Soldering Iron?
Jan 18, 2007 at 9:09 PM Post #16 of 45
30 seconds? I get about 15 seconds to full temp on my 936, and I run mine hot.
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Jan 19, 2007 at 12:35 AM Post #18 of 45
Quote:

Originally Posted by Fitz /img/forum/go_quote.gif
30 seconds? I get about 15 seconds to full temp on my 936, and I run mine hot.
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That's about right. After I thought about it, 30 seconds was a tad long. I love the quick heat time since I can do a little planning, flip the switch then solder a few.. turn off.. back to planning/routing. Especially nice when you are soldeing during commercial breaks
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Jan 19, 2007 at 2:04 AM Post #21 of 45
There are a few places selling for under 80 online. Just having a holder and sponge is worth the 80 clams. The sponge holder is neat. There is a hole punched in the main sponge, that plug from the hole is put below the main sponge and is what is in the water in the reservoir and soaks the water up to the main sponge. Keeps the sponge moist for a few days (at least when the heat is not on). I like to use distilled, bottled, or carbon filtered water since our water is not the best here. Helps keep the tip cleaner.

Anyhoo..
 
Jan 19, 2007 at 2:58 AM Post #22 of 45
Quote:

It is only rated at 15 watts right? Well hmmm...show me waht chapter in my physics bok that directly relates watts to HEAT! That iron gets to 800 Watts my friend! Unless you are trying to solder with molten iron than i would have to say it gets plenty hot. You see how small that tip looks? It is even smaller in person! And all that heat is concentrated on that little tiny tip.


My Physics book says 3.412 Watts = 1 Btuh.
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The two quantities are exactly equivalent as measures of Energy, sometimes described as Heat. (In the SI system of units, heat is expressed in Watts, anyway.) Something like a soldering iron is about 99% efficient - just about all that 15W drawn from the wall outlet goes into heat. The trick in the soldering iron design is, as you say, to get it all concentrated into the tip. (Tip efficiency is something different.)

It sounds like you're trying to say 800 degrees (Fahrenheit), not Watts. Energy (heat) can neither be created or destroyed by the iron, unless Weller has a new cold fusion model.
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Temperature - mostly at the tip - depends on the transfer of heat (energy). Hopefully, a lot more energy is transferred through conduction as opposed to radiation or convection.

However - back to the Physics book - that small tip's ability to transfer heat is directly proportional to its surface contact area. Thus, in order for it to support the heat flow supplied by the 15W, it must assume a much higher temperature. It's perfectly analogous to using more voltage to transfer the same power with less current. Unused, the tip's temperature will continue to rise until it reaches some steady state with its surroundings through radiation and convection. Apparently for this iron, that's 800 degrees F.

In use, the heat transfer through conduction is much greater than radiation and convection. Since the 15W does not vary, the tip quickly attains a much lower temperature in operation. This mostly prevents damage to the components, as the 15W becomes the limiting factor in this process. Other factors are largely uncontrolled, but with a disciplined technique, good results can be consistent.

However, a temperature-controlled iron is much better: introducing a feedback loop by controlling general temperature of the iron through varying wattage. Ditto with the others on the Hakko 936 - great value for a soldering station!
 
Jan 19, 2007 at 3:47 AM Post #23 of 45
I was being facetious tomb but thanks for that great phyics lesson! The point was dont let the meager 15watt rating fool you. It will get plenty hot to melt solder for SMD or intricate pin soldering.
 
Jan 19, 2007 at 12:02 PM Post #24 of 45
Quote:

Originally Posted by picklgreen /img/forum/go_quote.gif
I was being facetious tomb but thanks for that great phyics lesson! The point was dont let the meager 15watt rating fool you. It will get plenty hot to melt solder for SMD or intricate pin soldering.


Yes, you are correct - and thanks for your patience on the diatribe. It's actually Mechanical Engineering. Around here, there's seldom a chance for an ME topic, so I jump on it when I can get it.
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Jan 19, 2007 at 12:28 PM Post #25 of 45
are these cold heat irons and good? all i really will be using it for is a grado rewire and a few interconnects? if no could someone recommend a good budget iron in the uk?
 
Jan 19, 2007 at 12:34 PM Post #26 of 45
Cold irons are OK for home fix-it stuff, but not for what you mention. There are several threads about this, but the Hakko Dash series (3 irons at various wattages) is the finest simple soldering iron made, IMHO. In the US, they run about $25 ea.
 
Jan 19, 2007 at 12:54 PM Post #27 of 45
Quote:

Originally Posted by smegger /img/forum/go_quote.gif
are these cold heat irons and good? all i really will be using it for is a grado rewire and a few interconnects? if no could someone recommend a good budget iron in the uk?


I am using a 7 euro 25W iron with 1mm tip and solder sucker kit and some solder wick (1,5e), and I have successfully created two cmoys, one soha and one aliendac (smd). If you dont intent to do much DIY later on, buy any1/cheapest you can get. Especially for cable jobs, you do not need much precision...
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Jan 19, 2007 at 1:03 PM Post #28 of 45
Jan 19, 2007 at 2:24 PM Post #29 of 45
Quote:

Originally Posted by smegger /img/forum/go_quote.gif
are these cold heat irons and good? all i really will be using it for is a grado rewire and a few interconnects? if no could someone recommend a good budget iron in the uk?


The cold heat irons aren't really soldering irons. They're more like miniature arc welders, and work like absolute rubbish for electronics.
 
Jan 19, 2007 at 2:55 PM Post #30 of 45
I've used a variable temp Weller iron for years doing repairs (on for 6 plus hours a day). There are many different replacement tips available, but it may be a but pricey. The low line starts at ~$120.00.
 
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