Hi. And thanks for taking the time to read this post.
What is the best way to get solder out of a hole. I am trying to get a new capacitor soldered down onto a circuit board, have got the old one out with some difficulty, now there is a stubborn piece of old solder which has set up camp in the hole and will not shift.
I have tried pushing the leads of the new capacitor in, applying flux to both sides of the hole and ofcourse the obvious desoldering pump but none of these will work. I even took out my soldering bit and used a fine nail, but i think because it is so thin it cannot absorb enough heat and melt the solder. Now i have got a black mark on the circuit board from using too much heat. It seems the board or nearby components are absorbing a lot of the heat into themselves.
Can anyone please advise.
Many thanks. John.
What is the best way to get solder out of a hole. I am trying to get a new capacitor soldered down onto a circuit board, have got the old one out with some difficulty, now there is a stubborn piece of old solder which has set up camp in the hole and will not shift.
I have tried pushing the leads of the new capacitor in, applying flux to both sides of the hole and ofcourse the obvious desoldering pump but none of these will work. I even took out my soldering bit and used a fine nail, but i think because it is so thin it cannot absorb enough heat and melt the solder. Now i have got a black mark on the circuit board from using too much heat. It seems the board or nearby components are absorbing a lot of the heat into themselves.
Can anyone please advise.
Many thanks. John.
There's a few different ways to approach the problem. Perhaps the easiest...
Apply a small dome of solder right over the hole. Then, with the new capacitor at the ready, melt the solder and push the capacitor lead through the hole and the solder. Apply some more flux and position the cap appropriately, and ensure a good fillet and whetting.
The new solder will make contact with the old solder stuck in the hole and transfer its heat, melting the solder in the hole and allowing you to insert the new lead.
Apply a small dome of solder right over the hole. Then, with the new capacitor at the ready, melt the solder and push the capacitor lead through the hole and the solder. Apply some more flux and position the cap appropriately, and ensure a good fillet and whetting.
The new solder will make contact with the old solder stuck in the hole and transfer its heat, melting the solder in the hole and allowing you to insert the new lead.
Last edited:
Is it a through-plated hole, and if so do you need to keep it that way? If not, I find a very small drill bit on a 12v drill, or an Archimedes hand drill will clean, enlarge or create a hole. Sometimes it is the easiest option, but try to drill from the copper side if possible. I have bits from 0.5mm up, so I can get the hole size I need.
Drill? Ouch.
A sponge picks up water better if you wet it first. Somehow that sems similar to me. Trying to empty a half empty hole of solder is a lot harder than pulling solder from a full hole. Like sofa said.
Resolder the hole, then suck it all out. A full hole has eenough solder to melt and get to the entire hole. Nothing melts old solder like more molten solder.
A nail is too big for the hole. But if you have a bit of stubborn solder or maybe a scrap of wire lead still in the hole, use another piece of wire to push it out. Fill the hole with fresh solder, maintain heat on it, and push the wire of some resistor from your door into the hole. Shove any blockage out the other side, then pull the part back out. Now try clearing the hole.
A wire lead will work better than the pins of your new cap. The larger cap will act like a heatsink and draw heat from the joint yuo are trying to melt.
I keep a piece of stiff piano wire on my bench. I use it to poke any obstructions from the hollow tip of my desoldering station. But it is great for the above process too. And solder doesn;t stick to it as readily as to a resistor lead. Hobby/craft stores sell piano wire pieces. But a resistor works too.
A sponge picks up water better if you wet it first. Somehow that sems similar to me. Trying to empty a half empty hole of solder is a lot harder than pulling solder from a full hole. Like sofa said.
Resolder the hole, then suck it all out. A full hole has eenough solder to melt and get to the entire hole. Nothing melts old solder like more molten solder.
A nail is too big for the hole. But if you have a bit of stubborn solder or maybe a scrap of wire lead still in the hole, use another piece of wire to push it out. Fill the hole with fresh solder, maintain heat on it, and push the wire of some resistor from your door into the hole. Shove any blockage out the other side, then pull the part back out. Now try clearing the hole.
A wire lead will work better than the pins of your new cap. The larger cap will act like a heatsink and draw heat from the joint yuo are trying to melt.
I keep a piece of stiff piano wire on my bench. I use it to poke any obstructions from the hollow tip of my desoldering station. But it is great for the above process too. And solder doesn;t stick to it as readily as to a resistor lead. Hobby/craft stores sell piano wire pieces. But a resistor works too.
Why ouch? If I am missing something please let me know, as I don't want to damage my own boards.
It's rarely acceptable to destroy plate throughs and NEVER on multi layer boards as you may disconnect internal traces. You'd be better off getting a better soldering iron that has the power to heat up the hole. Using a variable temperature iron and jacking the temp up to max is NOT a solution.
A Metcal iron with an STTC-126 tip is excellent for clearing plate through holes without damage but some designers don't use thermal reliefs on ground planes and those can be a b**** to clear. You might try hot air for those cases.
Used Metcals fetch $100-$200 on eBay and I've bought more than a dozen over the years. After using a Metcal, everything else is just a 'tusk'.
G²
Hi. Many thanks for the replies.
Unfortunatly the solder is so stubborn wicking is only removing some surface stuff on the pcb, it is not getting right down into the hole and sucking it up
I tried wrapping a steel paper clip around the bit hoping to heat it up then push it through the hole in an effort to clear it. but it will not get it hot enough It is touching the solder but not melting it, instead the board is heating up and starting to blacken. I remember years ago someone told me to use brass that if you cannot find a suitable bit for your soldering iron get a brass rod and shave the end down, so am thinking perhaps brass is a better conductor of heat. I tried this out, unfortunatly the only brass i have at home is in the form of brass screws. I took out my soldering iron bit and inserted a large brass screw versus a steel screw, the brass melted solder on an old circuit board's solder very quickly, the steel one did nothing even after about two minutes of contact.
Think i might experiment with different metals to see which is the best, will get back to you on that. Perhaps copper?
Many thanks for your suggestions. I will try them all. John.
Unfortunatly the solder is so stubborn wicking is only removing some surface stuff on the pcb, it is not getting right down into the hole and sucking it up
I tried wrapping a steel paper clip around the bit hoping to heat it up then push it through the hole in an effort to clear it. but it will not get it hot enough It is touching the solder but not melting it, instead the board is heating up and starting to blacken. I remember years ago someone told me to use brass that if you cannot find a suitable bit for your soldering iron get a brass rod and shave the end down, so am thinking perhaps brass is a better conductor of heat. I tried this out, unfortunatly the only brass i have at home is in the form of brass screws. I took out my soldering iron bit and inserted a large brass screw versus a steel screw, the brass melted solder on an old circuit board's solder very quickly, the steel one did nothing even after about two minutes of contact.
Think i might experiment with different metals to see which is the best, will get back to you on that. Perhaps copper?
Many thanks for your suggestions. I will try them all. John.
Two soldering irons, one from each side. Then the Soldapullt DS017. This will be easiest with a helper.
If all else fails, small (around #70) drill bit held in a pin vise or X-acto handle. Solder is soft, so there's a reasonable chance the drill will only remove solder and not through-plating.
If all else fails, small (around #70) drill bit held in a pin vise or X-acto handle. Solder is soft, so there's a reasonable chance the drill will only remove solder and not through-plating.
I have employed each of the suggested methods at some time or another, with varying degrees of success. I think you need to consider a possibility that has defeated my efforts - not often, but on more than one occasion. That is, the "solder" slug isn't solder at all. It may be a broken piece of component lead, lodged in the hole. Or a partially-disintegrated "barrel" from a plated through hole. Or a broken-off piece of trace or pad, pulled into the hole when the previous component lead was pulled through. Because the obstructing material is coated with solder it looks like solder, but it's true composition isn't apparent until after it has been dislodged and removed with, e.g., a stainless steel dental pick.
Dale
Dale
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.