How to solder correctly (a not so brief lesson) Plus tips and more...

[togy]

The colophonium flux I bought is hard like glass. How should I get it out on the wires??

[Marine6680]

Originally Posted by togy

The colophonium flux I bought is hard like glass. How should I get it out on the wires??

Weird... never seen flux like that. Try warming it up.

You might could use the tip of the iron to melt a small section and then dip the wire into it. It will probably be stronger than liquid flux, so you may not need as much.

[togy]

Thanks I'll trye that;-)

[61Espo]

WOW!!!

This is just what I needed!!

Thank You Very Much Marine!

[Marine6680]

Glad to help guys.

[Groovadelic]

Just want to say thanks. I keep coming back to this article. I've been soldering for many years but really learned a lot from this.

[Marine6680]

Originally Posted by Groovadelic

Just want to say thanks. I keep coming back to this article. I've been soldering for many years but really learned a lot from this.

I try. Thanks

[grovey]

I am still at a loss on what solder to use.

I bought some MG chemicals 63/37 solder with RA flux core. They say it is non-corrosive. Should I still clean with 91% alcohol after?

This is the solder.

http://www.mgchemicals.com/products/...n63-pb37-4880/

Also, with the method mentioned of filling bullet connectors, should I place the wire in the bullet, and heat the wire AND connector at the same time while melting the solder? Not sure I understand fully there. I would hate to lose heat on the components and not have the solder adhere or bond properly on the wire and or bullet.

Lastly. Do I remove the pre-tin from new ESC and new batteries, or just tin over the existing solder?

[Marine6680]

I always clean regardless, as the flux is still slightly corrosive.

That solder should be good.

Yes, heat the connector and apply flux, the wire will heat as the connector heats. You could heat the wire instead, but usually the wire should not be stripped back far enough to do that, you only want a small gap between the wire insulation and the connector. Just enough to apply solder and ensure that you used the proper amount. This method takes practice, and needs a good iron, and large enough tip.

You can never actually remove the tinning... unless you use sandpaper, as the solder bonds molecularity. Now as for the excess tinning, you can remove the extra solder.

[Mic360]

Definitely the best post about soldering I have seen so far.
Many thanks !
- Michael -

[Marine6680]

Glad you liked it.

[brianapp]

Whenever I try to tin the solder tip or wires it always forms a bubble and rolls right off like oil on water. I have a decent temp controlled iron and have tried temps from 250-400C but it just rolls right off. I am using 40/60 rosin core solder. I thought the rosin core was good enough but maybe I need to buy separate flux and apply that first.

I have seen how it is supposed to flow into wires and on the tip but I can't get that to happen. It also take too long for me to get the solder to melt on the joint. I tried turning the iron up to 400C to get it too heat faster but it still takes too long. I see the videos where they just touch the iron to the wires for 1-2 seconds and everything flows perfect. Mine takes 10-15 seconds to get it to melt and most of it just rolls off in a ball. I am trying to heat the joint and have the joint melt the solder and not the iron. Should I be putting the solder on the tip/wire joint so it will melt faster?

[Kainam]

Kester recommends a tip temperature of 750°F (400°C) so you're ok there. Sounds like a contamination issue either of the soldering tip and/or the wires. Contamination of the soldering tip will hinder heat transfer to what you are soldering. Try cleaning your soldering tip to see if it improves.

Tip Temperatures
What is the recommended soldering iron tip temperature?
When hand soldering with a rosin flux such as the Kester #44 or the # 285 the recommended iron tip temperature is 750°F. If you are soldering with a low residue no clean solder such as the #245or # 275 we recommend a tip temperature of 600-650°F.

http://www.kester.com/SideMenu/Techn...ledgeBase.aspx


I prefer the brass wire dry sponge over the wet sponge. Doesn't subject the tip to the thermal shock of a wet sponge when cleaning, thus making your tips last longer.




http://www.amazon.com/gp/product/B00...ls_o04_s00_i00

[Kainam]

Originally Posted by brianapp

Should I be putting the solder on the tip/wire joint so it will melt faster?

Sometimes putting just a bit of solder at the tip wire joint will aid in heat transfer.

The best way is to have the wire sitting on top of the soldering tip (heat rises), and add the solder to the top of the wire. When the wire gets hot enough it will melt the solder and get wicked into the wire.

[rojack]

Flux.... don't be shy on the flux. Just be sure to clean it off later.
Flux will clean the contamination and the solder will flow onto the wire and not bead up.

[Marine6680]

Originally Posted by brianapp

Whenever I try to tin the solder tip or wires it always forms a bubble and rolls right off like oil on water. ***SNIP*** Should I be putting the solder on the tip/wire joint so it will melt faster?

Originally Posted by Kainam

Kester recommends a tip temperature of 750°F (400°C) so you're ok there. ***SNIP***
The best way is to have the wire sitting on top of the soldering tip (heat rises), and add the solder to the top of the wire. When the wire gets hot enough it will melt the solder and get wicked into the wire.

Originally Posted by rojack

Flux.... don't be shy on the flux. Just be sure to clean it off later.
Flux will clean the contamination and the solder will flow onto the wire and not bead up.

Like was said above... (though I prefer the wet sponge, as the thermal shock can be beneficial when making connections)

Contamination of the tip or wire... Old wire can be hard to tin, or wire that has formed a thin corrosion, sometimes the corrosion is not easy to see.

If you hava a clean tip, good solder and flux, and good wire... you should be fine. Though I have seen some wire that did not like solder, but that wire was copper strands coated with a plating metal, and some plating metals do not like solder. (this was wire designed to be used with crimp connections, so corrosion prevention was important and it can go against good solder wettability)

[brianapp]

Thanks for the ideas.

I am going to try-

1. 400C
2. a wider tip (I was trying to use the side of a point tip)
3. thinner solder
4. external flux (all I found is the paste type, using a drop of the liquid flux in the videos looked better but I couldn't find that)

So the thermal shock from a hot tip on a wet sponge is a good thing? I thought touching a 400C tip to a cold wet sponge would hurt or crack it but it is actually better?

[Marine6680]

Wider tip is going to help a lot.

Paste flux will work fine. I actually make it using liquid flux, by letting it dry out.

I have not found any detrimental effects from the wet sponge, so long as you follow the rules of tip care and keeping it clean during use, the tip should last a long time. Its benefit is really dependent on if your iron actually measures the tip temp, or just tries to output a certain power level to maintain a temp. When you touch/wipe the tip to the sponge to clean it, the temp lowers a little. Irons that measure the tip temp, see this drop and kick on the power to raise it, this helps maintain temps and aids thermal recovery.

[rojack]

Originally Posted by brianapp

Whenever I try to tin the solder tip or wires it always forms a bubble and rolls right off like oil on water.

Another thing I just realized that can make this happen besides not using flux is if the surface you are trying to put solder in is oxidized or coated in some way. No amount of flux is going to get through that.

The soldering iron tip should always have a nice shiny (thin) coating of melted solder. If the tip looks black then it's not going to transfer heat very well. Methods above for cleaning and "tinning" the tip of the soldering iron.

Sometimes wires are coated or have some oxidation and need to be scraped until shiny before they will accept solder. Contacts can also have some oxidation or contamination on them and will refuse to accept solder. A light sanding, scraping or even rubbing with the soldering iron tip can get through this layer, but be careful not to overheat the contact or wires.

Don't even bother to solder a wire to a connector unless both the wire and connector are "tinned", in other words have already have a nice thin, clean, shiny coating of solder on them. Not a blob of solder sitting on the surface, but the solder "flowed" into the wire or onto the surface of connector. Do the "tinning" on each first, separately, and then, add a little flux and solder them together.

It's a technique that requires practice. Best to get some scrap wire and practice on that until you have the technique and temperatures that work right for you.

[Marine6680]

Well... stronger flux can help cut through tougher oxidation... Plumbing flux will cut through just about anything. But I wouldn't use that unless I had no other option.

Limit sanding and scraping unless absolutely necessary. Usually if you get a small portion to start taking solder, adding a little more flux and fresh solder can get the rest to flow as well.

And practice on spare wire is a good idea... practice is usually a good idea.