Yes there will be a color difference when using Hard Solder,,it's a shade of yellow.
But you don't use it as a gap filler. You use it to repair the very close fitting break in the part.
A very fine hair line width joint results. That is all the color difference you will see.
Can't deal with that,,buy and fit another guard.
There are hundreds of different alloys of Hard Solder. All for different specific applications in industries and specialtys.
For this type of work, most any general use hard solder will do.
Need some Hard Solder,,I'll send you a couple feet of very fine dia wire Hard Solder wire. It's the same stuff B&L used to put eye glass frames together with when they still made them here in the USA.
I've been using it for many years.
For that job you'll use less than an inch of it.
You need flux of course and that you can but in a small jar at a real welding supply or hardware store.
You'll need a torch that can heat the joint to a bright red color to melt and flow the solder...Propane might not do it these days from my experience,,maybe it will . They seem to be pretty whimpy in the heat dept lately. Maybe just me.
It won;t damage the steel,,just solder the joint back together.
