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Topic: SMD soldering practice (Read 1 time) previous topic - next topic

TchnclFl

Indeed.  I bought a solder sucker when I first got into this stuff, and it works well for through-hole components, but I have a feeling it wouldn't for SMD components :P.

cr0sh

#16
Feb 15, 2010, 01:39 am Last Edit: Feb 15, 2010, 01:40 am by keeper63@cox.net Reason: 1
SMT technology has been around a really long time; it was used in the Apollo flight control computers, for cryin' out loud...

Just about any computer motherboard made in the 10 years has plenty of SMT stuff on it, from large and easy parts, to really tight pitch stuff, and in some cases, stuff that couldn't even be attempted by hand without destroying things.

Go down to a thrift store (Goodwill is a great place), and find an old computer motherboard (or CD player, or old game console, whatever), buy it, and practice on it. Heck, you could probably dumpster dive behind some office complexes and find plenty of junk (I've never had a problem scrounging junk this way). Garage sales are a good source for this kind of stuff too.

Don't spend more than $5.00 for whatever you plan to tear down.
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Osgeld

I find it 10x harder to salvage smd VS new stock being put on a board, but that me
http://arduino.cc/forum/index.php?action=unread;boards=2,3,4,5,67,6,7,8,9,10,11,66,12,13,15,14,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,86,87,89,1;ALL

cr0sh

I was only talking about learning SMD skills, Osgeld, not for salvaging components - when I talked about scrounging, it was mostly in finding stuff (usually old computers and the like), not for pulling parts off.

If you wanted to pull parts, though, it can be done - use non-stick tweezers, a heat-gun, and mount the board in a vice. Probably not the best way to get parts for a project, though, unless you enjoy the tedium or have no other choice...
I will not respond to Arduino help PM's from random forum users; if you have such a question, start a new topic thread.

florinc

#19
Feb 15, 2010, 03:16 am Last Edit: Feb 15, 2010, 03:17 am by florinc Reason: 1
You can practice soldering 1206 SMDs (resistors, leds, capacitors) on a regular protoboard, since the distance between the 1206's pins is 0.1".

TchnclFl

Quote
You can practice soldering 1206 SMDs (resistors, leds, capacitors) on a regular protoboard, since the distance between the 1206's pins is 0.1".


Nice tip, thanks!

Osgeld

Quote
I was only talking about learning SMD skills, Osgeld


so I am at a loss then, how does buying a already soldered board help you learn smd soldering skills ?
http://arduino.cc/forum/index.php?action=unread;boards=2,3,4,5,67,6,7,8,9,10,11,66,12,13,15,14,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,86,87,89,1;ALL

florinc

Quote
so I am at a loss then, how does buying a already soldered board help you learn smd soldering skills ?

You de-solder, then re-solder?

TchnclFl

As an SMD-nooby, I could be wrong, but isn't desoldering SMD ICs deviously difficult?

cr0sh

Quote
As an SMD-nooby, I could be wrong, but isn't desoldering SMD ICs deviously difficult?


Not any more difficult than desoldering thru-hole parts; it actually can be simpler:

1) Heat the solder joints up by stroking the iron across the leads (or by moving the hot-air source around if using a hot-air rework station), until all the solder it melted.

2) On 2-3 lead parts (caps, resistors, diodes, transistors); just push the part over out of the solder pools with a non-stick pair of tweezers (I've heard bamboo tweezers are particularly nice, but heat-resistant plastic ones will work too; stainless steel is ok as long as you don't get it "tinned").

3) On multi-lead part, keep it hot and pry the part up, a bit at a time. You can also cut the leads then clean up the legs. It is also possible to simply put a large blob of solder over all the pins, keeping it hot, then removing the part - then use braid to clean up the pads. Note that much of the time, you won't be able to salvage the multi-lead part.

4) If you are doing a large board, and don't particularly care about saving the board, just use a regular large heat gun to heat areas up, and either pick off with a dental pick and/or pliers, or "tap" the board to knock the parts loose (wear a face shield and goggles).
I will not respond to Arduino help PM's from random forum users; if you have such a question, start a new topic thread.

TchnclFl

But if it's a 2-lead component (like a resistor), the leads are on opposite sides, and I assume that by time you heat up one side, the other has cooled..?

kierin

I've got a soldering with two tips, acts like a set of tweezers, the tips are like blades and you can change how wide they are, great for quickly removing smd components.

Had it for that long I can't even remember where I got it from or how much it cost.

As for soldering components the best technique I found was to tin one pad then heat it and slide the component into place, then solder the other pads, a good set of non magnetic tweezers saves a lot of problems.

cr0sh

Quote
But if it's a 2-lead component (like a resistor), the leads are on opposite sides, and I assume that by time you heat up one side, the other has cooled..?


Not if you move quickly, it won't - just keep alternating sides (they aren't that far apart). Another idea (if you are removing parts):

If the board has most or all of the smt components on one side, and you don't care about the board, get an old hotplate or electric skillet (that you won't EVER cook on again), and set the temperature to about 400 degrees F (approx 200C), and put the board component side up in the center (add a bit mineral oil to even the temperature distrubution; not a lot, you're not deep-frying; use plenty of ventilation, too), when you see the solder joints go shiny, pick the parts off - you could also use a solder iron to add heat on the topside as well.
I will not respond to Arduino help PM's from random forum users; if you have such a question, start a new topic thread.

Osgeld

#28
Feb 15, 2010, 10:17 pm Last Edit: Feb 15, 2010, 10:18 pm by Osgeld Reason: 1
course this all goes back to my statement, its 10x harder to remove them than soldering them

its really a totally different skill set, one could argue that about through hole components but there has been very few times where a hot plate and tweeter irons are a requirement

but soldering smd components, is just a matter of how good your soldering skills are, and how steady you can hold your hand, its virtually identical skills
http://arduino.cc/forum/index.php?action=unread;boards=2,3,4,5,67,6,7,8,9,10,11,66,12,13,15,14,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,86,87,89,1;ALL

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