Dry Assembly Important In Getting A Good Finish
As with most areas of finishing, proper assembly procedure is a must.
Always Clamp Before You Glue
Clamp as you would after you have applied the glue. This will give you a chance to check clearances. Don't put too much pressure on the clamps. Excess pressure creates stresses in the joint, and when these stresses are glued in, they may cause failure of the joint later. Get the fit you want without too much pressure first, then glue.
Glue works best when both surfaces are in contact over the entire area to be glued. Planed surfaces glue better than sanded ones. Make sure you have the clamps you need ready before applying any glue.
Remember to use sanded wood protective blocks between the clamps and the project. Rough gluing blocks will leave marks. Leave enough space so that no glue can come in contact with both the clamp and the project. Chemical reaction of the glue and the clamp may discolor the wood of the project.
Gluing The Project
While excessive glue should be avoided, a small amount of glue squeezed out of the joint in clamping is acceptable. Just don't try to wipe it off right away. Wait until it gets rubbery and then trim it away with a sharp chisel or a knife. However, if excess glue drips on another part of the project away from the joint, remove it immediately with a damp, clean cloth. Don't let it set. Any glue that is allowed to penetrate and set in the pores of the wood will seal the surface against any finish that is applied and show up as a blotch.
One last point. Don't thin prepared glues. Remember to follow the instructions on the glue regarding temperature, humidity and clamping time.