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And now.......how NOT to solder !

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MonMotha:

Well, I'll weigh in.

I usually stick to 310-325C for leaded solder, but I'll kick it up to 350-375C if necessary for the lead free crap. When soldering enameled wire (magnet wire), you have to really crank things (435-450C) to melt the enamel while soldering.

I don't generally flip solder off the tip.  Too many worries about where it ends up, and I never got the motion right (probably due to disinterest and corresponding lack of practice).  My iron (Weller WESD-51) has pretty good recovery time and power (65W, IIRC), so a sponge is quite fine.  You don't want the thing soaking wet, just damp.  That will lessen tip cooling.  And yes, there is a motion that tends to result in near complete removal of gunk without much time in contact with the sponge.

Depending on what you're doing, you may not need a "clean" iron.  If you're doing 0402 passives, it's almost mandatory, though eventually you'll figure out how to largely keep things in check so you can do several pieces before you need to clean things off.

As for adding a little solder to the tip before touching the joint, it can help heat transfer when working on an old, corroded, or oddly shaped joint.  The molten solder on the tip will conform to the joint you're touching, resulting in more surface area in contact.  More surface contact usually results in faster heat transfer.

Fancy Metcal irons are really nice for small stuff, but I prefer the directly heated stuff like my Weller for larger work.  The Weller was a lot cheaper than a Metcal, too :)

I do use flux in some cases, but often the flux core is sufficient.  The big times I find flux useful is when drag soldering QFPs.  Flux the pads, place the part (the flux will somewhat hold it in place), tack a couple corners, then drag.  For normal repair type work and certainly through-hole stuff, I don't find it necessary.

I think one of the big issues many people face is lack of experience combined with crappy radio shack soldering irons.  If you plan on doing much work at all, buy a cheap temp controlled station.  I see stuff that works OK online for like $45 all the time.  This is about 4x the cost of a cheapo radio shack, yes, but the temp control is really nice.  The radio shack tips are also awful.  They simply won't take solder for some reason, probably bad plating.

Kevin Mullins:

Why everybody gotta knock us cheap ---daisies--- that still run the el' cheapo radio shack crap ?
 ;D

Ooh..... I gotta get a pic of my "spatter wall" too.
It's all in the technique, fwap, fwap.  :laugh2:

(seriously, I have a corner of sheetrock I tap the iron on to clear the excess solder)

MaximRecoil:


--- Quote from: MonMotha on September 02, 2009, 09:56:45 pm ---Fancy Metcal irons are really nice for small stuff, but I prefer the directly heated stuff like my Weller for larger work.  The Weller was a lot cheaper than a Metcal, too :)

--- End quote ---

Can your Weller do this?


--- Quote ---The clever thing about the [Metcal] design is the method of heating.  The
"station" consist of high power rf generator enclosed in well shielded
case.  The power is delivered to the tip via a coaxial cable.  The tip
is so constructed that it absorbs the energy at the working end and
heats up until it reaches a curie point temperature at which it
becomes high impedance. This transition is very sharp, meaning that
the tip is always at the correct temperature.  The response is
phenomenal.  It will hit operating temperature in seven seconds and
3/32" tip can solder a penny to a copper clad circuit board without
overheating anything. I had it feed through a SWR meter and could see
the needle jump  moment the tip touched the workpiece. The selection
of tips is large and replacement is easy as they just pull out of the
handle.

Boris Mohar

Emphasis mine
--- End quote ---

For bigger jobs you need more power and/or efficiency, which translates to the faster recovery times needed to maintain operating temperature during the excessive heat dumps of large solder joints; and that's where Metcals excel. Because of its incredible recovery time, smaller tips can do larger jobs, and larger tips can do very large jobs.

Metcals are very popular for assembly lines in factories, which is a big job, even if each individual joint is not necessarily that big (in my case I soldered terminal blocks, which made for larger joints than the typical through-hole IC, capacitor, or resistor joints on an old arcade board). The fact that so many joints are being soldered in succession in such a short time (less than 1 second per joint for hundreds of joints in a row; no stopping) means that it takes a very strong iron to keep up; i.e., not dump its heat into the solder joints faster than it can recover.

We had large commercial-grade Wellers at the factory left over from before they switched to Metcals. They collected dust in boxes under the benches; though anyone was free to use them if they wanted to.



MonMotha:

My Weller hits temp from cold (room temp) start in about 15-20 seconds.  The Metcals at work take 7-10 usually.  Yes, they are quicker.  However, we also have a Weller laying around for doing "big stuff" like trying to solder the tabs on heatsinks.  The Metcal just doesn't have the power to do it.  The temp control on the Metcal is exquisite.  Apparently the high-end Metcal stations are even capable of adjusting power output upon sensing when solder actually flows (vs. when the tip is simply in contact).  The easy tip change is also quite nice.

I'd love to have one, but I wouldn't dump my Weller in the trash for one.  However, I simply can't justify the expense for hobby usage (note that I use my soldering iron for more than just arcade related stuff).

I'll have to get a picture of my "soldering tile" some time.  I keep the solder station on a chunk of ceramic tile that I can use when I need to have a hot work object sitting directly on the table for some reason.  The tile is caked in flux goo, solder splashes, etc.

MaximRecoil:


--- Quote from: MonMotha on September 02, 2009, 11:27:53 pm ---My Weller hits temp from cold (room temp) start in about 15-20 seconds.  The Metcals at work take 7-10 usually.  Yes, they are quicker.  However, we also have a Weller laying around for doing "big stuff" like trying to solder the tabs on heatsinks.  The Metcal just doesn't have the power to do it. 
--- End quote ---

What tip cartridge are you using with the Metcal, and which particular base unit are you using (e.g., RFG-30, PS2E-01, MX-500)? Also, how old is the tip cartridge / how much usage has it seen? In my experience, Metcal tip cartridges only perform at their absolute best for about 80 hours of soldering.

Metcal makes a huge variety of tip sizes and styles, along with a few different temperatures. For soldering tabs on a heatsink, you'd want one of the larger blunt tips in one of the higher temperatures; for example, the STTC-117 "extra large chisel" .20" (5.0mm) 700°F degree tip (or STTC-817 if you want the 800°F version). That tip dwarfs a typical Metcal tip used for general purpose PCB soldering. Here is a comparison of it to the tip I normally use:




--- Quote ---I'd love to have one, but I wouldn't dump my Weller in the trash for one.  However, I simply can't justify the expense for hobby usage (note that I use my soldering iron for more than just arcade related stuff).
--- End quote ---

I payed less than $40 shipped for mine (used, working, eBay); and it included the base unit, the correct stand, the RM3E handpiece, and a used, working STTC-125 tip cartridge. My preference is the STTC-126 tip cartridge for general purpose PCB soldering, so I bought a new one.

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