For any of you who might have problems getting hold of thick paper for your watercolors, or any other media that involves placing water on paper, here’s a little trick to thicken up the paper you have on hand so it will perform better for you. Just take several sheets of paper and glue them together.
The image above shows a jar of Best-Test Paper Cement from Union Rubber, and a pad of drawing paper from Daler-Rowney that I picked up recently at a half price sale. The cement has a neutral pH and bonds paper very well. It’s not extremely strong, but is at least as strong as the cellulose holding the paper itself together. I brush on a coat to both sides of the paper sheets and press them together after the glue dries which takes only a minute. This drawing paper is 110lb. (130gsm) weight, and it takes about 10-12 sheets to equal the thickness of 3-ply illustration board, or 3-4 layers for a good watercolor surface. The assembled “board” can be used right away once you’ve got all your pieces glued together.
The main thing to pay attention to is the “grain” of the paper sheets. Yes, paper has a grain (of sorts.) The slurry of fiber pulp used to make paper (whether from wood or rag) flows in a particular direction as it settles and dries. You can see this by holding the sheet up to a light source and looking through it. It’s subtle, so it won’t be obvious linear streaks, but more like wave ripples. Different sheets can have different grain orientations, although those within one pad are usually all the same. When you glue the sheets together, rotate the grain so they are in perpendicular layers (90°.) This adds strength to the whole construction, like making plywood, and helps prevent curling when wet. Of course, it also means that the largest size of the paper you are making won’t be larger than the smallest size of the paper you are using, unless you fill it in with extra strips. That can work okay, but the seams can show when using thin paper. You can also mix your papers so that the lower layers are wood pulp and the top is rag, or glue a plate surface on top of cold-pressed paper, etc.
This cement is waterproof which improves the overall performance of the paper. The fumes of it require ventilation and it’s flammable, so use with caution, and keep the cap on when you are not gluing. Other glues will work too, but I like this one since it dries quickly, doesn’t shrink, and doesn’t require water or pressing.