Lead-Free boards

[Neonkiss]

I have had a very hard time replacing components on the newer Lead-Free printed circuit boards. The temp required to melt the high temp solder combined with multi layered board that act as a huge heat sink. Even with a good tip and a quality soldering iron these boards can be a headache.

I just found this product and it works great. Don't know why it took me so long to find this out, but wanted to share with others here.
This even work for thru-hole components like capacitors and resistors.

CHIP QUIK


<a href="http://www.youtube.com/v/7kyaz4Zrd78&rel=0" target="_blank">http://www.youtube.com/v/7kyaz4Zrd78&rel=0</a>

[FORDSBS]

 

[channelmaniac]

I add a bit of regular leaded solder to the joint then use my desoldering iron, hot air, or hot tweezers.

You MUST be careful to not popcorn the component from the extra heat requred for this pesky no-lead stuff!

If you hear a snap! sound, you've popcorned the component. Popcorn refers to the phenomenon of what happens with popcorn. The ICs have minute amounts of moisture that migrates inside and when it heats up, it turns to steam and the pressure will pop the component just like popcorn pops.

I have a couple of SRAMs that it happened to when using hot air to remove them. It's hard to see, but they have tiny cracks in the top of them.

Your best bet to keep that from happening is to bake the component at about 225 for 30 mins to an hour.

[Neonkiss]

Your best bet to keep that from happening is to bake the component at about 225 for 30 mins to an hour.

If water boils at 212F and I bake a board above that temp for 30 to 60 min, won't that popcorn the components?
I know the idea is the melt the solder before the component has a chance to get that hot. That's what makes the lead free solder so hard to handle. It doesn't melt until 700 deg. That's where the Chip Quick come into play. It changes the chemical composition of the lead free and it then melts at 300 deg.

That gives you enough time to get the job done before the component gets that hot.

[channelmaniac]

The idea is to slowly heat it so it drives the moisture out of the chip. The high temps in desoldering with hot air or infrared are on the order of 650 to 900 degrees for lead and higher for no-lead.

[Neonkiss]

The idea is to slowly heat it so it drives the moisture out of the chip. The high temps in desoldering with hot air or infrared are on the order of 650 to 900 degrees for lead and higher for no-lead.

Thanks,
I never wanted to get into SMD component replacement, but this stuff gives me the courage to try it.
I have a lot of boards that are POS so I'll be practicing this week.

[channelmaniac]

To put the chip down, the bottom of the legs of the chip and the pads both need to be clean of solder. Use plenty of rosin flux and a ball of solder on your iron to put the chip down. If you bridge a pin use some extra rosin flux and a clean iron to draw the excess solder off.

[ChizzleMonkey]

To remove those PITA thru-hole components, I just mix in some leaded solder and work the tip of my soldering iron(set @ 700 degrees or higher) around the pin to mix and soften the two together. With my soldering iron still in the mix, I use my desoldering gun(also at 700 degrees or a bit higher) to suck it off of the pin. Sometimes I need to repeat the process, but if you use the chipquik you probably will too. For the surface mount PITA components, I use a hot air rework station. There are some pretty cheap ones out there these days and they work really well. With a little patience and a good pair of tweezers the component just lifts right up off of the board. I set that hot air around 700 - 750 degrees(getting the rework station to blow the hot air just right can take some practice). Just use your tweezers and try to pick it up from time to time. As for replacing smd chips, the hot air rework station works great too. I put down a small line of solder paste across the pads, put the chip in place, then use the hot air to melt the solder paste. The components usually just line themselves up with this method. Yes, it is important to clean the pads after removing a component. I use my desoldering gun and finish with some IPA. This works well for me.