If you’re looking for the best glue for paper models, you’ve come to the right place. To build a paper model that lasts, use a pH-neutral PVA bookbinder’s glue. My wife, who has a master’s degree in art education, specifically recommended Books by Hand PVA Adhesive. Although it looks and smells and feels like regular white glue, I find it does a better job of not warping the paper and not bubbling. And for longevity’s sake, you want something that doesn’t change the pH balance of your paper. Books by Hand glue is pH neutral.
I started building model structures with Books by Hand glue in 2004. Those miniature buildings still look like I built them yesterday.
Apply a very thin layer of the glue with a cotton swab or a cheap paintbrush along the portion to be glued. Then align and press the two parts together. The glue grabs pretty quickly, but you have a little bit of work time if you need it. Wipe away any excess. Then clamp the joint or put weight on it to hold it together for a few minutes. Wooden clothespins work well as clamps. Let it set up, and then you can move on to the next joint.
Paper absorbs the PVA glue readily, so if you clamp it tightly, you’ll get a very strong bond. The prolific model railroader Wayne Wesolowski, who was a chemistry professor by trade, said in his books that the key to getting a strong bond with glue is to use a small amount of glue and lots of pressure. He understands the chemistry behind it much better than I ever will, but in my own experience, his advice works. To keep excess glue from seeping out and sticking to your clothespins, clamp the model in between two scraps of wax paper. If the glue sticks to the wax, it will peel off easily.
For extra strength, be sure to brace the models. See my post on keeping paper models from warping for help with that.