Hi!
Never done any frame work before but I do weld and have done a limited amount of silver brazing in the past with a small oxy-propane setup I have - mostly various stainless connector hardware for a camper trailer I made a while back.

Am toying with the idea of building out an old rigid mountain bike into a light bikepacker/commuter, I'd want to add some mid-fork eyelets at least and maybe also add some posts for mounting a frame pump. Honestly mainly want to give myself a change to practice brazing because I've always been a little too scared to attempt in the past.

I don't totally understand how worried (if at all?) I need to be about messing up heat treatment while brazing. My reading has gotten me far enough to suggest that some cromoly alloys are not really heat treated so there's nothing to mess up, and maybe that the brazing temp (so long as I don't heat excessively) is not hot enough to mess with any heat treatement? I'm not so worried about ruining a junky old frame practicing, but I really don't want to compromise a fork and not find out till I'm screaming down a hill with a fully loaded bike. Watched some youtube videos and did some reading but nothing really specifically sez "do braze this alloy, don't braze that one" (which leads me to think that probably it's all OK?)

I'll be silver brazing so presumably I'll be on the lower end of the temperature spectrum unless I really muck things up.

What's the deal? What do I need to know (or where do I figure out what I need to know?) Am I going to be just fine brazing in one or two pair of eyelets on a junky 80's MTB fork?