solder sights

I am having a blast of a time replacing a front sight . The problem seems to be my lack of getting the solder to take on the job.The solder just seems to sit there..melts ok but will not join..

The barrel is browned ...does it half to be cleaned down to the metal to take?
::

 

you need to use a flux and a good silver solder

 

[Zonie]

I have never been able to get solder to stick to rust.
IMO you need to clean the area down to bright shiny metal, then use the good flux Captchee mentioned.
It also works best if you "tin" the surfaces you want to solder.
This is done by fluxing both surfaces and then applying just enough solder to both surfaces to make them shiny with a thin layer of solder.
Then heat the thickest metal part just a little more than it takes to remelt the solder, position the sight and hold it tightly in place so the heat transfers to it and melts it's thin layer of solder.
Do not move anything until the solder freezes (sets).

You may have to add a little solder to the joint to fill any gaps.

Sometimes it is real difficult to get the surfaces clean enough for successful tinning and until you do, the solder won't stick.

 

[brushbuster]

there are basically 4 types of solder on the market .Silver core,rosin core,acid core,and solid core .with the solid core you MUST use flux.
with any solder all mating surfaces MUST be cleaned to shiny metal,apply flux to both surfaces then heat while touching the solder to your surfaces until the solder starts to melt maintain heat until the solder flows into the cavity .remove heat and allow solder to cool on its own.
when the part is cool to the touch you can clean up the drips and slag with a file and emery cloth. :thumbsup: eace:

 

Thanks to all. I am going to make another stab at it this weekend. :redthumb:

 

[squirejohn]

Would silver solder be appropriate to use for attaching a brass sight? I'm replacing the brass turtle sight on my NWTG with another brass turtle sight. (Going to replace the original since I'm going to put on a rear sight and the existing sight has been filed down too much). I heard somewhere that perhaps I should "cold solder" on the sight. Is this true and, if so, what is cold solder and where do you get it?

 

[brushbuster]

squire i may be wrong on this ,but the only thing i can think of as far as cold solder would be the low temp solder used for electronic boards /components it usually is very small in diameter and rosin cored therefore only needing a 15w to 35w soldering iron to melt and flow the solder.
silver solder requires a much higher temp to get it to flow properly when i soldered in my sights i used 50/50 solder with a past flux (c flux) and a propane torch.
you only need enough heat for the solder to flow into the cavity then remove the heat and let cool.
cooking in the solder will actually draw the solder back out the cavity and therefore weaken the joint

 

[squirejohn]

Thanks brushbuster, I guess I'll try the silver solder. I'll practice on some scrap metal first as my "home handyman" soldering repairs of water pipes usually wind up look like a small lava flow.

 

[rayb]

You're doing better than i am, mine look like a volcano \in a mountain range... ::


rayb

 

[brushbuster]

being a licensed plumber i've had lots of practice,heres a helpful hint,while the solder is still in the molten stage ,quickly use your flux brush or a clean rag and wipr the excess solder off of your joint.its a lot easier to clean up that way :winking: