A cure for a leaky decoy

I've found that the decoys tend to leak (IF and WHEN they do) at the seam where each half was bonded together.

After you've drilled a hole in the head to let the water out, spray the bottom with soapy water, cover the hole with your finger and squeeze. You will see bubbles where it's taking on water.

I use decoys whenever possible for marking aeration diffusers. Since they should be pulled up once a year and cleaned, it's easier to look at a decoy than any other type of marker buoy. I've found that decoys seem to last about 2 years in the pond 24/7/365 before they start taking on water.

I've had squirrels walk on the ice and chew the tops of the heads that were sticking up through the ice too. One was knawed on just enough so it looked like it had a head of hair.

I've tried silicone seal and other methods, including filling them with foam with marginal results, but I'll try the Flex Seal on them this Spring. Thanks!!