D'oh - Kettle Element Seal

This is going to be a tad awkward to explain without decent photos, which i hope to add tomorrow night but I'm desperate to sort this problem so am hoping someone can advise....

I made a very much DIY mash tun/chiller and separate boiler and ran my first AG brew last month without problems - using 1 kettle element.
The boiler is along the lines of this instructable but using a PP Mango Chutney barrel as apposed to a bucket:
http://www.instructables.com/id/Build-Your-Own-Brewery-for-Under-100-STEP-2-/

The other day I went to add a 2nd element to speed up the boil and drilled the hole a few mm too large! So, now the gasket/seal that came with the kettle does not seal and there is a steady low level leak.

I have been attempting to use the kettle socket as is, i.e. the screw holes connecting to the element screw threads.

I tried adding o-rings in various ways but cannot get it to seal properly. I am wondering whether I should forget the kettle connection assembly and screw into a wooden/metal block on the outside (and wire up from there).

In summary, I'm stuck. Any ideas?

Sorry for lack of photos - I'll add asap.

First, I am not a fan of elements in plastic containers.

Second, I would think you could find a large Stainless or Plastic washer that could be epoxied with high temp glue onto the barrel and have the correct sized hole for the element.

Thanks for the reply - I will look into epoxies again. I had a quick look at sealants but didn't see any 'food grade', at least not at 100C.

Twas only a quick look and you are right, it would be a simple fix.