Arduino Forum

Using Arduino => General Electronics => Topic started by: davetwilley on Jan 09, 2013, 08:59 pm

Title: Soldering Hell
Post by: davetwilley on Jan 09, 2013, 08:59 pm
Hi,

After years of soldering (badly), I need some help to find out what I'm doing wrong.

Essentially my problem is that the parts I am soldering often start to melt or get very hot before my solder gets hot enough to flow on to the parts.  I've had this with all sorts of jobs and the only way I have found around it is to put a small blob of solder on my tip first to bridge the part to the iron and that seems to allow me to feed the solder into the molten bit.

In all of the videos I've seen, the idea seems to be to bridge both parts with the iron then feed solder in but when I do this the iron is on the parts so long that they start to melt while I am trying to feed the solder in as the solder just bends up rather than melt as its fed in.

I'm wondering if the solder I have is the problem, I have heard some people saying that newer lead free solder can be extremely difficult to work with.

Having worked mainly on connectors for my RC hobby I've always been able to throw bits away or cut wires back for another attempt but having just tried to solder some wires to a small ultrasonic sensor, I can see that i'll soon be destroying valuable components if I don't sort myself out.

In all the videos, getting solder to flow seems to be the easy bit!

Thanks

Dave
Title: Re: Soldering Hell
Post by: tack on Jan 09, 2013, 09:04 pm
1) Always keep your sponge wet
2) Always keep your tip clean
3) Don't use the absolute point of the tip, it's not the hottest part. Use the side.
4) Make sure you have a good enough iron that is getting sufficiently hot. Too cold and you'll struggle, especially with lead free solder.
5) Use additional flux, if required, to help the solder flow. Of course, you need the iron tip to be hot enough for the solder to melt properly.

I'm sure there will be some more experienced solderers that can offer other advice.
Title: Re: Soldering Hell
Post by: larryd on Jan 09, 2013, 09:05 pm
If you don't mind lead use 60/40 medium diameter.
A [font=Verdana]HOT [/font]  iron is essential!  40/50Watt get in and out quickly.
Keep the point clean on a wet sponge.
Title: Re: Soldering Hell
Post by: cmiyc on Jan 09, 2013, 09:07 pm
Flux, Flux Flux.

I love these Flux Pens.  See if you can get one or something similar:
http://www.mgchemicals.com/products/prototyping-and-circuit-repair/pens/rosin-flux-835-p/
Title: Re: Soldering Hell
Post by: Docedison on Jan 09, 2013, 09:11 pm
There is one thing I've always found the and that is to apply the solder at the 'junction' of tip and work a slight delay after applying heat...
The 'slight delay' is the art of soldering.

Bob
Title: Re: Soldering Hell
Post by: fungus on Jan 09, 2013, 09:14 pm

I'm wondering if the solder I have is the problem, I have heard some people saying that newer lead free solder can be extremely difficult to work with.


Yep. Lead-free is very troublesome, I imagine that's the problem.

At a hobby level you're not going to save the planet by using lead-free. You might as well use lead.


Title: Re: Soldering Hell
Post by: bobthebanana on Jan 09, 2013, 10:02 pm
I would definitely recommend using extra flux. Ever since I started using flux I've never had a problem with wetting.
Title: Re: Soldering Hell
Post by: davetwilley on Jan 09, 2013, 10:12 pm
Thanks all for the quick replies.

I have a temperature controlled iron from Maplin (which I run at 350c, it'll go to 450c though) and I broke out some new tips this evening just for the sensor, I've got 1.2mm lead free solder.

This is the iron I use: http://www.maplin.co.uk/48w-lcd-display-solder-station-98133 (http://www.maplin.co.uk/48w-lcd-display-solder-station-98133)

I have a flux pen but if I'm honest I don't know how and when it should be used.

My solder station came with a sponge which I use all the time to keep things clean.

I'll get some leaded solder and see how that goes as a starting point.

Dave
Title: Re: Soldering Hell
Post by: udoklein on Jan 09, 2013, 10:32 pm
I would disagree with

Quote
1) Always keep your sponge wet


I never use a wet sponge. I prefer this http://dx.com/p/soldering-iron-tip-cleaner-ball-golden-137118 (http://dx.com/p/soldering-iron-tip-cleaner-ball-golden-137118) kind of stuff.
Title: Re: Soldering Hell
Post by: BulletMagnet83 on Jan 09, 2013, 10:38 pm
At work, I use a 120W iron normally set to 320C, and leaded 60/40 solder. Gets up to temperature and transfers heat to the workpiece quickly, and with the occasional tip-change the same iron works for everything from soldering shielding tape over everything, doing wiring looms, connectors and sticking stuff on PCBs. I'm hardly an expert (although I rarely fuck anything up so badly it can't be re-done), but the golden rules for me are:

1) Plenty of flux
2) Clean EVERYTHING with plenty of IPA before working on it
3) Keep that tip tinned and shiny
4) Use the brass brillo pad things instead of a wet sponge ;)

Lead-free solder is horrible, nobody I work with likes it, and thankfully we're not required to use it due to an exemption. I'd NEVER use the stuff at home either. Just wash your hands after handling it and there's no real harm... although good luck finding it at Maplin these days!

Title: Re: Soldering Hell
Post by: codlink on Jan 09, 2013, 10:58 pm

I have a flux pen but if I'm honest I don't know how and when it should be used.


If your putting solder to something, use flux.  If I turn my iron on, I am opening my flux.  I don't use a pen, so I have a small painters brush that I apply flux with.  And I put it on everything and lots of it.

I use leaded 60/40 at .032" solder.  I love it.  My iron sits at 300C most of the time.

I also use a wet sponge.  Works for me.  Every so often, I clean the tip and go back soldering.
Title: Re: Soldering Hell
Post by: rvasque on Jan 10, 2013, 01:21 am
I use lead-free solder, well, because I sell my stuff internationally... so I'd rather keep it lead-free. At first I hated it, but now it's no big deal to me. In fact, they're cleaner looking than using a 60/40 lead. (though not as shiny).

Keeping a CLEAN tip is a must... gunk on your soldering iron tip prevents efficient transfer of heat... which ruins soldering job.
I use this to keep my tips clean.
(http://i.ebayimg.com/t/Hakko-Solder-Soldering-Tip-Cleaner-599B-02-Non-Corrosive-No-Water-Coil-Brass-/00/s/MzAwWDMwMA==/$(KGrHqV,!l0E6CCDu!m3BOlb3WTIvw~~60_35.JPG)

Keeping the PCB surface clean and oil free helps too (use a 91% Isopropyl alcohol). 

Flux helps too for "stubborn parts". I use a dropper bottle with a syringe tip.

Title: Re: Soldering Hell
Post by: oric_dan on Jan 10, 2013, 01:37 am
Quote
the iron is on the parts so long that they start to melt


What I don't understand is what exactly is melting here? About the only thing I've seen
that will actually melt is the plastic case of an Led.

I've not used lead-free solder, but here's my 2-cents into the pot.

1. use a damp sponge, and not a wet sponge. Squeeze out the excess water.
2. wipe the tip on the sponge after every few solder joints.
3. use a beveled tip and not a pointy tip, as the former has a nice flat surface and
    will apply heat much better.
4. I don't know about heat levels, but my temperature-controlled station has a mark on
    the dial that works great for standard 60/40 flux solder. Then I sometimes have to
    adjust  +/- from there for very small parts or larger parts, pcb-heatsinks, etc.
5. I never use extra flux, as the solder has rosin flux in the core already.
6. some parts, typically TO-220s, have an oxidation on the leads, and I usually scrape
    this off with an exacto knife before soldernig.

7. be sure to tin the new solder tip, and also dab some solder on the tip after it's
    warmed up at the beginning.
8. apply the tip to one side of the joint for a second or 2, and then touch the solder
    to the other side of the joint so it flows across via surface tension. If the heat is
    adjusted correctly, it won't take any longer than this.
9. it also helps to again dab a bit of solder on the tip before making a joint, after
    the tip has been wiped clean.
10. for some reason, sometimes the pins on some DIP sockets don't take solder well, so
     if I happen to have received such sockets, I toss them in the garbage right off.

Title: Re: Soldering Hell
Post by: bot-thoughts on Jan 10, 2013, 08:17 am
A flux pen will change everything.

I like the Kester 2331-ZX. You could use radio shack flux paste, but honestly the pen works much better with less mess. I've tried the no clean Kester but I don't like it as well. Anyway your jaw will drop the first time you see solder flow after application of flux.

I proved to myself that it's possible to solder with a $ Store cheapo crap soldering iron provided I used a flux pen. (http://www.bot-thoughts.com/2012/10/dirt-cheap-soldering-iron.html)

The next great thing is a brass sponge tip cleaner.

Works so much better than water sponge, with so much less mess and no need to pour on new water.
Title: Re: Soldering Hell
Post by: cmiyc on Jan 10, 2013, 09:03 am

Anyway your jaw will drop the first time you see solder flow after application of flux.

Agreed.  The other jaw-dropping moment for me was when I applied the flux pen directly to solder braid.  The rate at which solder was wicked-up was almost like magic.
Title: Re: Soldering Hell
Post by: oric_dan on Jan 10, 2013, 07:53 pm
Interesting, I keep hearing about flux and flux pens, but I've never seen any problems
with solder not flowing flow or not adhering, except in a few minor situations, like pins
with oxidation on them [like TO-220 parts seem to have], or the occasional crappy socket
pins. I use rosin-core solder, and 99% of the time it just flows right onto the joints, no
problem. I don't do much smt.

What are you guys doing that needs a flux pen? Could you qualify this? Specific situations
or for every solder joint of every kind?
Title: Re: Soldering Hell
Post by: Docedison on Jan 10, 2013, 08:17 pm
Flux, Flux, Flux... Get rid of the lead free solder, use a good quality solder, Ersin, If they are still around Kester if not. I use leaded solder, a Hakko 936 iron and the brass tip cleaner. I have used water for all my life and I am finally free of the whole water mess.
I use the 'paste' flux from Radio shack for smd parts only. The paste is a petroleum jelly with Rosin in it.
Extremely messy but worth the effort.
FWIW, I learned to solder when i was 13 years old and passed the mil spec soldering requirements test at Gonset... I was the youngest to ever do that at Gonset. Gonset was a mfr of military RF devices, radios... Etc in the 40's and thru the 60's where I lost contact with them.
Soldering is an art, more than a science as with practice after  a while you just know when to apply solder and when to lift the iron from the work piece.
Yes that tin crap does require more flux and No your work with lead solder isn't going to hurt anything ecologically either so use the lead solder and be done with it.
My $0.02 worth...

Bob
Title: Re: Soldering Hell
Post by: oric_dan on Jan 10, 2013, 09:11 pm
If all else fails, go for 300W [just kidding],
http://www.aaroncake.net/electronics/300w_soldering_gun.jpg
tutorial:
http://www.aaroncake.net/electronics/solder.htm

One thing that shows your soldering iron tip is too hot .... many years ago I had a
cheapo Radio Shack soldering iron, non-temperature-controlled. After having the iron
turned on for a couple of hours, the tip was already starting to pit and deteriorate.
OTOH, I have been using a temperature-controlled iron for the past 7-8 years, and
the original tip still looks like new.
Title: Re: Soldering Hell
Post by: MarkT on Jan 11, 2013, 12:51 am


I'm wondering if the solder I have is the problem, I have heard some people saying that newer lead free solder can be extremely difficult to work with.


Yep. Lead-free is very troublesome, I imagine that's the problem.

At a hobby level you're not going to save the planet by using lead-free. You might as well use lead.


Lead-free is perfectly usable - but the iron _must_ be a bit hotter than for lead/tin - otherwise you've just back to the cold-iron issues.

I've used lead/tin solder for 20 years, and for the last 10 have used tin/silver and there is very little difference at all if
the iron is hot enough.  lead-free doesn't behave as well if reworking a joint, but you just have to add a little more.
With the iron at a higher temperature you have to switch off when not using to stop iron-oxide building up on the tip
(this prevents wetting of the tip).

One little detail (sort of mentioned above) is that the iron must melt the solder directly onto the part - place the end of the solder wire
between the iron and the part-to-be-soldered and squeeze it gently - once the solder melts (should take 1/2 second or less) it will
spread heat to the part to be soldered - you hold the iron there for 1 to 2 seconds to bring the part upto temperature, feeding in a
little more solder to fully wet the part, then withdraw iron and solder.  Yes you do need three hands!

If it takes longer than 2 or 3 seconds then something is wrong (large areas of copper like ground planes take longer though, 5 to 6 secs).

Always wet the iron tip with solder, then wipe it on the wet sponge immediately before each joint.  Any oxide build-up will
cause problems.  Parts must be clean and bright too.

Temperature-controlled soldering iron is pretty much a requirement.  Something like 300 C for lead/tin, 330 C for lead-free.

[PS lead contaminates your fingers and cannot be removed to any significant degree by normal soap - avoid lead solder!]
Title: Re: Soldering Hell
Post by: bot-thoughts on Jan 11, 2013, 01:52 am
@oric_dan(333) - I use two types of solder, Radio Shack 0.015" silver bearing (95% sure it's not rosin core) and a 0.032" rosin core. The latter I use for big through hole stuff, pin headers.

It flows good enough without any help from a flux pen. But only just good enough. (I'm not saying its the best rosin core solder).

However, whenever I need to rework a joint, the flux pen has to come out.  Also, with the pen, solder wicks into plated through holes better, so most of the time I just use the flux pen.

I use the thin solder for SMT and flux pen is a must there. The solder just flows so much better with it.

As for leaded solder, do your own research. LIke anything. There are multiple viewpoints on washing and how dangerous it is and such.
Title: Re: Soldering Hell
Post by: dtokez on Jan 11, 2013, 03:45 am


Anyway your jaw will drop the first time you see solder flow after application of flux.

Agreed.  The other jaw-dropping moment for me was when I applied the flux pen directly to solder braid.  The rate at which solder was wicked-up was almost like magic.


I always use flux pens on braid, top tip that! Certainly helps clean up pads and such :)
Title: Re: Soldering Hell
Post by: codlink on Jan 11, 2013, 12:35 pm
Since we're on the subject of the best soldering techniques, I am getting my hand into fine pitched ICs.  I have a few 2560s that I am trying to solder.  I have a syringe with solder paste and I used my hot air station.  The problem I am having is that no matter what I do, I keep getting solder bridges across the pins.  I use very little paste and still get bridges.  I use so little solder that it barely solders the pin, but I still get bridges.  I have tried not using extra flux and using a ton of it.  Using more paste, still get the same result.  It seems like the solder just isn't reflowing very well.  I have also tried different temps.

Solder paste is from Kester and is 63/37
Title: Re: Soldering Hell
Post by: dtokez on Jan 11, 2013, 01:35 pm
Maybe try an oven? I sometimes find that hot air moves the solder around too much and end up with bridges like you say
Title: Re: Soldering Hell
Post by: JoeN on Jan 11, 2013, 05:44 pm

I would disagree with

Quote
1) Always keep your sponge wet


I never use a wet sponge. I prefer this http://dx.com/p/soldering-iron-tip-cleaner-ball-golden-137118 (http://dx.com/p/soldering-iron-tip-cleaner-ball-golden-137118) kind of stuff.


You can use both.  I do.
Title: Re: Soldering Hell
Post by: oric_dan on Jan 11, 2013, 08:19 pm
Quote
The problem I am having is that no matter what I do, I keep getting solder bridges across the pins.  I use very little paste and still get bridges.

This is usual with manual soldering. People just take some solder wick, and wick away
the bridges.
Title: Re: Soldering Hell
Post by: rvasque on Jan 11, 2013, 08:56 pm

Since we're on the subject of the best soldering techniques, I am getting my hand into fine pitched ICs.  I have a few 2560s that I am trying to solder.  I have a syringe with solder paste and I used my hot air station.  The problem I am having is that no matter what I do, I keep getting solder bridges across the pins.  I use very little paste and still get bridges.  I use so little solder that it barely solders the pin, but I still get bridges.  I have tried not using extra flux and using a ton of it.  Using more paste, still get the same result.  It seems like the solder just isn't reflowing very well.  I have also tried different temps.

Solder paste is from Kester and is 63/37


Are you laying the solder paste across the pins? or individually on each pin?
I just lay a very *very* thin bead across all the pins, and on the outer edge.
(I'm using lead free solder paste.) 

Don't have your hot air blowing too hard... because that can push molten solder to places you don't want to (forming a bridge).

Still with this technique, 2 pins out of 16 may form a bridge (SSOP-16)... then just use some flux and wick to fix it.
Title: Re: Soldering Hell
Post by: codlink on Jan 11, 2013, 09:02 pm


Are you laying the solder paste across the pins? or individually on each pin?
I just lay a very *very* thin bead across all the pins, and on the outer edge.
(I'm using lead free solder paste.) 

Don't have your hot air blowing too hard... because that can push molten solder to places you don't want to (forming a bridge).

Still with this technique, 2 pins out of 16 may form a bridge (SSOP-16)... then just use some flux and wick to fix it.


I am laying across all the pins.  The tutorials I've watched use that method.  The velocity of the air was low. 


This is usual with manual soldering. People just take some solder wick, and wick away
the bridges.


It's funny you say that.  I have tried to use wick to remove the extra solder, but I can't get it suck up into the wick.  The bridges are on the board crossing the pads. 

I will just have to keep practicing.
Title: Re: Soldering Hell
Post by: oric_dan on Jan 11, 2013, 10:50 pm
Quote
It's funny you say that.  I have tried to use wick to remove the extra solder, but I can't get it suck up into the wick.  The bridges are on the board crossing the pads. 


I don't do a lot of really fine-pitch smt myself. But someone else mentioned that you
might try taking some flux or solder and flow it onto the wick first. It does tend to be
difficult to get the heat transferred enough to get the surface-tension working through
a dry wick, even on non-smt parts.
Title: Re: Soldering Hell
Post by: codlink on Jan 11, 2013, 11:54 pm
I have used flux on the wick, but never thought about tinning it.  I will try that.
Title: Re: Soldering Hell
Post by: kg4wsv on Jan 12, 2013, 04:09 pm
Quote
The bridges are on the board crossing the pads. 


Do your boards have soldermask?

This stuff isn't just for looks, it's actually more "solder-phobic" than bare substrate. When I made my own boards I found they'd bridge quite badly as compared to boards with soldermask.

-j
Title: Re: Soldering Hell
Post by: codlink on Jan 12, 2013, 06:15 pm

Do your boards have soldermask?


Yea

I tried tinning the wick and it works.  But I still want to get the solder to flow correctly without having to "clean up."  I have few ideas that I am going to try, one of them is to tin the pads before placing the IC.
Title: Re: Soldering Hell
Post by: oric_dan on Jan 12, 2013, 08:28 pm
Good point, which should have been mentioned previously. I always dab a bit of solder
on the chip pins before placing on the board, and I also usually take the exacto knife
and scrape the oxidation off the pins before that. I'll bet if you try this last bit it will
make a big difference. The solder will flow right to where it belongs without blobbing
up. Flip the chip over, and pre-tin the legs after scraping.

I'm sure the "official" smt fab schemes are designed to get around these silly extra
steps, but I don't do much smt fab.
Title: Re: Soldering Hell
Post by: bosleymusic on Feb 12, 2015, 01:08 am
If you're using paste, you should try using a stencil instead of a syringe. You can also get cheap boards with solder mask in low runs from a company called OSH Park. Solder mask can make a world of difference in how the solder flows and lays out.
Title: Re: Soldering Hell
Post by: Boardburner2 on Feb 12, 2015, 01:14 am
This is an old thread.

I have had similar threads pop up recently for no apparent reason


Title: Re: Soldering Hell
Post by: raschemmel on Feb 12, 2015, 02:49 am
I agree that flux is a great thing to have, but I solder all the time and don't usually need it. I know I need it if the solder doesn't flow onto the part and then I go hunt some down .  I think the problem is none of the above but the OP's technique.

@OP,
Are you  aware that the iron tip needs to "tinned" before you can start ?
Do you know what that means ?
Do you know that if the solder doesn't melt when you touch it to the iron tip at the point of contact, 2 to 3 seconds after touching the iron to the part that something is wrong ?
STEP-1: Warm up iron
        2: Tin iron tip
        3: pick up solder with left hand
        4: pick up iron with right hand
        5: touch tip to part, wait about 1 to 2 seconds
        6:  touch solder to part at point of contact closest to the iron tip
         7: wait a second or two for the solder to flow
         8: when the solder flows, remove tip. (tip should not be in contact with part > 5 seconds

If the solder isn't flowing either the part is contaminated (and needs cleaning with Muriatic acid (10%)
or you need flux to get it to flow. Flux is essential for surface mount work and soldering heavy guage
wire but isn't 100% necessary all the time. As I said, I know right away if I need it and that's when
I get it. If I'm working on surface mount I won't start without it.


Quote
This is an old thread. 
Oh damn ! I didn't catch that . oh well...
Title: Re: Soldering Hell
Post by: Marmotjr on Feb 12, 2015, 10:37 pm
Necro'ing an old thread such as this one is not bad, as there seemed to be lots of good info in it.  It's when somebody answers an old thread as if it's an actual response and doesn't add anything pertinent, that's a problem. 
Title: Re: Soldering Hell
Post by: Boardburner2 on Feb 13, 2015, 03:13 pm
Thanks all for the quick replies.

I have a temperature controlled iron from Maplin (which I run at 350c, it'll go to 450c though) and I broke out some new tips this evening just for the sensor, I've got 1.2mm lead free solder.

This is the iron I use: http://www.maplin.co.uk/48w-lcd-display-solder-station-98133 (http://www.maplin.co.uk/48w-lcd-display-solder-station-98133)

I have a flux pen but if I'm honest I don't know how and when it should be used.

My solder station came with a sponge which I use all the time to keep things clean.

I'll get some leaded solder and see how that goes as a starting point.

Dave
Sorry I cant follow that link.

I had one from maplin where the tips were very difficult to wet for some reason
Title: Re: Soldering Hell
Post by: Boardburner2 on Feb 13, 2015, 03:16 pm
Oh damn ! I didn't catch that . oh well...
ARRGH
Done it again
Title: Re: Soldering Hell
Post by: Marmotjr on Feb 13, 2015, 03:43 pm
ARRGH
Done it again
Seriously?  LOL.

You necro'd your own necro.... that's a new one.... I'll have to add that to my scoring system...