Friday, 3 December 2010

Too hot to handle

 Its officially summer here in New Zealand and the weather is warming up. The acoustic season has begun - there's nothing better than sitting out on the deck strumming a few chords, dog by your side and a cold beer on the go.
 There is a downside to it all - in the last week I've had two guitars in the workshop with the bridges clean off. They had been left in cars. 
 You wouldn't leave your dog or your kids in the car for hours on a sunny day and your guitar will be just as unhappy.
 Guitars are put together with 'heat reversible' glue (usually an alaphatic resin). This makes it possible for me to do my job. If I need to take your guitar apart I can by carefully applying heat. If you leave in the car too long a guitar will dismantle itself.

  This guitar is a nice, Spanish made classical guitar. It spent the afternoon in its case in a car with the outside temperature about 25C. Of course it was a lot hotter in the car.

 Whan the case was opened the bridge was off.

 As you can see, the glue has failed - there's still glue on both surfaces.
 The first thing I did after taking the strings off was check the internal braces. It is very common with repairs like this for there to be more damage on the inside than the outside.
 Everything was fine inside to I imagine the bridge came off before the string tension pulled the top too out of shape.

 I remove most of the old glue with a sharp chisel.
 Incidentally, I measue the sharpness of my chisels by testing them on the hairs of my left arm.

 That's a nice bald patch with no rash - a sharp chisel.
 Now you know how to spot a luthier.

 I use the belt sander to clean up the underside of the bridge.

 This bridge has a slight warp that I take out with the sander.

 I score the underside of the bridge to help give the glue a key.

  I mask off the bridge area on the body. This helps with both alignment and glue clean up.

 I use five long reach clamps to attach he bridge. The glue is Titebond Alaphatic resin.
It is very important to use a reversible glue. If this bridge had been held on with epoxy in all likelyhood it would not have failed. If it hadn't failed the top would be warped, there would be untold damage to the braces and the result would be a much more involved repair.

  As it is the guitar is ready to play again with no visible evidence.


Sammy doesn't like being left in the car either  - he'd rather be showing off his catching skills on the beach.



Tuesday, 16 November 2010

Hofner Pickup re-wind

I had a visit from Paul Crowther the other day (always a pleasure to see him). He's rather a legend for amongst other things his 'Hotcake' overdrive pedals and the 'Prunes and Custard' (my favorite for theremin).

 He wanted to know if my coil winding machine was up and running -  he had an interesting pickup for me to wind.

 Its an old Hofner pickup which I guess is from the 50's. The guitar has 3 of them and this one has a break in the windings so needs to be re-wound.
This would normally be a straight forward job except for the design of this pickup.

 This is the inside of it. The windings (around the outside) are not wrapped around a bobbin. They are just sitting in the pickup and have been wrapped in tape to protect them. In the middle you can see the magnets sitting in a hard putty. There are incidentally only 5 magnets.
 So the problem Paul left me with was how to wrap about 5000 turns of extremely thin wire into a coil and therefore make a pickup.
 After a long brainstorming session with Sheena we came up with a plan.

 We figured that the wire had to be wound around a bobbin and then somehow the bobbin removed.

 So I made this bobbin. The sides are plastic from a Strat pickguard (white) and the centre has been carved from candle wax.

The bobbin bolts together and is attached to another plastic plate which in turn fits to the winding machine.
 The idea is to wind the pickup on this and then warm the completed coil up and melt the wax. The wax should seep into the coil thus potting it as well. Then the sides can be unbolted and voila a copy of the original coil.

 Winding the coil wasn't any different from any other pickup - so now for the tricky bit.

 I warm the coil ever so gently with a heat gun. I put my free hand next to the work to judge the temperature - if it gets too hot the plastic will melt and I'll be starting again.

 When I see some wax oozing out I ever so gently remove the top plate.

 With the wax exposed I can apply more heat and watch it flow into the coil and as it cools becomes solid.

Then I wrap tape around it to hold everything in place. I cannot emphasize enough how fiddly this is. There are a few stray wires and if any of them break I'm starting again.

It may not be much to look at but its taken hours. The slight curve is to match the shape of the pickup casing. I've tested it and I'm pleased with it at 5.5Kohms.
 In the background you can see the magnetic lugs - I had to dig them out of the putty.

 I put the whole thing back together using 'friendly plastic' instead of putty then fill the casing with wax, solder the back on and its finished.

 Its been quite a task but I'm happy with the result.



Thursday, 28 October 2010

Guitar Making

Guitar making is a very different discipline to repair.
The repairer's day could involve anything from vintage instruments to brand new. Any sort of stringed instrument with any problem could walk in the door. Its certainly interesting and keeps you thinking.
 The guitar maker chooses what they do day to day. The process is often more creative and hugely rewarding.
 In some ways repair is harder - you work with what's there and of course you cannot afford to make a mistake. If a maker makes a big mistake they can start again with another piece of wood - its not that easy for a repairer especially with vintage instruments.
 When I started off in the mid 90's I made a few guitars but ended up concentrating on repair. In the ensuing 15 years I've seen a lot of instruments, listened and looked hard and tried to determine what goes into a great guitar. There are so many interacting elements, so many variables.
 I've now decided to start making again.
 I'm making a pair of Dreadnought guitars to begin with.
 Here are a few pictures of the progress so far:

 This is a back getting thicknessed by hand.  I've chosen Australian Blackwood for its acoustic properties - somewhere between Mahogany and Rosewood. This is New Zealand grown.

The bookmatched halves of the back are jointed together.

 My side bending machine. 

Fitted back braces.

Carving and tuning the top braces using a thumb plane and chisels.

 Working on the sides in the mould.

So the process is well under way. I'm making a pair of Dreadnoughts with Carpathian spruce tops, Blackwood back and sides with Honduras Mahogany necks. I'd love them to be finished by the end of the year but that really depends on my repair workload.



Saturday, 18 September 2010

Gibson LG2 - 1955

This is a beautiful old Gibson guitar from 1955.

There's no serial number on some of the less expensive older Gibsons. Instead it has a Factory Order Number. The first letter 'W' tells us the year. This number is not unique to the instrument but to the batch that was made at the same time.

It came into the workshop because the bridge pins were sitting wonky and the guitar was hard to re-string.

 This is a picture taken of the inside of the guitar using a mirror - the ball ends of the strings have dragged their way through the wood. But the main problem is the bridge plate. It was fitted in the wrong place - someone at Gibson must have been having a daydream, made the bridge plate too small but stuck it in anyway.

This diagram shows what it should look like. Although this is of a Martin the principle is the same.

So I decided to remove the existing plate and replace it with a new one. The bridge is bolted as well as glued on. As the bolts go through the bridge plate they need to be removed first. The bolt heads are hidden under two mother-of-pearl dots. I push the bolts out from inside and pop the dots out.

 The whole guitar is constructed using heat reversible glue so to remove the plate I can soften the glue by warming it up. I only want to warm up the bridge plate - the adjacent braces are also attached with the same glue and I'm keen not to get them too hot.
To localize the heat I use an iron which I warm up using a heat gun. As you can see its made from an old Strat neck plate with a wooden handle.
 I moisten the bridge plate with a sponge and very carefully using the iron heat it up.
 Its rather tricky and very easy to damage the guitar and burn your hand.

It takes time and patience. When I feel it is hot enough I can start to prise the plate of using a bent 6" ruler. There's more heating and more easing - it can take a while. I want to get the plate out in one piece. This photo is taken using a mirror inside the guitar.

Finally the plate is out cleanly.

I can now make the new bridge plate. I can use the old one to get the angle of the sides right. I'm using a rather nice piece of flamed maple I got from Adrian at Ash Customworks ( - I didn't happen to have any maple and he was kind enough to help me out.

Once I'm sure its the right size its ready for fitting. I tape a plastic covered piece of plywood to the underside to prevent the clamps from causing any damage. The plastic ensures the ply doesn't get glued to the bridge plate.

 It is now glued and clamped in place using animal glue of course - that's what Gibson used.

Here's the finished job - the pegs sit straight and the string ball ends have a positive anchor point. You can hear the difference in how focused the sound is.

Finally after 55 years she gets a proper bridge plate. Lets hope this guitar is still in regular use in another 55.


I am no longer repairing guitars - since covid 19 I now work full time making pickups

Wednesday, 11 August 2010

Music Man Stingray V de-fretting

 I got a call the other day from Matt from the Auckland Rockshop - "can I de-fret a Music Man Stingray 5 string Bass for them?"
 Well in fact he said "what will it cost?".
 This is a job I do from time to time so I thought I'd write a bit about the process.
 It turns out this bass is for Tony Levin

 He's playing at the G-Taranaki Guitar Festival in New Plymouth and isn't bringing an electric bass with him. Rockshop being the NZ dealer for Music Man are lending him an instrument (nice of them). The only 5 string Stingray they had was fretted - that's where I come in.
  Tony Levin is a brilliantly creative, thinking musician so I'm hugely chuffed to be working on an instrument for him. Not that I get to meet him - he's not stopping in Auckland at all.

 The first part of the job is to take the neck off the guitar and strip it of hardware. Then remove the nut and on to the frets.

 I gently lift the frets with my modified pincers but you can see from this picture that the board is crumbling a little. This guitar is new - straight out of the box so I'm a little surprised but it isn't too big a deal, I can fix that.
 Here's an area of the board with a few little chunks missing

 It's the three wee pieces in the middle of the picture I'm going to repair.

I put a piece of metal in the fret slot to prevent it from filling up with glue

I then pack the holes with rosewood dust. I keep jars of different coloured wood dust for jobs like this

Then I saturate the dust with a thin super glue. I prefer the 'Hot Stuff' brand.

Once the area has been sanded the fills are almost undetectable.

I've decided to fill the fret slots with Maple veneer. I can't hide them so I'm making a feature instead. If there was more time I could have made a new fingerboard but I only had 48 hours to do the entire job.
 I measure the radius of the board with guages I made when I was in college 15 years ago. Its 7.5 inches - rather less than I'd imagined.

I cut pieces of veneer with a 7.5 inch radius on the underside and to the exact length to fit the slot.

This is the most time consuming parts of the job - they all have to be an exact fit.

Once they're all made I glue them in using Titebond Alaphatic Resin. I leave it overnight to dry.

The following day I trim the excess veneer off with a very sharp chisel and sand the board smooth. I start at 150 grade and work through up to 1000 wetting the board between grits. There's no need to go to such a fine grade I just can't help myself - it feels so good.
 I string it and set it up and its ready to be picked up by Rockshop and delivered to Mr Levin.

Not wanting to take any chances I leave it with my highly trained head of security to guard while waiting for Richard from the Auckland Rockshop to pick it up.

 Matt tells me the bass is going to be for sale at Rockshop after Tony's used it at the festival. So there's a chance to get a one off instrument with some serious pedigree.




Tony liked the bass and played it at the gig. Matt from Rockshop sent me some pics of him with it.

I am no longer repairing guitars - since covid 19 I now work full time making pickups