How to Fix Loose Joints on Window Sashes
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Old glue may have deteriorated over time, moisture on end grain causing cycles of expansion and contraction and even a bit of rot may have loosened sash joints. As long as the timber retains enough structural strength the joints can be fixed without dismantling.
For this you will need a trip to chemists for a small syringe (needle not required). The idea is to inject the joints. First drill small holes (of a size to take the syringe nozzle) where appropriate so the glue can get to where it needs to be. Down the sides of tenons is usually the place to go and in to the meeting faces of the two pieces.
If there has been a bit of rot then inject first with wood hardener and leave to cure.
Then the holes can be injected with polyurethane adhesive. To make this easier first warm both the joint and the glue to reduce the glue viscosity, a few seconds in a microwave is effective for the glue. The glue can be injected at all points until it starts squeezing out somewhere. Be prepared this can get messy so gloves and rags are essential.
When cured the excess can be cut of and imperfections on the surface filled. There you have it loose window joints fixed.
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