40w solder iron

Discussion in 'General Electronics Chat' started by coco243, Nov 14, 2010.

  1. coco243

    Thread Starter Active Member

    Sep 2, 2010
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    I have a 40w solder iron, and I want to know if it is harmful for components soldering, in specialy diodes, transistors and further resistors and capacitors.

    It is possible to damage my electronic components if I use this soldering iron?

    Thanks.
     
  2. mik3

    Senior Member

    Feb 4, 2008
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    Of course, if you heat the components for a long time (a few seconds), the temperature of the semiconductor will rise above 150C and it will fail. A good practise is to use crocodile clips on the pin you solder to absorb some heat.
     
  3. PackratKing

    Well-Known Member

    Jul 13, 2008
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    A 40 watt is a good basis for a lot of apps. Limited only by imagination and working skill.
    Electronic Soldering requires cleanliness, proper non-corrosive flux, best alloy being 63/37 eutectic, and adequate heat to form each connection in one second or less, the latter insuring very little or no heat damage to components being installed.

    Nothing hard about it !!! ;)
     
    Last edited: Nov 14, 2010
  4. Kermit2

    AAC Fanatic!

    Feb 5, 2010
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    Blowing on it very hard for a few seconds immediately after removing the soldering iron will help cool off the metal and stop it from conducting too much heat into the component.

    Been soldering since I was 8 and I'm over 50 now. keep the tip clean and bright apply the iron and solder at the same time and get OFF the joint right after it flows(don't go too fast) then BLOW on it.

    Hint 2: a well tinned tip will turn a light yellow or gold color a few seconds after it is wiped clean, when it is the right temp for soldering. If it turns brown or bluish then the tip is too hot and should be cleaned or wiped in a damp sponge. If it stays a bright silver color for very long then it may not be hot enough to solder a large joint, but should do fine for smt size work. Having the tip hotter than it should be to start is good for a large joint, since sinking the heat into the cold joint will lower the tips temperature at first, so when solder does flow, it does so at the lowest temp at which it melts. By getting off the joint right after that and blowing on it the temp at the component never exceeds the max.
     
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  5. ablacon64

    New Member

    Nov 11, 2010
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    Hi, I'm new to this forum and was following this topic. My doubt is if I use a deep freeze spray (-45ºC or equivalent), like the ones used to find intermitent failures,will the fast temperature change damage the component?

    I work mainly on BGA resoldering/reballing and the temperature gets too high to melt the solder spheres below the component.
     
    Last edited: Nov 14, 2010
  6. mik3

    Senior Member

    Feb 4, 2008
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    It is possible for the component to crack due to the rapid change in temperature.
     
  7. Audioguru

    New Member

    Dec 20, 2007
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    My soldering iron is a Weller temperature controlled one. It is 40W or 60W (I can't remember) but it never gets too hot like cheap ones do. Because it never gets too hot then it does not destroy sensitive parts, does not burn away rosin in the solder and its tip lasts "forever".
    BTW, my Weller soldering iron is 43 years old and works like the same ones that they still sell today.
     
  8. coco243

    Thread Starter Active Member

    Sep 2, 2010
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    Mine is weller too, just it is not temperature controlled and I'm affraid to harm my components because I'm beginner in electronics. I have and a soldering gun, what you say? to use the iron gun for the first times?
     
  9. orbiter

    Active Member

    Jun 17, 2010
    58
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    Don't worry too much as you'll get used to your iron and be able to improvise your soldering techniqe to make the best of your iron. I understand a lot of guys use 40W soldering irons and even sometimes prefer them over the lesser wattage ones especially for through hole components.
    I used to find that when using slightly higher power irons you can be in and out quicker with the iron, whereas sometimes with low wattage irons there can be problems getting the component to heat up enough to accept the solder and this alone can mean that the iron will need to be in contact with the component longer.

    When your able to I would suggest that perhaps you try and upgrade to a controllable iron, the adjustability is always helpful.
     
  10. coco243

    Thread Starter Active Member

    Sep 2, 2010
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    Yes but, I will solder an integrated circuit and :) If I fry it is not so good :)
     
  11. Wendy

    Moderator

    Mar 24, 2008
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    I have found when I am practiced up the iron makes less difference. I can work with 25 watts just fine.

    However, when it is been a couple of months this changes. Then a temperature controlled tip makes things easier, especially a good type tip that doesn't corrode. Bare copper literally eats away with the electronic rosin in solder. Properly made tips don't.

    There is a definite knack and skill to doing this. Practice counts.

    This is why kits are good practice for beginners.
     
  12. orbiter

    Active Member

    Jun 17, 2010
    58
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    Yes that's the area where using a 40W iron may create problems especially if the tip is on the large size too. For the likes of DIP package IC's 40W can still be ok along with a smaller tip, however anything smaller like TQFP and a controllable iron with a small would be preferable.

    I must admit though that I use a controllable iron with various small tips and anything smaller than a DIP package IC and I need a lot more practice :)
     
  13. Kermit2

    AAC Fanatic!

    Feb 5, 2010
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    Human breath is about as much cooling as I could recommend. Using freeze spray will not be good for the mechanical stresses it could create across a small area.

    If I start blowing too fast and too hard the solder sometimes deforms(60/40 mixes). Try to get the Eutectic(63/37) since it has no plastic state when cooling. It's just one of those things like bike riding; you have to do it for awhile, then you get it and will never forget. ;)
     
  14. Blackbull

    Well-Known Member

    Jul 26, 2008
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    Anyone seen, on Youtube, surface mount IC’s being soldered with a blowtorch, puzzles me.
     
  15. Kermit2

    AAC Fanatic!

    Feb 5, 2010
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    are you sure its a torch and not a hot air blower?
     
  16. Blackbull

    Well-Known Member

    Jul 26, 2008
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    Kermit – You may be right - I can’t find it now (Why does this happen to me) but even so the melting point of PBF solder I have come across way exceeds Mic3’s 150 degrees, and they are playing the heat on for a considerable time. I have two eutectics listed one at 138C and one at 118C but are expensive and difficult to find.
     
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