Gluing parts together correctly isn't as simple as pouring a bunch of
glue all over the surface and putting on a clamp.
It's important to make sure the entire surface is uniformly covered, and that you've got glue every place you're supposed to have glue. And, hopefully, you don't have too much glue running down surfaces where you're not supposed to have glue. That means having an arsenal of tools you can use for applying glue correctly.
No Brush-Off, It's Brush On
With its multiple bristle head, a toothbrush works great for applying glue on edge-to-edge assemblies. Squeeze a bead of glue on, then use the brush to spread it. When you're done, the plastic bristles will be easy to clean (but it won't quite be clean enough to use for brushing your teeth again).
Credit For A Good Job
On wide surfaces, like when face gluing parts for a turning blank, you can spend a lot of time brushing glue around, and still not have a nice uniform coat. Instead, use a credit card to spread the glue.
Using a pair of pinking shears, cut one edge of the credit card (preferably an expired one), leaving behind a toothed surface, like a mastic knife.
Squeeze on a bead of glue, then pull the toothed edge through the glue. If you have dry spots, apply a little more glue and card it again. If you squeezed on too much glue, excess will gather under the card and be pulled off the end, leaving a perfect glue film.
Neat Solution For Dowel Holes
Try to get glue straight from a glue bottle into a dowel hole, and you're sure to have a mess on your hands. And, if you get too much glue in there, it can be nearly impossible to get the dowel inserted. However, the device that works great for getting schmutz out of your ears works great for getting glue into these tiny spots.
Pour the glue into a cup, dip a swab into the glue, and swab the glue inside the dowel hole. This is a nearly perfect way to insure the right film of glue inside these tiny holes.
Stick To What Works
Like dowel holes, mortises are another tricky spot to get glue into. Since the holes are larger than dowel holes, you can use a bigger applicator. Popsicle sticks work great. Dip the popsicle stick into a cup of glue, and use the tip to spread it around the mortise. You'll have no trouble getting a perfect glue film.