My Cheapo Chineese 3020t mini CNC Build (more like improvements) leanring all the way

[m_c]

If you're soldering new components, the flux in common solder should be more than enough to ensure a good solder joint. Any common solder you buy for electronics should be flux cored.

It must be over 10 years since I last used separate flux, and that was dealing with vehicle earth points that had been exposed to a couple British winters. I've certainly never used it on any PCB I've soldered.

[A_Camera]

If you're soldering new components, the flux in common solder should be more than enough to ensure a good solder joint. Any common solder you buy for electronics should be flux cored.

It must be over 10 years since I last used separate flux, and that was dealing with vehicle earth points that had been exposed to a couple British winters. I've certainly never used it on any PCB I've soldered.

I have been working with electronics since the mid 70's and as long as I remember, there have ALWAYS been flux in the solder wires I used. I never bought any separate flux ever in my life. As far as I know, flux in liquid or hard form is only used for soldering pipes and other very large surfaces, not PCB.

[Lee Roberts]

So far the only advice he's had is to get a solder sucker and start again, clearly there is more going on than that and he needs more experienced input, let's give him that instead shall we.

Flux cored or not something isn't right and it's probably a combination of things, additional Flux I think will help Ravi along in getting better joints, additional flux has been used in the SMD and rework/reflow arena's for years and for a very good reason!

What solder wire are you using?

Ravi, using additional flux cannot hinder the soldering process and can only assist you in doing a nice/better job, don't tell anyone this but that is the reason they put it in solder wire in the first place :).

Your soldering iron needs to be hot enough, balling up like that can come from the iron being too hot or cold, I'm betting yours is to cold, some lower end irons heat up but they don't do very well at staying hot once you start using them, this happens with low power irons too at around the 25w range, when you are trying to solder bigger components.

However my go to for most jobs is now a 12w Weller SP12, I inherited it along with technique from my grandfather who was a British telecom engineer, the iron is from around the 80-90's and still has the original tip, it along with a combination of technique, additional flux and a solder wire appropriately sized gets everything I solder just right for me - every time...Thanks Granddad!

40-60w is an average range on what allot of irons will be rated at, my other iron is a 25w similar to the Weller, I also have two gas soldering irons for mobile work. The bigger of the gas irons is handy with the tip removed as its basically a mini blow torch and works excellent on heat shrink and those jobs where you need a small flame with a bit more power.

What iron are you using ?

The tip of your iron needs to be "on point" Ravi, the problem comes from oxidation and not keeping your tip clean, once your tip becomes oxidized the solder will no longer want to flow or stick to it properly and this is a problem. Don't clean your tip in flux or water, this shocks the tip and damages the Iron and Chromium plating, just dip the tip in some pure Rosin after each joint and that should be good enough for the tips life time.

Solder to the tip of your iron and then to the area/joint to be soldered, your transferring the solder from one to the other, try and do this with as minimal amount of heat going into your component as you can and your now doing it correctly.

Soldering isn't rocket science Ravi, there are lots of options in terms of tools and technique but a few fundamentals need to be right for it to be successful, if left those balls of solder you've done so far could come lose and as such cause arcing, arcing not only damages components and equipment but it can cause fires too !!!!

[Lee Roberts]

Here is a video, the most relevant section about Flux starts at 7 minutes in, the astute of you will identify the difference in working with fresh unoxidized surfaces vs. oxidized surfaces such as those in the job Ravi is undertaking and the correlation in my recommendation of using flux.

I didn't recommend adding Flux to Ravi's game because it sounded good

[A_Camera]

Here is a video, the most relevant section about Flux starts at 7 minutes in, the astute of you will identify the difference in working with fresh unoxidized surfaces vs. oxidized surfaces such as those in the job Ravi is undertaking and the correlation in my recommendation of using flux.

I know very well what flux does and when to use it. In fact, the very same demonstration is done in your video, just like I am saying in post #56.

https://youtu.be/vIT4ra6Mo0s?t=8m1s

He is soldering large surface, so of course use of flux is a good idea. He is soldering to a copper plate with a blow torch from beneath, not a PCB, and what he does is the same as soldering pipes. So of course, use of liquid flux is a good idea, as it is demonstrated at the 7 and 8 minute marks. When soldering PCB manually flux is unnecessary because the solder wire already has enough. More important is HOW to solder and which tools are used. If the tip is too large or too small, or the temperature is too low, or the solder is applied to the tip and brought to the surface and so on...

Quite the opposite to you, if I make a PCB and see that it has a lot of oxide, or old flux or anything greasy on it I use PRF 6-68 to REMOVE flux, oxide and almost any other dirt, and that makes soldering really easy. I also use the same if I buy electronics from eBay and see that the PCB is badly cleaned or not cleaned at all, and is full of sticky flux. I routinely clean all my PCBs after manually soldering because there is always just too much flux rest after manually soldering PCB.

[ravihotwok]

Well I have redone the soldering, and im pretty happy with it. Its still balled up a little but the prongs stick out through the board a fair bit so didnt really have a choice as I wanted the whole of the prong covered in solder, they are very round and meet the metal contact on the board pretty much perfectly, plent of solder also flowed into the connection to begin with :-)
Before


After

[ravihotwok]

singed the board coating a little but the solder had made a solid connection and like I say plent of solder has flowed into the conection

[ravihotwok]

After you all explained what a star was in the box it was obvious where it was when I opened it up. I have drilled a small hole near the motor connections and linked a bolt to the star so I can attached the earthed wires from the motor cable screens to it

[A_Camera]

So far the only advice he's had is to get a solder sucker and start again

Well, that's not very fair, is it? Did you not read post #53 and #56? That's all there is to it. Like you say, soldering is not rocket science, but needs some practice. He was given a google link but I did not pick any specific video, I think he should do that selection on his own.

My iron is a 24v 50W Weller from 1978. It still works well. Of course, it does not have the fancy temperature regulator and display, but I never really felt any need for that.



I have used up several tips and also have different type, depending on the purpose, I change when necessary. I would not use a high voltage type of iron, which the 12W you have been given is, on any electronics, but I know many people use tools which are not suitable. Anyway, while it may have a nostalgic value for you, I personally would only keep it as a memory.

Regarding flux, I stand by what I have said. It is waste of money. On electronics one should not use any other type of soldering wire than the one with flux in the core of the wire. As a matter of fact, too much flux can also cause problems, so it is not true that using flux can not hurt. Flux fluid is used only in industrial soldering, where the PCB is travelling through a flux foam first and then through the melted soldering wave.



Manual soldering of electronics don't need any flux foam or liquid.

My experience is that if there are balls then it is enough to heat them well up, until completely melted and either suck it up or in many case it will float out because there is normally enough flux around the points. If if does not float out and look like figure A in the picture I provided then there is nothing else to do than suck it out and apply new solder.

Takes a 15 minutes to half an hour practising and that's it. Really very simple.

[Clive S]

So far the only advice he's had is to get a solder sucker and start again, clearly there is more going on than that and he needs more experienced input, let's give him that instead shall we.

Lee you have not read this post from the beginning I feel. The questions you have asked have all been answered.