CB, propane works,sorta. Mapp is hotter,and a bit faster. Thing is to not get in a hurry with this cast metal.
I clamped in my vise at the rear lug,and I know the vise heat sinked a bunch ,but clamping anywhere else made the guard unsteady. If anything, I dont need any extrie unsteady.lol
Anyway, get it curl red as you can,as far down the curl as possible, and using small hammer,slowly work the curl closed,keeping it hot so as to avoid cracking.
The one I modified with the curl cut narrow and bent forward, was done because the curl started cracking ,so I did a bit of hacking and filing,and more heat to get this result. I like it ok.
As I have noted, I have a heap of these guards in usable condition that I plan to get organized into some pics and post for sale at a good deal for several at one time.
In addition, I have a milk crate full of broken pieces/parts of these guards that can be smithed into a bunch of different styles.
My bud Bob W has several of these junkers resurected into nice Mountain types. Gonna get pics next time I go over there.
We dont call each other junkMan fer nuthin.
Been doing that on old cars and guns for 40 years. Have a good evening y'all. Best regards, dave F