Making panniers out of canvas map bags -- how to seal after the build? I'm planning to make my own panniers out of a set of army map bags -- these are small bags, about as large as a small front pannier, with a rigid back. 

The hooks I'm planning to use attach to the bag with two screws and nuts. I'll have to drill or punch a hole in the canvas and packing to get them to stay. How can I seal the holes so that the bags will stay fairly water resistant? 



(This is a bit of a test question -- will the board cover DIY-style topics like this? It is a real project I have going, though.)
I assuming you are going to put some washers on the inside of the bug so the bolt/net holds well.

I would expect silicone sealant under the washers (on the inside of the bug) and the clips combined with a rubber washers between the head of the bolts and clip and the inside washer and net would do the job.


End of bolt
Rubber Washer
Pannier clip
Silicone Sealant
Bag
Silicon Sealant
Metal Washer
Rubber Washer
Net


However after saying the above, as the clips will be on the inside of the bugs, you will have to be in very strong rain before they leak, you may well find you have other leaks.   A simple small waterproof rucksack liner inside of the bag may be the best option.