Talk:Soldering

Electronic components (pcbs) Beginnerspeak

A fair bit of beginner speak exists in this section.

"A soldering gun at 100 watts output may provide too much heat for printed circuit boards, while a 23 watt iron will not provide enough heat for joining copper roof flashing or large stained-glass lead came."

In fact 100w guns tend to provide to little heat for pcb work, not too much. The reason is time, a gun only on for 20 seconds doesnt develop the heat of an always-on 25w iron. (This is not the only problem with these guns.)

"For attachment of electronic components to a PCB, proper selection and use of flux is the best way to ensure that all solder pads and device terminals remain clean and oxide-free"

It doesnt do that though, it only helps avoid oxidation during soldering. It doesnt prevent oxidation during soldering, as anyone with soldering experience can testify, nor does it ensure joints are clean. Anyone who has soldered old component leads can testify to that.

"The devices must be mounted on the circuit board properly."

not at all, I've successfully and reliably soldered a huge number of entirely unrestrained joints. Its whats recommended to beginners because it simplifies the process, but its in no way a requirement.

Soldering is a very forgiving process, but components ought not to be solely supported by the solder joint - for example, wire leads should be wrapped around lugs on a tag strip before soldering, so that the component will stay put before the joint is completed; through-hole leads should be clinched to hold the part before soldering, also. Having said this, I have used a touch of solder instead of jumper clips for temporary connections - but you shouldn't find this technique in anything intended to be a reliable product. --Wtshymanski (talk) 17:13, 28 December 2007 (UTC)

My opinion is somewhere in between these two. Small parts (almost all PCB mounted parts in fact) don't need any other mechanical means of attachment. Heavier parts may. Middlenamefrank (talk) 03:56, 29 December 2007 (UTC)

Ideally the component should be mechanically stable, so that it doesn't move while cooling and create a 'dry' joint. That's what I learned in 'High Reliability Soldering' courses at the Australian Civil Aviation Authority. The term 'dry joint' isn't mentioned in the article either. I thought it was a common term. Usually the leads (thru hole soldering) were plenty to hold the parts in place, if you bent them properly.

When I talk high reliability, the process took, as I recall up to 20 minutes per joint! It was supposed to be up to military or even Aerospace standards! deburr pad, clean pad, clean lead, bend lead, insert lead, trim lead, clean solder!, trim solder, clean tip, solder joint, inspect joint, clean joint, inspect again!--220.101.28.25 (talk) 03:10, 25 October 2009 (UTC)

I was taught to solder to aerospace standards (for an aircraft manufacturer) and it never took anywhere near that long. Yes cleanliness it important but if the board is cleaned before you start it should stay clean until the board is done. Cleaning components and trimming leads doesn't take very long. Dry joints can be caused by a multitude of factors - it doesn't necessarily need to be movement while the joint cools. It could simply be that it was never heated enough to begin with. In my experience this is becoming more common now since people are still using their old "thermally balanced" irons with lead free solder, and they simply don't get hot enough. As a result you see entire boards where every single joint is obviously dry. CrispMuncher (talk) 22:43, 26 October 2009 (UTC)

"To achieve a properly heated joint, the soldering iron and the solder must be applied separately to the surfaces to be joined, rather than the iron being applied directly to the solder."

No, again its just beginners advice. Again I've soldered huge numbers of joints reliably by applying the solder to the iron. One merely has to then complete the joint before the flux ceases being active. Beginners are given this advice because they can tend to take an excessive time to make the joint, a time exceeding the life of the hot flux. However if you want to solder rapidly, or to solder with minimum component heating, applying solder direct to the iron is usually the way to achieve both those things.

Again, none of the sources I've read recomment heating the joint through liquid solder - the problem is that this leads to high solder

consumption and a good chance of a blob of molten solder running off the joint and landing somewhere it shouldn't. A properly tinned bit is important for heat transfer, since a completely dry tip will have a high thermal resistance (air gap) between the soldering bit and the joint - but you can't drown the joint, either. --Wtshymanski (talk) 17:13, 28 December 2007 (UTC)

Again I'm somewhere in the middle. I almost always use a bit of molten solder on the tip of the iron to increase thermal transfer to the joint, and on small joints that's often all that's needed. Make sure the flux is still active though! Middlenamefrank (talk) 03:56, 29 December 2007 (UTC)

I've heard of this as recommended practice several times (and find that it works bests for me). The contact area between a clean iron and the components is minimal, heat transfer between the two is poor and the result is the components don't wet properly because they're too cool. This is particularly important with cored solder where no additional flux is used, since then there isn't even any flux to fulfill the same role. A solder pool already on the bit massively increases the effective contact area, although as Middlenamefrank suggests you may still need a touch more solder, both to the fill the joint and provide some fresh flux. CrispMuncher (talk) 19:56, 26 August 2008 (UTC)

Yes absolutely. Just a little solder on the tip, we termed it a 'heat bridge', greatly increased the heat transfer to the joint. --220.101.28.25 (talk) 03:10, 25 October 2009 (UTC)

"When the surfaces are adequately heated up, the solder will melt and flow into the joint. The solder supply is then removed from the joint, followed by the heat source."

The solder source is normally removed before the joint flows, not after. It is almost impossible to get proper flow while solder is still being applied to the joint, as flow requires a higher temperature than solder melting point. When enoug solder has been applied the iron is usually kept on the joint a little longer to achieve full wetting & flow.

I dont think even distribution of solder throughout the joint is an aim, nor the norm, nor a requirement for a succesful bond. An uneven distribution with a shape I cant think of the name for is in fact the characteristic appearance of a good through-hole pcb joint.

Again, not my experience - a joint where only 1/3rd the circumferance of the through-hole via is soldered is a joint that will fail, in my experience. --Wtshymanski (talk) 17:13, 28 December 2007 (UTC)

This time I'll take a side. I don't know of an inspector anywhere that would allow a joint that's not at least ALMOST completely wetted out. If it isn't, it probably wasn't properly flux'ed or heated. Middlenamefrank (talk) 03:56, 29 December 2007 (UTC)

I was trained to never remove the solder before it flows. A good temperature controlled iron, careful tip selection to suit the joint type, correct heat setting, and lots of practice. One 'trick' was to move the solder around the pad to get complete coverage. This was an 'idealised' type of soldering, for maximum reliability.(not speed)--220.101.28.25 (talk) 03:10, 25 October 2009 (UTC)

"Excess solder and unconsumed flux and residues must be wiped from the soldering iron tip between joints"

beginner-speak.

Not necessarily - a large blob of carbonized gunk on the tip will make it difficult to make new joints. Again, every reference I've read says keep the tip clean and tinned, borne out by my own experience. --Wtshymanski (talk) 17:13, 28 December 2007 (UTC)

I agree with shy here too. It may not be NECESSARY to have a clean tip to make a good joint, but it sure makes life easier! Middlenamefrank (talk) 03:56, 29 December 2007 (UTC)

Concur, 'carbonised gunk' may indicate iron too hot, flux possibly 'burning'. Clean tip absolutely. --220.101.28.25 (talk) 03:10, 25 October 2009 (UTC)

"but the tip of the iron must be kept wetted with solder ("tinned") constantly when hot to prevent oxidation and corrosion of the tip itself."

mostly, yes, but constantly, no. When reprofiling a tip it is normal to heat it up as bare copper, and apply solder only once hot.

Cue controversy now... many seem to think that the popularity of coated tips somehow prohibits the use of uncoated copper tips.

And keeping the tip wetted does not prevent corrosion - this is precisely why coated tips are so popular. Tabby (talk) 11:33, 25 December 2007 (UTC)

I've used unplated and plated tips - the plated ones do last longer, but even a bare loop of #14 copper wire chucked into a soldering pistol will last a long time in an emergency. --Wtshymanski (talk) 17:13, 28 December 2007 (UTC)

I've used 'em both too, and I do believe that keeping any tip tinned makes it last longer. I once broke the tip off a dart when I needed an exceptionally fine point. Middlenamefrank (talk) 03:56, 29 December 2007 (UTC)

I seem to vaguely recall that exceess copper in the joint, from an unplated copper tip say, may have made the joint more brittle? --220.101.28.25 (talk) 03:10, 25 October 2009 (UTC)

I was taught it is nothing to do with the quality of the joint itself but for preserving the bit: tin from the solder and copper from the bit combine under the heat of the iron to form bronze which is an absolute pig to either solder to or with. Once you get a bronze layer on the tip it either needs filing off (fien with unplated bits) or the bit junking. CrispMuncher (talk) 22:43, 26 October 2009 (UTC)

"applying solder direct to the iron is usually the way to achieve both those things."

This method can yield soldered pcb joints in about 2 seconds each. Solder on the iron first means greater area of thermal contact to the joint for quicker heating, and as long as the joint is done within a few seconds there is no problem caused. This is pretty standard where high speed hand assembly is used. A high power iron is needed, either thermostatic or one with power boost. Tabby (talk) 03:49, 28 December 2007 (UTC)

I also have a big problem with this sentence as it depends on the type and brand of soldering iron used. "A 100 watt soldering iron may provide too much heat for printed circuit boards, while a 25 watt iron will not provide enough heat for large electrical connectors" It seems he is talking about the old soldering irons that had the premise that more power was better. Modern soldering irons mainly used in the electronics assembly and rework today have a cartridge configuration. The cartridge is composed of a hollow tube with wires inside that in the most advanced systems have a power (24V), ground and sensor cables connected to the very end of the tip where a heating element or resistance is. The resistance then transfers power to the copper (Cu) tip, which in turn melts the solder while transferring energy or heat to the joint or application worked on. While power is important, so is thermal transfer, tip mass and thermal recovery. There are microprocessor controlled 20W irons that will outperform a 70w iron as they have a low mass/power ratio, and great thermal recovery to maintain the temperature and be able to provide continuous stable power. See short video link. http://www.jbctools.com/KB/videosKB/2210penny.wmv —Preceding unsigned comment added by 71.8.208.229 (talk) 01:03, 9 February 2008 (UTC)

The video link above of soldering a heavily oxidized penny shows inclusions and no whetting of the solder, so it is worth noting this must be a how not to demonstration or an example of what heavy oxidation does to the process. — Preceding unsigned comment added by 98.249.62.137 (talk) 04:11, 7 October 2011 (UTC)

All good stuff above, but tip shape& size is also important to get the best contact to PCB and lead at the same time if possible. I'd personally never use a 100 watt iron on a PCB if I had a choice, if it was temperature controlled maybe. Shields or large ground planes on RF boards might need it. --220.101.28.25 (talk) 03:10, 25 October 2009 (UTC)

With controlled irons the power rating is pretty much meaningless in terms of frying things. From memory a lot of Weller's controlled irons are 80W - they are thermostatically controlled so it isn't a problem. It just means that you have a bit more headroom to keep the bit temperature stable. I use Antex and Hakko stuff myself with powers of 50 and 60W respectively. CrispMuncher (talk) 22:43, 26 October 2009 (UTC)

“Hand-soldering techniques require a great deal of skill for the as fine-pitch soldering of surface moutn chip packages.”

What does this mean? I don’t know enough about soldering to suggest an appropriate correction, but there is clearly something wrong with this sentence.--Observer6 (talk) 15:00, 21 May 2017 (UTC)

It had a spelling error and some stray letters...I believe I've fixed it now. It wasn't a soldering problem, it was a proofreading problem. --Wtshymanski (talk) 20:40, 21 May 2017 (UTC)

"Reballing" listed at Redirects for discussion

A discussion is taking place to address the redirect Reballing. The discussion will occur at Wikipedia:Redirects for discussion/Log/2020 July 10#Reballing until a consensus is reached, and readers of this page are welcome to contribute to the discussion. pandakekok9 (talk) Junk the Philippine anti-terror law! 08:37, 10 July 2020 (UTC)

March 2021 edits

I pulled out most of the application-specific material out of the old “Processes” section, and renamed it “Soldering vs. Brazing”, since the remaining material in that section is concerned mostly with that. The section still remains a bit of a mess, unfortunately. My interest is mainly with electronics soldering, and I’m not knowledgeable enough to compare and contrast soldering across diverse applications. I also renamed “Tools” to “Heating methods”. I feel that, aside from the heating methods, tools are (mostly) specific to the application and process, and does not benefit from consolidation in a single section. Material on application- and process-specific tools were moved to their respective sections. DriveByWriter (talk) 19:02, 19 March 2021 (UTC)

Literature

Hans-Joachim Peter: Handbook of Inductive Soldering, Hans-Joachim Peter Verlag Berlin, 2017, ISBN 978-3-00-064582-2 (www.induktionsloeten-peter.de/en) Hansjoa (talk) 15:15, 14 January 2023 (UTC)