My question is about glue (Titebond II). Directions usually call for the glue to be applied to both surfaces. I almost never do. I never have had a failure, and figured mashing the two surfaces together would do that for me. Is there a reason, other than making sure the glue is on every part, to apply to both surfaces? Should you let it soak in for a minute before marrying the parts?
Michael Dresdner: Glue air dries from the outside in. That means that if you apply glue to one side of a board, it will start soaking in while the area exposed to the air starts to form a skin. If it forms a skin before the parts are mated, there is a chance that the skin will block absorption of the glue into the mating wood part. That is why glue companies suggest applying to both sides — it is to make sure that both parts are wetted by the glue. If you put the parts together quickly enough, that may not be an issue, and that is probably why you have done so well with your method. However, it does raise the risk. As for letting it soak in before marrying the parts, that gets a resounding NO. The sooner you get the parts together and in clamps, the better. The glue will have plenty of time to “soak in” after you clamp it up.
Simon Watts: You’ve answered your own question: If you’ve never had a glue failure you must be doing it right! No, don’t wait, just lightly rub the two surfaces against each other, and clamp.