time to ditch my $20 25w iron and get sumpin' REAL!!!

[mathog]

Re: time to ditch my $20 25w iron and get sumpin' REAL!!!

As for motherboard work, it depends on the board. Some it works well with and others I resort to a large tipped soldering iron. There must be clearance around the component lead(s) for the vacuum units to work well. Via's can be damned close in tolerance to the leads and there just isn't enough room to get the solder out. Caps can be pulled down fairly tight on their bungs and sometimes "gooped-in" caps prevent air passage. It would be similar to taking a vacuum cleaner hose to your skin. The suction is wonderful, but there is no air movement.

If the "goop" seals the cap to the board that junk would presumably need to be scraped off with a small tool like a Jeweler's screw driver before removing the cap anyway, and hopefully that would open an air path. Maybe not if the goop ran under the cap though. In any case, I have never seen goop on a motherboard, only on LCD inverter/PS boards.

For the caps that are tight down on the board, with no goop, but maybe leaked a little, when the desoldering tool is applied and the solder melted, if the cap is then tilted a bit, just slightly pulling the lead up out of the hole, shouldn't the air flow for the sucker be restored?

Somewhere or other I read a suggestion that one could pull the can off the cap, leaving just the leads. Seemed like a bad idea since it might make a mess or break traces, but if there was no other way to get the cap off, I suppose it could be the last resort, and it should restore air flow.

[Toasty]

Re: time to ditch my $20 25w iron and get sumpin' REAL!!!

It's so tight that even with no blockage, you may not get sufficient flow. Your heat application must be short and high enough to liquefy the solder (best of luck with lead free) without damaging the surrounding components or the board. Back-heating the board with a infrared source or hair dryer is suggested to aid this. Getting the board to 150°F or so will help curtail some of the heat loss. You have to be very careful not to overheat the other components.

Snapping off a cap is an extreme situation and would best be accomplished by rocking it back and forth until the lead weakens enough to break. Pulling is not recommended, as you stated you can damage the traces or rip the via's right out of the board. Sometimes you can cut the cap's can with a pair of dykes and then "disassemble" the cap from above, down to the bung, leaving just the leads. Again, it's an extreme procedure.

Toast

[shovenose]

Re: time to ditch my $20 25w iron and get sumpin' REAL!!!

um-the best iron they could get me at the hardware store was a weller 40w...omg i does stuff so fast!!! ok i know its not so great but when im coming from a 25w junk iron its quite an improvement!

[mathog]

Re: time to ditch my $20 25w iron and get sumpin' REAL!!!

I was thinking maybe one could use Chip Quik to lower the melting point enough to clean out through holes on motherboards or other difficult multilayer boards. (Not needed for simple double sided boards, even the Radio Shack cheapo desoldering iron is good enough for that.) Seemed like such an obvious idea that it had to have been done, and a bit of Googling turned up this site:

http://www.zeph.com/lowmelt.htm

Their focus is clearly SMD but they do at least claim that the low melt solder, which seems to be very, very much like Chip Quik, can be used for through hole applications. There is a demo video for SMD removal, which is pretty slick, since they heat one side and remove a chip from the other without ever using an iron or hot air tool on the IC leads. The thing is, for the purposes of this group, I don't think exactly that approach is going to fly since if the leads to be desoldered are up the electrolytic capacitor can is going to be down. 150C may be ok for SMD components, which are designed to withstand high heats, but it is most likely going to blow up (literally) any electrolytics (including those you did not intend to replace) and could damage other components too.

Still, I can see some possibilities here. A little dab of the stuff and a low power iron might be enough to mix/melt the solder in the via working from the lead side of the board, so that the component could be pulled out. The hole would still be plugged, but at that point a desoldering tool, again working from the lead side of the board, should be able to clear it. Somewhat like the way they vacuum up the extra material at the end of the video. I worry though that this would not get all of it out, and that the residual contamination would weaken the solder holding in the replacement part.

Have any of you ever tried this approach?

[Hypnotoad]

Re: time to ditch my $20 25w iron and get sumpin' REAL!!!

I have a cheap elenco soldering station and once the iron gives out I am thinking of buying a Weller 35watt with smaller tips, can't see why it won't work as it plugs straight in. I use the same heat setting for all PCB work.

I recently got a Hakko 808 de soldering gun, it is the best thing I have ever bought. It makes short work of through hole capacitors, and removing op amps is a breeze even with lead free solder. Leaves the pads looking like new. Couldn't recommend it more highly.

[romansroad]

Re: time to ditch my $20 25w iron and get sumpin' REAL!!!

IMO, you can't go wrong with a quality tool. Face it, you'll be using this thing for years......I love my Hakko's.....936 is my favorite, and Fry's has the 808 Desoldering iron.....very nice!

[Hypnotoad]

Re: time to ditch my $20 25w iron and get sumpin' REAL!!!

IMO, you can't go wrong with a quality tool. Face it, you'll be using this thing for years......I love my Hakko's.....936 is my favorite, and Fry's has the 808 Desoldering iron.....very nice!

Everyone talked me into it, I bought the Hakko 936 SMD soldering station.

It's a fantastic setup, seems like I was fumbling around in the dark until I got the 808 dedoldering gun and the 936.

I can remove old components and have new ones soldered in the time it took my old Elenco station to heat up.

Thanks for the advice.

[romansroad]

Re: time to ditch my $20 25w iron and get sumpin' REAL!!!

Ahhh, its the simple things in life

[Caminokid]

Re: time to ditch my $20 25w iron and get sumpin' REAL!!!

The Hakko 936.

I have this one. Very happy with it. I work in a shop where I have had to furnish my own equipment and for the price you cant go wrong.