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Old 12th February 2006, 06:12 AM   #1
9am53 is offline 9am53  Canada
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Default guitar bridge area rebuild

Hello, I recently picked up a guitar that originally had a les paul style tunomatic bridge, but the owner wanted a floyd rose so he went bonkers with a plunge-router and left it with a gaping hole instead. I would like to put the old bridge back, so here is the plan...The back area for the springs is done well, so i wanted to glue a tightly fitting piece of matching maple there. The top is the hard part, what I want to do is clean the hole up with a router and either i) do the same as the back ang glue a tight fitting pieace of maple in there to fill the hole, or ii) pour in some fiberglass resin to fill the gap. I understand that I will likely have crappy sustain and overall tone compared to the original, but what would be my best bet,I thought of the resin becasue it gets really hard, and it would bond to the wood everywhere becasue I would pour it in... what do you think?
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Old 12th February 2006, 07:27 AM   #2
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I think it would be best to clean the hole with a router and install a tight fitting piece of wood. If you do that well, it may sound as good as it ever did.

If you absolutely have to use the fiberglass resin, mix in some kind of filler to avoid coldcreep and shrinking.

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Old 12th February 2006, 11:01 AM   #3
Bobken is offline Bobken  United Kingdom
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Hi,

Is this a solid-bodied guitar, or maybe hollow?

If the former, and I am guessing from what you say it probably must be, any such repair should not be too hard. Hollow-bodied are much more difficult to make a good cosmetic and soundwise repair to as there is much less of the parent material to work with.

I would avoid, at all costs, using anything other than wood for the repair though, as other materials will definitely screw up the tonality, and sustain etc., as you mention.

The most important part to keep to the original 'material' is where/how the bridge is attached to the body. If the bridge attachment points are made to fix into resin, for example, I think the sound will be rather poor, unfortunately, as this will have totally different characteristics from the original wood.

Having made a few solid-bodied guitars over the years, the wood used is just as important as with hollow-bodied ones, and the choice made by the constructor provides a large proportion of the entire charactistics of the sound.

With some care, it should be possible to clean up the aperture (even if this needs to be done from two sides) and make up a suitable 'plug' (or two, if you find it easier to work from both front & back, depending on how the 'hacking' has been done) and glue this (these) in place.

If the wood is the same as that originally used and the job is done carefully, there should be very little change in the ultimate sound.

For your own sake, don't rush into a quick and dirty repair (which I suggest using any resin would be) as if you are then dissatisfied (and if you are fussy, you will be!) it will be very much harder to start again.

If it helps, if you you can explain the shape of the unwanted cutouts better, perhaps with a sketch, then I would be pleased to suggest some more specific ways of dealing with the repair.

Also, how is it finished? i.e. Is it 'varnished/lacquered' wood with the grain showing through, or is it a 'painted/opaque' type of finish?

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Old 12th February 2006, 12:44 PM   #4
9am53 is offline 9am53  Canada
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Hi, thank you very much for your help! I am glad you think that the sound wont be too badly affected by the repair! I am fussy to a degree, so a bad job that sounded like a bad job would very much bother me. I thought that just using the hard fiberglass would be ok, I didnt realize that just being hard wasnt enough. I have attatched some picks of the holes...one is of the back of the guitar, one is of the front (note the bridge pickup cavity and the holes for the stop piece) the guitar is a Hamer explorer. since the foreign fiberglass would not sound good, would other woods that are foreign sound bad too? I have a church pew-load of teak here that I use on my boat, or would there be a tonal advantage to using a better (ie korina) wood?
ps: I found out that the guitar in fact has a 1 piece alder body with curly maple top,
pps: I have a friend that does airbrushing so I will get him to re-paint on those hella-cool hot rod flames
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Old 12th February 2006, 12:45 PM   #5
9am53 is offline 9am53  Canada
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here is the backside...
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Old 12th February 2006, 02:36 PM   #6
poobah is offline poobah  United States
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Don't use teak... it doesn't glue work a darn. Any hardwood will do nicely.
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Old 12th February 2006, 02:48 PM   #7
Bobken is offline Bobken  United Kingdom
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Default WoW! What a butcher!

Hi, well this is not so bad as I might have expected, and to me would not present any problem.

That is a good start, and it helps tremendously if you don't need to try and match up the wood grain etc., as you obviously don't need to here.

I am happy to try and talk you thro' anything you need, but to a large extent the results will depend on your own ability, the tools at your disposal, and how much time and effort you are prepared to put into this. At least the costs should be minimal, which I guess is important to you.
If you have had some previous experience working with wood, I have no doubts you can end up with a better job than most professionals will do, but even if not, I can try to help at any point you get stuck, provided you are keen enough to make the effort and have a go. Wood is cheap enough, and you can afford to try out several ways, if needs be, but I don't think it would come to that, especially as it is a solid-bodied job, and so long as you get the shape right, paint will cover the rest up OK.

Regrettably, all of the damage to the front is not as clear as I would like, so is there any chance of another shot, perhaps at an angle, rather than straight-on at the front? This would help me assess how deep the damage is etc. which will have some bearing on the suggestions.

Right now some generalisations which I hope will help.

Always start off with the most difficult part, and then when you come to do the rest, it will be like riding downhill. Otherwise, if you get disheartened in the early stages, you will probably be overwhelmed with what's still left to do.

Unless you are already experienced/skilled in such work, try to arrange a 'dummy run' somehow if possible, to practice on, especially if you are cutting a piece of wood to exactly fit an aperture. If you cut the insert too small, you are****ed, but anything larger can always be trimmed down to fit! By the same token, clean up and finish the aperture first, then you will have the exact dimensions to cut the plug to.

Generally, unless you are concerned about spoiling the surrounding finish (not here, I guess!) make any plugs too thick initially, glue them in place and let them set properly, and then finally trim them down carefully to be flush with the surrounding wood.

When 'cleaning up' any aperture to be subsequently filled in, think about how you will make the plug that fits into the aperture first. Its lousy if you make an excellent job of cleaning up the hole, only to find it difficult (or impossible with your resources) to subsequently make a well-fitting plug! I know, I've been there!

Take your time with everything, and if you have a deadline, do yourself a favour and forget it now, or you will end up spoiling things in the rush.

Take careful note of the parent wood, especially when you do any trimming here. See which way the grain runs, and assess the hardness of it. If it is Alder, as you say, it would be ideal to use Alder for the repair, but so long as the wood used is similar in texture/hardness etc, you should still end up with a good result.

Alder is not something I have used for many years, but I believe it was quite a close-grained medium-hardness wood, much like Ash which I am very used to. I used American Swamp Ash for my best construction effort so far, and it 'sounds' as good as its reputation has it, and used to be popular with the top-notch Fenders, I believe.

Try slightly denting the parent wood (in the damaged area) with your finger nail, or if this won't make any impression, use a tool like the sharp end of a nail, or whatever, to see how easy it deforms, and possibly recovers. Then do the same with the substitute wood you intend to use, in an attempt to match these characteristics as much as possible.
You could also try tapping both woods to see how they sound, but be wary that different sizes of timber will sound different, although they will have similar characteristics probably like a thud, or a ring, or whatever.
Luckily, colour doesn't matter here, and you might find that Teak is quite similar. Ash will be harder than Teak, Oak is much harder still than ASH, and Ebony will be the hardest you can usually get hold of, except for Lignum Vitae which is more like metal.

There will be lot of info on this on the 'net, as I have seen myself. Look at DIY guitars, timber sales, veneers etc, and you will learn a lot about these woods, and more than one guitar site even tells you about the relative 'sounds' of the woods in question.

In the end, the closer you can match the characteristics of the original wood, the better the result will be. Then all you will need to worry about is making a good 'mechanical' fit between the parts before you stick them together.

Give me an idea of any experiences you have had working with wood, any hand or power tools you can use, and I will post some more specific suggestions/ways of doing this.

Regards,
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Old 12th February 2006, 03:56 PM   #8
9am53 is offline 9am53  Canada
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WOW, I have never found anyone so helpful! well, I wasnt expecting the attention, so I wasnt completely honest, I dont actually have the guitar yet, so unfortunately I dont have anymore pics. Its from ebay, and those pictures were from the item description. I was asking these questions to guage how much I should spend on the guitar... I am happy to say I will buy it now! anyways, back to the problema t hand...I have access to many power tools, most of which are my neighbors, and I would say I am intermediate with woodworking. I can do a good job if I take my time. Advice should be given like I'm someone who can work well, but may not completely know the jargon...I will take your advice on testing out the hardness of the wood, someone else posted that teak doesnt glue well, I beleive that, it is very oily as it resists water on my boat very well. I have a basswood strat body that I tried to laquer unsuccessfully that I can use for the plug, would that be ok, or is that too soft? as you said I can look online for alder...or I can see if there are any places in town that sell "exotic" woods. I will sned you more pics when I can get them...but heres what I initially think I should do: My boat fxing experience tells me to get rid of any holes or gouges and a bit around them...so I was thinking of routering a big square or rectangle around the problem area on the top, and making the corners nice and sharp with a table mounted jigsaw, that way I could have an easy shape to mate with the plug. As you said I would make the plug bigger, and belt sand the edges till they fit as snuggly as possible, and belt/finish sand the top till its flush, then call the painter man...does this sound ok? and would I glue it, or shouldl I try to get it to fit tight with no glue...?
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Old 12th February 2006, 06:15 PM   #9
Bobken is offline Bobken  United Kingdom
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Default Excellent start!

Hi,

This is extremely encouraging to me, and hopefully very good news from your viewpoint.

When I said that this repair would be easy for me, this was not out of arrogance, but merely to indicate that I was now sure it was possible. If I didn't feel confident, myself, it would be wrong for me to flippantly encourage you to get yourself into a hole, especially now you say that you are not yet even committed to buying the guitar.

If you can get it at the right price, I wouldn't hesitate, and in view of the tools you have at your disposal, it should be a very good result given a little time and patience.

It is much, much easier to rout out a clean, straight-sided aperture like this with machine tools, than ever it is to do it by hand. I know, as I have done it both ways!

The ideal here is to end up with a close-fitting plug, and keep trimming it until near perfect while it is 'dry'. (i.e. before any gluing).

To do this (exactly as you suggest) it would be best to mark out a new aperture as rectangular as possible, and with absolutely parallel sides looking from the front face working inwards towards the bottom of the cut-out, so you can then simply make a parallel sided plug which will fit snugly all around, to the full depth of the plug.
If you use a quite small dia. router, it would not then need to be 'jig-sawn' to obtain any sharp corners necessarily, and this may help if the cutout at the front does not go fully through the body, which would probably otherwise be necessary (or at least much easier) if you need to use a jig-saw, or whatever.

Looking at the pics (so far) I think this would be the case here, and when routing out, you should be able to end up with a clean and flat-bottomed hole, which by hand would be a pig to do. The advantage of this is that you will end up with a much greater area of contact overall for the adhesive, and some of the mating surfaces will be in different planes too, which is a great advantage structurally, and I guess tonally.

You may find this is better done with some routing from the front, with a suitable plug for this, and then 'attacking' the back similarly, and it will not matter if the two routs are not fully aligned in such a case, in fact it would be preferable, if anything.

If you end up without square corners in the rout(s), merely round off the corners of the plug at the last minute, to suit the router's dia., which shouldn't be too hard for someone with your experience, especially with a belt sander being available.

Here, by angling the plug so that you can push one end into the aperture (but not fully in at the other end because of the excess wood which will foul the rounded corner routs at that stage) you can still 'gauge' the fit between the two parts. Then do the same with the opposite end, and then similarly with each side. This is all made very much easier if all of the routing is done 'in plan view' with parallel sides too, so you can slide the plug up and down (vertically, and horizontally) within the aperture.

If you cannot get at the backside of the rout, make certain you insert a shallow woodscrew (or maybe glue something onto the face of the plug which can be removed later) without damaging any part of the wood which will ultimately be left in the finished repair (a good reason to start out with a much thicker piece of wood here, if you do use a screw), or you may not be able to get the plug out again to apply the glue subsequently!

If the fit at the rounded corners is ultimately not quite perfect, it would not have much adverse affect, as there will still be four quite long 'bearing sides' for gluing, anyway, and hopefully at least some part of the bottom of the plug will be stuck against the flat bottom of the routed hole as well.

Another 'trick' when making the plug and finally trimming it, is to make it say 1/2" or more too deep initially (partly to allow for any later trimming in situ.) but then you can chamfer the bottom leading-edge gradually at a very fine angle, until the plug will just fit all around. Then all you need to do, is to copy this 'outline' all up the sides of the plug and you are there!

If you chamfer a bit too much off anywhere while doing this chamfer trimming, it would then be possible to take a suitable slice off the bottom of the plug (out of this spare 1/2" or so) to restore the full size 'footprint' to fill the aperture properly, and less needs then to be taken off the front face when finally finishing.

Try to match the guitar grain's direction for the plug, and only consider any gluing when you are absolutely happy with the dry fit. If necessary (for the front, at least) make another plug if the first try is not perfect, as you will be more experienced at the second attempt, and you will already have a more accurate 'template' to work from.

For the front, it is important for the overall integrity of the sound to get a really good dry fit here, and when planning the size of rout for this, watch out for any load-bearing screws/fixings for the bridge etc. You may need to cut the rout slightly larger here, if any fixing screws will end up near to the join, as these will later tend to 'spring' the join and look bad, but more importantly need to go into 'sound' wood (no pun intended) for the best tonal results.

When finally gluing, use a good PVA type of adhesive (Weldbond, which comes from your area, is excellent here), as this soaks well into the wood and expands it a bit as it sets. Epoxy types of adhesives tend to leave a thin film of a plastic nature between the surfaces all around as they don't dry out partly by evaporation like water-based glues, they don't soak as well into the grain of the wood, and they only set by a chemical reaction.

Any such 'plastic film' interposed between the wood parts will ultimately tend to have a slight isolating and damping affect on the sound, I reckon.

After the PVA has *fully* cured, if there are any cracks or small gaps etc. still apparent, use some cyano-acrylate (Super-Glue, but not the viscous gel-type though) as if this applied generously to the joints it will 'wick' into them deep into the wood join by capillary action and also soak into wood just like water-based glues. Unlike Epoxies, it does set quite hard and would be OK for the entire gluing process here as far as strength is concerned, but it would doubtless 'go off' part-way through the assembly, and you will need more time for this than cyano would allow!

The thinner viscosity cyano is very good here, and will fill any hairline cracks (maybe around the rounded corners, if the fit is not too good) and the final result will be stronger than the original wood. You can also set it off with a spray of special setting agent if needs be in larger gaps, or you can mix it into a putty with some wood-flour (made from the later sanding exercise) if you are fairly quick, and use this for any small surface holes etc.

Have a look at www.warmoth.com for info. on the characteristics of woods used in guitars, and their different 'sonic' attributes. Alder is their most popular wood, it seems, and appears to be rather like Ash, as I had guessed, if a little softer. Basswood, is also shown, and is reputedly also a bit softer (maybe quite like Alder, but I bet they would tell you, if you mail them and they think you are a potential customer!) and "Basswood has a nice warm tone".

I hope this helps, if there are any queries I will try to deal with them now, or if anything crops up, later on during the repair.

Good luck, but you won't need it anyway as I am fully confident you can do this, and you will soon look back and wonder what all the fuss was about!

Regards,
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Old 12th February 2006, 06:27 PM   #10
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Looking at those pics, I'm assuming you're not getting any hardware or electronics either, as they all seem to be stripped out.

Though probably a good hobby or learning project, I wouldn't pay any real money for that guitar...
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