I want to fill in this groove in my rifle barrel. Its made of 4150 steel. I don't have a TIG torch and I don't really want to do it with MIG due to fear of warping or messing up the heat treatment. I'm considering using silver solder (or another solder that will resist heat whilst shooting) but the groove is fairly large so I'm not sure I can get the solder to fill it flush. This issue is just cosmetic so heat resistance and general durability is the only concern I have. This surface isn't pressure bearing and doesn't ever interact with anything else. It will be painted over so I don't care about the materials compatibility with chemical surface conversions. Any recommendations?
>>2845549You don't even need to use silver or brazing solder. Most even fancy shotguns have been using 60/40 or 63/37/2 lead/tin soft solder with rosin cores as well as applying plenty of flux beforehand to attach, same for when they are repaired and ribs are re-attached. You just have to do good cleanup after, and regular lead/tin solder will even blue like regular carbon steel after, and a good solder fill will virtually last forever until heat messes it up again.
>>2845549if you want the solder to bond you're going to have to heat the barrel up to the melting point of the solder, which would probably introduce the same concerns of warping as welding.i would do bondo or something similar. if you're just painting it (as opposed to a chemical process like blueing) it should be fine... i think.
>>2845557Thanks. What's the best way to apply thin, soft solder wire to something like this? I don't solder often so I'm struggling to imagine how to properly fill it flush>>2845558>bondoI just might lmao. I think I have high heat JB somewhere. very tempting rn
>>2845549What are you going to use for a handguard?
>>2845598I'm using a regular AKM lower handguard. This is a Yugo barrel that I'm goobering into an AKM kit. I'm moving the groove and gas block back a bit because Yugo stuff is longer.
>>2845549Your fears are unfounded, just hit it with some weld, then dress it down.Anything else will be a pain in the ass to properly finish unless you intend on painting it.
>>2845549Car body filler.
>>2845564>Thanks. What's the best way to apply thin, soft solder wire to something like this? I don't solder often so I'm struggling to imagine how to properly fill it flushyou dont, you weld more material than you need and after welding you would put it on a lathe to machine it smooth again.
>>2845549>I want to fill in this groove in my rifle barrel. Its made of 4150 steel. I don't have a TIG torch and I don't really want to do it with MIG due to fear of warping or messing up the heat treatment.4150 is "not weldable" according to manufacturer datasheets.>I'm considering using silver solderThat needs above 700 °C degrees which anneals the steel and removes the heat treatment entirely. Annealing temp for 4150 is 680 °C – 720 °C4150 is annealed at relatively high temperatures, 540 - 680°C.Going from 500 to 650 reduces the yield strength from 1050 to 700 N/mm2.>(or another solder that will resist heat whilst shooting) but the groove is fairly large so I'm not sure I can get the solder to fill it flush.The only thing that i could imagine not being totally awful is tin-based low temperature solder.>Any recommendations?Leave it be. Epoxy if you insist.
>>2845549>This issue is just cosmeticthen use any random filler. epoxy putty might do well.
epoxy putty, the stuff that mixes like play dough
>>2845549>Any recommendations?yeah.get over it, move on with your life.
