As I mentioned on Friday, today’s post is about adhesives. One can (see Keith Smith‘s books for example) create books without any glue or paste at all, but many structures require sticking things together. There are many pastes, glues, and tapes to choose from. Which ones do I use for what? Let’s start with cooked wheat starch paste.
I buy wheat starch from a local Asian grocery. It is about one third the cost of the cheapest wheat starch available from binding/conservation supplies. (It is also available on Amazon, but at an even higher price.) While there may be further refining in the Japanese wheat starch sold to binders, the regular wheat starch is exactly the same product: food grade wheat starch. Make sure you get the whitest brand available. (Apparently some varieties are whiter than others. All the brands available locally are very white!) If you don’t have access to a Chinese grocery, try other ethnic specialty grocers: a number of European pastry recipes call for wheat starch. If you have to buy it on-line, ethnic food suppliers are again a place to start looking. Or if you are singularly ambitious, you can make your own from wheat flour.
The starch has to be cooked with water to form a paste. My recipe (based on the one in Japanese Bookbinding) is as follows:
1 part wheat starch
4 parts water
Whisk together and cook, stirring constantly, over medium low heat until desired thickness. (I usually cook mine to the consistency of mayonnaise/stirred yoghurt. It thickens further on cooling.)
To stop the cooking process and speed cooling, I put the pot in a sink of cold water (the water should be slightly deeper than the depth of paste in the pot) and continue stirring for several minutes until the paste is room temperature.
I usually add PVA at this point (1 part) as this mixture is the adhesive I use for most purposes. The fungicide in the PVA prolongs the life of the paste, and the mixture provides a stronger bond when dried than wheat starch alone. It is still reversible (yes, I have tested this) with a bit of moisture and patience.
The container on the right has been allowed to air dry for several hours. The surface is about the consistency of a glue stick and can be used on papers that stretch too easily with the moister mix on the left. (To prevent it from drying further, I keep a small amount of water in the bottom when it is stored with the lid on in the fridge.) Both the containers shown have been refrigerated for several months. The one on the left had separated slightly, so I stirred it before taking the picture.
The bag on the right is wheat starch, double bagged to keep out moisture. It stores indefinitely in powdered form, having no nutritional value whatever, so nothing eats it — not rodent or insect or mould! I sometimes use the wheat starch/PVA mix for paste papers. When working with students or just trying things out quickly, I use the wallpaper paste for the same purpose.
Occasionally I use a straight glue. (A tip when using straight PVA: moisten your brush first. Just dip it in water, then squeeze out as much as possible with your fingers. The moisture in the brush prevents the PVA from drying in the bristles while you are working, making clean up after gluing much easier.) The school glue is used when working on what I consider to be “temporary” books (non-archival) or when working with students. The straight PVA is used for joints that will be under a lot of stress. The box for this album would be an example.
The UHU glue stick is used when the driest possible application is required, though I try to avoid using it for works that I hope will last a long time.
I also try to avoid using tape when making books, but there are times when it is the only thing that will work. The blue dispenser contains acid-free/photo safe permanent glue tape. It is the gummy part without a support. Below that is a roll of Elmer’s double-sided acid-free/photo safe tape. The green roll is painter’s tape. I use this for interior packing to stick things like bubble pack or foam sheets together. It is easily removable and doesn’t put books at risk in the unpacking process. I also use it to create guides for masking when applying starch paste or glue stick to a precise area.
The upper image shows a sheet of paper set against painter’s tape guides. The bottom image shows a disposable strip of paper used as a mask so that paste/glue can be applied to the exposed area between the mask and the edge of the page and nowhere else.
The sticky tape and packing tape (pressure sensitive tapes) are used exclusively for packaging things, and only for outer wrappings.
Neither should ever be used in the assembly or repair of a book! They are non-reversible and over time will destroy the paper to which it is attached.