Before you can repair a wood joint or veneer, you must strip the old adhesive from the furniture. Traditionally, the glue held bits of veneer to furniture or added strength to wooden furniture joints. Before 1940, most furniture makers utilized animal-based glues. Made from rendering collagen from hooves, bones, skin and other connective tissue, the paste responds to warmth. Furniture manufactured after 1950 has polyvinyl acetate or PVA adhesive that reacts to alcohol. During the removal process, you will determine the sort of paste on the furniture.
Remove any large pieces of paste using a putty knife. Scrape off the tops the large lumps of glue, but don’t press on the knife to the wood.
Grind off the glue bits left from the knife. Utilize the abrasive tip on a drill, or a grinding wheel or attachment at a rotary or oscillating tool to provide you with the most control to pinpoint the adhesive.
Replace the abrasive point using a sanding disc or mat. A disc of 180-grit gives you a smooth end. If the area is small and a disc or pad would harm the end, use a smaller sanding ring to protect the furniture.
Place a drop of very hot water on the paste. If the glue softens, it’s animal-based. If the glue stays firm but lightens, it’s PVA-based.
Wipe any adhesive residue from the item. If you decide it’s animal adhesive, heat a moist rag at the microwave for 30 seconds. Wipe the paste slowly from the wood with the hot, moist fabric. If it’s PVA-based adhesive, wet the rag with isopropyl alcohol and wipe the adhesive residue from the wood.
Allow the wood to dry completely before staining, painting or regluing. Depending on the ambient humidity of your workspace, this can require around 24 hours.