Are glue sticks waterproof ?

Can I use glue sticks for exterior gluing? Are they waterproof / water resistant?

The problem with using a hot melt adhesive for exterior applications or applications involving direct water contact is that the adhesive is 100% thermoplastic with no added carriers, e.g. solvents. This means the adhesive sits on the surface of the materials being bonded rather than penetrating the surface with the help of the carrier (solvent).

If your substrates are porous (e.g. wood) or water can ingress/penetrate between the glue line and the substrate, this may cause the bond to fail, especially if there is a frost as this causes expansion.

Making a milk bottle igloo – if interior use Tecbond 261, if exterior and not required to be permanent again use Tecbond 261, but if you require a permanent waterproof bond use Everbuild EB25 sealant and adhesive

Exterior applications should be avoided with standard hot melt adhesives as a general rule, unless specified by a member of the gluegunsdirect team and following your own application tests, as over the years we have found many applications, where in theory a hot melt adhesive would not be recommended, but in practice they have worked a treat especially if you can protect the glue line from the elements !

Normally for exterior gluing you would use a product such as Everbuild EB25 sealant and adhesive which are slower to cure compared to a hot melt adhesive, but offer a waterproof bond and seal.