This is a surprisingly complex subject. Maybe it shouldn’t be surprising because this material has evolved over millennia as adhesive technology has advanced. So, there is always something new for the bookbinder to learn about while you still have to remember what was used in the past, and sometimes even replicate that. There is no single perfect adhesive that does everything. And the adhesives’ properties have to match how the binder is going to use it. As a binder becomes more experienced and develops their own style, the properties the binder expects of the adhesives will change.
But it’s all good news if you are just starting out. There are only 2 adhesives you should need for some time and they are both readily available and not expensive. They are PVA (polyvinyl acetate) and starch paste.
PVA and paste are very different creatures. PVA is a surface adhesive with high tack. Once it is placed down it keys to the surface quickly and strongly. It will not slip once in place, shouldn’t be removed and tends to transfer less moisture to the materials being joined. The other great property of PVA is that it remains flexible and is thus great for the spine of books. Paste on the other hand is penetrating and remains open for some time. The penetration comes from the moisture and the open time which allows the paste to migrate into the materials. A piece of book cloth not quiet in the right place can be slipped into place or even removed and placed again. But you have to be careful with pasted paper as the moisture can make it soft and likely to tear if you try and make it slip.
In the QBG Introduction course we tell people paste is for paper and PVA for cloth and card. But it also possible to mix PVA and paste to get the best of both worlds. When you need it, in a small saucer mix the needed amount of PVA and paste in a 50/50 ratio and you have an adhesive that has good adhesion but can also be removed to reposition or slip if the material being moved is strong enough.
So where do I get these glues?
The Rolls Royce of PVA is Jade 403 which you will need to go to a specialist bookbinding or paper arts store for or order online – for a price! To start out go to your local art or office supply store and find a PVA that is acid free and designed for paper. The one thing not to do is use woodworking PVA. This is designed to have strong bite into wood and is thus often acidic and dries rigid, not flexible.
Paste you can make yourself. If you look on the web you will find as many ways to make starch paste as there are days in the year. When you compare them, they all come down to roughly the same thing. Paste is made from starch and water and an optional preservative to make it keep longer. The starch and water are mixed in a ratio of 1 to 4 by volume and then cooked, not boiled, for at least 10 minutes. I used to make my starch in my jam making double boiler and now use my wife’s Thermomix so I don’t have to stand next to the stove stirring for 15 minutes. I have a post about using the Thermomix and have done a video about using the microwave to make paste. Here I’ll quickly describe using a double boiler.
In the double boiler combine 3 Australian (20ml) level tablespoons of starch (total of 60ml by volume) with 240ml (4 times 60ml) of water, whisk and then let sit for at least 10 minutes to let the starch grains start absorbing water. An optional step is to add 3 drops of oil of cloves which acts as a preservative. Put on the stove and bring to below boiling and hold there for at least 10 minutes while continually stirring. Take off the heat and stir another 5 minutes. Put in a jar sterilized with boiling water.
In America a tablespoon is 15ml, so it is an easy matter of using 4 tablespoons to get 60ml.
Once the paste has cooled it will become thick. Before using it should be pushed through a sieve a number of times. I use a silicone kitchen spatula to scoop out what I will need for that day and force through a fine kitchen sieve. I scrape it off the back of the sieve and push through again. I repeat this 4 times. I bought some cheap kitchen gear from the super market and keep these in my work area just for this purpose. It only takes me a few minutes to do and produces wonderfully smooth paste which is a joy to use. As you advance you will learn to add water to adjust the moisture content for different jobs.
But what starch do you use? At the QBG we recommend a locally available very pure laundry starch called Silver Star Starch which is available at IGA Supermarkets. Traditionally plain wheat flour has been used and is acceptable in most cases and in some cases preferred. Rice flour used in Asian cooking also works well but has the same issue as flour in that it contains proteins which are likely to yellow with age. Look for a rice flour with the lowest protein content. Again, if you want the Rolls Royce, go online and find the Japanese wheat starch Zen Shofu.
The best videos on the web on paste making are of course mine.P
There are a lot of videos on this subject out there. My favourite two are
Making the Perfect Wheat Starch Paste University of Cincinnati Libraries
To start you don’t need many brushes. For gluing out large areas get a few 1 inch (25mm) natural bristle trim brushes from the hardware store. For fine work I use a square tipped Princeton Snap! Number 4 which is just a natural bristled square tipped artist brush 13mm wide. I keep one brush for pure paste work and another for PVA and one for spare. Always clean up well at the end of the day and brushes should last years.
When gluing out book cloth or board you want to work the adhesive into the grain of the material. This is best done by gently stabbing the brush into the surface and then brushing away. Hold the brush near vertical and work from the centre out. When you lift the brush you will find it tends to lift the material you are working on too which can result in glue getting underneath and on the clean side. To avoid this, brush off to outside the material before lifting the brush. Of course, you will have a waste sheet underneath, so you don’t get glue all over your bench. When working on paper be gentler and the stabbing is not required unless it is a textured paper.
Okay, I’ve wasted 10 minutes reading this and I don’t have PVA and I’m not about to spend an hour in the kitchen cooking paste. But I want to quickly make a book with my kids, and they have craft supplies. I’m with you there too. Many of the simple artists’ book don’t use adhesives, and if they do it’s for simple things like putting on a label or sticking down a flap. I have a glue stick in my travelling tool kit and a couple on my benches. They are great for the small things I just mentioned when you’re just having fun and don’t want to use a brush. The common Clag Paste used to have a terrible reputation. I’ve tested it recently and it was pH neutral. If you’re just trying bookbinding out, go ahead and use it.