Right about rubber cement no good for such.
I've almost had to use a boot few times on good lawn tractor tires that got stobbed.. (but got by without) I have some old tire boots that are no longer sticky set back for such as what you are doing.
I've not tried such but have thought about trying shoe Goo.It comes in clear and black Really tough once it cures and is flexible.
You could try a dab on a old tire as trial run first to see if Shoe Goo bonds good.
It's readily available at around $5 tube.
I've used it on several other things with good results. It's slow curing, takes about 12 hours to fully cure at 70 degree, but would cure somewhat in about 6 hours. It's a tough flexible bond once it cures.
I put the unused portion in a zip lock bag and store in a fridge and it can still be used several months later, just slower curing when it comes out of the tube cold. I've used it on lawn tractor seats and shoe soles. Shoe soles have to be clamped/held in place until it cures. I also strap down a padded tractor seat until it cures.
Phil Swift says he has FLEX Seal products what will work for everything, but I've never tried such. (mainly due to cost)
Let us know what you decide to use?
