Martin d35 with S in top, too much relief and no trussrod. Can it be safed?

[Mario Kessels]

I want to wish eveybody a great 2015 with good health and guitar building joy.
I got a 1970 d35 in today with too high action. (7/64 at 12th)
The relief is too much but it has no trussrod..... The top has an S in it.
Now. How to proceed. Installing a bridge doctor ( i build similar ones myself) has shown me a very small gain in action only.
A neck reset will help with the action but the relief will stay too much and i will introduce a sort of hump then at body junction which i dont like.
The saddle is at lowest already so nothing to gain there.
I have thought about pressure fretting but i have never done that and i am just not a fan of fixing one deficiency with fitting frets that are too big really. I have no idea of how to steer this process to get the bow i want so i dont like this option.

Best thing i can come up with now is to take the fretboard off, level the neck and install one or two carbon rods and put the fretboard back on.

Anybody has an advice for this?

[Peter Wilcox]

If you have too much relief/forward bow in the neck, I've corrected this (in a classical/no truss rod guitar) by clamping the neck in slight back bow and heating the neck and fretboard for about a half hour with a hair dryer, then letting it cool while clamped overnight. Two years later the neck is still straight.

But might not work for higher tension steel strings.

[Mark Swanson]

The guitar most likely needs a neck reset. Almost all Martins do when they get a certain age, and the age of that one is plenty old enough. Chances are it needs a refret too, so consider taking the neck off, pull the frets, sand it level and refret, reset the neck.

[Robert Russell]

The guitar most likely needs a neck reset. Almost all Martins do when they get a certain age, and the age of that one is plenty old enough. Chances are it needs a refret too, so consider taking the neck off, pull the frets, sand it level and refret, reset the neck.

Mark is correct in how to repair your Martin. A couple of years ago I bought a Martin D-18 that needed a neck reset and it also had a forward bow in the neck. The D-18 has a non-adjustable square truss rod and the remedy was to pull the neck and frets, and level the fretboard and then re-fret using compression fretting to put a slight back bow in the neck.

I have thought about pressure fretting but i have never done that and i am just not a fan of fixing one deficiency with fitting frets that are too big really. I have no idea of how to steer this process to get the bow i want so i dont like this option.

Compression fretting is the normal way to put relief in a neck that does not have an adjustable truss rod so it is not a bad thing.

I am assuming when you say the top has an S in it you mean it has a belly behind the bridge and is sunken in front? That is very well an indication it has been stored in a dry environment. It could be a permanent situation or it could be the guitar is still dry. Before doing any work on it I would suggest putting it in a controlled environment for a few weeks to be sure of all the problems you have described are indeed permanent.

The best thing you could do right now is put it in a case with a hygrometer and a source of humidity. A sound hole humidifier is probably the best thing you could use but there are other ways of getting the guitar back to a stable humidity. Do not try to force the humidity up by going too severe (like putting it in a steamy bathroom). Slow gradual change is what you want or you could risk cracking. I keep my shop at 45% humidity all the time so if I were to take in a guitar such as you are talking about it would be in my shop for at least 3 weeks before I did a final evaluation on it. I certanly would not do any work on it until I knew it was stabilized at 45% humidity. You may find the problems you have have either disappeared or are not as severe as you think.

I have not been around the forum for some time but when I saw your post I thought I could be some help.

Bob

[Mario Kessels]

Thanks for the inputs, much appreciated.
Good input about the humidifying that might improve the top curve. Leaves us with the neck bow and angle. I am gonna measure if it needs the neckreset if i would be able to get it completely straight.
For the refret. I work with SM wire with normal tang. What wire are we talking about in this case if i would want to compression fret it? Is it not enough to just level the board and then do a normal fret?

[Michael Lewis]

D-35 has fairly light bracing compared to a D-18 or 28 and the plates are a bit more flexible. I would be looking for any loose braces and check the bridge plate for any separation. A reflected light across the top will show if there is a smooth bulge or if it has abrupt edges just behind the wings of the bridge. Smooth is a good sign, and abrupt signals the top and X bracing may be separating.

Get the body in good shape and then assess the neck. In my experience heat straightening a neck is only a temporary remedy, and a hair drier is nowhere near hot enough to effect this repair. You need to get the wood hot enough to take a set, like when one is bending sides for a new guitar. If you are going to remove the fingerboard why not put an adjustable rod in the neck along with the CF bars? Actually the compression fretting approach is less work and a reliable method to get the relief correct. You need string tension on the neck to check for relief, so you need the neck on the body for this.

[Robert Russell]

Mario,
You might just find the neck bow will come back with bringing the guitar back to normal humidity. It could take a month or more of humidity to see the results. However if it has been dried out for a long period of time it may not come back at all. One way to tell is to put the guitar in a tight case and use a hygrometer to measure the humidity. Get a guitar humidifier such as this:

http://www.amazon.com/Planet-Waves-Acou ... B0002D0COE

It is cheap and does the job very well. It slips between the strings and hangs inside the guitar where it will do the most good. It has a small sponge inside it and is very easy to pull out and re-wet.

You can easily tell if the guitar is very dry because you will probably have to re-wet the sponge once a day. On a normal humidified guitar the sponge will stay damp for well over a week in a closed case. Try not to open the case very much unless your environment is around 45% humidity otherwise you will be letting the humidity out and it will dry out the sponge quicker.

I would suggest taking measurements before you start. Use a straight edge on the neck and shim it up with several pieces of paper. Count how many thickness of paper it takes to make the straight edge even with the neck. Also do the same with the spot just behind the bridge and just in front of the bridge. Mark those spots with a small piece of tape exactly where your straight edge is. You can also mark on the tape how many shims of paper it takes under the straight edge. Set the guitar with the humidifier and a hygrometer in the case and only open it to check the humidity and the sponge once a day. After a few days of humidity you can check your measurements to see if it is coming back to life.

As for doing compression fretting. A lot of it depends on how severe your bow is and how flexible your neck is. It is a difficult thing to tell someone how best to do it because there are a lot of variables. What frets you are putting in, the width of the fret slots and how much movement you will get out of the neck are all things you need to be aware of when doing it. But for some general rules you would first determine what the fret slot width is and how easy the frets go in. If they seem to go in really easy then you know you will need to adjust the tang to make them fit a bit tighter or use a fret with a wider tang. If the frets go in normally (with medium amount of force) then I usually put in every other fret and adjust the tangs on the remaining frets (or again use a fret with a wider tang). Check the board before you start and after you have put in every other fret. That will give you an idea of how much you will need to adjust the tang.

The best way to do compression fretting is to use two different tang sizes which means buying separate fret wire. It can be done also by crimping the tang on the same wire which makes it fit tighter in the slot.

A good tool to adjust the tang is this:

http://www.stewmac.com/Luthier_Tools/To ... ml#details

Care must me used because it is possible to crimp a tang too much and split the fretboard or chew up the slot.

I will warn you though it takes some knowledge of what you are doing and skill to do a good compression fretting job so it may be something you might want to leave to a pro. You can do everything else and then have someone take a look at it an suggest the best way to proceed. If the neck is warped or bent compression fretting may not be what you need.

As I said, this is something very difficult to explain on a forum, and without having seen the guitar in hand and take measurements myself it makes it even more difficult to advise.

If you are not confident in your basic fretting abilities then compression fretting may be best to leave for a pro.

However if you are comfortable with fretting and understand the concept there isn't any reason you can't do it.

I hope this helps you,

Bob

I just saw Michael posted just before I did, I would agree with his comments also. You do want to make sure there are no loose braces (Good Point). An easy way to check is to thump the top with your finger like a drum. Listen for any unusual rattles or clicks when you are thumping over the braces.

[Mario Kessels]

Thanks guys. I have a lot of experience with refrets and neck resets etc. ( i am considered a pro ) its just that during all the years i have never done compression fretting since it has never been necessary.
Big difference i think with you on the other side of the water is that i just rarely get old martins etc in since there just aint as many here as over in the us. So i see a huge experience with you guys when it comes to guitars and problems like this, and i appreciate you sharing with me!
I will put it away ( i do this in a closed bag with a sponge which always works great) for 3 weeks and then I will reevaluate.
Thx

[Michael Lewis]

Mario, an easy method to determine if the guitar is dry or not is to stretch a thread under the strings and across the body immediately in front of the bridge. Hold the thread at the bindings so it nearly touches the bridge and look for clearance between the thread and the soundboard. There should be no gap, but if there is a little , less than a millimeter, is not so bad, but more gap indicates the guitar needs more humidity. Slow and sure, DO NOT RUSH adding humidity as it can be very dangerous to the guitar if too much is added.

I recommend getting the humidity sorted, then deal with the neck/fingerboard, and finally if all else is good and it still needs a reset then do it. You may find that once all the other issues are attended to that it may not need the reset.

[Mario Kessels]

Thank you Michael. You mean across the lower bout yes? How about when the top is not dry at all, but a serious S is in the top, will you not expect some clearance with this measurement as well?

[Michael Lewis]

Distortion? Not normal. Something is either loose inside or the top is flabby. Can you get a measurement of the top thickness? (this is why I have Hacklinger caliper)

[Mario Kessels]

At the moment i am conditioning the guitar and then i will have a look to see if there has been any change. My plan is to follow with the compression fretting but at the moment the client is having doubts as to invest any money in it at all without guarantees about the straightness of the neck after this so we will see.

[Mario Kessels]

Ok the guitar has been humidified, over the last two weeks. The neck is dead straight, but with string tension I expect to much relief.
I made pictures so you can see what I am seeing. My analysis at this moment is that there too much S in the top and that the neck angle is wrong.


<a href="http://s327.photobucket.com/user/mkesse ... b.jpg.html" target="_blank"><img src="http://i327.photobucket.com/albums/k472 ... 42639b.jpg" border="0" alt="Martin D35 photo 20150115_141731_zps0b42639b.jpg"/></a>


Measures from side to side just in front of the bridge I have 'dents' as can be seen on the picture. the soundboard is concave in front of the bridge, then convex near the bridge ends and then drops off again to the side (binding). Behing the bridge it is convex.

the neck is dead straight. Placing a ruler on the frets gives me the height at the bridge as depicted. This is too low, leading to an action of at least 6/64 with the neck like this, but knowing the flexibility of the neck and lack of trussrod the relief will add at least 2/64 more. Normally i would be ok with this measured height at the bridge but the lack of trussrod changes everything here.

very interested in your opinion!

[Barry Daniels]

The top is not that bad. I have seen much, much worse.

[Mark Swanson]

Me too. Re-set the neck, and set it up, call it good. Take a good look at the frets and if they need replacing, do it while the neck is off.

[Mario Kessels]

Ok that sounds good. I will reset the neck and knowing the relief it had when the guitar was brought in i will do a compression fretting with sm148 I think. That will keep the costs within the budget he gave me.
Another option is to aim for a neck angle which gives me a height at the bridge which is like 1-2 mm too high (resulting in lower action when neck would stay straight) , knowing the relief when stringed will solve this. This saves a refret of course.
I think i am going for your answer Mark but will set the neck just a tiny bit to the back to counter for the upbow. If the action turns out to be too high then I still have the option to refret like you said.

[Mark Swanson]

That seems like a good plan to me! Good luck.

[Michael Lewis]

You are dealing with guesses as to what the neck will do. I suggest you do the fret work with the neck on the body before it is removed. This way you will know how it responds to string tension for the relief, and you will know precisely how much you need to change the angle of the neck.

[Mark Swanson]

Ahh, that's a good idea Michael.

[Mario Kessels]

Ok. In the end i did the neck reset and put a set of 011 on. Little bump at the body intersection so i took out the frets from the 10th on, sanded de bump out and refretted that part only.
Its perfect.
Thanks a lot for the inputs