TekNoir

I just started learning about electronics last year and at the time I bought myself a very cheap soldering iron to start out with. (When I say "cheap," I mean that I gave the clerk a ten-dollar bill and received change back in exchange for the item.) I would like to upgrade, preferably to a complete station, but I am having a slight bit of difficulty with advertising terms.

What confuses me is the connection between temperature and advertised wattage.

From my understanding, it takes a tip temperature of somewhere around 361F (183C) to melt 63/37 solder efficiently. However, a great number of soldering irons and soldering stations, as well, only advertise a wattage rating, some give both, and some only give their temperature. I'm not exactly certain how wattage translates directly into temperature rating.

I realize that electricity moves through the heating element and the resistance causes heat and that the power dissipated can be measured in watts. Am I missing some simple connection? I would think that the two were unconnected, sort of like the marketing scheme of lighbulbs in watts which have nothing to do with their light output (in lumens). It could be assumed, of course, that higher wattage produces more heat (or light), but this is simply not always true. Thermal properties of the substances involved, basic construction, as well as other factors have to be figured in as well.

As an aside, I have noticed soldering stations advertised with tip temperatures adjustable between 350F and 800F, yet their advertised wattage were completely different (42W for one as compared to 80W for the other). I have been told (and read in a number of places online) that twenty-five to thirty-five watts was good enough for electronics work. Yet, I cannot comprehend "good enough." Does that mean that I should not get anything over thirty-five watts for fear of ruining components (which I, once again, would tend to believe has more to do with temperature than actual wattage) or that something with lower wattage simply won't get hot enough? (I should note that I saw some 15W soldering irons with tip temperatures of 600F.)

The only connection that I can somehow attribute from research is in the transfer of heat into the joint itself. Higher wattages would transfer the same amount of heat faster than a lower wattage would for the same temperature. I would think that this would be conducive to better and faster soldering so long as you didn't decide to daydream at the exact moment you decided to solder a joint. This is another reason that I question the 25W to 35W "rule." Shouldn't any soldering tool capable of delivering an appropriate amount of it's 360F+ tip temperature be "good enough?"

In closing, the two soldering stations that I am considering purchasing (the Hakko FP-102 and the CooperTools/Weller WSL, both comparably priced at 200$ USD and what I have budgeted to spend on a new soldering station) are both well over the 35W recommended for electronics work. I was trying to put together a clearer picture of what I should look at when purchasing my soldering companion for the next number of years.

Sorry for the long post and thank you all in advance...

Edit: I had inadvertently copied the melting point for lead alone. I have now corrected my data to correctly represent "ideal" electronics solder's melting point.

crust

When you touch the iron to the metal you want to heat, lots of the heat
can get dumped from the tip to the part. Thus the temperature of the tip
drops, if the area is big enough the drop can be sufficient such that it will
not easily melt the solder. A good iron is able to dump more power (watts)
into the tip to maintain the temperature. For instance, a Metcal iron is
_very_ good at doing this and maintaining temp. So a higher power iron
is usually capable of maintaining heat under a wider variety of conditions.

crust

When you touch the iron to the metal you want to heat, lots of the heat
can get dumped from the tip to the part. Thus the temperature of the tip
drops, if the area is big enough the drop can be sufficient such that it will
not easily melt the solder. A good iron is able to dump more power (watts)
into the tip to maintain the temperature. For instance, a Metcal iron is
_very_ good at doing this and maintaining temp. So a higher power iron
is usually capable of maintaining heat under a wider variety of conditions.

audioguru

Hey TekNoir,
I just finished replying to you on that other website, plugging the wonderful Weller WTCP that I have used for 40 years. You don't need those additional fancy gadgets. :lol:

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chemelec

I am using a couple of older soldering stations that were made by UNGER that are about 35 watts or so at a fixed temperature. UNGER was bought out by Weller a few years ago.
They work fine on amost anything EXCEPT Very Large copper areas or other metal stuff. Thats when a "100/140 Watt Weller Gun" comes in handy.

Most Important is Good "Temperature Control". Too Hot Burns out Parts. Too Cold Results in Poor Soldering. An Adjustable Temperature is a NICE Feature, but Not Essential.

Also make sure there are Various Sizes of Replacement Tips Available.
And Hopefully at a Reasonable Price.

Your $200.00 should get a Good Soldering Station.
But Shop around.

Take care..........Gary

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bmcculla

Take a look at Sparkfun.com . They have a temperature controlled soldering iron + hot air gun for $174. I haven't used the iron but I have the equivalent hot air station and it has been quite useful. I managed to load some tiny QFN packages that would have been really difficult with an iron. It's also nice for de-soldering complicated pakages without damaging pads or pins.

Roboticinfo

I own a weller and I bought one from this website the soldering Iron doesen't have a company name but it is a very good soldering iron plus it is digital.

http://www.mpja.com/productview.asp?product=15141+TL

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TekNoir

For anyone who is curious and based upon information I have gotten here and elsewhere, I decided to go with a Metcal PS-800 soldering system. It operates much like the Weller WCTP series in that the tip temperature is fully regulated and set according to which tip you have inserted. The tip temperature is held constant (within 1C) while the power adjusts to the load. More information can be found in the link given.

Thank you all for your help. I truly do appreciate it.

Roboticinfo

That's a good soldering iron.

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audioguru

Looks like it will do the job very well and I like the price, "Minimal Cost Of Ownership". :lol: :lol:

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Roboticinfo

How much was the price??????????

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TekNoir

I was able to get it for 40$ USD less than the price of the other two at which I was looking.

Roboticinfo

That is a really good price.

definitly worth it.

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evandude

also check out this:

http://web-tronics.com/cispdeesdsas.html

I have that and it is excellent, considering it only cost me $35. a cap in the power supply blew after a short while (because it runs around 30 volts, and the cap was only rated to 25v for some reason) but I replaced that and it's been fine ever since (including accidentally leaving it on all night at least once...) :wink:

You get 2 heating elements, so if the original one burns out you can replace it. (mine hasn't burned out yet, and i've soldered A LOT)

you can also buy a pair of SMD "tweezers" for it. those are REALLY handy for desoldering surface-mount parts.

They also sell a digital version that's basically the same one found at MPJA (same price, too)

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audioguru

Hi Evandude,
A house-brand soldering iron with a blown-up cap? But I guess it is worth it.
You can even stack the thingys. One for each hand! :lol:

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