O.k., I need to solder the very tip of my solid brass firewall trim (it broke off at the screw hole while I was attempting to finesse the curve with heat), but I can't remember what type of solder and flux to use. I have both rosin core and lead free silver bearing solder - which is correct? Also need to know what type of flux to use with the correct solder. Thanks!
Silver solder would be best because it will appear as brass and be stronger. But, NOT the "silver bearing solder" that they sell at Lowes. Maybe try McMaster Carr for the real stuff. Look for the lowest melting point you can get and buy the correct flux for it as well.
By the way, to finesse the curve with heat, try heating the area you want to bend to red hot, then quench with water, then bend. That will soften brass. (Yup, the opposite of what you would do with steel)
Thanks, Jerry! Now that the piece is broken, I was able to match the lower curve perfectly; I just need to solder it back together!
It sounds like you were trying to bend the brass while it was hot? It will break easily if you do that. It's best, if you are bending thin brass quite a bit or if it is old and has work hardened, to heat it with a propane torch until it is a dull red then let it cool completely before bending. You can quench it in a tub of water if you like. Heat it at night so you don't overheat it. I use the same solder and flux for brass as I would for copper plumbing work. I'm not sure what you are trying to do but you may be asking about silver brazing that should be done with an oxy/acetylene torch and yes, there is a flux for that.
I was just planning on using my propane or MAPP torch to do the soldering. I'm just trying to solder the two broken brass pieces together again.
Hi Bill, MAPP gas gives a really hot flame that can melt brass, aluminum, other soft metals. It heats fast, maybe too fast if you are not familiar with it. I would start with propane if you are using conventional solder. If you are silver soldering, propane may not be hot enough, but it may be. A small torch will give you better control than the standard burner you usually see on a propane bottle. Good luck!
I used Safety Silv 45 when I repaired a brass horn. It's melting point is favorable and it's brass colored. Any welding store should sell a single stick to you.
Go to your local welding supply store. Talk to them and get their input as to which products will work best for your needs. They have much more experience with their products and proper application.
Bill I have done a lot of silver soldering over my working years. As mentioned above it will give you the best and strongest fix, however it is imperative to have the correct flux for the rod you are using and the base metal has to be very clean. good luck.
Just a thought, it's usually best not to learn welding/ brazing or soldering skills on your project pieces.
Even if soldering were structurable (I doubt it will be) this repair will look like a repair. I recommend brass welding. If you don't have this skill, bring your parts to the Brass DIY Workshop at the MTFCA Museum on 3/24, and I'll weld it for you. The weld will then need to be filed and surface finished to be invisible, so count on spending appreciable time on it. Personally, for the time and effort required to make this type of repair invisible, and for it to remain attached, I would eat the 70.00 and replace the brass strip. Also, I bend the strip and confirm fit before drilling and counter-drilling the holes. Do not heat the strip to bend it.
Scott, I appreciate the offer - very kind of you. However, because of various other commitments I wouldn't be able to attend the upcoming workshop. I did consider just replacing the strip, but it is an original and has that look to it. I'll think about all the options out there but the good news is, the break was at the very bottom curve so even though it may still look like a repair, it's in a not so easily seen area of the dash.