Newbie soldering question

[TheNewGuy]

Hello Everyone on ETO,
I had a newbie question regarding soldering. The picture shows this one attempt I made to solder and it left a black layer over the pad that I could not remove. Also, I will often have black residue left on my iron. Am I using the wrong type of flux or something? Do I need a flux cleaner?

Any advice? I don't know why soldering is such a pain!

 

[JimB]

Yes, you are using the wrong type of flux.

The flux in your picture is type RA (Rosin Activated) is corrosive and not suitable for electronic work.

If you must use separate flux, use RMA (Rosin Mildly Activated) type.

For the type of joints that you are making there, I have never used additional flux, I simply rely on the flux which is in the solder.

While on the subject of solder, what type are you using?
For hobby use, 60/40 or 63/37 tin/lead solder is best.
Some people will try to tell you that leaded solder is illegal and that you must use lead free solder, that is not correct.
Most solders made for electronics have flux cores. That flux should be all you need.

Also consider your soldering iron, that should be the correct temperature,
too cold and the flux will not work correctly,
too hot and the flux will burn off as soon as it is heated by the iron and before it has helped to clean the joint.

JimB

 

[dr pepper]

Welcome to the forum.
Get yourself some quality electronics solder, leaded if at all possible.
If you iron has a temp control set it to about 350 degrees c.

 

[jpanhalt]

Judging form this joint:

I see shiny solder (good). As for the question about the lack area, I don't think it is from the flux. I think it is simply burned solder mask (i.e., the green coating) or burned conformal coating applied after soldering. Since it is charring, the only way to remove it is mechanical. A little alcohol on a Q-Tip may help at this point. In the future, you can try to scrape away a small area before soldering. Lacquer thinner on a Q-Tip to clean the area before soldering may also help. Also, applying a little less heat with a smaller tipped iron may help.

John

 

[KJ6EAD]

I don't think flux is your problem. You seem to be scorching the board, lifting pads and burning a lot of flux. These are all signs of a soldering iron that's not hot enough and bad technique. When the iron is not hot enough to heat the entire joint quickly to soldering temperature, you end up holding the iron on the joint longer to compensate and this creates the symptoms seen.

The black deposits on the iron can be caused by minerals in the water you're using with your sponge. Try rinsing the sponge with distilled water and use it from now on. Take a look at this video:

 

[audioguru]

My Weller soldering iron is about 48 years old and still works perfectly. It is temperature-controlled and the same one is made and sold today.
It never gets too hot to burn away the rosin and it never lifts pads or scorches. Its tip lasts for a long time even when the soldering iron is hot all day every day.
A solder joint takes it about 1 second. If I solder a huge wire then it quickly applies as much power as is necessary to get the solder joint to the correct temperature.

A cheap soldering iron gets hotter and hotter and hotter and hotter .... until it burns away everything.
Remember a soldering gun that had a tip that got red hot? It was useless to solder electronic circuits.

 

[shortbus=]

Another thing that no one seems to address is you should also clean the copper with a scotchbrite pad or even a pencil eraser before soldering. Just enough to make it "shiny", after you get the "hang" of soldering, you maybe can skip this step. But when starting out, any help you can use will give you confidence enough not to give up. Stick with it, you'll get it.

 

[killivolt]

Having rosin to re-tin your tip is pretty handy. I only use an Temp Adjustable type "Weller is a good brand" I used them a lot all day long.

Edit: I wash my boards off with ElectroWash - PM, Safe on Plastics gets the Job done.

 

[TheNewGuy]

Thank you everyone for the advice. I usually use cheap soldering irons that cost five or six dollars. First, I had issues with my soldering tips always corroding and so I bought this flux thinking that would help. I then realized I am using cheap soldering irons, so yesterday I got in the mail this Weller WLC100 and tried to use it. My attempt to use it resulted in the picture you guys see above. What do you think of this soldering iron audioguru?

Below is a picture of the solder that I use.

Ok, so I need to get RMA type flux. Should I get rid of this RA flux? Should I get a flux cleaner to clean my boards, tips, etc?

Also, how do I fix those connections on the board? Especially the lower black looking one, solder will not stick to the pad, no matter what I do. How do I fix that? Flux cleaner? I guess I had the soldering iron too hot like jpanhalt said.

Thank you everyone.

 

[jpanhalt]

There are two types of black on your board. One is the charred PCB. There is nothing you can do to unchar it. You can scrape it away.

The second is the copper oxide on the copper caused by overheating. That can be removed with acidic cleaners (not recommended) or with fine abrasive. 3M green or maroon non-metallic abrasive pads should work fine. Other brands should work too. Once the pad is cleaned, tin it, then solder. It will be a little easier if it is pre-tinned.

John

 

[audioguru]

Thank you everyone for the advice. I usually use cheap soldering irons that cost five or six dollars. First, I had issues with my soldering tips always corroding and so I bought this flux thinking that would help. I then realized I am using cheap soldering irons, so yesterday I got in the mail this Weller WLC100 and tried to use it. My attempt to use it resulted in the picture you guys see above. What do you think of this soldering iron audioguru?

It is not temperature controlled like my Weller soldering iron. It has a "light dimmer" circuit to adjust its power. Too high a setting or leaving it sitting too long makes it much too hot. Set too low then as soon as it touches a solder joint then it cools even more.
My soldering iron always keeps the tip at the correct temperature.

Below is a picture of the solder that I use.

It is not "name brand" Kester and does not say it is good for electronics. My solder is rosin core Kester 63/37, not 60/40.

 

[audioguru]

The new software on this site is very slow and does strange things.

 

[JimB]

Ok, so I need to get RMA type flux. Should I get rid of this RA flux?

No, you don't need any extra flux, you need the correct solder.
The solder you have appears to be a general purpose solder, the solder wire diameter is quite large 0.063" is 1.5mm, my thickest solder is 0.7mm and is intended for electronic use.
You need new solder and you do not need flux.
Buy the correct solder and the correct flux will be in the solder.

As for the RA flux and the solder you have already, save it for fixing something big and heavy like a water pipe.

JimB

 

[TheNewGuy]

There are two types of black on your board. One is the charred PCB. There is nothing you can do to unchar it. You can scrape it away.

The second is the copper oxide on the copper caused by overheating. That can be removed with acidic cleaners (not recommended) or with fine abrasive. 3M green or maroon non-metallic abrasive pads should work fine. Other brands should work too. Once the pad is cleaned, tin it, then solder. It will be a little easier if it is pre-tinned.

John

I will turn down the heat on my iron next time then. As for the board, I will try to scrape away some of the black substance to see if I can get a reliable joint. If not, I will take off all the components from the board and maybe try perfboard or something.

It is not temperature controlled like my Weller soldering iron. It has a "light dimmer" circuit to adjust its power. Too high a setting or leaving it sitting too long makes it much too hot. Set too low then as soon as it touches a solder joint then it cools even more.
My soldering iron always keeps the tip at the correct temperature.


It is not "name brand" Kester and does not say it is good for electronics. My solder is rosin core Kester 63/37, not 60/40.

This time I will turn down the heat and see if I can still use this solder successfully. If not I will try to look for the brand and type you mentioned. Also, I wish I had known about this temperature controlled technology before I bought this one. :/

Thank you both for you advice!

 

[TheNewGuy]

No, you don't need any extra flux, you need the correct solder.
The solder you have appears to be a general purpose solder, the solder wire diameter is quite large 0.063" is 1.5mm, my thickest solder is 0.7mm and is intended for electronic use.
You need new solder and you do not need flux.
Buy the correct solder and the correct flux will be in the solder.

As for the RA flux and the solder you have already, save it for fixing something big and heavy like a water pipe.

JimB

I didn't realize the diameter of the solder mattered. I will do some more researching on different solders...

 

[TheNewGuy]

The new software on this site is very slow and does strange things.

The Administrators must have implemented this new design recently. It is slower than the old design, but it has more features and looks more sleek.

 

[JimB]

I didn't realize the diameter of the solder mattered.

A thin solder gives you better control, helps to prevent big blobs of too much solder on the joint.

JimB

 

[killivolt]

A thin solder gives you better control, helps to prevent big blobs of too much solder on the joint.

JimB

We are talking rosin core solder, not water based solder Flux. It's very different.

The 2 don't mix, can't use both, one or the other, once the water based Flux is clean from the board you can do Board Repair, but, you should then use chemical cleaner. Water based flux is cleaned with water.

But, Rosin Core is done with cleaner, water won't do any good in cleaning.

 

[KeepItSimpleStupid]

For the most part, jut about everything got addressed except:

The tip should be tinned and wiped with a wet sponge. Tinning means solder is placed on the tip and wiped off. Iron clad tips worked fine for me.

Then there is technique. The idea is to heat the more massive part, so in the case of the pad and a component lead, heat the pad and push onto the lead with the soldering iron.

The solder gets applied, essential to the lead/pad interface and should not be applied to the iron. Experience suggests testing, to get an idea of the time you have to wait. e.g. touch the solder and see if the pad is hot enough to melt it.

0.063 is at least 2x more diameter than you need, if not more. Honestly, 1/2 the pad diameter should suffice for the solder diameter.

I think you got the other stuff covered. I've worked with glass (quartz and pyrex), silver soldering, plumbing soldering and electronic soldering. I've also used MAPP, and propane with and with and without oxygen. Oxy-Acetelyne and Oxy-hydrogen. I've had a stick welder, a TIG welder and a MIG welder in my hand as well. Basically one time each with very good results. I've used lots of solders including pure Indium and alloys. I even did spot welding of steel to making thermocouple junctions.

Flux prevents oxidation under heat and pay attention to the thermal masses. The parts have to initially be free of oxides.

63/37 lead solder should be used for SMT parts. 60/40 (Lead solder) should be used for parts with leads. If your allowed to use a lead solder. They are a LOT easier to work with than the lead free equivalents.

63/37 has a solidus and liguidus temperature that is identical, so it solidifies instantly. With 60/40 the points are different.

 

[TheNewGuy]

I just bought this today from my local Electronics Store:

**broken link removed**

I also bought a perfboard for a schematic I am going to build once I order all the parts I need off of Digi-Key or something.