Actually, I have a lot of experiance here. This is a post from another thread:

Most of the fuses I have dealt with start to get soft around 150 and up.

As a rule of thumb, anything above 120 degrees, you can not keep your hands on it, you can touch it, but you'll have to pull away, even though it won't burn you.

So sometimes even though you can't keep your hands on the fuse, if it's at say 140, you are still good.

Mileage may vary, and ceramic blankets, work well for this type of issue, mounted to the fuse. I've had no real good luck wrapping the pipe, but some have.