Classical guitar repairs?

[bugbear]

I have been followed home from a car boot sale by a classical guitar - an Almeria BM. I bought it on the strength of an undamaged, solid wood (not ply) body. These appear to cost around £100-£140 new.

On detailed inspection I note several issues.

• It was strung with steel strings, where I understand nylon would be correct for this model.
• It had no saddle, the bridge may be broken or altered during the removal
• the saddle may have been removed to lower the action, which I measured at 5/32" at the octave fret (with no saddle)
• on two of the tuners, the knobs have broken off
• the saddle may have been reglued badly

Repairs

• I can readily replace the strings (old strings would need replacing anyway)
• I can buy and fit a saddle (blanks are cheap)
• I have measured the tuner post spacing, and it seems to be the standard [thanks google] 35mm; replacement tuners
  sets are around a tenner.

I am more worried about the bridge/saddle. If the use of steel strings has torn the bridge off, or raised it, I'm in trouble.

Here's the top view of the lack-of-saddle

Here's the gap, and glue, under the rear edge of the bridge

Oddly, the front edge of the bridge sits perfectly neat and flush.

So - (since I know there are some luthiers amongst us) - is this repairable, and is it worth repairing?

Hints, tips, techniques and advice welcomed.

BugBear

 

[thick_mike]

Every guitar is repairable!

Looks like this one has been roundly abused though. Steel strings put more tension on the guitar than the nylon strings this guitar was designed for, leading to (amongst other things) neck bow, bridge lifting and bellying of the soundboard. All of these will give you a high string action.

First thing I'd do is remove the bridge. It looks like it's been reglued really badly. You'll need something like a scraper blade to get between bridge and soundboard. A bit of heat will help, but how difficult it will be will depend on the glue that was used.

With the bridge off, check the bracing inside (small mirror or video camera) to see if any of the bracing has become detached from the underside of the soundboard.

Also, you will need to check the neck relief...unfortunately classical guitars don't normally have truss rods that you can easily adjust that with. If the relief is bad, you might be able to back bend it with clamps to straighten it out...otherwise, removing the fretboard and planing and reattaching...or removing frets, planing the fretboard and re-fretting would be another option (neither of which is easy).

For a brilliant resource on all things to do with guitar repair, go to http://www.frets.com/FretsPages/pagelist.html. In fact just go there to see a brilliant craftsman solving problems brilliantly!

 

[bugbear]

Every guitar is repairable!

You've dodged the second part - is mine worth repairing?

(I read your whole post with interest, and am currently researching, and trying to learn how to diagnose the various potential faults you mention - thank you)

BugBear

 

[bugbear]

The neck seems near to straight, judging by a 12" straight edge across the frets. There's around a 5 thou hollow at worst.

But a 24" straight edge laid long the neck (on the frets) is only 3.5mm above the soundboard at the bridge. I am given to understand that this is not good.

I think I'm in trouble.

BugBear

 

[Setch]

The neck angle may have changed under the excess tension of the steel strings, or the top may have distorted so it is too high.

If it's the former , this might be a candidate for 'slipping the neck'. Basically you separate the back from the headblock, and a short section of the sides, then reglue it with the neck held at a slightly greater angle. A small amount of tidying up of the edges of the back where it overhangs the sides is then needed.

This is a quick and dirty repair for cheap instruments.

 

[tomasg]

Is it worth fixing ?
If it truly has a solid top ,,,
Check the edges of the soundhole north and south of the soundhole edge when guitar is standing upright for continuous grain lines ...
I have seen many many laminate tops that would fool you, as the spruce veneer their using is thinner these days than ever
before ,so much so that you can sometimes see the inner laminate telegraph through the softwood veneer.
sometimes the lacquer coat looks like a laminate aswell though so you really have to look hard.

If its a solid top its totally tonally subjective then, as every piece of wood is different
Looks like you need to make a new bridge as all you've got left is a tie block .
Its not a Torres replica guitar so you need to get a bone saddle aswell (or some lesser material )
Cheap paint scrapers are thin so i would use that to remove the bridge (take off the sharp corners and relieve the handle for clearance .
(be careful of that center seam though as the bridge looks like it is epoxyed on
and more than likely the center seam joint would give up before the bridge would come off .
Their is a big gap though so this might not be difficult ,if it wasn't budging i'd just slice it down to the spruce with a chisel .

As said check those braces beforehand ,apart from the structural and tonal quality's that's possibly achieved
you will find out what glue was used as it would be the same glue used on the seam .
Be careful !!! This could be the start of an addiction that inevitably leads to poverty and madness
Good luck
Tom

 

[bugbear]

I may have panicked too soon; this site

http://www.hillguitar.com/website/news/ ... setup.html

says:

"Normally a straight edge laid on the frets will give 4 – 5 mm clearance above the soundboard at the bridge."

I'm getting 3.5mm which is only 0.5 mm off that, which is 0.25 mm at the 12th fret. Tolerable, for the moment.

So I think I'll approach the problem incrementally.

I'm going to order a new set of tuners (unavoidable), new strings (unavoidable, and an ongoing consumable anyway) 2 new bone or horn bridge blanks, and a nut blank, The latter three will all come from one vendor, and share postage costs. The blanks themselves are cheap.

I can then install the tuners, work up a bridge, install the strings, see what happens, see how it sounds, and take it from there.

This is after only a £5, car-boot guitar.

I don't like the look of the cost of luthier tools.

If I'm going to spend loads of money on parts and tools, I'd have been better off buying a better s/h guitar in the first place.

A wise friend once told me the most expensive way to get a good bike was to have a friend sell you a good frame, cheap.

BugBear

 

[Jacob]

You can tell if it's got a solid top by shining a torch close up on it in a dark room. It'll light up the inside of the guitar - solid wood tends to be translucent, laminate much less so, if at all. I wouldn't be put off if it isn't - it isn't an absolute guarantee of sound quality and you might as well have a go and **** up a £5 one first!

 

[bugbear]

• on two of the tuners, the knobs have broken off

BugBear

Wow. It's not only dirty and corroded, it's not only got a missing knob, but the shaft of the missing one is bent.

I think this guitar got dropped.

BugBear

 

[Jacob]

The "BM" probably stands for "Barnes & Mullins" i.e it was made for them by Admira in Spain. This is an old tradition whereby a dealer would have stuff made for himself sometimes with his own brand name. The big one nowadays is "Stagg" who have a massive range of instruments made for them mostly in China and very good value for money

PS this is it http://www.bandm.co.uk/guitars/admira-almeria.html the current version - but specs change over the years
Admira the maker, Almeria the model name, made for B&M the client/dealer

 

[profchris]

The neck seems near to straight, judging by a 12" straight edge across the frets. There's around a 5 thou hollow at worst.

But a 24" straight edge laid long the neck (on the frets) is only 3.5mm above the soundboard at the bridge. I am given to understand that this is not good.

I think I'm in trouble.

BugBear

I build ukuleles, which are constructed much like classical guitars (only much smaller, of course).

The two important measurements you need are: (a) the height of your straight edge (laid on the frets) where it meets the saddle slot location; and (b) the height you want the strings to be at the 12th fret (the "action" for short, though action also takes in the nut height measurement which you should ignore for the moment).

Classical guitars have higher action than ukuleles, so I'd suggest (b) is something like 3.5mm at the low E string and 3mm at the high E.

To get the action right, the top of your saddle needs to be measurement (a) plus twice (b).

Thus your saddle height (above the top) should be 3.5mm plus 7mm = 10.5mm.

You want 2 to 3mm of saddle above the top of the bridge, so your bridge needs to be 7.5mm thick. That's a bit thin but not ludicrous. So my conclusion is that simple bridge replacement is probably all you need. You can buy a classical bridge from eBay for around £5 delivered and then work it down as required. Your saddle slot needs to be at least as deep as the amount of saddle protruding above, deeper if possible (I'd like it twice as deep but you need 1-2mm at the base). The bottom of the saddle slot has to be flat to get the best sound.

So far as removing the old bridge is concerned, my technique is to use heat from a domestic iron on the wool setting. You want the bridge too hot to touch comfortably (but not hot enough to char!). Protect the finish on the top with thick cardboard.

Once the bridge is hot, slide a spatula underneath until it pops (hide glue) or peels (PVA, more likely here) free. If the top is solid spruce then it's probably book matched. This means the runout will go in opposite directions on the two halves of the top, so work the spatula with the runout, not against it, to avoid digging in to the top.

Hide glue is agreed to be best for bridges, but Titebond original (not II or III) works well too. Most luthiers don't use white glue (there was a good white glue, but now unavailable). Clamping is, of course, a challenge, but YouTube and specialist forums like the Official Luthier's Forum will show you methods - the one which requires no specialist tools is to insert props between back and top, and then work out some method of clamping externally. Note that the thin "wings" of a classical guitar bridge will tend to curl up with glue, so each wing needs pressure as well as the main body of the bridge.

One more thing - you will probably read that the scale length of a guitar is twice the distance from the nut to the centre of the 12th fret. That is true, but the actual string length needs to be a fraction longer because as you press down the string you stretch it. The extra you require will be somewhere between 2mm and 4mm, so if you place the front of the saddle at scale length + 2mm you can work the top of the saddle to get good intonation. The fretted note at the 12th fret will be sharp compared to the open note, and you work the saddle back until it's correct. Each string will require a different amount of this "compensation" (though traditionally classical guitar makers use a straight saddle set as a compromise). There is a good chance the original saddle was not quite in the right place, which is common on entry level instruments, so you could actually improve this one!

Note, no special luthier tools required so far.

 

[xy mosian]

profchris,
What a fantastic amount of very useful information, and almost hidden away from all but the determined searcher. Thank you. I am not a luthier these days, but that is a very interesting read.
xy

 

[whiskywill]

I've found this site to be a source of cheap but OK guitar bits. http://www.aliexpress.com/premium/class ... =y&catId=0

No need to spend £10 on tuners.

 

[thick_mike]

If the bridge Is going to be replaced anyway there is no need to fanny about getting it off...just chisel it away!

 

[profchris]

If the bridge Is going to be replaced anyway there is no need to fanny about getting it off...just chisel it away!

The last half millimetre is the critical part - you don't want to nick the fibres of the top because the tension of the strings wants to peel up the bridge from back to front, and broken fibres don't resist that very well.

Conventional technique is to chisel most of it away, then heat and spatula as I explained earlier.

 

[profchris]

Bugbear, I've just seen the picture of your bridge glue line on another forum where I'm not registered to post. I fear it may not hold

If you used hide glue I can explain how to improve matters without removing it. If you need to remove and reglue I can give you clamping ideas.

It's worth getting a better joint, as if it pulls off it might take chunks of the soundboard with it.

 

[AJB Temple]

To address your question "is it worth repairing"? It is a low end guitar. It is never going to be valuable. The question then relates to functionality as a musical instrument. Having played most types of guitar for 30 years and collected many, I am well aware that what is "good" is a very personal thing. You can only tell by putting a saddle on, fixing a set of tuners on and stringing it up to tension. Good feel / tone / absence of string buzz?

With steel strings on it, if it has been used much, then there may be some fret wear to deal with as well as the other points you are aware of. Personally I would not spend much time on this instrument, unless you are using it as a learning experience.

 

[bugbear]

My thanks to Adrian and Chris for their interest, and advice.

As far as it goes ...

I bought the guitar because I fancied trying a classical/nylon string guitar.

Having realised it wasn't immediately playable, I tried to "make it so" for minimum outlay, out of stubborness
as much as anything.

Currently it's:

Guitar £5.00
Nut/Saddle blanks £10.00
Strings £1.99
Tuners £5.49

As the photo shows, it's now "complete" and strung (and the bridge is holding), and I've been learning the hippy classic "Father and Son".

The string action is monstrously high, around 5.5mm at the 12th fret; I think the neck and/or body has warped. The saddle
is as low as it can be - it's around 0.5mm above the bridge at the high 'e' string.

The nut is filed a little high out of cowardice.

But, for the moment, it is a playable, nylon stringed guitar, and the purpose is served.

I may try to improve it further, but so far it's been a fun and cheap tip-toe into both luthery and folk-y music.

BugBear

 

[profchris]

I reckon Bugbear has had his money's worth, just in the fun of getting this far for, what £25?

I only mentioned the bridge because my experience is that less than about 90 % surface to surface contact means it will soon fly off, and that rather kills off the idea of a working guitar. It's easier to fix now than later.

If Bugbear takes to this and, in due course, wants to get the action down to a more conventional 3-4 mm, we can have fun explaining slipping the back and then watching as he tries it!

[In place of "kills off" I wrote b*****s, and the forum software autodonked this to "pippers". A new word to me, and not what I'd expect to hear as hammer meets thumb.]

 

[bugbear]

I reckon Bugbear has had his money's worth, just in the fun of getting this far for, what £25?

I only mentioned the bridge because my experience is that less than about 90 % surface to surface contact means it will soon fly off, and that rather kills off the idea of a working guitar. It's easier to fix now than later.

If Bugbear takes to this and, in due course, wants to get the action down to a more conventional 3-4 mm, we can have fun explaining slipping the back and then watching as he tries it!

[In place of "kills off" I wrote b*****s, and the forum software autodonked this to "pippers". A new word to me, and not what I'd expect to hear as hammer meets thumb.]

Yeah - it's been fun.

My current plan for the immediate future is to take the saddle right down to 0.5mm above the bridge, take the nut slots down to minimum (carefully...) and live with whatever height action those two simple procedures give me.

I carefully worked the saddle to give a 4mm action on the G string, less on the 'e's, but once strung and tensioned, it measures at 5.5mm.

I *think* the bridge will hold, purely because one of the strings I took off was STEEL. This implies that the guitar (and bridge) once held the tension of steel strings, so I don't think (optimist!!) that nylon strings will pull the bridge off.

Body/neck damage from steel-string-tension may also account for the current action height.

BugBear