Soldering irons for PCB work

[OCNC]

What size soldering iron (temp and tip size) is appropriate for working on the control circuits we're discussing here in the Zone?

Thanks!

Chris

[Al_The_Man]

I use the weller range of temp controlled stations like the WTCPN etc. the temp is controlled by the type of tip you have so you can easily change out a tip for different type of work depending on the area of connection.
Al

[CNC Darren]

Tho not really ideal, I use a radio shack cheapie 15watt iron with the tip ground to a point.

Daren

[sol]

Yeah, in the cheap and dirty dept. I also use a cheapo RadioShack unit that is switchable 15 and 30 Watt. Turns out I get the best joint with the fewest cooked components by using low temp small gauge solder and a hot (30W) iron with a fine tip. I use my fingers as "heat sinks" when possible; if it burns I know I am working too slowly.

Were I soldering more than a few minutes a week I'd definitely go Al-the-Man's route...but they aren't $6.95.

[pminmo]

After 25 years of using a radio shack variety cheapy, I went the full temperature controlled solder station. Yep $120, but I gotta say I wish I had done it many years ago. NBD, to power up and solder one joint. Maybe 30 seconds to get ready to solder.

Phil

[JFettig]

For light pcb work, I would suggest 15watt, if your really good and quick, use up to 45watt, I have one of each, for very fine stuff I like the 15watt but for larger wires I like the 45watt, when I have lots to do and have it already set and ready I like to use the 45watt even when its small stuff, if you use a 30+ and heat the connection for too long (struggling with solder or whatever the case may be) it can damage stuff or melt things you don't want melted, it can also pick up traces off of pcb, I have actually done that with a 15watt soldering iron too.

Jon

[Johnuk]

I have a Hakko FM202 station.
Soldering stations
Desoldering

RRP - $475.

Approximate heat up time... 3 seconds...

Definitly the nicest soldering iron I've ever used.

I have the station on eBay at the moment, as I'm hoping to raise some funds for a CNC project.

eBay

John

[lurch]

I recently assembled the hobbycnc board using a 15 watt Radio shack iron, tip ground on one side. I used this iron with .032 thin solder wire. Melted great, one qualification: Solder pads connecting to large traces took a bit longer, around 20 seconds more than average. No complaints about this setup. This was my first full board assembly. No major problems in use or usability with this combo, especially for a beginner! KISS , easy as could be....This is a great forum!!!

[DAB_Design]

hehe, you want to talk about cheap and dirty.....I use (probably until my next soldering project after reading this) an OLD wood burning iron thing. The ones with the little cork thing on the end to hold it by.

[Johnuk]

I used to use a 15 watt iron from Tandy. It was totally useless for most work, it'd just never get the parts hot enough for the solder to flow correctly.

This was particularly a problem when I tried to solder the contacts of a heavy foot switch for a guitar effect.

It drove my absolutely insane. I must have burnt myself five or ten times.

I ended up trying to solder it with the flame from a Bic lighter.

[Mechanoid]

Looks like I am a bit late to the party but - soldering irons! - that obscure object of desire! which no other tool of trade approaches in price range, even considering only handpiece soldering devices and excluding mechanical stages, hot air BGA stations and other top-dollar equipment they range from $1 to $3000, that is 3000 times difference!

At one hand, an experienced user knows how to solder with anything hot and... well, anything simply hot. I once had to repair a PCB using a large nail locked in a hemostat and using a gas stove as a heat source (raise your hand please if you had a backup generator start up properly every time a power outage occured). I would certainly not use that contraption every day, but then once in a while... maybe if I had to solder once a month... I would not use it either, no way!!! But obviously YMMV.

On the other hand, there is no job you could not do with an expensive sophisticated station that could be done with a simple one, i.e. you will see very little specialisation when going up the scale.

Anyhow, no nail/open flame soldering instruction follows.

If you go the cheap route, a 40W iron and a light dimmer will probably do everytihng. The usable range of dimmer scale is perhaps the last 1/10, so you would be better off getting a dimmer with a large, 3" or so rotary knob, since a 70mm slide pot in a soap-on-a-rope dimmer would be hard to adjust with required precision.

If you want to select an inexpensive temperature soldering station, which is a much, much, very much a better solution, you should consider the following:

1. You are going to shell out just under $100 as a minimum
2. Consider not only the price of the station and pencil: check availability and price of replacement tips. They do wear out!
3. Unlike an uncontrolled iron, the more power the better. The power rating is for maximum power, but this power is throttled in a temp-controlled station to deliver "just enough" to sustain stable temperature.
4. How fast the pencil heats up is approximately how fast it compensates a sudden temperature drop: the faster is the better. However, what deviation of temperature you would allow? If only tinkering with DIY CNC controllers, the station that has a 70 to 700 time of 20-30 s is more than adequate. You won't need a Metcal.

Personally, I think that Weller's WES51 is the best device one ben can buy you (an older model WES50 is essentially same). It is a temp-controlled, grounded 50W pencil that uses cheap ET series tips, which you can buy at $3 each for no-name, so you can collect a whole range of different tips and use an appropriate one for a job - which is better than using a $1000 station with incorrectly sized tip because a correct one is yet another $250...

Unfortunately, I cannot think of any alternatives to this station in the same price range - not because there is none, but more probably because I just do not happen to know any.

Another advice that I would give is do not ever think of grinding a tip! You would not grind a new TiN-coated cutter to different angles, would you? The same holds for soldering tips: they are coated. Usually, tips are made of copper. Copper is soluble in molten solder, and a pure copper tip's edge is going from | to ( in minutes of work. The very end of a tip is coated with iron, that prevents copper erosion from molten solder. Solder easily wets clean iron surface, and the iron tip should always be covered in bright layer of solder, both between touches and before - maybe especially - cooling the tip down for storage. Metalworkers know it how easily iron oxidises and corrodes -take great care of that very tip of the tip! Seriously, the most important part of a soldering iron is its tip. If a tip becomes unwettable by solder and covered in brown to black scales or "acne", heat transfer to the point of soldering greatly diminishes and it is almost impossible to make a good joint with such an unwettable tip. The process is self-escalating: non-wettable tip cannot hold continuous protecting solder layer, and oxidises quicker and quicker as it loses wettable area. Light work with a brass brush usually revives the tip, unless it is heavily scaled, but this may happen only out of neglect.

When iron coat wears out and punctures, copper erodes very quickly, and the tip must be discarded.

Upper part of the tip, not wettable by solder, is coated with nickel or chromium. I heard the hard coat prevents the tip from sticking in the body of the iron, but I cannot imagine how exactly it helps that, and may be totally wrong on this. Anyway, do not try to wet the upper part - it is not supposed to be wettable! Too much wettable surface would allow stray solder accumulation on it, which would randomly go down onto work, forming big ugly drops than would have to be wicked.

Finally, the inside of a tip, if there is a temperature sensor hole, is coated with a layer of stainless steel, to prevent oxidation and sticking at the point where tip and the temperature sensor touch inside the handpiece body.

Does not look like a thing easily improved by grinding, no?

[OCNC]

Mechanoid-

Thanks for the post. The info on tips was very helpful and not something I've seen before.

Chris