Patch a tube? No, I put the patch inside the tire, so that debris cannot enter the puncture hole and puncture another tube.
Prepping the tube is also important to get the patch to stick to the rubber, whether it is the tire or the tube, especially if the tube has some talcum powder on it.
Prepping the tube is also important to get the patch to stick to the rubber, whether it is the tire or the tube, especially if the tube has some talcum powder on it.