Thank you for posting your question here on Fixya.com.

Purchase a can of spray foam insulation and then drill a hole in each end of the handle to match the spray tube on the insulation. Let the handle dry once the holes are drilled then fill the handle with the foam from one end until it begins to expand out of the holes. Once the foam has set you can trim off the excess and scoop out a dimple of foam from each of the holes. Seal the holes with a two-part epoxy but even if the handle still leaks the foam will prevent much water from getting in and the handle will remain buoyant.

If this answer does not fix your problem, please comment with additional details prior to rating the answer. You may also contact me thru our website at www.arrowpools.net. Positive feedback is appreciated once your problem is solved!

John