Gluing Techniques

Above is a 3-1/2 minute video on simple gluing techniques.

Application

Applying glue is easy. Any 2nd grader could do it. What they might not be able to do is apply it neatly, or so that the result is the strongest bond possible. Also, I don't think they'd be known for their alignment accuracy. These are techniques you need to master during the TGF Project.

Here is a short list of things to learn:

  1. applying the right amount of glue
  2. spreading glue accurately, evenly, and completely
  3. understanding working time so your glue remains wet
  4. aligning the wetted glue tab nicely
  5. rubbing and pinching the glue joint until it grips well enough to release it
  6. how to fix a gap in a glue seam

Tack, Bonding, Setting, Drying and Curing

Glues have several properties worth understanding because these will help you avoid problems. When a glue seam is under a lot of physical stresses, failure can be avoided by knowing that it has had enough time to hold under the load. There are four time-related properties with different meanings:

  1. TACK is the differing levels of grip the glue develops as it thickens. The more it grips, the tackier it is. However, if you wait too long, the glue will skin over (dry on the surface), making it lose its tack.
  2. BONDING is the process of tacking up, and is well bonded when you can release clamping pressure and leave the seam alone. If the seam is held firmly together, as the glue tacks up, it bonds more securely.
  3. SETTING is when there is no more tackiness, and the seam cannot be pulled apart without destroying it. Elmer's Glue, fully sets when it dries, which takes about 30 minutes. Setting for epoxies is when it solidifies and loses tackiness.
  4. DRYING is when the moisture has evaporated from the glue. Epoxies do not dry; they solidify. Water, alcohol, and volatile chemicals dry through evaporation. Elmer's has water in it, so it dries. Drying shrinks the glue. Epoxy does not shrink because it does not evaporate. Elmer's does shrink down quite a bit.
  5. CURING is when the chemical reaction is complete. This can take place in seconds, minutes, hours or days depending on the glue or adhesive. Typical PVA glues including Elmer's take about 24 hours to cure.