Make a mandolin

After gluing on the fingerboard and nut I touched up the varnish and gave the whole instrument a good final cleanup and wax.

Then it was time to add the tailpiece and machine heads and the instrument was almost finished.

The final-ish thing was to make a bridge – I used some leftover Tasmanian Blackwood and made a bridge, tuning in the strings with stepped forward and back slots.

Finally I got some new strings and strung it up for the first time. It needs playing in but the sound is wonderful and will only get better!

You can read all the steps here
http://fourstrings.wordpress.com/?s=mandolin

This was very well worth doing!

Cheers
Jerry

The sides glued up well, and progress continues – after removing the clamps I gave the sides a quick clean-up with sandpaper to remove glue squeeze-out. Titebond liquid hide glue is great to work with, allowing some slip time to get everything lined up ok, but then once it starts to bind it holds well and dries within a few hours.

The mandolin is now starting to look like an instrument, but it is still fairly rough around the edges. The binding provides a decorative border, but also provides additional strength and protection for the joints. I have been quite worried about the gluing process, because hide glue has a use-by date, and I was half-way through before I read the bottle and found it was out of date by six months. Apparently Titebond put a 12 month use-by date on, but liquid hide glue can last 12-18 months. Perhaps I was lucky this time. But if any components fail I will be buying a new bottle forthwith. I could use the hide granules, but that would involve messy use of double boilers and rushing to use it before it cools etc. The liquid glue is very easy to use, is versatile at room temperature and works well.

Anyhow, I had bought some inlay banding strips at the 2008 Canberra Timber and Working With Wood show with a view to their potential for instrument bindings. The banding strips are about 1.5mm thick and about 6mm wide and 1.2metres long. They are easy to use, being flexible enough to do each of the bouts without steam bending, and thin enough to cut easily with a sharp knife.

You’ll have to wait to see how it looks, as they are still taped in position after gluing, but the early indications are good :-)

The next pictures won’t look much different as I still have to add the bindings for the back/bout interface!

I basically have the back bindings, fitting the fingerboard and some finishing work on the head before fitting it up ready to play – so not long now!

You can see the rest of the process on my Fourstrings blog: http://fourstrings.wordpress.com/?s=mandolin

Cheers
Jerry

Cheers
Jerry

I used a cross-bracing pattern rather than tone bars to get a good bright response with good playability. I shaved the braces to tune the top to G by tapping and shaving until the right tone was achieved. I figured this would give better bass response. But I’m open to suggestions from any luthiers out there!

I also used hide glue – it’s not vegetarian, but it is acoustically transparent – it doesn’t interfere with the sound.

Next up I’ll be making the neck

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.

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.

Cheers
Jerry

I previously used a piece of water pipe and a blow torch for forming 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.

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.

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.

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.

You can see more about this bending iron on http://fourstrings.wordpress.com

After roughing out the neck, I set to work with a plane, chisel 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.

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

Cheers
Jerry

It is time to start roughing out the neck. I selected a solid billet of Queensland maple large enough to do the neck in one piece. Then, using the round-back mandolin as a guide, marked out the block to get a sense of the 3D shape I was after.

Queensland maple is very hard timber so I began the roughing out process by making a series of cross cuts, adjusting the height of the saw to follow the contours.

Then the waste was removed with a chisel – there is nothing quite like getting the chips flying!

The next part in roughing it out, was to rip cut down each side, finishing short of the head.

And here is the result so far – a roughed-out neck ready for final contouring.

See more images on http://fourstrings.wordpress.com/2008/12/10/making-a-travel-mandolin-part-8-roughing-the-neck/

You can read more on the progress so far as follows:
Part 1 – making a start (selecting the timber)

Part 2 – preparing the top

Part 3 – cutting out the back

Part 4- starting the ribs

part 5 – sawing the ribs

part 6 – thinning the ribs

part 7 – kerfing the linings

part 8 – roughing out the neck

Cheers
Jerry

It has been a productive weekend. Having brought the ribs, or sides, to the right thickness, I rubbed on some orange shellac which really brought out the flaming in the Tasmanian blackwood.

The next task is to make the linings – these are backing pieces which help to attach the sides to the top and back, and also give a broader gluing area for the top and back. These important structural components need to be fairly robust, yet be flexible enough to be able to be bent into the shape of the mandolin. To achieve this, kerfs are sawn into the linings at regular intervals, so that the wood is cut, but not cut through.

This results in a flexible snake of blocks connected by a thin timber, which can then be steam bent into shape. They are much larger than those for a violin, as they help to provide extra rigidity to the instrument, and that is supposed to help the sustain. They also need to be large enough to provide gluing area for the sides – even after the sides have been cut away slightly to allow for the binding veneers.

I clamped a stop block to the scroll saw and was able to make the kerf cuts quickly and evenly, as shown in the photo.

You can read the rest of the story here:
Part 1 – making a start (selecting the timber)

Part 2 – preparing the top

Part 3 – cutting out the back

Part 4- starting the ribs

part 5 – sawing the ribs

part 6 – thinning the sides

making a travel mandolin – part 7 – kerfing the linings.

After sawing the ribs, there is then a fairly careful process of thinning the ribs to the right thickness of about 1.5mm. The sawing left rough faces which then needed to be smoothed out and the sides taken down to the right thickness. Initially I used double-sided tape to tape the sides down and took the worst of the sawing marks off with the plane. Then a more delicate process with the scraper, and finally, after selecting the best or face side I took to it with 380 grit then 600 grit sandpaper, and finally 1500 grit to get the surface really smooth.

You can read the rest of the story here:
Part 1 – making a start (selecting the timber)

Part 2 – preparing the top

Part 3 – cutting out the back

Part 4- starting the ribs

part 5 – sawing the ribs

Some small progress this week – I selected some figured blackwood for the ribs and began preparation of the timber using my trusty old Russian plane freshly sharpened and reset. Once the surface is good on both sides I shall saw the board in half along its length and resaw it into thin slats ready for final thinning and bending.

You can read more about this project at http://fourstrings.wordpress.com/