December 2008


Armed with a bending iron and not afraid to use it, I set about shaping the linings to fit the top and back. I had prepared the timber (pine slats) by cutting kerfs and then cutting the linings in half along their length to make twice the length for half the effort.

I soaked them for about an hour in a large tub of rainwater, and then measured them up ready for bending.

I turned on the heat gun and waited a couple of minutes to ensure the pipe got really warm on the 600C setting, and set to work.

using a luthier's bending iron
I did the linings in sections so that complex curves were kept to a minimum, and left room for the end and neck blocks.

The linings were then clamped in place held by clothes pegs and allowed to dry so they wouldn’t spring back which would make gluing more difficult.

And here is the result.

mandolin linings

mandolin linings

Cheers
Jerry

A while ago, I used a piece of water pipe and a blow torch for bending the sides of my travel violin with some success, but I felt I needed something more reliable for the mandolin. I had read of the possibility of using a heat gun – the sort used to strip paint – to provide a steady heat source, but saw no plans for doing so.

It was time to think it through and find my own solution. And here it is.

luthier's bending iron

Please note that the air needs a place to escape so that the end of the heat gun doesn’t melt. But the solution is a durable one.

luthier's bending iron

The pipe structure comprises an internal plug with a square top – which is held in the vise. Attached is an T-junction connector, with one opening towards the heat gun, the other vertical. To the vertical end is attached a short piece of water pipe using a connector. And that’s it. The heat enters the wider aperture of the T-junction, finds the lower aperture plugged, and diverts up the vertical tube. The vertical tube is narrower than the T-junction, so the tube gets to be heated, while waste air is released out the top – away from the person doing the bending.

luthier's bending iron

On the hot setting (600C) the vertical tube is plenty hot enough to boil water on contact, but because the waste heat can escape, there is no heat buildup to melt the heat gun, and there is no hot blast of air against the body of the operator.

The proof is in this piece of binding which was used to test the bending iron.

luthier's bending iron

Cheers
Jerry

Steve Maus’ blog has a good piece on producing vibrato on the violin. I’m a great fan of the arm vibrato, as that way the vibrato comes from the elbow, which gives great mechanical advantage and excellent control – far more than the wrist vibrato favoured in some circles.

Vibrato is the art of making a note waver slightly up and down around the main note, much the way the voice does while singing. It makes the note more interesting to the ear, ad is a great decoration to use on slow tunes or where you have a long note that is not otherwise decorated.

The easy way to practice it is to get a ruler of about 45cm and practice vibrato while stuck at traffic lights or during ad breaks on TV, or during a slow moment at the office.

Just bring your hand up to the playing position, and place your fingers as though they were on a fingerboard. Now make a slight movement from the elbow as though bringing the hand toward you and away from you so that the fingers rock slightly on the ends of your fingers, and keep the wrist fairly straight. This will give you great control because you have the whole arm to provide leverage, making it easy to control the speed and intensity of the vibrato.

Happy Christmas – and happy holidays

Cheers
Jerry

After roughing out the neck, I set to work with a plane and scraper to smooth out the head part of the neck. This is quite time consuming, so progress this week has been fairly slow – but it is definite progress.

To give some idea of the current status, this is the neck so far with the fretboard placed (not yet attached) in position

mandoneckrough1.jpg

And to provide some context, this photo shows the relationship of the components

mandonecklook.jpg

Cheers
Jerry

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