Newb soldering issues
« on: December 06, 2018, 10:54:48 AM »
Hey guys,

I am practicing my soldering and some are perfect, but others I struggle with. I am unsure why some "fail" so looking for some tips here.

I use a Hakko 936 iron at about 360 Celsius/700 fahrenheit. Sometimes the solder does not want "fall" through to the other side of the board, so it stays a bulge at the top side. I'm using a fine tip, with a small flat side to it. If pictures are needed, I can take some and post them.

thanks!

Chris


pucho812

Re: Newb soldering issues
« Reply #1 on: December 06, 2018, 11:47:21 AM »
always keep your tip clean.

You tell me whar a man gits his corn pone, en I'll tell you what his 'pinions is.

pucho812

Re: Newb soldering issues
« Reply #2 on: December 06, 2018, 11:48:02 AM »
and this
You tell me whar a man gits his corn pone, en I'll tell you what his 'pinions is.

JohnRoberts

Re: Newb soldering issues
« Reply #3 on: December 06, 2018, 01:16:21 PM »
Practice makes perfect better...

With a solder sucker or solder wick you can remove excess solder and retry... as long as you have fresh flux you can resolder a joint any number of times.

Tarnished or dirty leads/pads can make soldering difficult.

JR   
John Roberts
http://circularscience.com
Tune it, or don't play it...

Re: Newb soldering issues
« Reply #4 on: December 06, 2018, 02:30:30 PM »
A cold joint means I did not heat the component and pad enough to start?

Re: Newb soldering issues
« Reply #5 on: December 06, 2018, 02:38:56 PM »
What's the problem with "too much" solder?
Too much within reason of course.

pucho812

Re: Newb soldering issues
« Reply #6 on: December 06, 2018, 03:24:22 PM »
A cold joint means I did not heat the component and pad enough to start?

A 'Cold Joint' is one where the solder did not melt completely. It is often characterized by a rough or lumpy surface. Cold joints are unreliable. ...

you can usually fix them just by reheating the joint.

What's the problem with "too much" solder?
Too much within reason of course.

it looks ugly.  ;)
You tell me whar a man gits his corn pone, en I'll tell you what his 'pinions is.

scott2000

Re: Newb soldering issues
« Reply #7 on: December 06, 2018, 03:28:35 PM »
What kind of solder we talking about??

JohnRoberts

Re: Newb soldering issues
« Reply #8 on: December 06, 2018, 03:42:04 PM »
What's the problem with "too much" solder?
Too much within reason of course.
Too much solder is bad because you cannot see  (to inspect) the quality of the solder joint beneath... Further mil-spec soldering requires a mechanical connection before the solder connection. 

I used to offer a flat fee repair service for my audio kits back in the 70s.  :o I saw lots of bad soldering... I've seen blobs of solder on top of the lead, while lead was still rattling around loose inside the pad/hole.

"Cold" solder joints suggest the solder and/or lead does not get hot enough to properly melt/flow. With old school lead based solder the cold connections were often dull (sometime overheated connections also looked dull). Modern lead-free solder is harder to gauge solder joint quality from appearance (not shiny).

JR
John Roberts
http://circularscience.com
Tune it, or don't play it...

PRR

Re: Newb soldering issues
« Reply #9 on: December 06, 2018, 03:53:28 PM »
> Too much solder is bad because you cannot see  (to inspect) the quality of the solder joint beneath...

+1


Re: Newb soldering issues
« Reply #10 on: December 06, 2018, 05:18:16 PM »
Thanks guys.
Will post more tomorrow, its late here now

Re: Newb soldering issues
« Reply #11 on: December 07, 2018, 01:07:26 AM »
Hey,

So I had another look this morning.

I think I am using lead-based solder, but the package is brandless so I am guessing that from the fact it cools down shiny, not matte.  I feel it takes me too long to heat the components and the solder to start flowing. When I watch some videos online: the moment the solder touches the iron it turns fluent instantly, with me that's not the case. Sometimes I'm waiting 3 to 5 more seconds before anything happens.

One thing I can imagine is that my soldering station is not calibrated. The temperature knob might say I am at 350 Celsius, but who knows what temperature I am really getting? I found myself turning the heat up to get things to work. I have also changed to a slightly larger and flat, screwdriver tip now, instead of the finest hoof tip I have. I think this may transfer the heat better. In my inexperienced-ness I just picked the smallest tip I had, thinking that would make things easier.



Re: Newb soldering issues
« Reply #12 on: December 07, 2018, 03:57:02 AM »
This sounds like your soldering iron tip is not properly wetted, so heat is not rapidly conducted to the work when you use it. Your iron and tip may be degraded, but perhaps your procedures are encouraging this degradation.

A soldering iron tip has the paradoxical requirement that it remains wetted with molten solder, but that the tip does not dissolve into that solder and leach away. To accomplish this, soldering iron tips are built with copper cores and iron clad surfaces that can be wetted with solder, but only reluctantly. If a soldering iron tip is allowed to oxidize because it is not attended to with fresh solder as needed, it will not conduct heat to the work when you want to use it.

Something as simple as leaving excess solder on the tip when you place the iron into the stand can help - people often clean the iron before they place it into the stand, and that only encourages the tip to become un-wetted. Only clean the iron when you remove it from the stand just before you use it - if you clean it before placing it into the stand after you've used it, then the thin layer of solder that remains after cleaning with a sponge will quickly disappear as the iron rests in the holder, and your tip will require re-wetting to work effectively.

If you want to make your tip work well, you can sometimes add solder to the tip before you put it into the stand, so that it will build a solder layer as it rests in the stand. After you use the iron, assess the wetting of the tip, clean it and then re-wet it so that it remains optimally wetted, with a good reservoir of solder wicked onto the tip, to not only prevent the tip from "drying out" but also to build a deep solder wetted layer onto the iron tip cladding.

One thing you mentioned early on is that you're using 700ºF as an iron temperature, and that's actually extremely high for anything but large pieces of metal with an iron that's too small. No PCB needs 700 degrees, 650 is also probably too high, and what will happen with 700 is that unless you constantly attend to your tip to make sure that it's wet with solder, and not coated with oxide, then it will become hopelessly coated with oxide, and your iron will not heat the work to allow you to make a nice joint.

It's hard to say what tip temperature you actually need for the work you're doing, but if you're having wetting problems and you're using 700ºF, please turn this down to 600ºF and see if life is not simpler. The melting point of 63/37 tin-lead solder is actually 361ºF, so 700 is completely excessive, only required if your iron's thermal mass is too small, and you're using it on work that's too large for your iron.

High temperatures like that also tend to burn up flux in the joint, and that also makes some joints work poorly, while others work well enough just by happenstance.

My recommendation for you is to practice with some very low iron temperatures, around 500-580ºF, and also to focus on making sure that the entire surface of your soldering iron tip is fully wetted all the time. If you have a well wetted iron tip and you contact it to both pieces of the work that you're soldering, then you can expect quality solder to flow after less than a second of heating, and you can make a quality joint in only a handful of seconds.

One final suggestion is to use liquid flux, which can help to prepare metal surfaces, especially older, not "brand new" components for soldering. Always use "no-clean" flux because you cannot expect to remove every trace of "must clean" flux - why risk corrosion. Flux pens are lovely things that can add a dab of flux to cranky oxidized metals, and result in gorgeous, well flowed joints. I bought a huge 1 liter jug of Kester 959, which is excessive for a hobbyist, but will serve me well for probably a decade of hand work. But, barring the investment into a lifetime supply of liquid flux, a quality no-clean flux pen will help to make cranky, older materials solder effectively.

Best of luck!

Re: Newb soldering issues
« Reply #13 on: December 07, 2018, 04:17:28 AM »
Hi Monte,

Thanks for the great insight.

I have tried it now, and I am getting better results now. I think the slightly larger and different tip size helped.  I am also paying attention now to keeping the tip wetted. You are right, I was "cleaning" the tip before putting it away. I will try it the other way around.  I've also turned the heat down as suggested. Will practice some more!

chris

Re: Newb soldering issues
« Reply #14 on: December 08, 2018, 12:52:30 PM »
yes a good 2-3mm chisel tip for more through hole type applications is pretty good i think

i was having some of the same issues as you not so many years back and found that if i made sure the tip was wetted (a bit of solder first) and then i heated up the pad connecting to the via first to get it nicely heated up did the trick for me - then move to the lead of the component you want to do - you can do the opposite too - hit the lead first and then go linger on the pad for a few seconds to get the via heated enough to suck the solder through - usually i would get the pad heated WHILE soldering and if i leave the tip in place for an extra second or so - an air bubble would come up through and 'burp' or else the solder would just wick through and you can see it from the soldering side - that's how you know it's wicking ... try it on a few practice holes maybe

and REMEMBER - in case it wasn't obvious - you wan to be heating the pad (or lead) and let the pad (or lead) melt the solder ... mostly - and provided your tip is wetted enough to get good heat flow

Whoops

Re: Newb soldering issues
« Reply #15 on: December 08, 2018, 08:45:26 PM »
What's the problem with "too much" solder?
Too much within reason of course.

If it's a good soldering joint there's not problem at all


 

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