Replies

1. 
   Rich14 | Oct 16, 2006 12:12am | #1

   Paul,

   Learning how to control glue squeeze-out is one of the hardest skills to learn, and an indication that you are becoming a craftsman when you finally start to "get it."

   The first step is to learn how to apply just enough glue. It takes a while to learn this and it takes practice, using trial joints that have no purpose other than gaining good glue technique. Very few people actually ever practice gluing and expect that they are going to learn "on the job" with "live" projects. That results in a lot of finishing problems.

   Ideally, just a few beads of glue should squeeze out from any joint. Not enough to run, but enough to be sure you haven't "starved" the joint. I use an applicator - a thin piece of wood, about 1/2" to 1" wide, as needed, with small notches (1/32") across the end to wipe and "meter" the glue onto the joint surfaces. It's amazing how effective this is. Squeezing the stuff out of a bottle is a sure way to wind up with a mess.

   Cleaning up the squeeze out depends on the glue you're using. Let PVA glues harden for about 1-2 hours, until they are firm, but still a little soft and pare the bead away with a sharp knife or chisel. Don't wipe the wet glue with a wet or dry cloth - you'll drive it into the wood. If you wait until it's hard, it's too difficult to remove and will have stained the surface.

   Polyurethane glue can be wiped off the wood surfaces with acetone, to leave a perfectly clean surface with no glue penetration or staining at all. But it can't be wiped after it has begun to harden - about 1 hr.

   Hot hide glue, when cool and firm, but not hard, can be scored at the joint and pulled away to leave the wood perfectly clean. But if not scored, pulling the soft glue bead can result in the entire mass of glue being pulled out of the joint.

   Ways to protect the adjacent wood surfaces vary from person to person. Yes, masking tape is used, as well as going so far as to partially or completely pre-finish the pieces, masking off the joint surfaces to prevent finish from getting there, then carefully wiping wet glue squeeze out from the surface of the finish, which should wipe clean without problem.

   Rich

   
   

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   Edited 10/15/2006 5:15 pm ET by Rich14

2. 
   hammer1 | Oct 16, 2006 02:24am | #2

   I agree that it is primarily how much glue you put on the parts and how you put it on. A good glue brush is a must have. I use those inexpensive 1/2" natural bristle brushes and cut the bristles down to about 3/4" long. It has just the right stiffness to spread and pick up excess. I find sizing end grain with a light coat first, then applying a touch more helps with end grain absorption and starving the joint. I know I have it right when just a few small beads form, about the size of a small pin head. I usually leave them until they skin over well and cut them off either with a chisel or cabinet scraper.

   That's not to say that I don't often make a mess. You don't want to be too light with the application or you won't have enough glue. When I've used masking tape, I glue that down too and make more of a mess. You can clean up small squeeze out with a damp rag but you have to be careful not to be too wet or have too much to clean up. You'll just end up spreading a thin layer of glue where you don't want it. I find with cutting, that timing on the hardness of the glue is essential. Don't wait until it's hard and make sure no metal from your clamps touches the glue. It will often stain the wood.

   I think glue application should receive the same care and attention to detail as any other part of the project. The glue is often the most important part and just smearing it around increases your labor time cleaning up and risks the integrety of the joint.

   Beat it to fit / Paint it to match