First attempt at desoldering..some advice please?

[Zero999]

Oh deer, I don't know what to suggest. I can't say I've ever had such a problem with de-soldering LEDs, even when I was a total beginner and had a crappy old unregulated soldering iron.

Don't cut the legs off the LEDs. It will make it more difficult to remove them. There should be no need to add any more flux. If anything, add a little more solder to help it wet the contacts. Use a large enough soldering iron tip to enable you to heat both leads at the same time, then the LED should just fall out.

[BurningTantalum]

I have sucked a lot of solder over the years, so all of the above posts contain good advice especially about a hot iron. I prefer a 'hoof' tip but without much recess- like the old Weller TCP1 tips.
 I have a Pace desoldering iron tool but often still reach for the spring solder sucker if I can't be bothered to wait for the Pace to heat up.
I have some green anodised Radio Spares teflon-tipped suckers that go back to the 70s. They still work fine.
A while ago my friend's son wanted some advice on a his dead aircon unit, so we isolated the fault and I sent him off to buy a soldering iron and sucker. The sucker was absolutely unuseable, I think because the hole was too big, and the recoil was like a Colt 45.
We did the job with one of my RS suckers but try as I did, I could not teach him how to use it- he could not synchronise touching the iron on the lead and then pulling it away as he fired the sucker.

Practice and practice with a scrap board from the dumpster.
BT

[Ian.M]

When I need to open a hole,
I use small drill bits of the suitable  diameter
...
with a  small manual  drill
...
Which I heat directly with the soldering iron. Of course, it is not good for the steel, but these bits are very  cheap, and can be reserved for this kind of use. If  needed, one can finish by drilling  the hole a little, but need to be careful about removing the tin of the hole. For the present case, as there is a lead across, it does not matter.

While a Pin Vise is useful for holding tools for clearing holes, I would question the use of twist drill bits for that purpose.  A lightly oiled mounted steel needle is my preferred tool for clearing difficult holes as there is far less risk of damaging the copper barrel plating inside the hole.   Heat whichever side has the best access and thermal contact, adding a little fresh solder if you cant get it to melt right through the hole, push the needle through, removing the iron, and wobble the needle slightly to maintain a clearance as the solder cools. As long as the needle is bright polished it will slide back out easily.   

Mount needles in a 3" length of 1/4" dowel as a handle in a close fitting hole 1/3 the needle length, abrading the eye end of the needle, using a small amount of epoxy. 

If you know anyone who rigs dinghies, or keelboats who can give you some offcuts of 1x19 stainless rigging wire of various diameters, unlay it to salvage the straight center strand, which can also be used to make useful mounted probes for hole cleaning and general prodding around in solder joints.  Flatten the handle end of the wire by hammering it on an anvil to give the epoxy a better grip. 316 stainless wire is even less likely to stick to solder than steel needles, and is virtually impossible to snap if abused.  You can even bend a hook on the end for unwrapping soldered terminal pins. 

[JacquesBBB]

The nice thing with drill bits is that they are well calibrated.

The other good aspect is that they are made with  very hard  steel that does not easily  stick to  solder.

It is true that one needs to be cautious, unless it is with a single side board. But an easy way to  overcome that if
you wonder about the possibility to damage the   plating of the hole, is to mount your drill bit in the reverse way.

[Mechatrommer]

i dont recommened drill bit... it will screw hole plating and pad, it risk breaking your bit, the hassle to bring out everything on the bench etc. it can be done with simpler thing as a single soldering iron i dont see much reason why an advice of the overkill. if anything, i will advice the OP to buy a decent solder sucker, its more general purpose, drill bit is only applicable to this very specific application where you dont have anything in the hole except a dried blob.

[wblock]

While a Pin Vise is useful for holding tools for clearing holes, I would question the use of twist drill bits for that purpose.

They work nicely if you know the trick.  Which is: put them in the pin vise backwards.  In other words, put the cutting end in the pin vise and use the smooth, non-cutting back end.

I heat one side of the board and push the smooth end of the bit through the other side.  This leaves a little tube of solder that can be cut off flush.

The drill-style welding tip cleaners include a low-quality pin vise and a handy assortment of drill sizes that store in the handle.

[richnormand]

I use the drill trick to clear holes, or even enlarge it a bit for the component wire, but only on single-sided boards or on one-sided traces.

On double sided board, unless you insert a wire in there and make sure there is solder on both sides, you run the risk of disconnecting the top and bottom traces (if connected)  from each others. You would be surprised how many board use an inner plating in a component hole (just like a via) to interconnect or are even cheaper and assume the component lead is the interconnect. On multi-layer boards (like 5 layers in motherboards) there might even be an intermediate connection that gets damaged. Only once did I come across that issue, troubleshooting a Dage tension meter controller board. The person that did the previous repair had "cleaned" the through hole well on both sides and soldered the capacitor wire on the back. However the top of the board was completely clean around the top trace. Of course the capacitor was masking the fact there was no electrical contact to the top trace.... took a while to find the issue.

Get a good sucker that is powerful enough to clean the hole clear of all solder.  Before I got my Pace rework station with an active pump desolderer, I used to melt the solder in the hole with my soldering iron and then use a can of compressed "air"  with a tube to give it a point blast. It would eject all the solder out the other side.

[tautech]

IIRC in the days before suckers and most of the desoldering stations the "book" procedure was 1 of 2 methods:
Use a drinking straw to blow away the solder.
Rubber bulb puffers to blow away the solder.

Both still valid when caught in the field short of tools. 

[FlyingHacker]

I always start by ADDING fresh solder quickly to each joint. Then if is easy to use either a desoldering station (even the cheap ones from China work pretty well. See Dave's review) or solder wick. If you don't get it the first time ADD more fresh solder and do it again. Don't just try to hold the iron and wick there longer.

But get Chem Wick from Chemtronics. Most other wick is trash. Make sure you trim the wick before each desoldering. This makes it much easier than trying to use different parts on the wick.

Never pull hard on anything, wether it be pulling on a part to get it out, or trying to pull off stuck solder wick. Pulling these often pulls pads right off the board.

[forrestc]

So I have to desolder roughly 80 LED's and some diodes.

Here are my suggestions:

1) flux is your friend.  If you don't have any, then adding *more* solder is your friend.   The new solder contains flux which will help the old solder behave better.  Solder tends to oxidize, and oxidized solder just doesn't behave correctly.  Like it doesn't melt.  Or flow.  Flux fixes this, mostly.

2) Don't be afraid to add more solder.   Often it's the fastest way to get the old solder out.

3) Gravity is your friend.   So is a bit of tapping.   Assuming you've cut the led's off the board, try heating the solder, and then tapping the board semi-gently against your work bench while the solder is hot - you'll be surprised how quickly those leads fall out of the hole, and often all of the solder comes out of the hole with it.   Just be careful and wear eye protection.    For something with two leads, like a LED, unless the leads are crimped/bent, often heating both leads at the same time (i.e. alternating between them) and tapping will result in the entire component falling out.

4) My experience is wick is best for cleaning up afterwards, not actually doing the desoldering.    I'm spoiled in that I have a vacuum desoldering iron which sucks all the solder out.  Before that, I'd almost always use gravity and/or the tapping method to get the lead out, then wick to clear out any remaining solder.

5) Beware of pad lift, and try to heat the lead/solder and not the board.   If a pad gets too hot, it will unglue from the board, and will often cause a failure.   Fast work is the best.  If you aren't able to get a pad cleaned within a very short time, move on and come back after it's cooled.   

6) If you've got a crappy iron, we'll all feel sorry for you (but not enough to buy you a inexpensive but nice iron).   If you have a decent iron, try different settings:  Too low, and you won't be able to work quickly enough.  Too hot, and you'll destroy everything.   There's a fine line in the middle.

[BMack]

Another suggestion, if it's not a modern board ignore all the temperature advice. If you use high temp on an older board you're likely to burn the board. It's a lot like soldering, you use the lowest temperature you can get away with, it will take some experience because too low and you'll do nothing but too high and you'll start burning things. Know what kind of solder you're working with, lead-free is high temp, old leaded solder is low temp. Sometimes you need to adjust based on the component like having to take off.

Our shop does repairs for several hospitals and some of their equipment still uses CRTs. Those need a lot less heat or you'll burn up the board and lose the trace. I'm barely above leaded solder melting point.

A dab of ChipQuik will save you a lot of headaches but learn how to do it properly and don't use ChipQuik as a crutch because that's an expensive crutch. https://www.amazon.com/ChipQuik-SMD1-Leaded-Temperature-Removal/dp/B0019UZP7I

[stj]

read this:
https://www.eevblog.com/forum/beginners/desoldering-bulb/