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1968 Martin D-35 Pickguard Crack

1.0 Martin d-35 brazillian rosewood pickguard crack.JPG 1.1 Martin d-35 brazillian rosewood pickguard crack remove guard.JPG
1. The Notorious Martin Lifting Pickguard and Pickguard Crack commonly occurs on Martin guitars manufactured during the 1960’s and 1970’s. The acetate based cellulose plastic used in this period of Martin’s history has proven unstable. This pickguard was attached to the top of the guitar by melting the underside of the guard with a solvent. The pickguard was then affixed to the unfinished top of the guitar. This created such a strong bond that as the pick-guard shrank over time it actually cracked the spruce top of the guitar. Oh ya, the corner of the pickguard is starting to come unattached. 2. Removing the Pickguard with a palette knife. A little patience goes a long way.
1.2 Martin d-35 brazillian rosewood pickguard crack clean crack.JPG 1.4 Martin d-35 brazillian rosewood pickguard crack layout patch.JPG
3. Cleaning the Crack with distilled water and a soft bristle toothebrush will get rid of any dirt and oils that would inhibit the glue I’ll be using in the repair of this crack. 4. Laying Out the Cleate (aka: cross patch). Since the top of the guitar is slightly curled at the crack and because this crack won’t completely close I’ll stabalize the top with a cleate before I directly address the crack. A low watt lightbulb inside the guitar and a divider give me the measurements I’ll need to make a cleate that will center on the crack and butt up against the cross braces.
1.5 Martin d-35 brazillian rosewood pickguard crack fabricate cleate.JPG 1.6 Martin d-35 brazillian rosewood pickguard crack clamping caul.JPG
5. Fabricating the Cleate. A sharp chisel and the shop’s adjust- able bench dog are the perfet tools for this job. The cleate should be thin in order to prevent alteration of the guitar’s tone. 6. The Outer Clamping Caul I’ll be using is a piece of plexi glass. I’ve layerd scotch tape on the caul matching the contour of the pickguard. The tape is equal to the thickness of the guitar’s finish (actually, a touch thicker to compensate for the compression of the tape under clamping pressure). The purpose of the tape is to ensure equal clamping pressure on both sides of the crack (remember, there’s no finish where the pickguard was attached).
1.7 Martin d-35 brazillian rosewood pickguard crack hide glue.JPG 1.8 Martin d-35 brazillian rosewood pickguard crack clamping cross patch.JPG
7. Gluing the Cleate. Hot hide glue is my glue of choice for this task because it has a strong initial tack, is easy to clean up and forms a strong bond between the glued parts. 8. Clamping the Cleate. This c-clamp has more than enough clamping pressure for this task. In- side the guitar there is a wooden cork-lined clamping caul. Cauls protect the workpiece to be clamped (in this case, the cleate and the top of the guitar) and ensure equal distribution of clamping pressure throughout the clamped surface.
1.9 Martin d-35 brazillian rosewood pickguard crack cleate insid.jpg 2.0 Martin d-35 brazillian rosewood pickguard crack taper crack.jpg
9. The Glued in Cleate. Note the grain orientation of the cleate. It’s almost parallell with the grain of the guitar’s top (it’s actually a few degrees askew). In most cases, a cleate is glued so the cleate’s grain orientation is perpendicular to the grain orient- ation of the instrument. This maximizes the ability of the cleate to hold a crack closed. Since this is an open crack which I’ll be splinting and the surface to be cleated is larger than most non- pickguard cracks I’ve glued this cleate slightly off parallell to both reduce the negative impact on tone and prevent any unwanted damage to the instrument should the guitar be subjected to severe changes in relative humidity. Since the splint itself will add significant strength to the repair and because the top exhibited minimal distortion before the repair only a few degrees of difference between the grain orientations of the cleate and top are necessary. 10. Tapering the Crack. An exacto knife will slightly taper the inner walls of the crack. I’m not actually cutting the spruce, rather, the tapered blade of the knife compressess the inner walls of the crack. This will make fitting a seam- less splint possible as well as increase the gluing surface of the splint which will strengthen the repaired crack.
2.1 Martin d-35 brazillian rosewood pickguard crack rough cut splint.jpg 2.2 Martin d-35 brazillian rosewood pickguard crack thickness splint.jpg
11. Fabricating the Splint begins with the process of cutting out the splint from suitable spruce. This piece of spruce is really old and exhibits oxidation and a some- what wide grain. The oxidation will approximately match the color of the top of this vinitage martin guitar that I’m repairing. Also, since the crack in this D-35 is only slightly open, the splint I’m fabricating will be quite thin. I’ll make this splint out of the soft wood fibers between the hard grain material in this scrap piece of spruce. The wide grain of this scrap spruce will make that task easier. 12. Thinning the Spruce with a razor sharp chisel. I’m cutting the spruce to an even thick- ness, then I’ll taper the splint to match the taper of the crack’s inner walls.
2.3 Martin d-35 brazillian rosewood pickguard crack compress splint.jpg 2.4 Martin d-35 brazillian rosewood pickguard crack glue splint.jpg
13. Compressing the Splint will ensure a tight fit. As I shaped the splint, I periodically test fitted it in the crack. When the splint was just a hair too thick to fit into the crack with moderate pressure I stopped removing material with the chisel from the splint. 14. Gluing the Splint with hide glue. I first pressed the splint into place, now I’m applying some hide glue. The glue is somewhat self- penetrating, just to be safe I’ll work some glue in between the splint and the inner walls of the crack with my clean finger tips. The glue quickly penetrates into the porous surfaces of the spruce and swells up the splint to it’s dimension before I delicately compressed it with a hammer and anvil.
2.5 Martin d-35 brazillian rosewood pickguard crack trim splint.jpg 2.6 Martin d-35 brazillian rosewood pickguard crack level finish.jpg
15. Trimming the Splint Flushto the Top’s Finish. A cranknecked trimming chisel is my fav-orite tool for this job. Next I’lluse a paring chisel to make twocuts perpendicular accross the topof the splint. This slightly recessesthe splint below the surface of thefinish. 16. Touching Up the Finish. I filled the splint with nitro-cellulose lacquer and built a finish on the bare wood where the pickguard was originally attached to the bare spruce. The lacquer helps hide the splinted crack and will substantially improve adhesion between the new pickguard and the top of the guitar. I brushed on lacquer until it was slightly proud of the surrounding finish. Now that the finish has had two weeks to cure I’m scraping it almost flush with the surrounding, original finish. A razor blade with a burr and a single layer of scotch tape wrapped around the excess blade allows me to accurately and safely bring down the finish very close to the thickness of the original finish without damaging the orig- inal finish.
2.7 Martin d-35 brazillian rosewood pickguard crack polish finish.jpg 2.8 Martin d-35 brazillian rosewood pickguard crack.JPG
17. Sanding and Polishing the Finish. Sanding the finish with 800 grit wet dry sandpaper leveled the finish. Now I’m polishing the finish with mircro abrassives. Next I’ll buff out the guitar by hand with a buffing compound. 18. Making a New Pickguard. Since the edges of the original pick- guard were so badly warped, I decided to make a new one from pvc plastic that won’t distort and curl up as the original had. Whenever possible, it is prefferable to reglue the original pickguard. In this case, the original guard wouldn’t stay put had I simply reglued it.
2.9 Martin d-35 brazillian rosewood pickguard crack.JPG 3.0 Martin d-35 brazillian rosewood pickguard crack cauls.jpg
19. The New Pickguard. I’ll further refine the shape and taper the edges of the new guard before attaching it with extremely thin double sided tape to the top of the guitar. 22. Pickguard Clamping Cauls will allow me to apply a lot of clamping pressure to the top and pickguard during gluing. This will both help correct the minor distortion in the instrument’s top and ensure a strong bond between the top and the pickguard. The outer clamping caul (pictured left) is lined with rubberized cork. The cork will protect the pickguard from unwanted scratches. The inner clamping caul has dados to accomodate the bracing inside the guitar beneath the pickguard.
3.1 Martin d-35 brazillian rosewood pickguard crack clamp new pickguard.jpg 3.2 Martin d-35 brazillian rosewood pickguard crack crack after.jpg
23. Clamping the Pickguard. Five c-clamps provide ample clamping pressure to ensure excellent adhesion between the pickguard and the top. 24. The Splinted Crack. Although the repair is visible, it is none-the-less visually subtle and strong.
3.3 Martin d-35 brazillian rosewood pickguard crack pickguard after.jpg
25. The New Pickguard. From a short distance the repair is practically invisible.