[time-nuts] I love the smell of tantalum in the morning

Graham / KE9H ke9h.graham at gmail.com
Sun Nov 6 16:32:49 EST 2016


If you are in a position where you are worried about damaging the PCB.
(And I would really be worried cutting any part in half with cutters, or
cutting leads off an IC with diagonal cutters.)
For two leaded parts, "Hot tweezers" work fine.
For parts with more leads, like ICs, you need hot air tools.

If you don't have those tools, or you have an unusually expensive or rare
PCB, consider low temperature solder.

You can buy a kit (from Mouser or others) for $16 called "ChipQuik" SMD1

Watch the video:
http://www.chipquik.com/store/product_info.php?products_id=210001

Manufacturer's Part number SMD1
Mouser part number: 910-SMD1

Remove as much normal (lead containing or lead-free) solder as you can from
each lead with solder wick.
Flood each pin with the low temp solder alloy (melting temp about 136
degrees F or 58 degrees C)
Usually putting a soldering iron on any one pin (or use a hot air pencil)
will raise the entire part and nearby board above 136 degrees F, so just
pick the part off with tweezers.
Now clean off all the low temp solder with solder-wick or as instructed.

For $16, you get enough for several years of casual reworks.
This is much gentler on the PC board than any other technique.

--- Graham

==

On Sun, Nov 6, 2016 at 2:42 PM, Bryan _ <bpl521 at outlook.com> wrote:

> If the SMD is small enough I have found it easy to remove by just applying
> a blob of solder to one end, this will quickly gap over to the other lead,
> and the SMD component and solder ball just slides off the board. Only works
> on the very small components though.
>
>
> -=Bryan=-
>
>
> ________________________________
> From: time-nuts <time-nuts-bounces at febo.com> on behalf of Robert
> LaJeunesse <lajeunesse at mail.com>
> Sent: November 6, 2016 8:42 AM
> To: time-nuts at febo.com
> Subject: Re: [time-nuts] I love the smell of tantalum in the morning
>
> Another admittedly low-budget way of heating both ends is to use a heat
> spreader. Solder a short piece of braid to one component end, fold it over
> the top of the part, and solder it to the other end. Heat the braid in the
> center, add solder until both ends are melted, and lift the combination off
> with tweezers. Sometimes a heavy enough copper wire bent around the part
> will also work as the heat spreader..
>
> Bob LaJeunesse
>
> > Sent: Saturday, November 05, 2016 at 9:05 PM
> > From: "Andy ZL3AG via time-nuts" <time-nuts at febo.com>
> > To: "Discussion of precise time and frequency measurement" <
> time-nuts at febo.com>
> > Subject: Re: [time-nuts] I love the smell of tantalum in the morning
> >
> >
> > Yes. Unless you're grinding it away with a dremel (which I wouldn't
> recommend as far as chemical dust is concerned), nibbling away with
> sidecutters would be trying to force the 2 ends of the component apart.
> That may be stressing the pads they're soldered to, leading to a possible
> pad lifting at some stage.
> >
> > Any of the methods mentioned that heat both ends at the same time -
> allowing the component to be wiped off the board - would have to be the
> best, stress-wise.
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