I have used my last glue patch but I have plenty of glue remaining and I was thinking about cutting an old tube and making patches out of it. Any cons I need to be aware of?

It doesn't work. I tried this when I was looking for different uses for an old tube, the two pieces of rubber just didn't stick together. You can get packs of 100 patches if you want<----- never ending

+1

If you are can talk your store in to it, a lot of distributors have big rolls of patch material. Think duct tape type roll, except patch material. I have one in my garage because I talked my LBS into ordering it for me.

No cons. Tubes make AWESOME patches. Just rough the tire and the tube so the glue will keep it in place. It is best to roll the tube with a can or something of the likes to make sure the shape is not infringing on it holding air. Just roll it flat for about 3 minutes. Pump it up. You'll never have a flat in that spot again.

I found an article on Sheldon Brown's site that discusses this. It can be done you just have to prep the tube and patch.

https://www.sheldonbrown.com/brandt/patching.html

Works fine for me, just prepare the patch like you would the tube, I put a little 'glue' on the patch as well.

May not work the way you did it? What size tube/tire? Did you prepare the tube, especially getting rid of any talc'd surface? Use glue? Come on man, explain! Curious minds need to know!

It's a lot of work. Not only do you have to sand down the tube, but you MUST sand down the piece of tube you cut up to use as patch. It worked fine, but more care and prep has to be done. I used to do this in my student days to save... $10-20/yr on patch kits. Then I found a lot of auto-repair shops can order me 100-pack of 1" Camel patches for $5.