Here is a method that was used with some success to repair cracks in Old Type handles. It would not work with razors where the handle is two piece. Beware that this is for information purposes and no one can be held responsible but yourself if your repair makes it worse.
- Slow setting 2 part epoxy, marine grade. Don't use the 5 minute kind.
- Three or 4 small pipe clamps. They need to be small enough to not distort or oval on the handle.
- A tube or rod slightly smaller than the inside diameter of the handle. I used a Bic pen. If you wanted a heavier handle, you could use a solid rod to add weight.
- First, remove the ends of the handle. You should be able to twist/pull/tug them loose.
- Second, clean everything good, inside and out.
- Third, cut the tube/rod to the length of the handle, minus the length of the ends that will be in the handle.
- Fourth, mix the epoxy and apply a good coat to the ends and the tube/rod. Don't over do it, any that oozes out has to be scraped/cut off to remove it.
- Fifth, insert the tube/rod into the handle, then insert the ends.
- Sixth, put the clamps on. Tighten them firm, but do not overtighten. This will pull the crack out, and the increased surface of the insert will give the epoxy something to adhere to.
- Seventh, let this set overnight.
- After removing the clamps, you can take a knife and remove any epoxy that oozed out during the repair.