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Surface mount soldering info...

Posted on 2000-02-17
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Last Modified: 2012-06-21
Hi guys,

I am looking for some good info, tips and tricks etc, about surface mount soldering. I would like to find a site that gives tips how to use standard soldering iron etc to best effect without having all the kit, or tells how to make simple gadgets to help.

I have a pile of 3 chip 30pin 1mb SIMMs and a pile of 4mb 72 pin SIMMs and want to end up with a pile of 8mb SIMMs, (the 4mbs are on 8mb capable circuit boards, plan to fill the backs with the 1mbx4 chips off the 1mbs)

thanks,

Road Warrior
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Question by:RoadWarrior
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Expert Comment

by:frache
ID: 2534478
I do it ...
- You need a hot air generator. You can use a hot air paint stripper  with a electronic regulator ( triac based regulator). Make many try before to adjust temperature ...
-You need "liquid" (pastry?) soldering (CMS soldering) . To determine quantity, you can use a hypodermic (disposable) syringe.
- Clean mount surface (circuit board) : use a ink eraser and after acetone solvent.

-A micro iron solder ( From Radioshack ) and a magnifying glass coulb be useful.
Better, a tool to inspect (examine) negative or slide...

 
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Expert Comment

by:MortenL
ID: 2534815
Are U sure it's worth the effort :)

Well... use the hot air generator at the backside of the PCB's U want to strip for componets - this way U will possibly not burn the chips by excessive heat. Just apply heat until the chis falls off. Help them with a pincher...

Resoldering... U ´will certainly need some fluss, to ensure that soldering is possible on the more or less coroded soldering pads.

It can be done - I have change quite a lot of Motorola 68000 FPGA, or whatever they are called in SMD style
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by:3rsrichard
ID: 2535066
Go to
http://www.esisupply.com
to their line sheet, where there will be some links to manufacturers of SM equipment and supplies.  Some may have dealers in UK.

The blow gun is good for part removal,
but will cause heat damage if too hot.

You use thick flux to hold the parts in place while you solder.
You probably should not try the combination solder/flux, it requires too much control.
You will need a good cleaner/defluxer for afterward.  Can you get TCE in UK?
You need an iron with a very pointed tip, very good close vision, steady hands, tiny solder, and patience.
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by:3rsrichard
ID: 2535074
Oh, and something called "Solderwick", which is a sort of braided copper to use as a sponge to pick up little beads of excess solder.
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by:RoadWarrior
ID: 2537555
I am not worried about getting the chips off the 1mb simms, they are SOJ type and I just score along the solder line a few times then crack them off by sticking penknife blade underneath, done that many times for salvaging 40 pin SOJ's to upgrade graphics cards, no heat=no heat damage and the pins have anough spring that I have never done mechanical damage.

It is the soldering them onto the 4mb boards that I am looking for a good solution for, I go cross eyed trying to solder that fine and close with a fine tipped iron, and often end up frying the component or lifting the pads off the PCB.


Frache,

Is the solder paste for use with a hot air gun? Around how hot does it need to be to melt?

I don't have a hot air gun, but I have a hair dryer that gets VERY hot for a hair drier, can't bear to hold my hand in front of it, have used it on heat shrink tubing before. At a guess it can get over 100 degrees centigrade when it is on a while. If it needs much hotter than that, I can maybe rig a hot air gun up with toaster parts and a shop vacuum I have that blows. Or a blow torch far away?

Trying to do this cheap, otherwise I may as well buy some 8mb SIMMs. But I have far more time than money.

3rsrichard, I am now in Canada by the way, guess I should note that on my profile huh?

Thanks,

Road Warrior



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by:
frache earned 100 total points
ID: 2541767
"Is the solder paste for use with a hot air gun" -> yes ...

solder paste = silver (2%) + tin + lead + flux + solvant
You must buy solder paste.
http://www.aimsolder.com/
http://www.solders.com/bow.htm

Temperature : 200-260 degres celcius - time 10s max. You can't use a hair dryer.

Example of hot air generators : Leister /Pace / Hakko

follow this links: http://www.heatgun.com/electn.htm
http://www.leister.com/index.htm
You can see  Leister Hot air generators.
http://www.hakkousa.com/
You can see Hakko hot air stations ( hot air rework).


Another interresting link :

http://www.platoproducts.com/
Many tools ... and you can order a catalog..
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by:RoadWarrior
ID: 2544928
Thanks Frache, the paste sounds like the way to go, will have to see if I can beg or borrow a hot air gun though, hmmm have a darn great big plumbers soldering iron 75W+ maybe holding that nearby would work, will have to experiment. Thanks.

Road Warrior
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by:frache
ID: 2545303
Good luck.
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