# Solder



## porthos (Jan 5, 2022)

there is flux core solder and solder that needs flux. is there any advantage to using solid core solder? i'm sort of a novice in soldering.


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## markba633csi (Jan 5, 2022)

For electrical work, rosin core solder is always used.  For some types of sheet metal joining, acid core is sometimes used, or solid core with a separate paste or liquid flux.
Also, for filling a solder pot large solid core bar solder is used, with the flux being applied to the part being dipped
Radiator repair shops probably make some use of solid core
-Mark


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## C-Bag (Jan 5, 2022)

porthos said:


> there is flux core solder and solder that needs flux. is there any advantage to using solid core solder? i'm sort of a novice in soldering.


As you can see by Mark’s reply it is very dependent on what you’re doing. I use appropriate flux even with flux core as sometimes the flux drains out. I’ve also after decades of using my one pot, run out of flux and bought some new stuff and it was useless. Luckily my neighbor had a ton of the old stuff so filled me up.

Depending on the job heat source is critical too. I‘ve done a ton of soldering, acid and rosen along with brazing. Just yesterday I did silver solder on a stainless steel counter end for the first time and that was another whole ball o wax. Every solder process needs different heat source too. So without knowing what you’re doing it hard to know what you need.


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## Janderso (Jan 5, 2022)

I haven’t done a wide variety of soldering but i have learned this much,
Clean your parts very well, sand, grind then acetone.
Use the right high quality flux for the job and the correct solder.
Determining what’s correct for the job has been challenging for me.
I like to learn as I go


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## RJSakowski (Jan 5, 2022)

You want to buy solder made from virgin metals.  Cheap solders are often made with reclaimed metals which can contain impurities which prevent proper flow of the molten solder.  Fluxes also come in different activities.  The more active fluxes will more aggressively attack oxidation that prevents proper wetting of the  metals being joined.  I has preferred Ersin solder in the past as it offered an alloy called Savbit which contained a small amount of silver which greatly reduced erosion of the soldering iron tip.  Kester would be a second choice.

The 63/37 alloy has the lowest melting point.  Significantly lower than lead free solder being used for RoHS compliant products.  The lower temperature means less chance of damaging sensitive components.  I prefer either a 63/37 or 60/40 alloy if I can get it.

{Plumbing solder uses an acid core or acid flux if solid core.  The "acid" is usually zinc chloride.  It should noit be used for electrical or electronic work though as it will corrode the base metal.

50/50 solder is used for body work.  It is usually solid core  if in a wire form or it comes in bars.  Acid flux is used with it.

Edit:  Alpha is another good brand


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## woodchucker (Jan 5, 2022)

I've used solid with electronics, my friend freaked out .. but I use liquid rosin flux by MG chemicals, or Kester acid paste flux sp30.
I've not had a problem with that method. I still use rosin cored solder when out in the field and at home...
but I'm not afraid to use the solid. These 2 fluxes make up for the lack of rosin core.

As someone said, sometimes the cored fluxes leak out, so by having my own flux, I can control things.. 

Just another opinion.. you know what opinions are like right?


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## porthos (Jan 5, 2022)

*OK, acid core and rosin core.  different uses and why??*


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## woodchucker (Jan 5, 2022)

I use rosin mostly for electronics. But if I have a broken mount for a board, I will use the acid. I clean it immediately.
I use acid for electrical, heavy stuff. For my F3B winches, I crimped the welding cables with terminal ends (forget what they are called), then used the acid core, and soldered the connection. We want full  contact, so that we are not changing resistance. Each winch has to meet a certain resistance, and if the connection is weathering it changes. With ACID and ROSIN I clean all connections afterwards. I use alcohol wipe it clean, and/or flood it.

As long as you clean up both will be safe.

I find old electrical that was soldered, when resoldering, I find the kester Acid to work better at reflowing and resoldering.

I am no expert by the way, it's just what I found that works for me.

edit: btw both were sold by my semi local Electronics house... Greenbrook Electronics.   Not a plumbing supply or Home center.


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## RJSakowski (Jan 5, 2022)

porthos said:


> *OK, acid core and rosin core.  different uses and why??*


See post #5

Additionally, rosin core wouldn't be used for plumbing because it isn't as aggressive at dissolving oxidation and remnants aren't wasily removed from plumbing.  Acid flux is soluble in water.


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## markba633csi (Jan 5, 2022)

Acid core is for hard to solder metals, like steel.  But the acid can cause corrosion if not cleaned off afterwards, and even then it sometimes corrodes. 
Rosin core is for relatively easy to solder metals, like clean copper wires and brass items.  
-M


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## RJSakowski (Jan 5, 2022)

I have successfully soldered stainless steel and aluminum with rosin core solder.  Clean metal and good solder are key to success.


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## porthos (Jan 6, 2022)

*thanks. i best buy some literature and watch some  instructions on you-tube*


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## guero_gordo (Jan 11, 2022)

I vividly recall my dad tearing my brother a new one for using rosin core solder on the wrong iron  I can barely solder two stranded copper wires together, maybe it was a scarring experience ;-)


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## SLK001 (Jan 11, 2022)

woodchucker said:


> I use acid for electrical, heavy stuff. For my F3B winches, I crimped the welding cables with terminal ends (forget what they are called), then used the acid core, and soldered the connection.



If the cables are stranded, soldering with an acid is a _*very *_bad idea.  The acid will wick between the strands and slowly eat away at the copper wire until terminal failure.  Even soldering a crimped connection with a resin core is a bad idea.  A crimped connection, properly executed, is a solid airtight connection and needs NO additional processes.  If the connection is soldered, the solder will wick between the strands and create a stress point at the end of the solder, which will lead to fatigue cracking of the strands one-by-one, until total failure.


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## RJSakowski (Jan 11, 2022)

Crimped connections are reliable if made with the proper tool.  Unfortunately the tools sold in hardware stores or DIY stores aren't.  For reliable connections, especially those exposed to the elements, I will solder the crimp.  I can';t recall ever having a crimped, then soldered fail.  If soldering is done properly and the wire is clean, the solder will also wick back into the insulation, giving additional support to the wire and preventing stress breakage.


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## SLK001 (Jan 11, 2022)

RJSakowski said:


> I can';t recall ever having a crimped, then soldered fail.


You're lucky.



RJSakowski said:


> If soldering is done properly and the wire is clean, the solder will also wick back into the insulation, giving additional support to the wire and preventing stress breakage.



That actually creates a stress point.  

If your system incurs enough vibration, then your wire will fatigue and break.  If there is no. or minimal vibration, then your wire, although vulnerable, is probably safe.


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## RJSakowski (Jan 11, 2022)

In my experience, the solder doesn't wick up uniformly, distributing the stress over a greater area, much like the flexible stress reliever on the ends of connectors.  I have used this practice for over fifty years for automotive and marine connections with no ill effects.  I started soldering crimped connectors years ago when crimped connections were failing due to corrosion from salt.  I just got tired of rewiring trailers every year or two.


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## tq60 (Jan 11, 2022)

Properly supported wires will not likely fail when soldered.

We have a bunch of Anderson connectors we are using for assorted chargers.

Crimping the pins makes them one Tim use an given we are cheap we solder them.

Uses a lot but we have a 5 pound roll from estate sale not good for circut boards but good for wiring.

The cheap crimper tools do a poor job and the wire often is only held by a few strands.

Sta-kon deforms much better, key is use correct size terminal for the wire and good crimper.

If exposed to environment solder is good, one only needs to heat tip of connector and as soon as solder wicks in good, minimal up the wire this way.

Proper support to insure minimal stresses never a bad idea.

Sent from my SM-G781V using Tapatalk


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