Lead free solder iron?

[m_charles]

Was going to buy a new solder station...

Do I really have to buy a "lead-free" iron, if I use lead free solder?

Seems kinda silly. I want to buy this: http://webtronics.stores.yahoo.net/aueltecosost.html

I saw some posts reccomending it, but I saw "lead free" irons on the circuit specialists website.

I'm assuming the regular iron will be fine with my lead-free solder (it has been so far) but just wanted to check before I order.

thanks!

chuck

[ambulancevoice]

soldering irons dont have lead on them or in them
solder itself (60% tin 40% lead electronics solder, flux resin core!) has lead in it
lead free solder is (i think) less conductive or efficient
but it is workable, and there isnt really any special iron for it, just get one somewhere bettween 15w to 40w

youd probably be better off with normal 60/40 (make sure its 60/40) solder
just wear rubber gloves or wash your hands well with soap after using it

correct me if im wrong

[MarcoMike]

I guess it may be a Temperature issue... the eutectic lead/tin melts at lower temp than both pure lead and tin. so melting tin requires a warmer iron...
the eutetic melts around 180°C, while tin melts around 230°C, which is kind of a lot more!
not sure if this is THE reason, but sounds reasonable...

[ambulancevoice]

60/40 melts around 200'C doesnt it?

[The Tone God]

The fact the solder is made with lead or lead free parts has little to do with the temperature range of a soldering iron or what you can do with it. I think the idea the are trying to convey with the term "Lead free" is that it can be sold to EU countries as RoHS compliant not that it has any special ability for working with lead free solder.

If you want to go lead free then just getting lead free or untinned tips should be enough. No need for the whole iron to be lead free. I don't see the point in that. My solder irons are made with leaded parts but I use it just fine with lead free solder. I just make sure I keep my different lead and lead free tips apart so not to mix them up. Beyond that no problems.

There are different types of lead free solder too. Some really stink. I like the Sn96.5/Ag3.0/Cu0.5 mix. For lead solder I'm a 63/37 fan. I would still wear good gloves be it lead or lead free solder.

Andrew

[momo]

If I understand this right, you guys wear gloves when you solder? , I do wash my hands after work but putting gloves to solder, I have a hard time manipulating components bear hands, I cannot imagine working with gloves, is this really important for the amount we handle in lets say 1 month?

[R.G.]

OK, fact time.
Plagiarizing from some research work at JPL:

Eutectic tin-lead solder has a unique melting point of 183°C (361°F), whereas near-eutectic tin-lead solder melts within the range of 183°-189°C (361°-372°F).

Tin-lead solder forms stable solder joints capable of operating in a wide variety of service environments. It is easy to use, and because it has a relatively low melting point, rework and repair are also easy. In addition, the reliability of tin-lead solder joints is well understood. Using Coffin-Manson curves and Weibull distribution plots of thermally cycled solder joints, it is possible to estimate the amount of useful life remaining for tin-lead solder joints after exposure to a known number of thermal cycles.

That is, it does what is needed and intended, and is extremely well understood.
Continuing:

Four (4) lead-free solder pastes were selected based on an extensive search of the literature. Two PWBs per solder type were assembled using the four different solder pastes resulting in total of eight assemblies. These are:

    * Sn96.5Ag3.5 (eutectic)                         221°C (TM)
    * Sn95.5Ag3.8Cu0.7                              217-218°C (TM)
    * Sn96.2Ag2.5Cu0.8Sb0.5 (Castin®)      217-218°C (TM)
    * Sn77.2In20.0Ag2.8 (Indalloy 227®)     175°C (TS) -187°C (TL)

The next phase of the project will be to downselect to two (2) of these pastes, assembly four (4) PWAs per paste and assembly four using eutectic tin-lead (Sn63Pb37—183°C (TM)) as a control, and thermal cycle the boards.

That is, there are several proposed replacements, none of which are as well understood as SnPb, and we need to find out if any of them are good enough for our work.

There's more info than you want to read here:
http://www.boulder.nist.gov/div853/lead%20free/props01.html

The biggest consideration for effects workers is that the lead free stuff melts at a higher temperature. If your iron is temperature controlled, it needs to be able to get that high. And higher. The iron I use for tin-lead is never set below 700F because I can get a good, fast joint without conducting heat into the parts. I have regularly soldered germanium without heat sink clips. DO NOT try that before you have a decade or two of soldering experience, though.

You don't need a special soldering iron, just a hot enough one.

Oh, yeah - if your soldering tip has EVER been used on tin-lead, it is now illegal to use it on any electronics going to RoHS countries, even for one joint.

[The Tone God]

If you wash your hands well your probably okay for the contamination issue. I still like to wear gloves and I believe everyone should and not just for lead contamination issues. Things like solder spits, flying/dropping solder, iron burns, holding hot components while you solder, cuts, scrapes, shocks, chemicals, handling live circuits, etc. are partially addressed when wearing gloves.

I use mechanics gloves which are tough but still allow you manipulate small things that mechanics need to work with like bolts, screws, and tools which are also things we need to do as well as solder and other jobs. It is cheap insurance IMHO. Its alittle weird at first but you get used to it and become proficient. Also learning to use pliers to hold parts while soldering is helpful.

Oh, yeah - if your soldering tip has EVER been used on tin-lead, it is now illegal to use it on any electronics going to RoHS countries, even for one joint.

This is exactly the reason I mentioned that I have lead and lead free tips and keep them separate from each other. It just easier that way so I don't have to think about if my soldering is truly lead free. For the cost a few extra tips I have piece of mind. I also mark them with a sharpie.

Also I too solder at what many would consider a very high temperature. I have a small collection soldering irons on my main work area and the lowest one, which has a very small chisel tip for in and out work, is set at just over 720 for lead work. It is not for the faint of heart though. The nice thing is once you are good a high temp lead work cranking the heat up for lead free work is not that difficult to adjust to and less scary.

Andrew

[m_charles]

does anyone use one of those mini-airsucker solder fan things?

[ambulancevoice]

solder sucker?
there are different types
there is a bulb which can blow or suck 
and there is plastic and metal desoldering pumps

or there is the copper braid, which is like a sponge for solder

[m_charles]

sorry, you misunderstood. I mean the small solder station fans that suck up the solder smoke/fumes...

[Dark Fader]

does anyone use one of those mini-airsucker solder fan things?

I made my own using a PC power supply and a carbon filter. Works pretty well and only cost me the price of a filter (from rapid electronics in UK).

[R.G.]

It's easy to go nutso when there is any possibility of problems that gets blown out of proportion by government and/or media action.

For lead safety when soldering, all you need to do is:
1. Don't chew on the solder. While that seems laughable, we had a tech that used to do that. I don't know that he ever got lead poisoning, but it seems like bad practice.
2. Don't eat or drink while soldering.
3. Wash your hands afterwards.

You're done. No further safeguards against lead are needed. I read studies on industrial contamination that poo-poo'ed the death by unwashed hands connection except for true poisons. In general, you just don't carry enough lead on your hands to poison yourself, and the transfer to any foods is very small even if you don't wear it away by touching other things first.

You are at considerably greater risk for harm by not wearing surgical gloves when touching things in public places, shaking hands, and so on. Bacteria and viruses ARE dangerous in concentrations down to one.

Solder. Then wash your hands.

The smoke filter thing is to get rid of flux fumes, not lead. Vaporized flux is a respiratory *irritant* (not poison) and can make you cough and irritate your throat, unless you're one of the poor souls who should be in a plastic bubble and to whom everything is deadly. Filter or not, as you choose, but it does not change your breathed *lead* exposure.

I speak from having worked in labs myself and with individuals in labs with un-gloved, un-filtered soldering going on for decades. None of the people involved have had lead related issues, and we were plenty sensitized to it by a nanny-state employer.

[gez]

It's worth pointing out that some people (who are susceptible to this sort of thing) can develop an allergy to the rosin in solder through handling it.  IIR, they get something similar to eczema.

[gez]

It's also worth pointing out that good tip design has a lot to do with how efficient irons work with lead-free solder.  I use the Antex range of Irons and they're not that high wattage, yet solder melts like butter with them...presumably due to the tips.