When making something made out of wood, glue is a common choice for attaching boards together in a permanent way. Although there are removable glues, for most woodworkers a permanent bond is desired. Titebond dominates this market for all but a handful of high performance applications. The question then is which titebond formulation to use for your project, be it for a personal piece or a commercial product.
Titebond has numerous formulations, but for all but very large companies there are three choices: one, two, and three. Each has their own characteristics. Titebond 1 is for indoor use only, more specifically no exposure to moisture. It is also the weakest. Titebond 2 can be used outdoors and tolerates the moisture from weather exposure. Titebond 3 is the strongest and is waterproof.
If Titebond 3 has the highest performance, why do people choose Titebond 1 and 2? Titebond 3 is the most expensive, and by a significant margin. Large volume gluing operations go through an enormous amount of glue. Titebond is not only sold in the squeeze bottles you find at home improvement stores, but by the gallon and the 55 gallon drum. The clamp times and assembly times between these three varieties are not meaningfully different. Cost of glue is the most important consideration for most medium sized companies. Large companies that have very high throughput may find that paying more for a shorter drying time is worthwhile.
How important are the differences between the glues to a small to midsize operation? In general not very important. Clamp times are only meaningful in very high output operations. Strength wise even Titebond 1 is stronger than the wood that it is joining. Titebond 1 has 90% the strength of Titebond 3. As a result strength is most of the time a trivial concern between the glues. Let’s suppose you had some wood parts that were being placed outdoors. Should you use the weatherproof Titebond 2 or the waterproof Titebond 3? I have known professional carpenters who never used Titebond 3 for their outdoor projects and had zero issues. In general, you should be just fine using Titebond 2. However, if the glue joint is near the ground where it may be submerged in a heavy rain, I would use Titebond 3.
Which should you choose? For a one-off or small quantity the price difference is negligible. Choose whatever is convenient for your supplier that meets the water tolerance requirements for your project. We keep Titebond 2 in stock here and can get it quite easily so it tends to be what we use. Most crates and wood widgets that we make are not subject to direct water exposure. All three Titebond varieties are widely available to us and most woodworkers so if you have a specific requirement it should not be an issue.