Desoldering Methods?
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blip

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Hey all,

As a lot of you know,I am in the process of getting ready to build CMoys. Since this will be my first attempt at building anything more complex than a fan control rig for my computer, I will probably scew up along the way.

Thus I was wondering what your favorite desoldering methods are and when you use them? I've read tangents superb general article on DIY tools, but I'd like some other opinions.

Also, does anyone have tips about how to desolder effectively?
 
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JMT

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Desoldering braid is a DIYers best friend. Also, get a solder sucker to pull that last remaining bits of solder out of the pads. When using desoldering braid, make sure you are patient and that you allow time for the braid to heat. Use some flux if necessary. It really is cool watching the braid absorb the solder.
 
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andrzejpw

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I use desoldering braid. Its easy to use, and its a good conductor of heat. I tried a soldering pump a couple of times, but I didn't really like it. Maybe its just a matter of getting used to it, but it almost seems like you need a third arm. Oh, and desoldering braid just looks really cool when the solder flows on it, turning it silver.
 
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puppyslugg

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Hey blip,

I prefer using a desolder wick. I've tried desolder pumps, but they don't get it clean and have go back with a wick anyway. But maybe it's just my poor(or lack of) technique.

If your interested, here's a link for tips on soldering:

http://www.audioasylum.com/audio/twe...ges/71400.html
 
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tangent

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Some tips for more successful desoldering with a pump:

1. The bigger the pump, the more likely you'll get all the solder out the first time. Maybe you need to upgrade.

2. Clean the pump every now and then, and make sure the lube on the O ring is still good and hasn't fouled with solder bits. One good test for vacuum integrity is to put the tip on your moistened finger and trigger it -- if the spring doesn't fully return the cocking slide to the end of the pump, the O ring and the pump tips are good. If you can't get it to "hang" like that, or it slowly leaks, your pump needs maintenance.

3. You have to have the iron and the pump tip on the joint on opposite sides before triggering the suction. Actually, it often helps to remove the iron from the joint immediately before triggering the pump, so that the iron tip doesn't block the hole.

4. The pump tip has to be flat against the board to get a decent seal. And, a worn pump may have a misshapen tip which needs to be replaced or flattened back out to maintain suction.

5. If you've got a hole with solder on the sides and a small hole in the center, it's often a good idea to re-block the hole with new solder and try to desolder it again. This maintains vacuum until the solder all begins to move, instead of wasting vacuum through the pinhole before the solder starts moving.
 
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Mr_Happy

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I like using the desoldering braid that they sell at Radio Shack. Be sure not to hold on to it with your fingers when you're desoldering as it can be very painful! (I have personal experience with this)
 
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Gariver

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Recently, I bought a 30 Watt Desoldering Iron with a Built-in Pump for $23.65 at PartsExpress.com. Replacement tips cost $6.95. Is it any good? Yes, yes, yes! It works like a charm, and I highly recommend it!

How does it work? Well, first you melt the solder at a joint. Then you push a button to start the vacuum pump action. Whooosh! The solder is gone! You can't even see it go!

http://www.partsexpress.com/pe/showd...ID=10654&DID=7

Most of the better pumps I've seen sell for around $20. So this Soldering Iron/Pump is a bargain!
 
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Gariver

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Michael Percy sells a desoldering braid that has rosin flux in it. It works very, very well.

Why is rosin flux important? As you heat up a joint, the flux is burned out of a joint. If you burn out all the flux, you can't get the solder to melt. It stays solid. That's why you need some rosin during desoldering.
 
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I agree about desoldering irons, Gariver. Radio Shack (believe it or not) sells a reasonable one. The only reason I don't use mine more often is that it makes for a second hot thing on my crowded bench at once -- too much risk for me. I only fire it up when I need to do mass desoldering.
 
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Thanks for the tips, tangent. Armed with you tips, I'll dig up my pump and give it a try.
 
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blip

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Wow! Thanks for all of the replies. I love this forum because everyone is so forthcomming with knowledgeable advice.

Anyway, I like the idea of the desoldering iron... it seems good conceptually and I might as well get some good out of having a near by Rat Shack.
I think I'll try to pick up some wick too just in case.
 
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I prefer the pump, I couldn't quite get the hang of the braid, but I need to work at using it more. The pump is great for those big clumps of solder.
 
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if you're replacing ICs, get some fine fingered cutters. cut the fingers off the ICs. then when desoldering the fingers push to where the middle of the IC was and use the solder pump in the opposite angle - less likely to lift an etch.

for old solder, add a little new solder while heating. it'll mix faster. use the pump.

when soldering components do not bend the leads over. it'll make it harder to remove in the future. press against component side and solder correctly. then cut the leads when the joint has completely cooled (never before). i always pre-cut components so that the cut is a nice even 90 degree cut (like the top of a flat roof on a building).

always check for cold solder joints and bridged etches.

use heat spreaders or a clamp to transfer heat away from the component side.

the smaller the diameter of the component, the small the wattage necessary. small components should be soldered with a 15 watt'r. very large components components can be done with 40's, and medium components with a 25 or 30 watt'r.

no, you don't use a 100 watt ironing gun on small transistors...
 
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