Before & After Pictures of
Crack Repairs on
Guitars
Martin D-28 Pickguard Replacement &
Top Crack Repair
Cracks on either side of the pickguard are very common when the pickguard is glued directly to the
top. Martin did this until the mid 80's
and this is often deemed "the Martin pickguard crack", but any instrument which has the pickguard glued directly to bare wood can suffer the same fate
if the pickguard shrinks.
Sometimes I'll have a dozen of these in at one time. In cases where the pickguard maintains a firm grip on the top, it pulls so strongly at the grain when shrinking that it can cause a crack or two along the grain.
When repairing these I remove the guard which
releases the tension on the top and normally allows
the crack to close with some coercion.
I then finish the bare pickguard area with lacquer and make a new pickguard from scratch. Most of the time these old black Martin pickguards have curled up to such a degree that they look like a potato chip and can not be reused. I do my best salvage old pickguards but it is not possible in all cases.

Taylor Top Crack & Repairing U.V. Cured Finishes
Here's a top crack caused by impact. The crunch was bad enough to not only crack along the grain but the force pushed the top to the point of "folding" (meaning it bent and splintered across the grain.)
Along with the damage to the top the crack had also been subject to a good amount of dirt collection.

Picture 1 above is before any cleaning took place. In picture 2 I've done my best to remove dirt from the cracks. The rippling look to the finish was caused by the folding of the top across it's grain.

After the repair a small thin line is
visible. Filled chips are still visible but smooth to the touch. From a very short distance it is extremely difficult to see though.
The clamping method required made use of my go-go-gadget long skinny arms and a mini jack. In effect, it needed to be sandwiched and propped all at the same time, which is always a challenge on cracks so far from the soundhole. The size of my arms is truly an advantage here. Many times conventional clamps and clamping methods are not an option, such was the case.
A spruce patch now reinforces the area and butts right up to the kerf lining. It helped "iron out the wrinkles" and will also stabilize the cracks encouraging them to remain closed. Once all cracks were repaired and reinforced the finish cracks and chips were then filled with cynoacrylate (Superglue) and leveled with the remaining finish. Is it invisible? Noooo! Although it isn't terribly obvious in the photographs ah?
Martin JC-16RGTE (Concave Top with Crack)
This is a very common repair, especially during the winter. As you can see in the photos this top has lost enough moisture to render it concave. The top crack which runs for bridge to end block along the grain line is easily 1/32" wide.
Read more about this repair here.
Before

Concave and cracked.
After

Pretty hard to spot now, but this is a one shot deal. I have plenty of instruments brought to me with misaligned, dirty, poorly repaired top cracks that are extremely visible. Unfortunately it is very hard if not impossible to undo poor repairs.
Related Articles:
Crack Repair
Humidity & Your Instrument
Finish FAQ's
Pickguards
Guitars, Gear & Parts