leaking 5 litre barrel

[ROD01]

I have tried searching but with no success...
On looking into my 5 litre barrel I realized it was lined with wax, so I marked the head, took off 2 of the hoops and scraped out all the wax.
I then charred it lightly with my torch and put it back together.
It has been soaking in a bucket of water for 2 days now but is still slowly leaking around the head, though much slower than at first.
If it doesn't stop in another couple of days do I have a decoration or is it fixable?
Has anyone had success with trying to plug leaks by driving in thin shims of oak?
Any suggestions appreciated.
Thanks,
rod01