This cello came in with multiple areas of significant damage that required a combination of structural repair and restoration. The back seam was largely unglued and had shifted out of alignment, while the top had several cracks extending into the f-hole area, including a wing crack. In addition, there was a broken corner and sections of missing, sheared-off edge. The repair involved carefully bringing the body back into alignment, securing the cracks with hot hide glue and internal cleats, and rebuilding the damaged areas. Each step required working through limited access points and adapting techniques to restore both the strength and overall shape of the instrument. Back Crack and Cleat Repair Steps- Open the back seam: Carefully unglue one full side of the back to relieve tension and gain access to the crack.
- Realign the crack: Gently bring the crack back into proper alignment before applying glue.
- Apply very hot hide glue: Work very hot hide glue deeply into the crack so it penetrates the joint thoroughly.
- Clamp the crack: Apply clamping pressure to hold the crack in alignment while the glue sets.
- Reglue the seams: Glue the opened back seams back onto the ribs once the crack is aligned and secure.
- Prepare the cleats: Make small cleats with a tiny hole drilled through the center.
- Soak the cleats: Soak each cleat in water for about five minutes before installation.
- Set up the guide rod: Place a magnet on the end of a slightly bent metal rod.
- Mount the cleat on the rod: Push the cleat onto the rod and adjust its orientation so it is ready for placement.
- Apply wood glue: Coat the cleat with wood glue for the permanent bond.
- Skin the glue: Lightly warm the glue with a heat gun so it skins over and does not drip during placement.
- Guide the cleat into position: Use a magnet on the underside of the back to help guide the glued cleat into the correct location.
- Release the guide wire: Once the cleat is in position, slide a small tube over the wire and push the magnet until the wire pops free from the cleat.
- Adjust the orientation: Rotate or shift the cleat slightly if needed so it sits properly across the crack.
- Clean off excess glue: Wipe away any glue squeeze-out before it dries.
- Position the balloon clamp: Feed a balloon through the f-hole and place it over the center of the cleat.
- Inflate and allow to cure: Inflate the balloon to apply pressure and leave it in place for about half a day to a full day.
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Top Crack Repair and Cleating - Address the top cracks: Begin by preparing the cracks for gluing and reinforcement.
- Glue from the outside: Use spanning clamps to close and secure the cracks from the outside of the top.
- Prepare the cleats: Make the cleats and soak them in water to allow for easier shaping and placement.
- Plan cleat placement: Position each cleat where it will sit and mark the clamp angle with a pencil.
- Secure the outside mold: Place an outside mold on the top and tape it in place so it does not shift during clamping.
- Attach cleat to clamp: Use a small drop of CA glue and a magnet to temporarily adhere the cleat to the clamp.
- Apply glue to the cleat: Coat the cleat with glue for permanent installation.
- Skin the glue: Lightly heat the glue with a heat gun so it skins over and does not drip during placement.
- Install the cleat: Feed the clamp and cleat through the f-hole and position it over the crack, then clamp firmly.
- Release the clamp: The next day, give the clamp a slight twist to break the CA bond and remove it from the cleat.
- Repeat as needed: Repeat this process for each cleat, in this case installing four cleats in total.
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Corner and Edge Reconstruction - Create a corner mold: Make a styrofoam mold of the missing corner and tape it securely in place.
- Fill the mold: Pour the liquid hardwood substitute into the mold to form the new corner.
- Allow to cure: Let the material set for about one day.
- Shape the corner: Using a template of the original corner, trim and shape the new material to match.
- Rebuild the edge: Mix the wood substitute material for the missing edge section.
- Form the edge: Apply the material and use cellophane to help shape it roughly to the correct contour.
- Final edge shaping: After curing, refine and shape the edge to match the surrounding area.
- Seal the cracks: Apply a clear seal to the repaired cracks to protect them.
- Touch up varnish: Perform varnish touch-up on the cracks, corner, and edge to blend the repair.
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