How would you treat the canvas (?) material of your Carradice saddle bag to improve rain proofedness?

Some sort of silicone paste?

I used Martexin Original Wax from Acorn Bags on my canvas Acorn bags. Martexin Original Wax ? Acorn Bags

Good stuff. I'm guessing it would work on Carradice bags as well. Follow the directions, using a hair dryer to warm things up worked well.

If you don't want to wax the bag (kind of a messy process) there are spray can products available at outdoor stores made for waterproofing tents. I used some on a cotton/poly windbreaker I have, and it works great. I'll see if I still have the can and get you a brand name. Boating websites have a lot of info on this. Sounds like the trick is to get the right spray for the right material, use a lot of it, and let it dry fully.

Of course, once you get a can of the stuff, you're going to have to get a boat

Boats, even sailboats, make vintage bicycles appear very cheap.

This sort of thing makes me wonder what's really vintage. I look in Schwinn catalogs and it's all black vinyl

Carradice Cotton Duck Reproofing Wax - £3.99

Thanks all!

Are you anticipating rain?! Oh yeah, we're in Oregon. Never mind.

when i was in high school and it was cool to ski in jeans, we would spray them down the night before with scotchgard. worked great.

of course, not crashing helped...

and still does!

Yep, and on new ones, you'd fall and leave a blue streak.....

To the OP. Go to someplace like REI or on line to Campmor and get the spray, and get seam sealer, too. Works well. I'd recommend spray on the inside, seam sealer, and wax the high-impact areas (above the wheels, etc). You can make them pretty good at holding out water.

We used to buy the cheaper dome tents, then buy the seam sealer and brush-on waterproofer, treat the tent and rain tarp, hang the assembled tent on the clothesline.

I'm not sure if Rustoleum's Never-Wet would work. I don't see why not. Absolutely repels water.

oldskool would be wax such as some mentioned above or Barbour's (even the Queen wears that brand!) but the newskool trick may be that Rustoluem Never-Wet^^...I bought a can and have yet to spray something with it but maybe a bag is a good test-case.

When I was still with USPS as a walking mail carrier in wet, soggy Cleveland, I used to treat my shoes and boots with Pecard silicone. Yes, even the canvas-sided 'hunting'-style boots. Worked great.

I still have the same 4oz brush-applicator can from 25 years ago. A little goes a looooong way! The packaging has changed somewhat since then, but...

I've made a lot of canvas items for my boat (try sewing 24oz duck by hand!) and have used a treatment of equal parts (by weight) of beeswax, linseed oil, and turpentine. You have to heat the ingredients to mix it up, but it gels into a paste that you just rub on.

I use Otter Wax on jackets and bags to great effect. You put the can of wax in a small pan of water and heat it up, then rub it into the fabric with a rag. It's very easy. It takes about 3 reheatings and 45 minutes to do a jacket, but you can do a saddlebag in 1 heating and about 15 minutes or so. I also use a hair dryer while the wax is still warm to make sure it melts in well.

(I use the can, but they also make a bar you can just rub on. Can't vouch for how well it works but I'll probably try it when my can runs out.)

https://www.otterwax.com/

I use this stuff on my Belstaff jacket so you know I trust it.