Soldering Irons

[CaptKirk]

This is a Hakko191 Soldering Iron Tip Thermometer for $14, free ship and no tax. http://www.dealextreme.com/p/1-6-lcd...rmometer-80100

[Jrd]

This is a Hakko191 Soldering Iron Tip Thermometer for $14, free ship and no tax. http://www.dealextreme.com/p/1-6-lcd...rmometer-80100

So then, this would be the correct way to measure the temperature of a soldering iron tip.

[CaptKirk]

I don't think it is the only way, but this sure is a hobbist affordable way to do it. This uses a thermocouple (the triangle wire thingies) to measure the tip temp fairly accurately. If you search for this thing on the web, it seems to go for around $100 normally, so $14 is a pretty good price.

[Sigmo]

Hello. This is my first post to this forum.

I signed up to see if I could find some information because I'm assembling some Ren SS24s for a friend, but that's for another thread or maybe I'll find what I need just by browsing around.

I saw this thread and ended up reading it all (or at least skimming all of the posts).

I thought I'd offer some of what I've learned in about 35 years of working on electronic circuit boards. I hope what I have to say is of some help to everyone.

Are any of the Weller irons any good?

Yes. That's what I've been using for all of this time, and I've still got the original ones I bought back in the mid '70s. And some new ones we got where I now work still seem to be very good.

Gotcha. So definately don't need to go below 20W to be safe?

The need to use a low-wattage iron is a myth or misunderstanding. If the iron is temperature controlled, you can theoretically have as powerful of a heating element as you want because it'll be throttled to whatever is required to maintain the temperature you've selected. More power means you can solder more large connections in quick succession or solder very large connections. But it has no detrimental or dangerous effect because, again, the power is turned off or throttled as the tip temperature recovers to the setpoint. I like having at least 40 Watts available, and for some jobs, you need far more.

Having just assembled three Ren SS24s, the only areas that required quite a bit of power were the fuse clips. The 40-Watt station I was using was perfectly adequate, but the TIP used was important!

You must envision what's happening when you solder a connection.

The idea is to heat all parts of the connection (the component lead and the board's plated-through hole in most cases) to the desired temperature quickly so that the solder will flow well and be pulled into every place you want it to be by capillary action.

No matter how powerful the heating element of your iron, if the tip's cross sectional area is too small to allow a large amount of heat to flow through it into the joint, it will take too long to heat the connection.

Two things ruin circuit board traces/plate-throughs: Pressure (physical force) and lengthy heating. The same is mostly true for most electronic components. Heating them for a long time is what murders them. You need to have "enough tip" to get the joint heated quickly and get it soldered before you ruin the board or component. I've never seen a board or component damaged by using a tip that's too large. I have seen many parts and boards damaged by people using tips that are too small or irons with too little power such that they had to heat the joint for a long time. Also, uncontrolled high temperatures are very bad!

So you want to have a tip that's small enough to let you comfortably manipulate it to touch the joint you're soldering while not touching the adjacent one. And you need to have a small enough radius on the top to fit it in nice and close to the junction of the component lead and the solder pad/hole for good heat transfer. But sometimes the very slender tips are a real liability because they don't conduct the heat from the heating element rapidly enough AND they don't "store" enough heat out near the tip to be able to dump that heat into the joint quickly.

Think of the tip as both a conductor and a capacitor for heat energy.

A small tip is a poor conductor and a low-value capacitor. A large, thick tip is both a better conductor and a larger value capacitor for heat.

When you connect the large tip to the joint, the temperatures of the two objects will try to equalize. The tip's temperature is pulled down and the joint's (and solder's) temperatures are pulled up. The heating element won't know that the tip's temperature is being pulled down instantly, and even if it did, the element can't heat instantly, nor can the tip conduct that heat out to the tip instantly all the way from the heating element.

So you're relying on the stored heat in the tip for that instantaneous heating of the joint and solder. Bigger is better, of course.

Again, you've got a temperature controlled system (we hope), so you're not going to overheat the connection by using a large tip and a high power heating element. 700 degrees is 700 degrees whether you've got a big tip or a small one. But the big tip can get the joint up to that 700 degrees a lot faster than a small tip.

So the tip's size should match the size/mass of the joint you're trying to heat. You can use a relatively small tip for soldering IC pins into their holes because the IC legs are small (low mass) and the mass of copper foil on the board for an IC leg (should be) small, too. But I tend to solder ICs (or sockets in this case) in very quickly. I get a batch of them inserted and held in place by a foam-rubber piece under the board holding them up in place, and then I zip down a long row of (perhaps) hundreds of these legs soldering them in one after the other. A very slender tip is noticeably slower!

I can feel the solder not melting as quickly after a few joints, and I have to wait a short time for the tip temperature to recover. Putting in a slightly larger tip, I can go considerably faster.

So the point of all of that is that you should buy an assortment of tips and then swap tips as you move from one size of joint to the next. This isn't much of a problem on these Ren SS24s. The Wiki instructions are well thought-out as to the order in which you're assembling things. I like to start with the lowest components and work up to taller ones on a board because then your foam-rubber component holder-upper-thing will work well. And because you're doing groups of similar parts in stages, it's not as if you'll be doing a lot of tip swapping. You need a break every once in a while anyhow to get up and stretch and rest your eyes, etc.

Swapping tips is a good excuse for a break

OK. Now more thermodynamics and heat-flow theory. And that's all that soldering is. It's something you get a "feel for", but sometimes it's good to explain it just to get to that "ahaa!!" moment with it quicker.

Consider what happens when you solder a joint between a component leg and the hole it's poking up through. You get your soldering iron and you touch its tip to that joint. Doing the best you can, you get the tip to touch the component lead and the solder pad both at the same time in close to the hole. Great.

But imagine what's happening on a microscopic scale.

The tip touches the lead in one point. It touches the pad in one point. From geometry class, we know that a point has an infinitely small area. Two points is still virtually zero area. How much heat can be conducted through zero area? That's right. Zero.

So we need to do something to achieve a large area of thermal contact between the soldering iron tip and the pad and the lead. That's where the solder comes into play. You have to get the solder into just the right position so that it begins to melt immediately, flowing into the joint so that you establish a large cross sectional area through which more heat can flow to heat the joint up.

In practice, this just looks like one smooth, fast movement. But as you play with it, you find that you do great on some joints, then "miss" occasionally so you have to work on your positioning of everything.

Another thing that's not obvious is that for the solder to flow into a joint properly, the flux has to get in there first. Ideally, you'd be able to inject some molten flux into every joint before you ever got there with the iron and the solder. But the flux is (usually) inside the solder. It's a "core" in there.

What I find very beneficial is to imagine that tiny core of flux inside the solder and place the solder such that the flux core is aimed right down into a place in the joint that has a good gap. Not where the leg is resting against the side of the hole, but where it can get into an opening and flow down into that annulus. Of course, I'm also positioning the solder so the tip will begin melting it immediately just as the tip contacts it, the component lead, and the solder pad all at once. Then, I consciously push the solder down so that the flux core is forced into that gap down into the hole. That way, some flux will hopefully get in there ahead of the solder.

If you plug off the opening with solder before the flux can get in there, that joint will be somewhat doomed. I'm not saying it won't work at all, but you'll see the difference. The solder won't flow down into the hole quickly and nicely the way it does on the joints where you manage to squirt some melted flux into the opening.

I wish my eyes were as good as they used to be, but they are not! I used to be able to do this with my glasses on (nearsighted) and nothing else. Now I use one of those "old guy" head-gear dual magnifier thingamabobs so I can really really see this all well. It really makes things go smooth and fast.

And when I inspect the board up on the topside, I can see the great joints where the solder pulled up through the holes and made a nice fillet on the top side, and I can see the ones where I didn't get the dance just right, and they didn't pull through. I sometimes touch those joints up on the top side just because. I know it'll make adequate contact assuming the plate-through is good. But I just like to know that I'm not really relying on the plated through hole. That probably goes back to the early days when we were very suspicious of any plate-throughs and layed out boards with the goal of having as few plate-throughs as possible and NO vias (plate-throughs without a lead through them). Modern boards are amazingly good, and the vias are reliable.

Still, I like to see the solder pull through the hole and form a good fillet on the "component side" of the board, too. It's an old-guy thing, maybe.

This is also why I often mount parts like the LEDs on these boards and the caps, too, up a bit off of the board. I want to be able to see that fillet of solder pulled up through the hole. I am also very wary of soldering on LEDs. They're the ONLY component other than polystyrene caps I've ever seen damaged by what I consider to be reasonable soldering practice.

And while we're on LEDs, they've often got silver plated leads. Silver tarnishes. Tarnish is "solder repellant". If you think about it, scrape the LED legs a bit before soldering them. You do NOT want to have to roast LEDs for any length of time when soldering, so if the legs are tarnished, you may well fry them before you can get a good connection to them.

OK. That was a rant. Sorry.

~~~End of part one~~~

[Sigmo]

~~~Part 2~~~

I bought a Weller WPCPT. Best iron I have ever owned, bar none. About 110.00 at Fry's, list for about 140.00. Heats up in about 20 seconds and the heat is controlled through the tip somehow. I can solder all day long at 0.10" with my trusty Optivisor DA-5 (your eyesight is the first to go, then your memory. Now where was I.....

You got all of that right! I love having a magnifying visor thing! And the WPCPTs are a classic. The temperature control is a very clever thing.

The tips are marked as to the temperature at which they operate. The temperature is controlled by a switch in the handle. There is a magnetic slug on the back of each tip. That slug is formulated so that its "curie point" is at the desired temperature. When the tip reaches that temperature, it loses its magnetic characteristic. That lets the switch be opened by a spring. Once the tip cools down sufficiently, that slug of metal on the back of the tip becomes magnetic again, and the switch is pulled closed! You can hear the soldering iron handle "click" every so often as it switches the power on and of. They're fantastic and amazingly reliable. Good old seemingly low-tech, but in fact, extremely elegant!

Just out of curiosity has anyone every had much success with the butane type soldering irons?

While they're handy for a lot of uses where you don't have power available, I would not bother with one for soldering entire boards together. They've got their place, but this is not it IMO.

I vary my temps dending on the thickness of the material I am soldering. I usually run between 380 for the finest wires, up to about 550 for fuses and triacs. I have done 16 Ren 16's, a Ren 24, a Grinch, 8 ssr's and an Ledtriks board, and the tip still looks pretty good. Has developed a very minor bend at the very tip........
Probably time to order a couple of spares......

See above. For me, the temperature is dictated by the solder formulation. Then, you select the proper tip size to fit the size of the joint(s) you'll be soldering. If you expose the solder to a temperature that's too high, it will oxidize rapidly, thwarting your soldering. If the temperature is too low, it won't flow and make a good joint. Find the right temperature for the solder you're using, make sure your iron has enough power, and choose the appropriate tip size for the joints to be soldered. (This all assumes you're using a temperature controlled iron/station - and you should be)!

having just read the last page or 2 about tips needing replaceing.

am i missing something here. i have soldered 3 x ren 16, ren - 64, 2 x grinches + ren-c , ledtricks panels and controller boards etc. plus various other stuff all in the last year. and the tip is no different to when i started.

this is a 10 yo weller iron and the tip is at least 5 yo and been using it consistantly over that time without any sign of wear.

all i do is just wipe the tip on a wet sponge every time i stick it back in the holder.

are the newer tips lower quality or what? anyone know?

i was gonna get a new iron but im im gonna have to replace the tip every 6 months im gonna rethink.

Peter

Different things attack tips. The flux, the formulation of the solder, and the tip material. The good Weller tips are copper (for good heat conductivity) plated with iron for good tinnability and resistance to corrosion. Once you get through the iron plating, however, and are into the copper, then they go away in a big hurry! Keep some spare tips around.

I use a Weller WTCPT its old old model but still works great.....

Again. Thumbs up for the good classic Weller stations.

Most of the inexpensive soldering irons out there (like the walmart ones) use heavy gauge copper wire (like 4ga or 6ga) that is threaded on one end as the tip. In a pinch you can use a file to put a new tip on them. Then retin it with plenty of flux and solder. Problem is everytime you use it the molecular action of the solder and copper wears away the copper. Also the high heat and cooling cycles degrade the copper. The more expensive units usually have an iron alloy tip that avoids these problems.
I was pleasently supprised by a very inexpensive model I found on line. It is not fancy, just basic but it works great. It has a grounded tip and attatchment point for ground strap. Adjustable temperature and a changeable alloy tip. I have made 2 grinch boards, 2 Ren-c's, 32SSRs, 1 mini grinch and about a dozen other perfboard projects and other odds and ends around the house. The tip is still as good as new. Not to bad for 12.95 plus shipping.
http://www.kitsusa.net/phpstore/html/OLC-98-Variable-Temperature-Soldering-Station-1132.html"]http://www.kitsusa.net/phpstore/html...tion-1132.html[/URL]

I agree with all of that! Plain copper tips will be dissolved by the solder. So not only do you have a tip that's constantly going away, but you are polluting your solder formulation with that dissolved copper. Not a good idea.

Never use a wet sponge.
The temp shock can ruin your tip.

Always use the brass scouring pad as rkhanso recommends.

Btw... you can get replacements for these balls at www.dealextreme.com for only $2.63 with free shipping.

We've used the wet sponge method for many many years. They work just fine. The kind of tip cleaner you recommend might be great, too. I'd like to try one.

But the old wet sponge technique has served us well for tens of thousands of hand-soldered PC boards over the years.

I like to get the sponges with little slits in them to help trap the solder blobs. And I like them to be moist, but not soaked. If they're really soaked, it DOES cool the tip off, and you have to wait for the tip to "recover" AND it actually makes it less likely to pull the slag off of the tip, too, because the solder "freezes" on the tip rather than being pulled off into the sponge. So keep the sponge moist enough to prevent it from burning, but not so wet that it cools the tip down. As with many tools, it's all in how you use it.

I'm not sure if you can get these anymore, but check this out. It's a gadget I bought in about 1987:

p915650559.jpg

Two counter-rotating moist sponges. You insert the soldering iron tip, and it pulls the gunk right off.

We dubbed it the "roto-lips" back then.

I use around 350 for most parts. Crank it up to 375 or 400 for larger, non-sensative parts like the fuse clips or power connectors, since they have a large area that serves as a heat sink.

I tend to like 700 degrees F for almost everything.

I solder everything on the boards at 680 deg F.

If you can find it, 63/37 is the easiest to work with, followed by 60/40 and hardest is the lead-free -- which takes a much hotter iron temperature. Small diameter (.031") makes for fewer solder bridges.

63/37 is very nice because it's what they always referred to as a "eutectic" solder back in the day. The idea is that with this alloy, the difference between the "liquidus" phase and the "solidus" phase is virtually nothing. So the solder goes from a liquid to a solid immediately as it cools, without passing through a dangerous "slush" phase where, if you happen to move anything in the joint, you'll end up with a "cold" solder joint.

If you're not using a eutectic solder, you need to be sure to keep everything held very still as the solder cools so that you are not moving anything as the solder passes through the "slush" phase. If the joint is disturbed while the solder is in the slush phase, the connection will be spoiled, and you can see this later because the joint will look dull and crystalline instead of bright and shiny. So if you can get the 63/37 alloy, I highly recommend it. But if you use good-old 60/40, just be careful to allow all joints to cool undisturbed!!

where do we get the copper wick to use instead of the solder sucker?

I almost never use solder wick. It has application in some rare instances, but it's a circuit board killer because it encourages people to do the two things that must happen to remove a foil from a board: Apply heat for a long time and apply physical pressure to that heated circuit board foil.

Remember that the foil is simply glued to the board! If you heat it AND press on it, guess what happens?

If you use solder wick, be very careful. I keep some around, but it's for very rare and special occasions. I literally use it about once every few years. The thousands and thousands of other times I'm removing solder, I use a solder sucker.

my local radio shack carries copper wick maybe yours will...but from personal experience the sucker works a lot better, i mean to use both is even better but if i were to chose one or the other i would choose the sucker

Right on!

Ok, so I have done my reading ... still deciding on the Station 2A or "splurging" on the WES51, although I am not sure there is a difference in the quality of those to soldering stations. Now on to solder. Once again, have read up and searched for the recommeded kinds. Out of these two, which is better suited or is there a difference? The one says it is "organic" and the other says it is "clean" solder. Thanks

http://cgi.ebay.com/Kester-245-No-Cl...item519743eab9

http://cgi.ebay.com/Kester-331-Organ...item35af920ed8

I'm sure they're talking about the flux. Solder itself, by definition, is metallic (thus inorganic). Fluxes are almost always organic chemicals.

well, 1 pound will last YEARS! look for a 250 gram or a 1/4 spool of "no clean" solder, 0.031" or smaller. You want 60/40 or 63/37.

I go through a few pounds a year myself. Back when I was assembling a lot of boards, I went through a LOT more.

I should have weighed how much I went through building three Ren SS24s. That would have been good information. I'd guess that it was maybe 1/10th of a pound for the three boards?

Hi:
Guys, I hate to burst the bubble about cleaning soldering iron tips, but the wet sponge in no way cools the tip or does anything to it except clean it. The myth that says the tip "cools" is just so much B.S. If it does, by the time the iron reaches the work, it's back up to temperature.

I discovered this method many years ago before it was common practice. I heard the same thing from the "big boys" where I worked. Except no one was able to prove it!

I talked with the owner of a business that assembles PC boards for other companies and we discussed this very thing. He assembles both SMD and through-hole boards, using all different types of soldering, including hand soldering with irons. All his employees use a wet sponge to clean their irons. He says it does not affect the iron at all.

We've used damp sponges everywhere I've ever worked, assembling boards, and at my company, too. It's the standard of the industry as far as I can tell, and has been for at least 35 years.

It's not just Europe - most companies in the US are the same. There are several companies/schools that will not accept devices without the ROHS sticker on them.

Personally I don't think there's much to lead fumes when soldering but if it helps you sleep at night by all means get a fan..

I'd be curious as to how much lead vaporizes and goes off as fumes, too. Lead is somewhat volatile but not highly so, even at soldering temperatures. You're melting the solder, but not boiling it!! The boiling point for lead is listed as 1740.0 °C. That's HOT!!! Now that doesn't mean it doesn't give off some vapor when molten, but not a lot, I'd guess. What is the vapor pressure of lead at normal soldering temperatures?

I think the main concern, requiring fume extraction, is the smoke from the flux.

But it's never a bad idea to be careful with any of this. Especially be sure to wash your hands between soldering and eating or smoking. And don't scratch your face, pick your nose, or rub your eyes while you've got lead oxide residue on your fingertips!

I never really thought about a fume extractor...

Lets see...
Do you guys have any of these:


The symptoms of lead poisoning may include:

* Abdominal pain and cramping (usually the first sign of a high, toxic dose of lead poison)
* Aggressive behavior
* Anemia
* Constipation
* Difficulty sleeping
* Headaches
* Irritability
* Loss of previous developmental skills (in young children)
* Low appetite and energy
* Reduced sensations
Baldness

Looks like I need a fume extractor and I don't even solder

I have all of that, too.


But to be serious, I've done a LOT of soldering for a long time, and at one point, I did have my blood tested for lead, and it came back perfectly normal. And back in the day, we didn't use any fume extraction. But I don't smoke, and I have always been careful to wash my hands (especially fingertips) after soldering.

I would think that an IR Thermometer has too large an aperture to do this. We use them to scan large equipment for hotspots. I could see a small pinpoint heat very hard to measure accurately with that.

I agree with that. Even though these things often have a laser for aiming, the fact is that the "cone of investigation" is quite broad for most of them. They do not "view" a pinpoint. They take a fairly wide-angle view. Some of them have charts showing the angle of view.

[ukewarrior]

Here is a link to a reprint of a Cooper Tools (The Weller folks) that shows the melting temperature of various solder forumlations.
I think the numbers may surprise some folks.

http://www.elexp.com/t_solder.htm

There is also a diagram of how tips are made.

This also states that sponges are okay for cleaning !

As I stated before, I don't think you can go wrong with a good Weller station.

[Wayne J]

Hello. This is my first post to this forum.

Welcome to DIYC! Great first post(s). I hope you enjoy hanging out with us. You know... you do have time to solder up a few boards for your own display.

[rfallatt]

FYI,
$5 discount code HAKKO5 at all-spec (Enter coupon code HAKKO5 and receive $5 off a Hakko order of $50 or more. (Enter at end of checkout))

http://www.all-spec.com/start/hakko3...FQW0nQoddUkHdw

[corytcline]

This was my first iron, I bought it at autozone for 5 bucks.
I built one renardss 24 with it and it took forever. The tip kept melting away as fast as the solder. This year I got the same unit WLC ventures sells the csi-3dlf. WOW what an amazing difference! I was able to assemble two rev7 a ren w sma and a renard as 24 all in one day with no tip melting away. If your on the fence about purchasing one of these jump off and go getcha one they are well worth the price.

[tdx]

Definitely worth investing in a good iron. The tips melting away on the cheap sticks is because soldering tips are supposed to be made with a copper core, with a special iron clad, and then finished with chromium, the cheap tips that melt away is because of very subpar and incorrect metals used in tip construction, once the chromium is compromised the tip itself just corrodes and dissapears into your solder joints and contaminates them in the long run. My Hakko 936 still has the stock tip, and after thousands of solder joints and lots of electronics repair reworking, the tip itself looks brand new.