Radiator Overflow Tanks

[crawdad]

I had to order a replacement overflow tank for my truck recently. I got the first one on and found out it leaked. Sent it back and got a replacement and it leaked also. Sent it back for a refund. Both of those tanks leaked in the same place as the original one on my truck which, as far as I can tell, is right down near the bolt hole closest to where the overflow tube connects. Does anyone have a good way to seal up a hole in one of these tanks, or do you know where I can get one that want leak. Thanks.