Guitar companies are making models for the masses while the instruments artists play are typically modified to get special tones in the instrument rather from amps or software (see the 'Schematics' page). All companies have custom shop brands or options where you can get this done for $5 - $10 thousand +. Since 2008 a lot of info has been available on the internet revealing schematics and modifications to get the artist tones. This opens the window to have special instrument tones in your guitar or have a mod guitar that has the features of a $$ custom shop model. This blog will pick a few projects to get classic tones and increased flexibility on board. Not for everyone but it is a matter of style, understanding what goes into a custom shop $10 thousand guitar and why great players use a hand full of onboard modifications to trademark their sound.

Second Hand -"It's probably a well-known story . . . I went into a shop in Nashville called Sho Bud which was owned by Buddy Emmons – the famous pedal steel player – and they had things like Rickenbackers in the front of the shop going for quite high prices. In the back they had this second-hand department, and there was a row of Stratocasters, and I bought them all. Blackie was made out of three of these guitars – the body of one, the neck of another and the pickups of another." Eric Clapton



Cracks


Crack Repair

Most common cracks are caused by improper climate control or impact.   A closed crack will essentially close after proper humidification.   An open crack has a gap after proper humidification. 

Glue selection

Titebond has longer open time but releases so easily with heat that I think every instrument owner should take a few joints apart just to see how easy it is. Perhaps then fewer instruments would be left in hot cars to disassemble themselves. Unlike hide glue, dry heat will simply melt Titebond and the joint will come apart. Hide glue is extremely difficult to release with dry heat, but succumbs to steam readily. Steam also releases Titebond just as easily as hide glue if not easier.
Approach to Fixing a Crack

The most important aspect after a crack is noticed is to loosen the strings to relieve all tension and start humidifying the instrument.  Continued use will cause the cracks to grow making repair more difficult.

Do not touch the crack since dirt and oil will darken the wood.

Humidify the instrument by placing a wet sponge in a plastic dish and placing the guitar in a plastic bag.  Check daily and see if it will close all the way.  If not it is considered an open crack 


How do You Repair Closed Cracks?

Although there are multiple methods of repairing closed cracks I prefer to glue cracks with hot hide glue.  Preferred repair is without cleats.  After the crack closes repair with hot hide glue and clamping:

 Place your hand in the guitar and press the wood out/up applying glue.  Clean, clamp and let set.

You can reinforce the crack from the inside of the instrument with small diamond pieces of wood in order to prevent the crack from reopening in the future but this should only be done if necessary and more common for open cracks.  Touching up the finish is usually necessary if the repair is to be invisible.
Open Cracks


Open cracks typically form from the improper seasoning of wood or improper climate control during an instrument’s construction or repair. After lumber is harvested it is seasoned. Seasoning essentially brings the moisture content of the wood down to a level that is sustainable at 50% relative humidity throughout the life of a fretted stringed instrument. When many of today’s vintage instruments were constructed, today’s exacting methods of seasoning lumber and climate control wasn’t possible to consistently achieve. Therefore many vintage guitars have dried out over the years and developed open cracks (cracks with a visible gap at 50% relative humidity).

 How do You Repair Open Cracks?
Although there are many methods of repairing open cracks the preferred method is to inlay a splint into the open crack after the wood is hydrated. Instead of attempting to glue closed a crack that will only reopen it is more desirable to fill the crack with a thin piece of wood or “splint”.  Splints should always be touched up in order to hide the repair.

Using a splint may also eliminate or reduce the need for a cleat since the end-to-end gluing will help stabilize the wood.

Color matching the splint is best done with stain that does not seal- avoid minwax for example.  Use IPA based dilute stains that can be layered to match the wood.  Topcoat after the color is matched.

Example of a difficult crack repair- Modern Martin 'made in Mexico' plywood sides.

Internal damage as the impact split two braces in the area of the cracks then the back splits doubled over so the wood was no longer flush edge-to-edge.  The sides were stiff and moved in keeping the back overlapping.

Repair steps:
1. Tried razor cutting the splits so the wood can align- not successful
2. Tried angle brace to spread the sides and loosen the wood- not successful

Easy fix not possible so needed to remove a portion of the back/ side seam connection.

3. Cut the top away from the sides using razor blade for thin cut.
4. After enough of the back was cut (6-8 inches) then level the splits and added cleats to hold with             magnet clamps. Let them set.
5. Filled the splits with hot hide glue.
6. After the top was stable glued the top back onto the braces (tight bond) using brace clamps.
7. Used pressure clamps to pull the sides even with the edge of the back- long process since sides                 were so stiff and moved in 2-3 mm in spots.  Had to be done in 2-3 inch sections and would only          move about 1 mm each 24 hours.  Holes were drilled in the side to accommodate the pressure                 clamp wire. Glue used was tightbond same as Martin factory for the side to back connection.
8. Replaced damaged kerf pieces from using the pressure clamps- hide glue.
9. Cosmetic repair- filled with mahogany sawdust/glue mix and mahogany grain filler. Multiple                 applications.
10. Stained where necessary to match- mahogany and IPA waterbased mix.
11. Flat polyurethane topcoat (same as Martin) then matched sheen with light buffing 3600 finishing             paper.




 

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