What's failing, the cord or the plug/socket?
If it's the cord, you should replace it completely. If the insulation is failing at one point, it is likely to do so at another point.
What you have to look for is whether the insulation is rated for high temperatures - as in it is of some woven, fiber-glass like material.
If it's regular insulation, and the plug/socket us rated for the heat, it will be much easier to replace the cord.
If it's the plug/socket, you should replace it immediately. If the plug/socket is placed such that it does not need to be rated for the heat, all the better - it will be easier to replace.
Now, whether it's the cord or the plug/socket that you replace - just go ahead and replace the other while you're at it.
Any conductor or connector which has had to be repaired more than once bears scrutiny and consideration of completely replacing both. If they are rated for temps above what one would normally encounter in say, a desk lamp or TV, you may need high-temp conductors and finding a multi-conductor cable may be a little work - finding the proper plug/socket setup will require some research as well, but that stuff is out there. An unlike substitute rated for the application may even require changes to how it is mounted.
If you're dipping your alloy, a new pot isn't that much. If it's a bottom-pour, they cost a bit more, but either way, if you're not particularly electrically inclined, I'd just replace the whole pot. I hate to discard "old" stuff myself, but sometimes it's not worth it.
Try these guys.
http://www.tempco.com/accessories/Plugs.htmThey have high-temp wire also - in case you need it and I am not certain you do. I am not even certain you need a high-temp plug/socket, but don't buy household use stuff for this. Tempco has a good site, good products and their catalog is full of useful information in the back. I used to use them once in a while when I was in process heating and I was always impressed that they actually knew something about their products. Very helpful people. I can't say if they will work with a private individual but it's worth a shot.
Boiler plate: I am not suggesting you do your own electrical work or even specify your own components. You burn your house down, well, it's your own fault. There are tons of codes one must consider when doing electrical work, namely NFPA, or National
FIRE PROTECTION Association, state codes, local codes and then, there's the insurance companies, lawyers, civil court,.......
Sorry. I have to say that.