thru hole - diyAudio
Go Back   Home > Forums > Design & Build > Construction Tips

Construction Tips Construction techniques and tips

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 8th May 2012, 05:48 AM   #1
diyAudio Member
 
Join Date: Feb 2011
Default thru hole

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.
  Reply With Quote
Old 8th May 2012, 06:13 AM   #2
diyAudio Member
 
sofaspud's Avatar
 
Join Date: Nov 2005
Location: San Antonio
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.
__________________
It is error only, and not truth, that shrinks from enquiry. - Thomas Paine

Last edited by sofaspud; 8th May 2012 at 06:16 AM.
  Reply With Quote
Old 8th May 2012, 07:31 AM   #3
diyAudio Member
 
Join Date: Dec 2005
Location: Plymouth, England
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.
  Reply With Quote
Old 8th May 2012, 08:20 AM   #4
Enzo is offline Enzo  United States
diyAudio Member
 
Join Date: Sep 2004
Location: Lansing, Michigan
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.
  Reply With Quote
Old 8th May 2012, 09:26 AM   #5
diyAudio Member
 
Join Date: Jul 2003
Location: Dona paula, Goa
The way u explain, looks like it is an extra thick copper pcb for high power electronics. Even removing a solder from these is a PITA.

Gajanan Phadte
  Reply With Quote
Old 8th May 2012, 10:26 AM   #6
diyAudio Member
 
Join Date: Dec 2005
Location: Plymouth, England
Quote:
Originally Posted by Enzo View Post
Drill? Ouch.
Why ouch? If I am missing something please let me know, as I don't want to damage my own boards.
  Reply With Quote
Old 8th May 2012, 11:13 PM   #7
Enzo is offline Enzo  United States
diyAudio Member
 
Join Date: Sep 2004
Location: Lansing, Michigan
We do what we have to do, of course. I never have had to drill out a solder filled hole. Just my opinion, it seems like potential for damage. A snagged trace can tear or lift.
  Reply With Quote
Old 9th May 2012, 04:36 AM   #8
diyAudio Member
 
Join Date: Nov 2009
Location: Los Angeles
Quote:
Originally Posted by awkwardbydesign View Post
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.
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'.

G
  Reply With Quote
Old 9th May 2012, 04:53 AM   #9
CBS240 is offline CBS240  United States
diyAudio Member
 
CBS240's Avatar
 
Join Date: Aug 2005
Location: K-town
A squeeze bulb to blow air through the hole when the solder is wetted with flux and melted with the iron. If the hole is really small, this may not work either, but usually a hole large enough for a through hole component can be blown out.
__________________
All the trouble I've ever been in started out as fun......
  Reply With Quote
Old 9th May 2012, 05:52 AM   #10
diyAudio Member
 
Join Date: Feb 2011
Default thru hole

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.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Drilling a hole lorriman Tubes / Valves 11 25th December 2011 04:19 PM
A hole in the suspension ziocalepino Full Range 19 4th March 2011 10:22 PM
Hole Saw or Router oublie Construction Tips 27 31st May 2010 06:20 AM
Hole drills TubeMack Tubes / Valves 36 14th June 2009 11:59 PM
Black hole? Nappylady Multi-Way 24 12th June 2004 11:26 AM


New To Site? Need Help?

All times are GMT. The time now is 02:59 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2