The Importance of HempingProper pipe maintenance is essential for a good stable tone, air-tightness and ease of tuning. Hemping is a huge part of this and when done properly, hemped joints will give years of worry free piping.
When hemping a joint it is important to apply waxed hemp as tightly and evenly as possible. This will make the finished joint pack down well and be parallel so that it will need no extra hemp added or subtracted in the future. Waxed hemp will resist moisture. Making the joint completely parallel will ensure that no air can leak around it. This means that the joint going into the stock will be airtight and the tenon joint will not let any air 'bleed' which would cause tonal instability.
Always ensure that the tenon that goes into the stock is tighter than the tuning pin tenon. This will ensure that you can easily tune your drones with one hand and perhaps more importantly, keep your Pipe Major happy!
When receiving a new set of pipes it is a good idea to strip off the hemp provided and re-hemp the pipe properly. Manufacturers cannot spend the time necessary to do this job properly and will often hemp the pipe roughly with un-waxed hemp in order to assemble the pipe. Un-waxed hemp will absorb moisture quickly and swell up which could lead to problems.
The video below demonstrates the best way to hemp joints. It takes some time but is well worth the effort.