Inject glue into joints without disassembly using a syringe

Use a glue syringe or squeeze bottle with a needle tip to inject wood glue or thin epoxy directly into a loose joint through a small drilled hole, without having to take the piece apart. This is the practical approach when a chair or table has joints that are too difficult or risky to disassemble.

How It Works

A syringe with a blunt-tipped needle or a glue bottle with a fine applicator tip can force adhesive deep into the gap of a loose joint. By drilling a small (1/16-inch) access hole into the joint from an inconspicuous location, you create an injection point. The glue flows into the gap between the tenon and mortise, re-bonding the joint.

Step-by-Step

1. Work the joint back and forth to determine the extent of looseness
2. Choose an inconspicuous spot on the joint and drill a 1/16-inch hole into the joint cavity
3. Fill a glue syringe with thinned wood glue (mix roughly 10% water to thin slightly) or use a low-viscosity epoxy
4. Insert the syringe tip into the hole and inject glue slowly
5. Rock the joint back and forth while injecting to help glue penetrate all surfaces
6. Continue injecting until glue seeps out of the joint lines
7. Clamp the joint tightly
8. Wipe excess glue immediately
9. Plug the injection hole with a toothpick dipped in glue, trim flush after drying
10. Allow 24 hours to cure

Tips

• Veterinary syringes (available at farm supply stores) work well and are inexpensive
• Chair Doctor brand makes a kit specifically for this purpose with thin glue and applicator
• For very loose joints, thin CA (super glue) can wick deep into the gap, but it is less forgiving than PVA
• This technique is popular for repairing Windsor chairs and other chairs with round tenons that are nearly impossible to disassemble
• Work from the bottom or back of the joint where the access hole will not be visible

Common Mistakes

• Not injecting enough glue: you want the cavity saturated, not just damp
• Skipping the clamping step: the glue needs pressure to create a good bond
• Using glue that is too thick to flow through the syringe and into the gap