Drumbuilding Manual:Second Stretch
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In this stage, the head will be stretched for the final time before tacking. The head will be under even greater pressure than during the first stretch, but it is still important to keep the tension even across the head.
Setting up the Skin
The first few steps of the second stretch are the same as the first. Set up the skinning stand the same way, place the drum body on top, and make sure everything is centered and stable.
Use paraffin wax to wax the top rim of the barrel (put it everywhere where the skin will make contact). This will help the skin to slide over the lip more easily, so that the tension stays in the head, instead of just stretching the sides of the drum.
Remove the towels that are inside the soaking head and wipe up the excess water.
Put the head back on the drum, making sure it is the appropriate side of the drum and that it is aligned properly.
If they have been removed, weave the rods (3/8" diameter stainless steel rods, 5 3/4" long) into the mimi holes.
Weave the looped rope around the drum: the rope rests on top of the rods, dropping a loop down between each one.
Align the loops of rope between each mimi with the eye bolts on the base of the skinning stand.
Hook the ratchet hoists from each eye bolt to the loops of rope at the top. Make sure the hoists are not upside-down. Put small pieces of carpet (soft side towards the drum) between the hooks and drum body to protect the drum.
Crank out the slack in the rachet hoists on all sides.
Center the skin on the barrel, if necessary, using the grease-pencil line as a guide.
Stretching the Skin
Now, start tightening the hoists, going around the barrel and ratcheting each a little at a time. As you ratchet, place your hand on the edge to feel the skin moving from the head of the drum to the side of the drum, to make sure that the skin is not just stretching from the edge on down. Watch the mimi where the skin is noticeably thinner: make sure that the mimi stay parallel to the head and don't rip. If the mimi rip, you cannot tighten any more.
Be careful when ratcheting! Heavy duty ratchets are very strong: it does not take much effort to crank them, but they really tighten up. Keep an eye on the head of the drum to know when to stop, because it won't be easy to tell from how hard it is to crank the ratchets.
When the head is pretty tight, wipe off your feet with a clean wet cloth and carefully climb onto the barrel (don't worry, it won't break!). The goal is to break down the fibers in the skin and get a better stretch, so jog in place, bounce a little, and work the heels of your feet into the edges. Work the hard spots (you will be able to feel them with your feet), and massage the skin until the tension feels even over the whole head. Take your time, then climb down.
Tighten the ratchets again. It is difficult to know when the drum is tight enough, but Mark Miyoshi recommends hitting the head with a bachi periodically as you stretch. When the sound goes "up" after you hit it instead of going down, the head is tight enough. Hit the head around the edge to determine if the sound is even. Tighten the edges with a lower pitch.
It is important to work slowly: with ratchets, it is difficult to release tension once it has been introduced, so don't crank a whole lot at once.
Jump on top of the head a second time; be sure to work the edges and the hard spots in the skin.
Hit the edges of the head again and make sure the pitch is even all around the drum. Hit the center and determine if you are done. Remember: when the pitch rises, the drum is tight enough.
Don't try to tune the drum to a specific pitch, because the pitch you hear when you hit the head is much lower than it will be when the head dries. The pitch you hear after the drum dries will be higher than when the head is finally broken in. In short, the pitch changes depending on a lot of factors: the skin, the tension, the age of the head, the humidity, etc., so focus on getting a good sounding drum, not a particular pitch.