Connections using hot melt glue

The process of gluing a spigot into a shaft using hot melt glue is detailed below. This can be used as a guide for making hot melt glue connections when assembling your paddle. The same principles can be applied if you are gluing a handle or a blade to a shaft.

Step 1. Make sure that all glued surfaces are sanded with medium (80 grit) sandpaper, that’s the outer surface of the spigot and the inner surface of the shaft in this case. Sanding to a rough surface will aid adhesion. Make sure to wipe away all dust before making the glue joint.

Step 2. Test fit the pieces without glue. Make sure they fit together easily but not so loose that there is movement in the joint, and not too too tight that it requires a lot of force to slide the pieces together. Sand the spigot if it’s too tight. It also pays to heat up the spigot and the shaft to see that they fit easily when hot, as this will be the condition when assembling with hot melt glue.

Step 3. Apply masking tape to the end of the shaft and on the spigot to mark the desired insertion depth. If the spigot and the shaft require a particular alignment, for example if the spigot must align with a blade or tee-grip, then make this alignment and mark using a pen as shown below. When you assemble the glued components, you will match these marks to achieve the correct alignment.

Step 4. Now to apply the hot melt. You will require a heat gun for this step. Apply a coating of hot melt glue to the inner surface of the shaft. To do this, heat one end of the glue stick until it begins to soften and melt. Also heat up the end of the shaft. The glue adheres better to warm surfaces. Apply the glue to the inside surface of the shaft and then spread it using a stirring stick at least 50mm into the end of the shaft. Only apply as much heat as required to melt the glue and do not overheat the shaft as this could damage the shaft. Keep the shaft rotating and do not apply heat in one location continuously to avoid overheating that location. Place the now pre-glued shaft to one side.

Step 5. Apply a coating of hot melt glue to the spigot. Do this by heating one end of the glue stick and apply dabs of glue to the surface of spigot that will be glued. When the spigot is covered in dabs of glue, use the mixing stick to spread the hot melt glue evenly over the surface of the spigot. Heating the spigot with the dabs of glue will soften the glue and make spreading easier. Again, take care not to overheat the spigot, keeping the spigot rotating and not applying heat in one spot continuously.

Step 6. With the glue on the spigot still hot and sticky, pick up the shaft and reheat the glue on its inside surface with the heat gun. In this step you will be heating both the inside surface of the shaft and the outside surface of the spigot at the same time. The goal is to heat and activate the glue on both the shaft and the spigot so they can be brought together for assembly.

Step 7. Insert the spigot into the shaft so that the masking tape on the shaft and the spigot meet. Align the pen marks (if required). Do this quickly so that the glue doesn’t have time to cool and harden. If assembly becomes difficult because the glue has cooled, heat with the heat gun to re-soften the glue. Wipe away the bulk of the overflow glue with the mixing stick. Remove the masking tape while the glue is still a bit soft, making sure not to move the alignment of the spigot while doing so. If the joint needs further tidying, use a turpentine soaked rag to dissolve any glue overrun.