I'm trying to solder rail to screws at my bridge section so the rails don't move. Anyhow, it seems to me that the solder goes everywhere but between the screw and rail. What is the foremost thing I could be doing wrong?
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First, you must clean and expose raw fresh metal. Lots of ways to do this, sand, file, use a rotary tool.
Then heat- you heat the metal not the solder. You need the metal hot enough to melt the solder when touching it. The solder flows towards the heat.
You need flux- it both helps conducts heat, but prevents oxidation- another reason why it probably is not sticking.
You may be trying to solder difficult metals- what exact rail and what exact screw are we doing here?
Pictures!!!
What's the the screw made of? Solder won't flow on all metals. A google search will tell you what you can and can't solder. Do a search on Youtube for how to videos on soldering.
@BobRoyals posted:I'm trying to solder rail to screws at my bridge section so the rails don't move. Anyhow, it seems to me that the solder goes everywhere but between the screw and rail. What is the foremost thing I could be doing wrong?
Instead of soldering, these screws in why not use Loctite Blue. It will allow you to remove them if needed, but will hold them tight and they will not loosen under any circumstance.
You probably need a bigger soldering tool. The bridge acts as a big heat sink so the spot doesn’t get hot enough even though the iron may be set really hot. I have a large 80 watt Weller I use when one of the pieces is large, and a smaller, more convenient one to do the bulk of soldering wires.
Lots to consider here; most noted above. Clean surfaces, materials that you can actually solder (some metals are easy, some hard, some nigh on impossible for the mere mortal), good flux (had to toss one of my bottles recently), and a good soldering heat (as much as you can bring to bear that gets in fast and out faster. Good solder is also important. Also good to consider is connection positioning to be good and snug between surfaces.
- keep the soldering iron clean. Any flaky residue on the barrel will reduce heat.
- flux- rosin flux for electrical and areas exposed to moisture, but acid flux is far more effective, just not on copper wires.
- "tin" the surfaces to be soldered, heat and apply a thin layer of solder to both before attempting to join them.
- use "low heat" solder- there are some available with a melt as low as 350 degrees F. Lead, tin and antimony alloyed solders are best. SILVER solder is far harder to melt, and not usually required except in delicate jewelry, electronics work and areas where strength is more important.
As others have said: (in slightly varying ways)
- scratch or abrade the surface to allow the solder to stick.
- a large object (like rail) will not allow the heat to concentrate in the area, so you have to use more heat- a large source like a soldering iron is better than a soldering gun.
Mike touches on a key point, tin each surface first. I use zinc chloride flux, Stay Clean is one brand. Works even on many stainless alloys. A 40 watt pencil iron should do the job. Alternatively if you don’t want to get a bigger iron you can use a lower melting point solder like TIX. A resistance soldering tool would make short work of this but unless you plan to build a lot of brass models, likely not worth the investment.
Pete
It would be easier and faster to use J B Weld metal filled epoxy to glue them together. Clean up and scratch up before using.
Charlie
@BobRoyals posted:I'm trying to solder rail to screws at my bridge section so the rails don't move. Anyhow, it seems to me that the solder goes everywhere but between the screw and rail. What is the foremost thing I could be doing wrong?
After following along with all the responses, I think a couple pictures of exactly what you're trying to adhere would be helpful. It seems to be a static application with minimal shear or loading (like hanging something from a wire).
If you have "solder going everywhere", there are two major principles at work. The first being solder follows flux, and for the larger part, it only follows flux. Don't be too liberal with it.
Second, you may also have too much heat where you don't need it or want it. Solder will become more liquid with more heat and that's exactly where it's going to run.
After you clean the respective surfaces, apply flux before you heat. Oxidation can occur rather quickly without flux and make your job much harder. Avoid heating any metal to the point that you see color changes. That is really important. If you re using zinc chloride-based flux, it must be removed after soldering, or risk your parts turn ugly colors from corrosion, even well after the fact. That can easily be done with a damp rag while the parts are still warm. Rosin flux should be cleaned off too.
Electric solder or anything in the 60/40 or 50/50 range is going to be easiest to use. It's not just a matter of less heat, but the higher lead-bearing solders have a bit of a pasty stage with low-moderate heat. That allows the solder to actually pool or flow and not run all over the place. Kinda like Greek yogurt...but again, more heat = more liquid.
Unless you need higher strength, avoid solders containing high amounts of antimony or tin (95/5 or Silverbrite). They do not have a pasty stage. They are much more difficult to control since they are either rock-hard, or liquid and running all over the place. Those solders will not be easy for a novice.
Happy Trails!
Thank you all so very much. I have much to consider based on your insights.
Here’s a thread I posted that I believe is similar to your situation. Good luck. Let us know how it goes.
