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How to Solder Correctly - and Why

Video Overview:

 

The goal of this guide is to explain how to solder electronic components, and also provide some guidance on choosing tools and materials

Contents:

  1. Select a Soldering Iron
  2. What kind of solder (rosin cored, etc. lead-free)? What is flux and when is it necessary?
  3. Prepare the work - How and why to clean components, wire stripping and tinning guide
  4. Tin the tip - Tips for prolonging tip life, making soldering easier
  5. Heat and Solder the Joint - including closeup pics of the proper way to hold the iron against the work. Also, numerous good and bad joint pics.
  6. Cleanup - Do you really need to clean off flux residues?
  7. Protection - What is a conformal coating? Some applications encase electronics in solid epoxy...
  8. Desoldering - Illustrations showing how to use solder wick, a solder sucker, and an iron with a vacuum bulb. Plus a special surface mount removal tool and other tips for removing smt chips.
  9. References - There are hundreds of other great how-to guides and resources out there, here is a review and listing of some of those.

 
 
 

Other references and guides:



Related Products:

Comments:

Dec 10 2007, admin said:

Feedback and corrections are greatly appreciated.

Dec 15 2007, anonymous said:

I can only get the first half of the video to play

Dec 15 2007, admin said:

sometimes the video can take a while to load—try reloading the page. A slightly lower resolution version of the how to solder video can be seen at YouTube.

Jan 09 2008, anonymous said:

great vid, very helpful!

Jan 18 2008, anonymous said:

Thank you for this video !!! Helped me out a lot !!! Really appreciate it !!

Jan 19 2008, anonymous said:

I have always had trouble getting good solder joints and to get solder to adhere on wire. Thank You for a very informative easy to understand Video and Narration.

Jan 27 2008, anonymous said:

cool!

Jan 28 2008, anonymous said:

sigh Remember people that lead is still by far the worse problem here. It takes about 8-15 micrograms (micro, not a mistake and I’ve thoroughly checked that) ingested per day to cause “lead poisoning” in a 6-year old. That means at least “special education” for Timmy, and it’s comparably bad for adults on a /kg basis. Just be smart and use lead-free. It’s a no-brainer for those who know the facts involved.

Jan 28 2008, anonymous said:

egads, I just watched the video. The way he is cleaning the solder tip, etc… When it’s sitting on a joint or used with prudence it’s one thing…. even intact solder will release lead oxide (a readily distributable powder) for a variety of reasons, and if you’re going to step on it, allow to oxidize under heat …. sand! Parts usually are pre-tinned with lead alloys. BAD IDEA…. look, using lead solder is a bad idea, okay. Don’t.

it’s illegal to use lead solder in plumbing, but the amount you’d get on your hands from doing these things here could be thousands of times what would leach out of solder joints into water you drink. True, I don’t know how much gets ingested from what’s on your hands, table feet floor, but we clearly have a problem here. It would be most interesting to try an experiment with an appropriate amount of bitrex on the surface of all the solder, and see if you notice how you end up ingesting it eventually – that would demonstrate how you cannot keep the lead in one place if you use it like this.
The hobbyist should be the last to use lead solder, and yet many in industry have already stopped. I’m not talking about “the environment”, I’m talking about not harming yourself and your household. Just think for a second the sort of concentrations we’re talking about in a landfill vs. your house. If having lead around matters in a landfill, it should matter in your house. Why am I writing this, apparently with some ulterior motive? Because I’ve seen how bad lead is, and I don’t want to have to put up with somebody else’s mess. Lead is so hard to clean up and easy to not put down, it’s time to grow up and start being a bit more responsible about it.
I hardly object to it’s use in SLA batteries for instance, but this is not it’s place.

Jan 28 2008, scott (admin) said:

While it’s certainly a good idea to wash your hands after soldering with lead-based solder, I’m not convinced that there’s significant risk to using lead-based solder. Sure, ingesting small amounts can be harmful, but how likely is it that small amounts wil actually be ingested?

Lead-free solder has its risks, too….

This claims there is evidence that the fumes from lead-free solder are more harmful (just how much more harmful? not sure…)

The lead-free alternatives have environmental costs as well.

It would be interesting to find out just how much lead from hand-soldering becomes ingested on average. I suspect it’s not a harmful amount. Assembly line workers have been assembling equipment with lead-based solder for a couple decades now, and I haven’t been able to find any studies showing a harmful amount of ingestion, although there are many that discuss the asthma risks from the flux fumes. (see this OKi ad)

Some more food for thought: this
article claims that there have actually been no documented studies showing ground water contamination from lead in land-fills (the main impetus for RoHS and WEEE regulations). Apparently lead from electronics comprises less than 1% of lead used, the rest coming mainly from batteries and CRT monitors (although the disposal of these is much more controlled). Note, lead can in fact be leached from PCBs, so I’m definitely not arguing against the prudence of those regulations.

I’d be very grateful for links to studies showing documented cases of lead-poisoning from hand-soldering.

Feb 13 2008, anonymous said:

excellent video – clear and to the point – great work.

Mar 05 2008, anonymous said:

Thanks a million. That video is a huge help. Very well done.

Mar 05 2008, anonymous said:

@scott: I’d highly suggest you watch Manufactured Landscape which has nothing to do with this except for one part where he goes to villages in China known for recycling electronics and noticed that you can smell the heavy metals from miles away and that the government now has to deliver water by truck as the natural sources are all contaminated.

Mar 05 2008, scott (admin) said:

point taken :) If you have a link to youtube that’d be great…

I wonder what all is being thrown into that particular village… a lot of lead is used in car batteries here in the States, but their recycling is very much controlled, so little battery lead ends up in land fills.

Sounds like that village missed out on China’s version of RoHS.

Mar 12 2008, anonymous said:

why pronounce it “sawder”? Took me ages to work out what he was on about.

May 04 2008, anonymous said:

same reason it’s spelled “could” and sounds like “kude”

May 19 2008, anonymous said:

Outstanding video! I will be building a kit soon, and I found the information in the film will be of great help. Thanks so very much.

Dick Williams KB3OMJ

May 22 2008, anonymous said:

A good tutorial. I’ve been soldering for over 20 years (professionally and hobbyist), but it’s always good to brush up on techniques.

May 22 2008, scott (admin) said:

thanks… we’d love to hear any critiques you have or better ways of doing things that you’ve picked up over the years.

May 22 2008, anonymous said:

In further answer to the March 12, 2008 question “why pronounce it “sawder”? Took me ages to work out what he was on about,” please note that the questioner is not a native American english speaker, but rather a United Kingdom native speaker, wherever he/she actually resides. The North American pronunciation of “solder” is indeed “sawder.” But I would also point out that the phrase “he was on about” is equally obscure on this continent. It is not used here, except by those trying to emulate usage in Great Britain and its commonwealth. I would suggest that the original poster not be so critical, particularly while revealing his own linguistic shortcomings and lack of exposure to the usages of English around the world. The other commentator was a bit more cryptic, if more humorous than I, when he said "same reason it’s spelled “could” and sounds like “kude”. And finally, no less a personage than Sir Winston Churchill said something to the effect that “the UK & USA were two countries divided by the same language.” It was a good joke when he said it, and all the more so because it was so true, both then and now.

Now on to more important things. After all that, I will add that I thought the video was very well done, and will recommend it to a number of people with whom I work who will profit a great deal by it. I have been occasionally soldering electronic components for over 55 years now, and while I can recognize both bad and good solder joints, I have not been able to convey that knowledge to those 1/3 my age in nearly so clear a form as this video. Good work, and many thanks.

May 22 2008, scott (admin) said:

thanks!

May 23 2008, anonymous said:

And now for something completely different.

The online etymological dictionary says:

http://www.etymonline.com/index.php?term=solder

As for the snippish comment about “could”:

http://www.etymonline.com/index.php?term=could

Jun 14 2008, anon (unregistered) said:

Great Video! I’m just starting to get into some of this for repairing/modding old video game systems, to make them into musical devices and this gives me hope that with time I can start to understand the process enough not to mess it up.

Jun 14 2008, anon (unregistered) said:

I just broke the piece of metal on my glasses that connects the two lenses together and I was wondering if that was something that would be able to be soldered? I also have a 1 year old that loves grabbing at them so I would assume lead based solder wire would not be a good idea, any advice?

Sep 03 2008, Kusanagi (unregistered) said:

Hey, does anyone know what solder and devices would be needed for a newbie to desolder and resolder the audio wires for a nintendo ds lite??

I need it for no other purpose than that

Sep 03 2008, scott (admin) said:

please post questions in our soldering forum

thanks!

Oct 11 2008, Trevor (unregistered) said:

wow everything you said not to do I’ve done so this video is GREATLY apprieciated thank you!!!

Jan 06 2009, Jb (unregistered) said:

This must be the best Tut Vid i have seen online !!

Jan 06 2009, Mikk (unregistered) said:

Tip requires sanding as the solder alloys with the copper of the tip forming brass. Brass has different solderability (wettability + thermal conductivity) than original high copper tip. Section a tip and metallographically prepare and etch it and it is readily apparant we are dealing with two metallurgically distinct regions. Sanding (grinding) is the solution .. excessive tinning might be the problem (along with excessive heat) under no-load conditions.

Spock out!

Jan 08 2009, Gary, KE7FIZ, PE, CID+ (unregistered) said:

Very good vid. I especially like how you show bad examples, as well as good – that’s missing from other training videos I’ve seen.

And thanks too for tempering the OMG-Lead-We’re-Gonna-Die hysteria. Good links and rational info provided on the subject. I searched once trying to find the vapor pressure of lead at soldering temperatures. No luck except for one paper that had measured it at higher temps and extrapolated the result to soldering temps, describing it as: ‘a really hard vacuum’. The only other thing I’ve found are reports of no elevated blood levels of lead in electronics workers after years of ‘exposure’.

I’ve also read of the poor children in the contaminated ‘recycling villages’ in China (and elsewhere). If they weren’t being exposed to the tiny bit of lead in electronics, they will certainly be exposed to the much greater amount of lead in CRT’s and batteries. It’s all done illegally anyway, and if it’s not lead it’ll be something else that’s toxic, illegal, and profitable, that someone will use to expolit people at that level in that type of society. Removing lead in electronics is “not” a solution to that problem.

Feb 26 2009, Mike (unregistered) said:

Thanks for the video. I’ve done a little electronics soldering here and there over the last 20 years or so, and I’ve honestly never really had a clue what I was doing. This video was much more helpful than reading about it in a book.

Apr 13 2009, Jordan (unregistered) said:

Thanks a lot, this was a great help, I had done larger scale stuff, like pipes, but that’s a total different ball game.

Sep 12 2009, gail (unregistered) said:

Very good, just one suggestion: speak a little slower. Thank you!

Sep 12 2009, Van Bever Koen (unregistered) said:

great tutorial for someone who knows nothing from soldering

Sep 23 2009, bacteria (unregistered) said:

Excellent guide! Very useful.

Dec 27 2009, daniel [mex] (unregistered) said:

i hoped to see this video moths ago, i reallly did a mess in my pcb projects, so now that i know how soldering, i will try hard to make a better work, thanks a lot ^^

Jan 04 2010, Tom Luque (unregistered) said:

I have done NASA certified soldering, and you have shown excellent views of good and bad joints. We used soft erasers to clean board pads and componant leads. Gold pads were more difficult to achieve a good shiny flow.

Apr 04 2010, Marcus (unregistered) said:

Great video, it’s all more clear now :-) Thank you.

Apr 05 2010, Tom (unregistered) said:

This is the best how to solder video I’ve seen yet, and I’ve been looking at many. You explained the technique as well as the chemistry behind the process, and had good repetitive video samples. I had never heard of the heat bridge and soldering from the opposite side of the wire. Thanks a billion!