Desoldering?

[ncdave]

Re: moby solder sucker

I need an SPDT "Y-valve" rather than a simple SPST on/off valve, so that I can switch the tip back and forth between atmosphere and vacuum, but I can't seem to find such a valve. :-( Does anyone know where I could get one?

I've learned that they are called L-type 3-way ball valves. They may also be called multiport valves, diverter valves, or selecting valves.

Brass & stainless L-type 3-way valves can be bought on eBay starting at about $10.

Here's a company which sells many types of plastic 3-way ball valves:
http://www.usplastic.com/catalog/def...arentcatid=870

Note that some of them are spec'd as "not for vacuum." I'm no expert, but I suspect that, in general, ball valves are probably better for controlling pressurized fluids than for controlling vacuum, because the pressure presses the ball against the port, to help make a tight seal. This might be particularly true with "floating ball" designs. However, I think one of these would probably work well for the Moby Solder Sucker.

If I understand correctly, there are two broad categories of 3-way ball valves:
L-type are "break-before-make." For this application, that's what we'd want.
T-type are "make-before-break."

Wikipedia, though worse than useless for anything even slightly controversial, has some good info on this, here:
https://en.wikipedia.org/wiki/Ball_valve#Multiport

Here's a diagram, from a valve manufacturer on Alibaba:


And here's the Moby Solder Sucker, needing one of those valves:

[mcel]

Back in my mainframe computer development days, hundreds of years ago, we were pretty proud we'd reached a 12 layer central processor backplane. But I see manufacturers now talk of 20 or more layers... Now on that sort of board, you really don't want to mess with the plated thru holes!

[stretch0069]

Someone PM'd me about drilling out the holes. I said it was a bad idea. He/she did it anyway (I guess) and tried converting me to drilling as well! Oh well. Some people.

I realize that not everyone has access to a good soldering/desoldering station or the money to buy one, but I have access to an old (at least 10 years) Pace PPS-200C. So far I've replaced two sets of caps and a ZIF socket. It worked awesome. No problems getting the holes clear. If only I had one two years ago.

Yes....I said ZIF. Ok....I was bored and didn't have anything new to calculate (see 'ton of caps' )

[kc8adu]

i watched an idiot drill solder out of a board with an isotip pc drill attachment.
warned him that if the slightest bit off center he would damage the throughholes.he did it anyway rather than having me take the board home and doing it right.
after his "repair" the board had several new problems.
took me 5 hours of rework to fix that mess.
he had spun out the throughholes in 9 places and soldered heavy enough to hide them.
customer fired the idiot on the spot when i told the boss what their resident "tech" had done.
mitsubishi wanted 3k for that board.
and they had payed 9k for the machine(wire edm) knowing it had issues.

Whatever you do, don't use a drill to clear out holes, even if you think it's smaller. These are multilayer boards with internal planes, for at least ground and +V, in addition to the tracks you can see on each side. The holes are plated through and arranged to make contact where necessary with the internal tracks. Drilling could destroy these connections.
Mike

[mcel]

Whatever you do, don't use a drill to clear out holes, even if you think it's smaller. These are multilayer boards with internal planes, for at least ground and +V, in addition to the tracks you can see on each side. The holes are plated through and arranged to make contact where necessary with the internal tracks. Drilling could destroy these connections.
Mike

[MD Willington]

I like the ghetto solder sucker there...I suppose a shopvac could be rigged up to do the same, the only thing is that moving a lot of air across the heated area will cool it down pretty quick.

MD

[(In)Sanity]

Best way I've found to clean the holes is to use a good heat iron and about 6 or so inches of copper phone wire, the solid stuff. You strip the wire off just before your going to use it, heat the hole and push it through. It will pull all the solder with it leaving a nice clean hole. You can reuse the same wire many times before you'll need a new one. This works far better then the desoldering braid. If you can't get the solder hot enough to push through, add a little more solder to the hole.

Also another idea.

These guys sell drills smaller then anything you can get at a hardware store.

http://www.drillbitcity.com/

[kdr9232]

quick way

take large dikes and cut cap in two, use rubbing achole to clean up mess and reuse the old legs, solder two old legs for quick fix. its quicker exspecially if
you dont have a good soldering station.

[ncdave]

moby solder sucker

Any other recommendations for removing that stubborn piece of solder?

Don't call this a "recommendation," but, for your amusement, and with apologies to Tim "The Toolman" Taylor, here are a couple of photos of my solution:
http://www.burtonsys.com/BP6_desoldering1.jpg
http://www.burtonsys.com/BP6_desoldering2.jpg
Yes, they are hooked "in series," with the bags removed for extra power. (Removing the beater-brush or belt might also help a bit.) They made a most impressive roar, lemme tell you! Note that the power cords snake off in different directions, because I plugged them into different circuits, so that they wouldn't trip a breaker.

I tried to improve the design with a ball valve in place of the clamped hose...
http://www.burtonsys.com/soldersucker5.jpg
...but no joy: it leaked the slightest smidgen, which made it impossible to fill the desoldering tip with molten solder. I need an SPDT "Y-valve" rather than a simple SPST on/off valve, so that I can switch the tip back and forth between atmosphere and vacuum, but I can't seem to find such a valve. :-( Does anyone know where I could get one?

Other variations are possible, too:
http://www.burtonsys.com/soldersucker2.jpg
http://www.burtonsys.com/soldersucker1.jpg

Really, I think TopCat's dental pick or sewing needle is a better solution for those stubborn little holes.

-Dave

[kc8adu]

seems you are still not getting enough heat if the suction doesnt get the hole clear.
i use a heat gun to preheat stubborn ones and it does the trick.

[Topcat]

Reheat the hole with the iron, add a little fresh solder to reflow and melt the old, and then poke a needle or dental pick through it with the iron still applied. Remove the iron leaving the pick in the hole. When the solder hardens, gently spin the pick (the solder won't adhere to stainless steel) to break it loose, and pull it out. Scrape any remaining solder boogers away with an exact-o knife or fingernail, and viola! A clean open hole!

Good Luck!

[Kako]

I'm also having trouble cleaning out the center of the holes from the solder. I bought the desoldering tool from Radio Shack, and it works great, as long as the cap is still in place. But the center of the hole is just stuborn. I don't even think its clean solder anymore, that its probably picked up a bit of filth from time after time of trying to melt it away. The recommendation that the leads be cut to close to appropriate size during installation, I'll try and do that. I just don't want to waste a cap destroying it in the process of putting it in. Any other recommendations for removing that stubborn piece of solder?

[Ark42]

I got a few boards changed since that post.
My tool of choice for both desoldering and solding the new caps on is the 40W desoldering iron from radioshack with the built-in solder-sucker bulb thing.
I like it because the tip is a cone with a hole, not a point, and you can put it around a lead sticking out the back of the board to more easily desolder things.
I use it to solder new caps on as well for the same reason - I found if you cut the leads to near the proper length, its a lot easier to force them through holes without even trying to clean out the old solder first. The shape of the desoldering iron really helps in this process too.

[alwayzamd]

Solder Braid

Have you tried the copper solder removal braid? I think that stuff works great. It soaks up the solder like a spunge. You just put the braid over the hole that still has solder in it. Then put your iron tip over the braid, and it soaks up the solder. Works for me - just my two cents.

T.J.

[Ark42]

With my boards, I dont think that would work. I tried heating the hole and sticking the new cap in (I did not cut the leads) but it did not go in at all. The solder in the very center of the hole would stay solid no matter what I tried.

[Fatal0E]

I do the same as clsk, just heat the holes and stick the cap in, done 4 boards now, minimal problems.

[Ark42]

People told me to try that, but it did not work. I tried tinning the leads of the cap and heating the lead with the iron, and also heating the back of the hole with the iron, trying to push the cap leads through the solder, but the solder stays solid and thus the cap can't push through. I think when the old cap is there, its lead helps draw heat around the solder, melts it just long enough to pull the cap out, but then I can never re-melt that piece of solder in the center. Say the hole is 1mm wide and 6mm deep, I can clean out the top 2mm or so from either side using the iron and sucker, but the 2mm in the center of the hole stays there. I don't have the problem on all the holes, but I am thinking maybe the ones I do have the problem with are the ones with big green pads around them, drawing away all the heat. Maybe I'm just not patient enough, but after holding the iron on the hole for a full minute and not melting the solder, I give up because I don't want to damage the board.

[clsk]

just a question....do you have to clean the holes? i think im the most ghetto...i use my 2$ iron i got at a discout store and instead of cleaning the solder out of the holes i just cut the contacts of the new capacitor to size place it over the 2 holes and just do the reverse of taking it out...heat up 1 hole while pushing it in then the other and repeate...i also dont have any solder around, i did 3 motherboards like this, and havent had a problem (yet)

[Ark42]

I'm really thinking there has to be an easier way to clean holes. I spent all frickin day picking at these holes with all kinds of things from paperclips, pieces of wire, thumbtacks, needles, etc. I tried adding a blob of fresh solder and using the bulb and vacuum to suck away solder from the hole, but the center of the hole stays solid no matter what I do. I have not tried a drill yet, but I'm thinking of finding a bit that is 1mm or smaller and using it next time.

[kc8adu]

now you have experiance for the next job.