Soldering iron issues

[carbonzit]

Hello all; back after a several-year hiatus. Glad this place is still around.

My question concerns the lowly soldering iron, which is my weapon of choice when it comes to electronic construction. I'm strictly a hobbyist, make occasional projects, and I know about fancier devices like a real temp-controlled soldering station but I'm not interested--at all--in switching to anything like that. (Both because I don't think I need it and because I'm cheap.)

My current iron is a decent one, a Weller 25-watt general-purpose one with a plain conical tip. In the past I've even used dollar-store irons (same size) successfully. However, there's one annoying thing about all them: the tips eventually corrode. In fact, with this Weller that I've had for maybe a year or so and only used infrequently, I saw something I never saw before, which was the tip actually disintegrating; a layer just peeled off the outside.

So what I do when this happens is what a lot of people do: I simply reshape the tip and go on my merry way. I'll take it to a grinder if it needs major reshaping, or just hit it a few licks with a file. This gets it down to fresh copper, which works fine so long as you keep it tinned (and don't let it oxidize immediately after reshaping!).

Question is, what causes tips to corrode? I use standard 60/40 lead solder, rosin core. No plumbing flux! I use a wet sponge (H2O only) to clean the tip each time. It can't be the lead or tin, can it? I mean, those elements aren't corrosive so far as I know. Is it the flux? Or is it because the tip overheats (sometimes I'll leave it on for a while before soldering)? I'm really curious to know what ends up eating up my tips, whether it's chemical, physical or both.

Also curious about new tips: they're copper but with some kind of plating. What is the plating and what is its purpose? It's shiny silver; I though I read that it was iron, but it looks more like chrome or something similar. Of course, this coating soon disappears and you're down to copper anyhow.

Not that it really matters; when it gets misshapen enough I simply refile or regrind it. But I'm curious.

 

[Tony Stewart]

alibaba-express had a great deal with 6 pc. tips and variable temperature 65W with free shipping for $10. not sure if still on.

 

[rjenkinsgb]

The solder dissolves a small percentage of copper every time you make a joint, so plain copper tips erode quite quickly, and the inside of an iron plated tip will dissolve if the plating is damaged.

Iron plated are far better than plain copper, as that is not affected by the solder in the same way.

Good quality plated ones should last years of continuous use, as long as they are never filed?
Possibly the ones you are getting are clones rather than Weller original ones?

I prefer Antex, I've been using the TCS temperature controlled irons for the last twenty years or so, with a new bit probably every 3 - 4 years.

 

[carbonzit]

Nope, I'm using the one that came with the iron, and it was plated, just like every other tip I've ever used. I just can't see how a thin coating could last more than a few soldering sessions. But as I wrote, I'm used to using bare copper tips and just maintaining their shape.

I'm still curious to know: how, exactly, does the solder dissolve the tip? Is it an electrolytic reaction, accelerated by the heat? And doesn't that eventually erode the iron plating?

 

[granddad]

carbonzit... I always was of the same opinion about temperature controlled irons , however eventually decided to invest, as my preferred small Antex low wattage (12W) 0.5mm tip was good for smd , with through hole not so good, and keeping two irons on the go was impractical, I still have a 0.5 tip on the iron, Antex 660A and they last about a year, I imagine the flux is the cause of eventual breakdown of the tip.

 

[For The Popcorn]

One thing you might do is to add a diode in series with the the soldering iron, with a switch to short across it. Non-temperature-regulated irons tend to cook between soldering joint. The diode in series cuts the power in half (when not shorted across by the switch), so the iron won't get as hot when idle, but quickly reaches temperature when the switch is flipped.

An easy way to do this (which I did was I was about 13 years old) is to wire the switch in a box with a line cord and outlet. Plug the iron into the box, and have high/low temperature control.

 

[Nigel Goodwin]

The solder dissolves a small percentage of copper every time you make a joint, so plain copper tips erode quite quickly, and the inside of an iron plated tip will dissolve if the plating is damaged.

Iron plated are far better than plain copper, as that is not affected by the solder in the same way.

Good quality plated ones should last years of continuous use, as long as they are never filed?
Possibly the ones you are getting are clones rather than Weller original ones?

I prefer Antex, I've been using the TCS temperature controlled irons for the last twenty years or so, with a new bit probably every 3 - 4 years.

Likewise, I've used Antex for decades, great soldering irons - the iron tipped bits last for years, I certainly don't replace them every three or four years. My one at home must be 40+ years old now?, and I've been using the one at work (FAR more heavily for over six years, and it wasn't new when I started using it - I imagine it's possibly 14 years old?, as that's when the company was started).

I most admit, I'm quite amazed how much solder you get through doing small scale manufacturing, I get through probably two full reels a year? - at home, I've only ever owned one reel of solder

I agree as well, never, never, ever, file a soldering iron tip - a gentle wipe on a damp sponge is all that's required.

Prior to me introducing Antex irons where I used to work, we used Solon ones - these had copper tips, and had very short lives.

 

[Tony Stewart]

I recall it is plated with Molybdenum. My Aerospace tech, used a dimmer box on her soldering iron with a 1/16" tip for pretty much everything. They were all NASA certified techs. and the soldering manual was bigger than the Koran and Bible put together. 600 'F max were common tips also on Weller stations.

The RF irons are really impressive

Metcal, at a big trade show in Vegas, had a contest to see how fast you could desolder SMT RAM chips with the adapter tip for SOIC's. I didn't win removing 10 chips in 6 sec. The metal tip was thermo-resistive so it instantly regulates temp at the surface.

 

[Tony Stewart]

https://www.aliexpress.com/item/1005005698130977.html?spm=a2g0o.productlist.main.1.2393l9PXl9PXu1&algo_pvid=46790d3e-fea2-4d72-8f6f-c9bd0d31a0de&algo_exp_id=46790d3e-fea2-4d72-8f6f-c9bd0d31a0de-0&pdp_npi=4%40dis%21CAD%2137.68%2112.44%21%21%21192.52%2163.53%21%402101c5a417239034560295676eee78%2112000034096594486%21sea%21CA%21166275598%21X&curPageLogUid=ql3AsV1tvKZa&utparam-url=scene%3Asearch%7Cquery_from%3A

fast delivery

 

[ZipZapOuch]

New tips for my old weller cost under $5. Since I tip the pizza delivery guy more than that, I don't really fret about spending $5 on a tip every few months to a year. Not worth discussion.

Comically, I've been told I can buy a new $150 soldering station that doesn't need new tips so often - note - that is more than 30-years to get my payback (the Weller will likely still sell the replacement tips in 30-years, but the AliExpress models will not likely be available next month.

 

[rjenkinsgb]

I'm still curious to know: how, exactly, does the solder dissolve the tip? Is it an electrolytic reaction, accelerated by the heat? And doesn't that eventually erode the iron plating?

The molten solder literally dissolves copper into the molten alloy. It's a relatively slow process, but the more solder you use, the more copper is removed. "Savbit" solder has a trace of copper in the alloy already, which slows the removed of copper from the bits.

Iron is just not affected; it's presumably not able to form an alloy with tin or lead at those temperatures, unlike copper.

(I sometimes use a lot of force on the bits, prying bent leads or pins straight while doing board repairs, and also high temperatures at times for working on large joints or sheet metal; that may be why I get through bits faster than Nigel).

 

[Tony Stewart]

If ZipZap destroys solder tips every few months, imagine how the soldering looks.

 

[carbonzit]

One thing you might do is to add a diode in series with the the soldering iron, with a switch to short across it.

Very good idea, and it turns out something I'd already done, years ago, but haven't used lately. I made this rig with a microswitch, normally closed, so that when you park the iron it opens and puts the diode in series. I should start using it again.

 

[ZipZapOuch]

If ZipZap destroys solder tips every few months, imagine how the soldering looks.

I wouldn't say "destroy" but I do want a perfect bit and the 1/32" conical bits for small smds tend to degrade quickly. Once the plating erodes, the lead-free solder flows differently and tends to cling to the tip more which can cause solder bridges.

Let me know if you are having trouble imagining.

 

[Nigel Goodwin]

Very good idea, and it turns out something I'd already done, years ago, but haven't used lately. I made this rig with a microswitch, normally closed, so that when you park the iron it opens and puts the diode in series. I should start using it again.

Wow, we've fallen through a time warp back to the 60's

 

[carbonzit]

Yep, that came from my "vintage electronics" parts box. Love that old stuff.

I just started using this rig again, and I think I already notice a difference: the tip doesn't seem to be dissolving quite so fast. Only drawback is I have to wait a bit for the tip to heat up when I pick it up; I count to 10, then solder. Small price to pay.

 

[ZipZapOuch]

Small price to pay.

So is $5 for a new tip.

 

[Nigel Goodwin]

Yep, that came from my "vintage electronics" parts box. Love that old stuff.

I just started using this rig again, and I think I already notice a difference: the tip doesn't seem to be dissolving quite so fast. Only drawback is I have to wait a bit for the tip to heat up when I pick it up; I count to 10, then solder. Small price to pay.

But it means you're also using an old crappy soldering iron that isn't temperature controlled, and while an extra ten seconds every soldered joint is OK(ish) for one or two joints at home, it's completely useful for any kind of work use.

 

[Tony Stewart]

I don't see anything wrong with this kit , 6 tips , regulated temp 80W iron free delivery in 2 wks. I got mine sooner. 4.7 stars. I would add a ground wire under a wet sponge.

 

[carbonzit]

But it means you're also using an old crappy soldering iron that isn't temperature controlled, and while an extra ten seconds every soldered joint is OK(ish) for one or two joints at home, it's completely useful for any kind of work use.

Well, as I stated above, I'm a hobbyist, not a production person, so my method of working is perfectly adequate for what I do. If I ever did go into any kind of production I'd certainly look into a more sophisticated soldering setup.