I now have WD style pannier racks and panniers fitted to my M33 as BSA listed in 1952(talk about using up existing stocks!!). I went to my local Camping supplies shop today and asked if they sold a waterproofing material for the panniers. I was told the canvas fibres would swell when wet and become 'waterproof'.
So my question is :- Have any of you used anything for waterproofing or have you just left them to face the elements? 
email (option): ian@integsci.com
Hi Frank...I gave mine a good dose of Thompsons water proofer that you can buy at builders merchants...A lot cheaper than the camping shops and does the same thing...
I also put heavy duty bin liners inside the bags when loading up for touring...Nothing has ever got wet so far!....Ian
email (option): ian@wright52.plus.com
An erudite reply Ian.. Thanks for that..
email (option): ian@integsci.com
A tin of 'Finilec' tyre sealant discharged inside the pannier will waterproof it effectively.
I know this....
make sure there is no loose clothing there at the same time...not nice...
When I lent my M20 to a pal to take to Normandy one year he thought it would be a good idea to put the large bottle of fizzy orange drink he'd bought into the pannier..
It didn't take too many miles before the bottle exploded....
....
I also remember a trip to Scotland when after a long days ride my primus cooker had been completely reduced to a kit of component parts...No vibration then...
...Ian
email (option): ian@wright52.plus.com
, two pots of fresh cream and a bottle of unpasturised Guernsey milk 
[' two pots of fresh cream and a bottle of unpasturised Guernsey milk']
Try clotted cream...much more durable.. ...Ian
email (option): ian@wright52.plus.com