Bryan’s Work bench

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Where stuff happens

 Just Say No to Cracks

Impact cracks are the result of a guitar taking a hit, and, like a lack-of-humidity crack, they tend to appear
along the grain line.

In my last column [“Humidity—Friend and Foe,” March 2018], we defined the parameters of the “safe humidity zone.” And its importance was stressed because humidity control is the single most crucial step a guitar owner can take to protect instruments. But wait! There is more sad news. Stuff is going to happen to your guitars, and discovering a crack can be absolutely heartbreaking. Fortunately, damage is often repairable to keep your instrument stable and ready for action, but understanding what you are dealing with is key to making the best decisions during the repair process.

Lack-of-humidity cracks and impact cracks are without a doubt the two most common types. Lack-of-humidity cracks typically run along the grain of the wood. As wood shrinks in low humidity environments, it eventually reaches a point where the wood can stretch no further and, well, it cracks. Guitars with lack-of-humidity cracks generally show up in my shop around mid-October, which is about the time people turn on the heat in their homes and the relative humidity drops below 40 percent. These cracks aren’t hard to spot. Most often they’re located just behind the bridge on the top, but they can show up in other places. Another defining factor of lack-of-humidity cracks is separation in the guitar’s top—as much as 10 to 15 thousandths of an inch.

The fix is in. Impact cracks, which occur when a guitar takes a hit, are not open. They do, however, typically break the wood along the grain as well. (Photo 1). And most of the time, impact cracks go right back together with minimal effort (Photo 2). There’s a scenario where the guitar has a lack-of-humidity crack that separated in the winter but closed back up in the summer, and has the appearance of an impact crack. Regardless, these cracks can be repaired the same way as impact cracks.

By touching or rubbing the crack, you are working dirt and oils into the area, and this can make things much more difficult when gluing the guitar back together.

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So what can you do if an unnerving crack shows up on your guitar? The first and most important thing to do is not freak out. Whether the crack is caused by humidity or by impact, there is no immediate danger to the guitar. Second, if you notice a crack, your first instinct may be to touch or rub it. Tip: Don’t do this! By touching or rubbing the crack, you are working dirt and oils into the area, and this can make things much more difficult when gluing it back together. For lack-of-humidity cracks, you should take quick action and re-humidify your guitar with a soundhole humidifier as soon as possible. This will—more often than not—close the crack. If you ignore this scenario, however, the wood could take a memory over time and will be much more difficult to repair down the road.

Visit the doctor. The next step is to see the repairperson. Between the two of you, you should identify what type of crack you are dealing with and determine what the next best course of action will be. If it’s an impact crack, a simple re-gluing usually does the trick with no need for further action.

A qualified repairperson can often fix impact cracks with minimal effort and no need for backers or cleats.

In the case of a lack-of-humidity crack, the technician will usually continue re-humidifying the guitar until the crack closes. Only then will the crack be ready to be re-glued. Again, most of the time, the glue will be enough to hold the wood together. But a qualified repair person should advise you on how to better humidify your instrument to prevent the crack from returning in the future.

In either case, the glue seals the crack to protect the wood once it’s repaired—at least from a structural and sealed standpoint. But now you are likely thinking about the finish and if the repaired crack needs inner support. Here’s where I’m going to suggest that you relax and weigh your options. Both backers and finish touch-ups are what I consider to be phase two of the process, and are not always a necessary step in a repair.

When touch-up work on the finish is performed, it’s done to try to make the crack look better. It does not make it more structurally sound, and unless the guitar is almost brand-new—when finishes are more easily re-bonded—a finish touch-up on an older instrument generally looks, well, terrible. As someone who has been around world-class acoustic guitars and guitarists for over 40 years, a cleanly repaired crack is what I’d prefer to look at. As for backers or cleats, they are often not necessary to further stabilize the already re-glued and stable crack. So be sure to discuss this with repairpersons to ensure they aren’t making any moves that can’t be undone once in place.

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Posted 6/13/2019

Top 25 places to buy custom

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Galloup Guitars has been chosen as one of the top 25 places to buy custom hand made guitars.

Having a custom guitar means that it is made exactly to your specifications. The shape, hardware, colors and other components are chosen by you so that it fits into your hands like a glove. There are several companies who have an excellent reputation for making guitars.

The Best Places To Buy Custom Guitars Online
We chose these award winners based on the following criteria:

Craftsmanship of guitars
Uniqueness and variety of guitars
Website layout and use
Uniqueness and story behind brand
Response times of customer support

THERE ARE HUNDREDS of places to buy custom guitars online. As a result, this made it difficult for us to pick our top choices. However, after extensive analyses and looking at hundreds of places to buy custom guitars, YOU WILL FIND BELOW THE TOP 25 PLACES TO BUY CUSTOM GUITARS ONLINE:

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Posted 6/12/2019

Humidity—Friend and Foe


Photo 1 — If left unchecked in an improperly humidified environment, your guitar could meet the same fate as this D-18, and leave you and your repairperson with a difficult fix.

What is the biggest cause of premature death for acoustic guitars? No, it’s not rambunctious children or spurned lovers. It’s humidity. And storing a guitar in an environment with improper humidity will not only shorten the life of an instrument; it’s certain to cause problems with playability and tone along the way. I consulted with Sam Guidry, our senior instructor/luthier here at the Galloup School of Guitar Building and Repair, on this very important, but generally overlooked topic. And the following is our take on what you should know to protect your guitar from humidity-related issues.

An acoustic guitar needs to live in a relatively stable environment. Most acoustic guitars are built in climate-controlled shops that maintain approximately 40 to 50 percent relative humidity. As the guitar goes out into the world, it should be kept in a range no less than 45 percent and no greater than 75 percent relative humidity. When the guitar is left outside that range for a prolonged period of time, strange things begin to happen. Recognizing the symptoms can save you from a trip to your repair shop, or worse.

The time of year is the first clue that you should monitor the humidity for your guitar. In northern climates, when the temperatures drop and the heater in your home begins to run, it will dry the air in your home and create an unfriendly environment for guitars. When this happens, it’s really time to start thinking about humidification.You may think that simply raising the saddle a bit will fix the problem, but the real issue is that your guitar needs supplemental humidification.

When wood dries out, it shrinks. This can be observed in several ways. First, you may notice that you can begin to feel the fret ends protruding slightly from the edge of the neck. This is because the fretboard is drying out and shrinking, but the metal frets do not. Another symptom is that your guitar will start to buzz. When an acoustic guitar’s top dries out and shrinks, the dome of the top will lessen, and this causes the string action to change. You may think that simply raising the saddle a bit will fix the problem, but the real issue is that your guitar needs supplemental humidification.

If left unchecked in a dry climate, an acoustic guitar will eventually crack. This most commonly happens along the grain of the top or back, but the fretboard and bridge can also suffer a similar fate in extreme conditions. If caught soon enough, many humidity-related issues can be repaired. But over time, the area around the cracks can develop a memory, and repairs will be much more difficult (Photo 1).


Photo 2 — Whether it’s an old-school sling variety or a more modern style with a digital readout, a psychrometer is a sound investment for keeping tabs on the humidity in your environment.


While dry conditions are the most problematic for us in the northern climates, areas like the Southeast U.S. have the opposite problem: too much humidity. Wood swells as it takes on humidity and this causes a guitar’s top to expand. Also, acoustic instruments will sound less responsive or dull when they take on too much moisture. So, while not as destructive as being too dry, a humid environment can definitely change the way your instrument sounds and plays.

You can’t change the weather, but there are steps you can take to ensure your acoustic guitar is properly protected through humidity fluctuation. First, keep it in the case when not being played. This is the single most important thing you can do to protect your instrument. There are also several products available to humidify the inside of acoustic instruments. Some devices feature a sponge that’s wetted and then placed in the soundhole while it’s being stored. These devices can do a lot to stabilize the humidity of your guitar. As the sponge dries and hardens, it’s telling you to add more water. Simple! Other more hands-on units offer the ability to both humidify and de-humidify, but these systems do have a life span and need to be monitored often. We also recommend that you invest in either an old-school sling psychrometer or a more modern digital psychrometer (Photo 2) to ensure you are getting accurate humidity readings in your environment.

Humidity should be a prime concern for anyone who owns a wooden musical instrument, but with a little knowledge and foresight, you can take comfort in knowing that your guitar isn’t in danger of an early demise.

Posted 6/10/2019

The start of a long month of re-fins.

I found this photo, it’s from a few years back but it was a fun month. 61 Strat, 65 Strat, 72 Strat and a 50’s P Bass.

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Posted 6/7/2019

Gibson plastic bridge replacement

OK, here’s the deal. Yes, there are many issues in a coupled acoustic system that can lead to better tonal possibilities. First and foremost is the top or sound board of any acoustic instrument. It needs to be the most responsive element of the guitar for it to sound great. With that comes the importance of the bridge. The bridge is a pretty big deal given that 100% of the kinetic energy transferred into the string has to then be transferred through the bridge to drive the top, allowing “the magic” to happen. So choosing a solid material for the bridge that is of the right weight and density is ideal to do the job correctly. The saddle in a flat top style bridge system should also be a material that can move kinetic energy correctly to the bridge. Again, this energy needs to be dispersed to the sound board. This material can be many things but the best choices for tone always seem to have a similar weight and density.

Over the years I have settled into a pattern of not changing anything on an instrument, if at all possible, but this has not always been true. I have experienced some tough lessons in the past of what is the best choice, even though the general standard is to do something different.

The Gibson Adjustable Bridge brings up one such issue. The general consensus is, if the 1/4 inch adjustable saddle is changed to a 1/8th inch bone saddle, it sounds better. Well, I’m not so sure about that. I have made this alteration several times over the years, and I was not totally convinced it sounded better. In fact an alteration where the adjustable bridge is removed and replaced for the sole propose of installing a 1/8th inch slot is a mistake in my mind. There is probably not much chance that all of that new wood and glue will sound as good as the older, well seasoned original stock system. Noting that it’s not the vintage Brazilian bridge and hide glue joint that’s in question, it’s the adjustable saddle. 

But what about those big ½ inch nuts and brass inserts bolted to the top with those adjusting posts screwed into them, those can’t be good, right? Well, not so quick, let’s look at these. What do they weigh, and how much does this weight affect the pitch of the top. Where is the top tuned? Maybe the top is tuned high enough that a little extra weight drops the pitch to better couple with the air resonance and the back of the guitar. These are important issues to look at if you are going to alter a vintage instrument from its original factory specs. I can tell you that the last such alteration I performed did not sound better, and in fact, it changed the guitars tone in let’s say “not a positive way”. I wished I had never touched it, and it was the last time I ever changed anything from vintage stock without some extensive research to back up such a decision. 

And the last piece of the puzzle is…………….it looks terrible. Vintage factory specs are the correct look and it should be kept in tacked at all cost. When I look at a 1965 J-50 ADJ, I want to see the adjustable saddle not some aftermarket alteration.

So that brings us to the mid 60’s Gibson injected plastic molded bridge. I’m going to go on recorded and say (and you can quote me) this was not a good idea. There is nothing good about it from beginning to end. It definitely is bad for tone, and it did not hold up well over time. I have no problem replacing these systems with wooden replicas, (with the key work here being replica) that will retain the era correct adjustable saddle and look. In addition, there are a few little tricks I’ll do along the way that will most likely contribute to better kinetic energy transfer to hopefully improve tone.

Here is the suspect; you can see it a mile away. The first giveaway is that the fret board is rosewood and the bridge is black. It’s common that in most cases that the fret board and the bridge are made of the same material. Not true with an injected plastic molded bridge, they’re always black.

As we can clearly see this low quality plastic bridge is cracked and has over the years lost its original form. The first step is to remove the strings in preparation of removing the bridge itself.

Next step is to unbolt the adjustment screws until the saddle and screws simply fall out. Then you can reach inside with a ¼ inch wrench and unscrew the bridge. This entire process takes about 5 minutes.

OK, this is an injected molded plastic bridge, so this means that every one is exactly the same. No matter the time frame or model of guitar, they are the same footprint, height, pin spacing, saddle placement, everything no exceptions.  This was a perfect opportunity draw this up in CAD and cut in on my CNC. This way whenever I need another (or anyone else) I’ll simply cut it and away I go.

Here is a prototype made from pine to check the fit and outer footprint. This fit perfectly in all dimensions and will look exactly like the wooden version also produced by Gibson around this same time frame.

  

If you notice we also left the wooded nibs were the screws would have fastened. This will locate the bridge and fill the holes all at once. 

 

On the Brazilian Rosewood replacement we also added the ¼ inch holes to accept the pearl dots that were common on all Gibson bridges. This will not only be vintage correct by look, I will be able to add the small screws and nut as would have been installed from the factory; laying on the guitar it looks correct.

To glue it up I place a custom made wax paper covered backer inside that has two holes to accept the nuts of the adjustment system and I pushed a little wax into the adjustment holes to stop any glue from oozing in. The wooden plugs we left on the bottom on the bridge will act as the locators so this is good to go. I mixed up hide glue and clamped it up. 

The wooden plugs we left on the bottom on the bridge will act as the locators so this is good to go. I mixed up hide glue and clamped it up. 

Here’s the bridge glued up and it looks right, no question there. One thing I forgot to mention, before I removed the original plastic bridge I checked the intonation. I used my Peterson strobe tuner to see if it was even in the ball park and it was pretty close. On some of these jobs I’ve made a custom bone saddle replica of the original ceramic that was intonated for each string. This is a great thing for nailing the intonation and it doesn’t hurt the vintage value. It’s a direct replacement that looks right, you just inform the customer to hold onto the original. Huge improvement, no harm no foul.

It’s still a little rough, so I’ll move on to final stages. 

Gibson routinely used two screws to the outsides of both E strings as fasteners. If you’ve ever seen the ¼ inch pearl dots on Gibson bridges, those are covering those fasteners. We programmed and cut these ¼ inch holes so we’re good to go to install the vintage style screws.

First drill the holes for the screws, and then I can choose the correct style and size screws for this vintage.

This not a big deal, you can find these anywhere, but I have a nice little collection I’ve acquired over the years. In this series of photos you can see I’m using a Philips head screws but I’ve seen both Philips and single blade heads throughout the years with single blade being the most common. Once fitted, I installed and tightened them into place.  

The final touch is the ¼ inch pearl dot to cover the heads of the screws. I made these by gluing bulk pearl to the end of a ¼ inch wooden dowel and sanding them to the correct size. Then I glued them into place.

This is what the vintage system should look like from the inside.

The final product looks vintage correct, there’s no question there. Yes, I do understand that some will argue that a fixed bone saddle sounds better but I’ve been on both sides of that fence and I did not hear much of a difference if any either way.  

If you want to improve tone one trick is to place a hard wood shim of the correct thickness under the ceramic saddle so when tightened down firm the entire saddle area is making good contact with the top. There is a steel spring under the vintage saddle that may have to be removed to pull this off but in this case all I had to do was tighten it down it was correct with the steel spring left in place. This trick increases the saddles contact area and significantly improves the kinetic energy transfer. Just by doing this alone I have noticed improvement in tone.

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The Shape of Things

In my previous column [“The Name Game,” December 2018], we talked about tonewoods and how they might affect both the sound and longevity of an instrument. I also stressed the importance of understanding their material qualities, to help avoid the hype generally associated with tonewoods. We will definitely be revisiting these topics, but we should first look at how body sizes and their resonances affect the sound of an instrument. Once you have a better idea of what you are dealing with, you can make better choices to suit your playing style.

Guitarists often find themselves attracted to certain body sizes because they seem to fit their playing style. This isn’t just coincidence. Body size and shape play a role in the sound of an instrument by affecting its resonant frequencies. And a guitar’s resonant frequencies act somewhat like a notch filter that boosts output in the frequency range in which they are active.

The guitar has three main low-frequency resonances: the air resonance, the top resonance, and the back resonance. Large, deep-bodied guitars put the emphasis on the lower end. Smaller, shallower guitars have less low-end response, which makes their lows tighter and more defined. This doesn’tmean the smaller guitars have less volume. They are in fact the same volume within their resonant range, but just can’t pump the bottom.Yes, larger guitars have been made, but these two models define what players prefer for that big, acoustic sound.

Body sizes are commonly referred to in terms used by well-known instruments, like the Martin dreadnought and OM (orchestra model), or, for you Gibson lovers, it’s the Jumbo and L-00. When looking for low-resonance body styles or instruments with a big bottom, people are generally drawn to guitars in the vein of Martin dreadnoughts or Gibson Jumbos. Yes, larger guitars have been made, but these two models define what players prefer for that big, acoustic sound. In the case of the dreadnought, its 15.75″ bout and deep sides lower the air resonance to around 95 Hz, while the Gibson’s full 16″ bout can drop the resonance below 90 Hz for its classic boom. This is why some players like the Martin for its more-defined low end, while others prefer the Gibson for its smoother, lusher bottom.

Mid-resonant body styles such as the Martin OM and the Gibson L-00 are smaller in width and depth, resulting in higher resonant frequencies—with air resonances ranging between 100 Hz to 115 Hz. Their slightly higher resonances are preferred by fingerstyle players for excellent separation of notes and tonal balance.


The Guidry (left) shows deeper sides and a wider bout when compared to the Martin, which is a common design many modern boutique fingerstyle guitar makers use to boost low-end frequencies.

Even higher-resonance guitars—commonly known as parlor guitars—achieve air resonances ranging between 110 Hz to 125 Hz. While their bass response is limited, the clarity is unique and defined. No, a parlor guitar probably wouldn’t be your first choice if you’re limited to just one guitar, but many players have parlors in their collection to round out their sound.

On the other hand, the Gibson J-185, for example, is a model that bridges the gap between jumbos and OMs. Its shape is the same as a J-200, but it’s sized down from 17″ to 16″ at the bout, which kind of makes it the J-200’s little brother. Between the Martin OM and the Gibson J-185, these two models inspired the modern fingerstyle boutique market. For one example, our senior builder Sam Guidry pulled inspiration from both models in designing his SG-2 guitar. When it’s viewed next to a Martin 000-18 [Photo 1], one can see that even though the SG-2 model was designed deeper to lower the air resonance, the body styles have a similar footprint.

What seems to be true with all makers, big or small, is that while they might play around with the subtleties of the shape, in the end it’s the air resonance that separates the classes between a jumbo, OM, and parlor. When you understand there are defined, measurable differences between body styles, it helps you appreciate why certain classes of guitar are so prominent, and why they have earned their place in the market.

2 Replies to “Bryan’s Work bench”

  1. Good morning, Bryan! Just wanted to say thanks for the shop/school tour that I was privileged to have last Monday morning with Ben Kahler. What a knowledgeable young lad, compared to me at least! I have followed your website for a few years now and am very impressed by what I see and read. As I expected, the atmosphere at the shop/school is so well structured and well maintained that anyone with any knowledge of what it takes to build such beautiful instruments would be very impressed with your facility! I have emailed with Jean a couple times over the last few years and have hopes of seeing you again in the future!

  2. That’s very generous of you Bryan to share this valuable information,thank you.

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