Monday 9 February 2015
Finished, more or less.
Well it's taken about a month but the Zither Mandolin Banjo is pretty much finished. I could continue making little changes here and there but my aim was to get it playable and I've done that. It's been an interesting process, learnt a few new things along the way. Just got to figure out how to play it now, how hard can it be..?
Ageing the bridge
I decided the shiny new metal and maple bridge looked a little incongruent with the rest of the instrument.
To make it match it was going to need ageing a little. After removing it I gave the slots a quick sand with some 2000 grit paper to reduce any burr or unevenness in them that could make the strings rattle then applied some Dijon Mustard to the metal surface and gave it 3 or 4 hours before wiping it off leaving a very mild patina.
The wood being maple is low in tannins and so difficult to age. I added some black tea and ground coffee to distilled vinegar and heated it a few times in the microwave to speed up the stewing to make a stain.
Using a bit of cotton wool I applied it to the maple, let it dry then reapplied it twice again. As expected this uniformly darkened the wood considerably. However I wanted to see the grain better. Once it was finally dry I added some Bicarbonate of Soda (Baking Soda) to water forming a strong thick solution and painted that over the wooden part of the bridge.
To control the drying and timing precisely I sat it on a windowsill and went to do some work on the allotment. When I rolled back again it was dry and I used a dry toothbrush to remove the bicarbonate of soda that was crusted onto it then sanded it with 2000 grit sandpaper.
The staining and sanding brought out the grain and, I feel, makes it look more natural than it did initially with it's light colour of the wood with it's horizontal banding making it looked like a piece of plywood. I think it also matches the age of the instrument far better too.
To make it match it was going to need ageing a little. After removing it I gave the slots a quick sand with some 2000 grit paper to reduce any burr or unevenness in them that could make the strings rattle then applied some Dijon Mustard to the metal surface and gave it 3 or 4 hours before wiping it off leaving a very mild patina.
The wood being maple is low in tannins and so difficult to age. I added some black tea and ground coffee to distilled vinegar and heated it a few times in the microwave to speed up the stewing to make a stain.
Using a bit of cotton wool I applied it to the maple, let it dry then reapplied it twice again. As expected this uniformly darkened the wood considerably. However I wanted to see the grain better. Once it was finally dry I added some Bicarbonate of Soda (Baking Soda) to water forming a strong thick solution and painted that over the wooden part of the bridge.
To control the drying and timing precisely I sat it on a windowsill and went to do some work on the allotment. When I rolled back again it was dry and I used a dry toothbrush to remove the bicarbonate of soda that was crusted onto it then sanded it with 2000 grit sandpaper.
The staining and sanding brought out the grain and, I feel, makes it look more natural than it did initially with it's light colour of the wood with it's horizontal banding making it looked like a piece of plywood. I think it also matches the age of the instrument far better too.
Sunday 8 February 2015
There's a buzz
I thought I'd finished restoring the Zither Mandolin Banjo and gave it a quick strum and twang. There was a noticeable buzzing sound. After a bit of prodding and poking I found I was able to stop the rattle by pressing down on the part of the tailpiece that overlaps the edge of the pot. It could just be the angle of the bridge but there was also a little gap between the top of the pot and the top of the tailpiece from where I'd sanded the rim flat after regluing it as the tailpiece was still using it's original screw holes.
Looking online it seems the usual remedy for rattling strings at the tailpiece is to add a little strip of leather between the rattling surfaces. Whilst that's usually it's between the strings and the metal I suspect it'll work between the metal and the pot if that's what's rattling. I think the pressure from the strings will probably squash it flat. So, I popped to Hobbycraft and got some leather chord, it took ages to find as it was in the jewellery making which unsurprisingly I'm not very familiar with. I cut two strips the length of the overlap then as it was a natural beigey colour which didn't match anything on the mandolin I coloured them black with permanent marker. After undoing the strings and loosening the pot bolts I removed the head again and undid the tailpiece nuts.
I tried putting the leather onto the pot then attaching the tailpiece but it kept falling off. In the end I inverted the tailpiece, sat the leather in it then held the instrument upside down and pressed it to the tailpiece and held it in place whilst tightening the the nuts and bolts.
Replacing the head I swapped out one of the brackets that was a little long for a spare I'd made that was a better fit -well metalwork evidently isn't my forte, set the pot bolts, popped the bridge on, restrung it and tuned it again. There was a bit of a buzz still but tweaking the angle of the bridge sorted that out. I may need to sand the foot of the bridge at some point if it keeps moving but for now it's playable.
Looking online it seems the usual remedy for rattling strings at the tailpiece is to add a little strip of leather between the rattling surfaces. Whilst that's usually it's between the strings and the metal I suspect it'll work between the metal and the pot if that's what's rattling. I think the pressure from the strings will probably squash it flat. So, I popped to Hobbycraft and got some leather chord, it took ages to find as it was in the jewellery making which unsurprisingly I'm not very familiar with. I cut two strips the length of the overlap then as it was a natural beigey colour which didn't match anything on the mandolin I coloured them black with permanent marker. After undoing the strings and loosening the pot bolts I removed the head again and undid the tailpiece nuts.
I tried putting the leather onto the pot then attaching the tailpiece but it kept falling off. In the end I inverted the tailpiece, sat the leather in it then held the instrument upside down and pressed it to the tailpiece and held it in place whilst tightening the the nuts and bolts.
Replacing the head I swapped out one of the brackets that was a little long for a spare I'd made that was a better fit -well metalwork evidently isn't my forte, set the pot bolts, popped the bridge on, restrung it and tuned it again. There was a bit of a buzz still but tweaking the angle of the bridge sorted that out. I may need to sand the foot of the bridge at some point if it keeps moving but for now it's playable.
Saturday 7 February 2015
Adding Strings and the Bridge
Whilst Traditional Banjos originally used gut strings and Zither Banjos originally used a combination of steel, gut and wire wound silk strings, from what I gather Mandolin Banjos had always used wire strings. This may be why Mandolins Banjos all seem to use geared tuning machines whilst many Banjos still used friction pegs.
Mandolins come in 4, 8 or 12 strings varieties, with the latter two have 4 or 6 paired courses. Mandolin Banjos seem to all be 8 string whilst another hybrid instrument the Banjolin is 4 stringed. Mandolins, Tenor Banjos and Violins all use the same GDAE tuning although looking at different online sources there's alternative tunings, and different octaves however the most common and the one my tuner uses is G3 D4 A4 E5. Some people tune their instruments using a tuning fork and a supernatural hearing sense. I've tried tuning a Ukulele with tuning fork previously but didn't get close to being in tune. There's also tuning pipes which is basically a whistle you tune your string to match, I'm not even going to try that.
Electronic tuners have been around for many years and as Smart Phones improved there's also various tuning apps some of which just play the note whilst the better ones include a chromatic tuner which will use your phone mic to tell you what frequency your string is vibrating at. A clip on electric tuner is only a couple of quid on eBay. I got one for £3.99 delivered from Hong Kong, it was the cheapest on eBay at the time. It's actually a Violin tuner but you tune the Mandolin the same. Most of these tuners cover a few instruments, for example this one also covers Viola and Cello.
Electronic tuners have been around for many years and as Smart Phones improved there's also various tuning apps some of which just play the note whilst the better ones include a chromatic tuner which will use your phone mic to tell you what frequency your string is vibrating at. A clip on electric tuner is only a couple of quid on eBay. I got one for £3.99 delivered from Hong Kong, it was the cheapest on eBay at the time. It's actually a Violin tuner but you tune the Mandolin the same. Most of these tuners cover a few instruments, for example this one also covers Viola and Cello.
Having previously snapped a Ukulele string by blindly trusting a clip on tuner I decided to use the chromatic tuner function of Easy Ukulele Tuner Android app on my phone to keep things on track. I found the individual frequencies on the Seventh String website.
Course 1 E5 659.25 Hz
Course 2 A4 440 Hz
Course 3 D4 293.66 Hz
Course 4 G3 196 Hz
Course 2 A4 440 Hz
Course 3 D4 293.66 Hz
Course 4 G3 196 Hz
These old instruments pre-date the pitch standardisation of A4 being 440Hz. However I asked a friend who plays a 1901 Mandolin about this and he said he tunes his to 440Hz so I'll go with that. I actually tried it using 432Hz just to see how it sounded but didn't really notice an appreciable difference.
Before adding the strings the tuning machines need lubricating. The obvious thing to do is apply a little oil but it's not the best thing for your instrument. Instead a PTFE based lubricant should lubricate and protect the moving parts without attracting dust and gunk.
As I'm new to wire strings and Mandolin Banjos I figure there's a good chance I'll accidentally snap a string or too along the way, so I opted for the cheapest Mandolin Strings eBay could offer.
So far the instrument has been lacking a bridge. Guitars, Violins, Ukuleles, Cellos etc have wooden surfaces which the bridge is attached to but Banjo type instruments have a flexible skin top so that's not an option. Instead the bridge is unattached and held in place on the vellum by the pressing of the strings. Quite a few old Banjos offered up for sale have long lost their bridges. Luckily replacement bridges are readily available. However most of these were 4, 5 or 6 string instruments or supplied as blanks where you had to cut notches for the strings yourself. Without an original bridge to use a reference I ruled out using a blank. In the end I ordered a Standard Mandolin Banjo Bridge from Andy Banjo for the princely sum of £2.50. It's maple with a metal saddle.
To get the string length between the nut and the bridge right the bridge needs to go in exactly the right place. Initially measure the distance from the bottom edge of the nut to the middle of the twelfth fret. Then position the bridge that distance again from the middle of the twelfth fret.
Once the bridge is in place you can add a few more strings. some articles suggest adding just a top and bottom string whilst positioning the bridge so it's easier to move, I just went ahead and added all 8. The strings have a loop that fits over a hook in the tailpiece. With 8 strings it looks a little crowded down there.
Using the tuner tune the bottom G string and the top E string. Then, this is the clever bit, place a finger onto the G at the twelfth fret not had enough to press it to the fretboard but just touching it to stop it vibrating. Then give the string a twang. If the bridge is in the right place the tuner will tell you it's still a G. If the pitch is too high you need to move the bridge down towards the tail a bit, if it's too low you need to move it up towards the neck a bit. Then do the same thing with the E string. You'll probably end up with the bridge at a slight angle when it's in the exact right place.
That done you can add the rest of the strings if they're not already on and tighten and tune them. I cut down a guitar string winder to turn the buttons when the strings got tight, I'd suggest not doing this when there's a cat in the room -mine really enjoyed trying to catch the string ends as I turned the pegs which wasn't particularly helpful. Once the strings were in place and tuned I tidied it up by trimming back the ends.
Before adding the strings the tuning machines need lubricating. The obvious thing to do is apply a little oil but it's not the best thing for your instrument. Instead a PTFE based lubricant should lubricate and protect the moving parts without attracting dust and gunk.
As I'm new to wire strings and Mandolin Banjos I figure there's a good chance I'll accidentally snap a string or too along the way, so I opted for the cheapest Mandolin Strings eBay could offer.
So far the instrument has been lacking a bridge. Guitars, Violins, Ukuleles, Cellos etc have wooden surfaces which the bridge is attached to but Banjo type instruments have a flexible skin top so that's not an option. Instead the bridge is unattached and held in place on the vellum by the pressing of the strings. Quite a few old Banjos offered up for sale have long lost their bridges. Luckily replacement bridges are readily available. However most of these were 4, 5 or 6 string instruments or supplied as blanks where you had to cut notches for the strings yourself. Without an original bridge to use a reference I ruled out using a blank. In the end I ordered a Standard Mandolin Banjo Bridge from Andy Banjo for the princely sum of £2.50. It's maple with a metal saddle.
To get the string length between the nut and the bridge right the bridge needs to go in exactly the right place. Initially measure the distance from the bottom edge of the nut to the middle of the twelfth fret. Then position the bridge that distance again from the middle of the twelfth fret.
Once the bridge is in place you can add a few more strings. some articles suggest adding just a top and bottom string whilst positioning the bridge so it's easier to move, I just went ahead and added all 8. The strings have a loop that fits over a hook in the tailpiece. With 8 strings it looks a little crowded down there.
Using the tuner tune the bottom G string and the top E string. Then, this is the clever bit, place a finger onto the G at the twelfth fret not had enough to press it to the fretboard but just touching it to stop it vibrating. Then give the string a twang. If the bridge is in the right place the tuner will tell you it's still a G. If the pitch is too high you need to move the bridge down towards the tail a bit, if it's too low you need to move it up towards the neck a bit. Then do the same thing with the E string. You'll probably end up with the bridge at a slight angle when it's in the exact right place.
That done you can add the rest of the strings if they're not already on and tighten and tune them. I cut down a guitar string winder to turn the buttons when the strings got tight, I'd suggest not doing this when there's a cat in the room -mine really enjoyed trying to catch the string ends as I turned the pegs which wasn't particularly helpful. Once the strings were in place and tuned I tidied it up by trimming back the ends.
Thursday 5 February 2015
Pot Bolts
Traditional Banjos have a perch pole
(an adjustable wooden dowel in the pot) or adjustment rods (adjustable
metal rods) to stop the stings pulling the pot or rim out of shape, some
of the better built full size Zither Banjos also have a perch pole but
not the smaller Zither Banjos and Mandolins.Instead there are two small bolts attached to the tension hoop one at the neck side and one at the tail side. I don't know what they're called but I'll call them Pot Bolts because of their function.
The bolts like the tension bolts have a hexagonal head the same size as the tension bolts. I found they fitted a 6mm socket,
so being imperial they're probably 1/4". Obviously I couldn't fit a
socket between the edge of the pot and the metal ring so I had to make a
trip to Halfords for a 6mm wrench.
Some zither instruments have brackets at 12 and 6 o'clock on the tension hoop which would probably preserve the shape of the pot without the user having to make adjustments. I'd guess with less scope for user error those instruments will've probably fared better with the passage of time. With the pot bolts adjusted the instrument was ready for a bridge and some strings.
Fitting the Head
Having cleaned the Tension hoop, Vellum and tone ring as best I could without wanting to damage the vellum with chemicals I fitted the new brackets. Having the metal work knowledge of someone who's spent thirty minutes with Youtube and Google my new brackets aren't perfect but should make it easier to fit the head into the stock than the original bent and mismatched ones.
Attaching them to the head was a bit of a challenge as there's nothing to stop the brackets turning with the bolt. Eventually I settled on holding the head vertically so it was almost hanging by the bracket which I held still with an adjustable wrench as I tightened it with a 6mm socket nut driver. Some of them took a little manipulation to get as straight as I wanted, mostly because the tone hoop wasn't flat having previously been overtightened and partially because the handcut threads in the brackets probably weren't spot on.
The head was a tight fit and after a bit of thought I figured the easiest way to fit it without damaging the pot or vellum was to put a piece of wood over the brackets then with press that against my chest and pull the pot towards me. Given the rounded shape of the pot and the metal stud I'm pretty sure something would've broken if I'd just tried to push the head down into the pot. Once the head was more or less in I used my thumbs to press it home. In hindsight a dot of petroleum jelly on the brackets as a lubricant might've made things easier.
After a little googling about drilling guide holes I discovered the 'self tapping' screws I'd bought were actually self drilling screws (common labelling mistake apparently) so didn't need holes drilling. However after trying to get the first one straight without the slotted head screwdriver slipping out I decided to drill some 0.8mm guide holes slightly shallower than the the screw length to help get them started.
Attaching them to the head was a bit of a challenge as there's nothing to stop the brackets turning with the bolt. Eventually I settled on holding the head vertically so it was almost hanging by the bracket which I held still with an adjustable wrench as I tightened it with a 6mm socket nut driver. Some of them took a little manipulation to get as straight as I wanted, mostly because the tone hoop wasn't flat having previously been overtightened and partially because the handcut threads in the brackets probably weren't spot on.
The head was a tight fit and after a bit of thought I figured the easiest way to fit it without damaging the pot or vellum was to put a piece of wood over the brackets then with press that against my chest and pull the pot towards me. Given the rounded shape of the pot and the metal stud I'm pretty sure something would've broken if I'd just tried to push the head down into the pot. Once the head was more or less in I used my thumbs to press it home. In hindsight a dot of petroleum jelly on the brackets as a lubricant might've made things easier.
After a little googling about drilling guide holes I discovered the 'self tapping' screws I'd bought were actually self drilling screws (common labelling mistake apparently) so didn't need holes drilling. However after trying to get the first one straight without the slotted head screwdriver slipping out I decided to drill some 0.8mm guide holes slightly shallower than the the screw length to help get them started.
Tuesday 3 February 2015
This Corrosion
Well this patina anyway. A couple of the original screws holding the head into the pot were missing, one'd been replaced with a different shape and size screw the other was just left missing, the remaining six were all damaged and rusty. I decided to replaced eight.
The originals were small imperial slotted self tapping screws, although I identified the thread I forget what they were -I certainly couldn't find any identical replacements online. Eventually I found a company called Model Fixings who seem to specialise in model helicopter bits who had a huge range of tiny screws. I ordered a pack of No2 Slot Countersunk Self Tapping 9.5mm screws in Stainless Steel.
A couple of days later a bag of 100 shiny bright wood screws came through my letterbox. They looked to be about the right size. Just one problem though: the old screws being, probably predating stainless steel, were blackened by time rather than bright silver.
To keep the instrument looking authentic I'd have to patinate the new screws -or their heads anyway, the threads will be hidden in the wood so won't matter. Stainless Steel, unsurprisingly, is difficult stuff to mark. There's probably patinating, darkening and etching solutions that'd work but I didn't have any of those. What I did have was some drain cleaner and a gas hob. I was pretty sure I could do something with those.
First up I mixed a strong lye solution in a jar. If you're making lye (Caustic Soda in Water) always add the Caustic Soda to the water and bear in mind it's going to get pretty hot. It also gives off Hydrogen gas. Dangerous stuff and to cover my back in case some avid internet reader burns their house down I suggest nobody actually does this.
Using pliers to hold a screw head into the gas flame I heated the head to red hot
Then dipped it into the lye. Actually bearing in mind this solution is chucking out Hydrogen gas which has an autoignition point of about 536 degrees Celcius and red hot metal is probably at least 500 degrees Celcius I let it cool from red before dunking it into the lye -I think the metal pliers worked as a heatsink anyway so it only took a second or two.
I then returned the screw head to the flame, dunked it back into the solution agains and repeated the process a few more times then let it cool. When I'd done the same thing to 8 screws I dropped them in a sink of water and cleaned off the baked on Caustic Soda with a scrubbing brush. I figured with enough water it'd be too diluted to burn my fingers too badly -gloves might've been a good idea but it went okay.
The picture below shows the 8 newly patinated stainless steel screws. The shiny one is a spare stainless steel screw looking how the others had originally and the three on the right are some of the old aged screws.
The originals were small imperial slotted self tapping screws, although I identified the thread I forget what they were -I certainly couldn't find any identical replacements online. Eventually I found a company called Model Fixings who seem to specialise in model helicopter bits who had a huge range of tiny screws. I ordered a pack of No2 Slot Countersunk Self Tapping 9.5mm screws in Stainless Steel.
A couple of days later a bag of 100 shiny bright wood screws came through my letterbox. They looked to be about the right size. Just one problem though: the old screws being, probably predating stainless steel, were blackened by time rather than bright silver.
To keep the instrument looking authentic I'd have to patinate the new screws -or their heads anyway, the threads will be hidden in the wood so won't matter. Stainless Steel, unsurprisingly, is difficult stuff to mark. There's probably patinating, darkening and etching solutions that'd work but I didn't have any of those. What I did have was some drain cleaner and a gas hob. I was pretty sure I could do something with those.
Using pliers to hold a screw head into the gas flame I heated the head to red hot
Then dipped it into the lye. Actually bearing in mind this solution is chucking out Hydrogen gas which has an autoignition point of about 536 degrees Celcius and red hot metal is probably at least 500 degrees Celcius I let it cool from red before dunking it into the lye -I think the metal pliers worked as a heatsink anyway so it only took a second or two.
I then returned the screw head to the flame, dunked it back into the solution agains and repeated the process a few more times then let it cool. When I'd done the same thing to 8 screws I dropped them in a sink of water and cleaned off the baked on Caustic Soda with a scrubbing brush. I figured with enough water it'd be too diluted to burn my fingers too badly -gloves might've been a good idea but it went okay.
The picture below shows the 8 newly patinated stainless steel screws. The shiny one is a spare stainless steel screw looking how the others had originally and the three on the right are some of the old aged screws.
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