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Help: Soldering surface mount components?

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louarnold

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Do I need a high heat, fast heat soldering iron? or the opposite?

I burned out some low voltage power supply components on the microntroller board, and I wanted to remove those little black ones and replace them with shiny new ones.

Any suggestions...my solder sucker is ready!

Lou.
 

keith1200rs

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It depends on the components. Generally best to cut the legs off and desolder one at a time unless you have something to heat the whole chip for larger components otherwise you will pull tracks off the PCB. Hot and quick for soldering new parts.

Keith
 

louarnold

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I guess I should have stated that these were surface mount components without legs. Handling them is apparently somewhat more difficult than those that solder into holes in the PCB.

I have limited experience soldering anyway and I thought I might benefit from a temp controlled soldering iron. But someone told me that low heat was the key for surface mount. I just wanted to get some other opinions.

Thanks.
Lou.
 

Rob B

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I usually use a tip at 430C for most soldering tasks (No. 8 in a 45W Weller TCP), if it is a special task I might get the MT1500 out (why were these discontinued?).

Hot air is sometimes more convenient but for 0603~0805 packages an iron can be used if you can heat both sides simultaneously. Clean the pads with desoldering wick after removal.
 

keith1200rs

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louarnold said:
I guess I should have stated that these were surface mount components without legs. Handling them is apparently somewhat more difficult than those that solder into holes in the PCB.

Lou,

How many pads do they have? As Rob said, you can do 0603/0805 with a soldering iron - I usually do. You need to heat up both sides simultaneously, or at least move very quickly from one side to the other. For more than 2 pads it can be tricky without a hot air gun or desoldering tweezers.

Keith.
 

louarnold

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keith1200rs said:
louarnold said:
I guess I should have stated that these were surface mount components without legs. Handling them is apparently somewhat more difficult than those that solder into holes in the PCB.

Lou,

How many pads do they have? As Rob said, you can do 0603/0805 with a soldering iron - I usually do. You need to heat up both sides simultaneously, or at least move very quickly from one side to the other. For more than 2 pads it can be tricky without a hot air gun or desoldering tweezers.

Keith.
Well, the components are resistors, caps and diodes. Two pads each.

I don't understand about "0603/0805", but it seems that heating two pads at once with a single heat pen is not possible. So there has to be some other solution

Lou.
 

keith1200rs

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Lou,

0603/0805 refers to the component size. From what you say it should be possible to do it with a soldering iron. One hint is to smother the device with solder - both ends. Then you should be able to heat both sides simultaneously. Alternatively you go quickly from one side to the other. Again, extra solder helps as it stops it cooling down too quickly as you move to the other side. Then clean the solder off with de-solder wick. It is perfectly possible with a soldering iron - I do it all the time as I am sure lots of people do. It does take practice though, so if you can try it out on something non-critical, that would be good!

Keith.
 

louarnold

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keith1200rs said:
Lou,

0603/0805 refers to the component size. From what you say it should be possible to do it with a soldering iron. One hint is to smother the device with solder - both ends. Then you should be able to heat both sides simultaneously. Alternatively you go quickly from one side to the other. Again, extra solder helps as it stops it cooling down too quickly as you move to the other side. Then clean the solder off with de-solder wick. It is perfectly possible with a soldering iron - I do it all the time as I am sure lots of people do. It does take practice though, so if you can try it out on something non-critical, that would be good!

Keith.
haha, I'll see if I can find any non-critical PCBs with surface mount components to practice on.

Anyway, should I get the $150 adjustable soldering iron or skip it. I mean, I do very little soldering.
 

keith1200rs

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daver01a

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Normally when hand soldering SMD Resistors and Discrete components - you want to use a solder paste.
This holds the component to the pad.
Then you just touch it with a fine tip soldering iron tip to melt the solder paste.
..
Hopes this helps..
..
Dave
 

sk1

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Hi there , for soldering of smd you require a hot air gun. I was using it to replace components of moblie phones.There are two settings for it first for temperture and second for air pressure . You have to mask the pad with solder material using micro solder iron then apply some flux to it, place the component on it and blow the heat using hot air gun the pressure must be such that it shouldnot blow the component away.It requires practice hope this will help you.
 

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