No Glue - Air Bubbles and Voids

Small air bubbles in the joint may not affect the overall strength of the joint but can cause leaks or in some cases be an aesthetic issue. 

These bubbles may originate from the adhesive packaging but can also be due to shrinkage of the adhesive as it cures. Most of the acrylic-based adhesives will shrink on cure slightly whilst epoxies tend to show lower shrinkage. Applying smaller volumes of adhesive will minimise the shrinkage voids and so in some applications it may be necessary to apply the adhesive in two lots . 

The dispensing system may also be the cause of bubbles any liquid will absorb air in solution when it is pressurised and this air is released in the form of bubbles when the liquid adhesive returns to atmospheric pressure. The best example of this is a bottle of lemonade. The lemonade appears perfectly clear until such time when the top is unscrewed and the pressure is released and immediately bubbles will appear 

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