I am sure you have all looked at "Hard Nose" soft plastic baits.
A hard nose bait lasts longer because it is harder at the end wher the hook pulls on the bait.
And you can see the mold lines for the hard nose section.
Well, in trying to figure out how to make UV (Ultraviolet) soft plastic lures that were not.
I discovered mixing engine oil UV treatment to find leaks and WD-40 will make a lure a lot harder. (read my other post about the importance of UV lures)
Basically get a quart (canning jar) and a WD-40 spray can with the spray nozzel and put the nozzel in the jar with the lid close on top to keep the fumes to a minimum.
Empty the can
Add about 8 drops of engine oil UV - to find leaks of engine oil - from the local automotive parts store. (not sure if it is the WD-40 or the combination that makes soft plastic hard).
In a new jar place enough to harden the section of the end of the soft plastic lure that you want
Figure our a way to keep the rest of the lure from falling into the jar.
Soak for 24 hours.
Wash with hot soapy water to end the chemical reaction.
Oh, if you have butter fingers & such use proper safety equipment
Now you have Hard Nose worms or in my case tube jigs... so they last longer.
Best Regards
MarkGuru