that the entire hole is filled. Drying under weight completes the procedure.

Mending this letter will take several hours but in this case is a wise allocation of resources. When done, we will have substantially lowered the risk of damage to the letter from further tearing. The treatment is now done, except for ensuring that the letter is housed in an appropriate protective enclosure for safe storage.