I have an old project where a relay is oddly stuck in a state with the
common rail connected to the normally open contact. I can only assume
that the two connections fused together during a high-current
transient. The relay breaks a connection between an audio amplifier
circuit and a subwoofer. I think my only choice is to replace the
relay. There is however a problem where the pins of the relay are
soldered to plated through-holes. This is making the relay nearly
impossible to remove without risking damaging the pcb. Does anyone
have any neat tricks to remove such a component safely?
Thanks

In article .com,
wrote:
I have an old project where a relay is oddly stuck in a state with the
common rail connected to the normally open contact. I can only assume
that the two connections fused together during a high-current
transient. The relay breaks a connection between an audio amplifier
circuit and a subwoofer. I think my only choice is to replace the
relay. There is however a problem where the pins of the relay are
soldered to plated through-holes. This is making the relay nearly
impossible to remove without risking damaging the pcb. Does anyone
have any neat tricks to remove such a component safely?

If using a desolder tool and solder braid still leaves it stuck it's often
best to carefully wreck the component so you can treat each pin
individually.

--
*Why is it that doctors call what they do "practice"?

Dave Plowman London SW
To e-mail, change noise into sound.

wrote in message
oups.com...
I have an old project where a relay is oddly stuck in a state with the
common rail connected to the normally open contact. I can only assume
that the two connections fused together during a high-current
transient. The relay breaks a connection between an audio amplifier
circuit and a subwoofer. I think my only choice is to replace the
relay. There is however a problem where the pins of the relay are
soldered to plated through-holes. This is making the relay nearly
impossible to remove without risking damaging the pcb. Does anyone
have any neat tricks to remove such a component safely?
Thanks


Make up a pyramidal truncated frustrum (Google) out of 4 pieces of tin-
plate, wired together. Mask off that area around the relay, with the
frustrum temporarily wired to the board. Mount board firmly in vice, near
the relay. Pull and wriggle the relay when you apply heat from a hot-air gun
directed into the frustrum.
If you don't believe it will work try the technique with plated thru comps
on a scrap board first. The hotter the air and quicker you are the better,
if board starts to discolour there is probably some other mechanical
restraint.


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

On 30 May, 09:44, wrote:

I have an old project where a relay is oddly stuck in a state with the
common rail connected to the normally open contact. I can only assume
that the two connections fused together during a high-current
transient. The relay breaks a connection between an audio amplifier
circuit and a subwoofer. I think my only choice is to replace the
relay. There is however a problem where the pins of the relay are
soldered to plated through-holes. This is making the relay nearly
impossible to remove without risking damaging the pcb. Does anyone
have any neat tricks to remove such a component safely?
Thanks

There is only one way: chop the relay up until you can get to each
pin, and desolder those individually.

I however would open the relay and file the contacts, far easier
option.


NT

N Cook wrote in message
...
wrote in message
oups.com...
I have an old project where a relay is oddly stuck in a state with the
common rail connected to the normally open contact. I can only assume
that the two connections fused together during a high-current
transient. The relay breaks a connection between an audio amplifier
circuit and a subwoofer. I think my only choice is to replace the
relay. There is however a problem where the pins of the relay are
soldered to plated through-holes. This is making the relay nearly
impossible to remove without risking damaging the pcb. Does anyone
have any neat tricks to remove such a component safely?
Thanks


Make up a pyramidal truncated frustrum (Google) out of 4 pieces of tin-
plate, wired together. Mask off that area around the relay, with the
frustrum temporarily wired to the board. Mount board firmly in vice, near
the relay. Pull and wriggle the relay when you apply heat from a hot-air
gun
directed into the frustrum.
If you don't believe it will work try the technique with plated thru comps
on a scrap board first. The hotter the air and quicker you are the better,
if board starts to discolour there is probably some other mechanical
restraint.


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/





As it happens, the last week I've been working on industrial boards with
plated-through soldering. Thick board so only tips of IC leads protrude,
very thin signal traces, traces to tiny pads on both sides of boards of same
pin in some cases and plated vias under ICs as well. I know if i'd used
"proper " vacuum assist desolder or butcher-and-remove single pins , many of
those traces/pads would have dislodged.
I had to sharpen the points of my large adapted circlip pliers to get the
extra purchase on the ends of these 14,16, and 28 pin ICs. Not one dislodged
track using a paint-strip hot-air gun. Next time i'll have to take some
before and after pics for the doubting thomases.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

In article ,
"N Cook" wrote:

N Cook wrote in message
...
wrote in message
oups.com...
I have an old project where a relay is oddly stuck in a state with the
common rail connected to the normally open contact. I can only assume
that the two connections fused together during a high-current
transient. The relay breaks a connection between an audio amplifier
circuit and a subwoofer. I think my only choice is to replace the
relay. There is however a problem where the pins of the relay are
soldered to plated through-holes. This is making the relay nearly
impossible to remove without risking damaging the pcb. Does anyone
have any neat tricks to remove such a component safely?
Thanks


Make up a pyramidal truncated frustrum (Google) out of 4 pieces of tin-
plate, wired together. Mask off that area around the relay, with the
frustrum temporarily wired to the board. Mount board firmly in vice, near
the relay. Pull and wriggle the relay when you apply heat from a hot-air
gun
directed into the frustrum.
If you don't believe it will work try the technique with plated thru comps
on a scrap board first. The hotter the air and quicker you are the better,
if board starts to discolour there is probably some other mechanical
restraint.


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/





As it happens, the last week I've been working on industrial boards with
plated-through soldering. Thick board so only tips of IC leads protrude,
very thin signal traces, traces to tiny pads on both sides of boards of same
pin in some cases and plated vias under ICs as well. I know if i'd used
"proper " vacuum assist desolder or butcher-and-remove single pins , many of
those traces/pads would have dislodged.
I had to sharpen the points of my large adapted circlip pliers to get the
extra purchase on the ends of these 14,16, and 28 pin ICs. Not one dislodged
track using a paint-strip hot-air gun. Next time i'll have to take some
before and after pics for the doubting thomases.

--

I'm not one of the doubting Thomases. Hot air works well. So do the
other methods, that you doubt. It's all about technique and finesse. The
professional desoldering stations work extremely well when used and
maintained properly, and virtually not at all otherwise. Blame the
operator.

wrote in message
ups.com...
There is only one way: chop the relay up until you can get to each
pin, and desolder those individually.

That's the way I'd do it.

On 30 May, 10:53, "N Cook" wrote:
wrote in message

oups.com...

I have an old project where a relay is oddly stuck in a state with the
common rail connected to the normally open contact. I can only assume
that the two connections fused together during a high-current
transient. The relay breaks a connection between an audio amplifier
circuit and a subwoofer. I think my only choice is to replace the
relay. There is however a problem where the pins of the relay are
soldered to plated through-holes. This is making the relay nearly
impossible to remove without risking damaging the pcb. Does anyone
have any neat tricks to remove such a component safely?
Thanks

Make up a pyramidal truncated frustrum (Google) out of 4 pieces of tin-
plate, wired together. Mask off that area around the relay, with the
frustrum temporarily wired to the board. Mount board firmly in vice, near
the relay. Pull and wriggle the relay when you apply heat from a hot-air gun
directed into the frustrum.
If you don't believe it will work try the technique with plated thru comps
on a scrap board first. The hotter the air and quicker you are the better,
if board starts to discolour there is probably some other mechanical
restraint.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list onhttp://home.graffiti.net/diverse:graffiti.net/

I would just leave it as it is rather than knacker the board

On May 30, 8:31 am, Meat Plow wrote:
On Wed, 30 May 2007 16:22:34 +0100, CWatters wrote:

wrote in message
oups.com...
There is only one way: chop the relay up until you can get to each
pin, and desolder those individually.

That's the way I'd do it.

That's the way I've done it.

Any recommendations on how to "chop up" the relay?
Its a sealed plastic type.

wrote:

On May 30, 8:31 am, Meat Plow wrote:
On Wed, 30 May 2007 16:22:34 +0100, CWatters wrote:

wrote in message
oups.com...
There is only one way: chop the relay up until you can get to each
pin, and desolder those individually.

That's the way I'd do it.

That's the way I've done it.

Any recommendations on how to "chop up" the relay?
Its a sealed plastic type.


Are the pins smaller than the plated through holes. or are they a
tight fit? If there is any free space you can remove the solder, then
heat the pin till the solder melts and gently bend it loose from the
wall of the plate through hole. I've done it that way for decades, but
you should practice on a scrap board first.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

On Thu, 31 May 2007 18:48:04 -0700, the renowned
wrote:

On May 30, 8:31 am, Meat Plow wrote:
On Wed, 30 May 2007 16:22:34 +0100, CWatters wrote:

wrote in message
oups.com...
There is only one way: chop the relay up until you can get to each
pin, and desolder those individually.

That's the way I'd do it.

That's the way I've done it.

Any recommendations on how to "chop up" the relay?
Its a sealed plastic type.

Sharp cutters like these: http://www.wassco.com/shearcutters.html

Cut into it from the top and keep cutting stuff away until just the
pins are left. Be careful cutting away the plastic bottom that you
don't scratch through traces or otherwise accidentally damage the
board.

If you have a *good* desoldering tool (with a vane pump etc.) it may
be possible to suck almost all the solder out of the holes so they
break away when wiggled without damaging the plated-through holes, but
it's not always possible, and it runs more risk even with good tools
and even if you have just cleaned the tool out.

On Thu, 31 May 2007 23:09:17 -0500, Spehro Pefhany wrote:

On Thu, 31 May 2007 18:48:04 -0700, the renowned
wrote:

On May 30, 8:31 am, Meat Plow wrote:
On Wed, 30 May 2007 16:22:34 +0100, CWatters wrote:

wrote in message
oups.com...
There is only one way: chop the relay up until you can get to each
pin, and desolder those individually.

That's the way I'd do it.

That's the way I've done it.

Any recommendations on how to "chop up" the relay?
Its a sealed plastic type.

Sharp cutters like these: http://www.wassco.com/shearcutters.html

Cut into it from the top and keep cutting stuff away until just the
pins are left. Be careful cutting away the plastic bottom that you
don't scratch through traces or otherwise accidentally damage the
board.

If you have a *good* desoldering tool (with a vane pump etc.) it may
be possible to suck almost all the solder out of the holes so they
break away when wiggled without damaging the plated-through holes, but
it's not always possible, and it runs more risk even with good tools
and even if you have just cleaned the tool out.

I've used a Dremel tool to remove relays, as well as other components, by
cutting them to pieces, carefully, of course. Then I unsolder one pin at a
time. Unless you need to do failure analysis on the bad part.

Al

Which bit do you use? A grinder or a saw bit

I've used a Dremel tool to remove relays, as well as other components, by
cutting them to pieces, carefully, of course. Then I unsolder one pin at a
time. Unless you need to do failure analysis on the bad part.

Al- Hide quoted text -

- Show quoted text -

On 2 Jun, 05:12, wrote:

Which bit do you use? A grinder or a saw bit



I've used a Dremel tool to remove relays, as well as other components, by
cutting them to pieces, carefully, of course. Then I unsolder one pin at a
time. Unless you need to do failure analysis on the bad part.

Cutting off the relay is the hard bit, as many have quite hefty bits
of steel in them. A cutting wheel in a die grinder (aka dremel) works,
but can be slow.


NT

wrote:
On 2 Jun, 05:12, wrote:

Which bit do you use? A grinder or a saw bit



I've used a Dremel tool to remove relays, as well as other components, by
cutting them to pieces, carefully, of course. Then I unsolder one pin at a
time. Unless you need to do failure analysis on the bad part.

Cutting off the relay is the hard bit, as many have quite hefty bits
of steel in them. A cutting wheel in a die grinder (aka dremel) works,
but can be slow.


My own method would be a good hot iron, plenty of solder braid and a lot
of patience.

Ron(UK)

On Sun, 03 Jun 2007 14:04:16 +0100, "Ron(UK)"
wrote:

wrote:
On 2 Jun, 05:12, wrote:

Which bit do you use? A grinder or a saw bit



I've used a Dremel tool to remove relays, as well as other components, by
cutting them to pieces, carefully, of course. Then I unsolder one pin at a
time. Unless you need to do failure analysis on the bad part.

Cutting off the relay is the hard bit, as many have quite hefty bits
of steel in them. A cutting wheel in a die grinder (aka dremel) works,
but can be slow.


My own method would be a good hot iron, plenty of solder braid and a lot
of patience.

Ron(UK)

I've often found that in a pinch, you can wick the solder out, re-fill
the holes with new solder, re wick the holes. Sometimes the
re-filling process can reflow the whole joint instead of wicking out
the top half and the bottom never gets hot enough. Of course, not
perfect, and should be done on a scrap board.

Steve

Steve wrote:


I've often found that in a pinch, you can wick the solder out, re-fill
the holes with new solder, re wick the holes. Sometimes the
re-filling process can reflow the whole joint instead of wicking out
the top half and the bottom never gets hot enough. Of course, not
perfect, and should be done on a scrap board.

That`s true. One of the things novices do wrong is to wick off most of
the solder, but leave a little behind deep in the hole, that wont be
drawn up into the solder braid. Then they get impatient and try to rip
the component out damaging the board in the process.

There needs to be enough solder to easily wick up into the braid, and
the iron need to be hot enough to melt all the solder in the joint
through the braid or there`s a chance that pulling the braid away takes
some of the pad with it.

There`s as much an art to desoldering as there is to soldering. (IMO)

Ron(UK)

"Ron(UK)" wrote:

Steve wrote:


I've often found that in a pinch, you can wick the solder out, re-fill
the holes with new solder, re wick the holes. Sometimes the
re-filling process can reflow the whole joint instead of wicking out
the top half and the bottom never gets hot enough. Of course, not
perfect, and should be done on a scrap board.

That`s true. One of the things novices do wrong is to wick off most of
the solder, but leave a little behind deep in the hole, that wont be
drawn up into the solder braid. Then they get impatient and try to rip
the component out damaging the board in the process.

There needs to be enough solder to easily wick up into the braid, and
the iron need to be hot enough to melt all the solder in the joint
through the braid or there`s a chance that pulling the braid away takes
some of the pad with it.

There`s as much an art to desoldering as there is to soldering. (IMO)

Ron(UK)



The solder used for wave soldering is 80/20 and has a higher melting
temperature. By removing what solder you can, then adding fresh 60/40
you move the melting point to somewhere in between, which then can be
either vacuum desoldered or removed with solder wick and a drop of
liquid rosin flux.

80/20 is used for wave soldering, because it has a very narrow
temperature range where it is in a plastic state. this reduces cold
solder joints, by not giving the leads a chance to move while the solder
passes through this state.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

In article ,
"Michael A. Terrell" wrote:

"Ron(UK)" wrote:

Steve wrote:


I've often found that in a pinch, you can wick the solder out, re-fill
the holes with new solder, re wick the holes. Sometimes the
re-filling process can reflow the whole joint instead of wicking out
the top half and the bottom never gets hot enough. Of course, not
perfect, and should be done on a scrap board.

That`s true. One of the things novices do wrong is to wick off most of
the solder, but leave a little behind deep in the hole, that wont be
drawn up into the solder braid. Then they get impatient and try to rip
the component out damaging the board in the process.

There needs to be enough solder to easily wick up into the braid, and
the iron need to be hot enough to melt all the solder in the joint
through the braid or there`s a chance that pulling the braid away takes
some of the pad with it.

There`s as much an art to desoldering as there is to soldering. (IMO)

Ron(UK)



The solder used for wave soldering is 80/20 and has a higher melting
temperature. By removing what solder you can, then adding fresh 60/40
you move the melting point to somewhere in between, which then can be
either vacuum desoldered or removed with solder wick and a drop of
liquid rosin flux.

80/20 is used for wave soldering, because it has a very narrow
temperature range where it is in a plastic state. this reduces cold
solder joints, by not giving the leads a chance to move while the solder
passes through this state.

80/20? 60/40? What kind of solder are you talking about? Eutectic
tin/lead is 63/37 and used in both hand and automated soldering.

Smitty Two wrote:

In article ,
"Michael A. Terrell" wrote:

"Ron(UK)" wrote:

Steve wrote:


I've often found that in a pinch, you can wick the solder out, re-fill
the holes with new solder, re wick the holes. Sometimes the
re-filling process can reflow the whole joint instead of wicking out
the top half and the bottom never gets hot enough. Of course, not
perfect, and should be done on a scrap board.

That`s true. One of the things novices do wrong is to wick off most of
the solder, but leave a little behind deep in the hole, that wont be
drawn up into the solder braid. Then they get impatient and try to rip
the component out damaging the board in the process.

There needs to be enough solder to easily wick up into the braid, and
the iron need to be hot enough to melt all the solder in the joint
through the braid or there`s a chance that pulling the braid away takes
some of the pad with it.

There`s as much an art to desoldering as there is to soldering. (IMO)

Ron(UK)



The solder used for wave soldering is 80/20 and has a higher melting
temperature. By removing what solder you can, then adding fresh 60/40
you move the melting point to somewhere in between, which then can be
either vacuum desoldered or removed with solder wick and a drop of
liquid rosin flux.

80/20 is used for wave soldering, because it has a very narrow
temperature range where it is in a plastic state. this reduces cold
solder joints, by not giving the leads a chance to move while the solder
passes through this state.

80/20? 60/40? What kind of solder are you talking about? Eutectic
tin/lead is 63/37 and used in both hand and automated soldering.


Really? I want proof. If 63/37 is the only solder used, please
explain to everyone WHY there are so many different solder alloys sold
for electronics. I have NEVER seen a wave solder machine filled with
eutectic solder. 80/20 was used in all the wave solder machines I've
seen because it has a higher melting temperature and goes from liquid to
solid almost immediately.

I shouldn't have included the reflow process, because there is too
damn many low temp plastics used in SMD components these days. Earlier
boards only had the resistors, capacitors and semiconductors reflowed,
which could use higher temperature solders. Now there are lots of
crappy SMD connectors, pots and relays that require a lot more work to
create a workable reflow profile for the oven. Every board design has
to be evaluated, and a custom profile created for that assembly. We had
over three hundred profiles stored on the Heller oven when I left
Microdyne, all sorted by assembly/stock number.

They kept changing the paste solder for reflow, and replaced the two
original ovens with the computer controlled Heller so I couldn't keep up
with all the variations in alloys, ball sizes and fluxes. It seemed
like as soon as we found paste solder that worked right, we couldn't get
more of it, and had to start looking again. I know that the solder I
used for rework was .015" 60/40.

http://www.kester.com/en-us/technical/alloy.aspx is a chart of alloys
currently available from Kester. They list 13 various tin/lead alloys.

--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

Steve wrote in
:

On Sun, 03 Jun 2007 14:04:16 +0100, "Ron(UK)"
wrote:

wrote:
On 2 Jun, 05:12, wrote:

Which bit do you use? A grinder or a saw bit



I've used a Dremel tool to remove relays, as well as other
components, by cutting them to pieces, carefully, of course. Then
I unsolder one pin at a time. Unless you need to do failure
analysis on the bad part.

Cutting off the relay is the hard bit, as many have quite hefty bits
of steel in them. A cutting wheel in a die grinder (aka dremel)
works, but can be slow.


My own method would be a good hot iron, plenty of solder braid and a
lot of patience.

Ron(UK)

I've often found that in a pinch, you can wick the solder out, re-fill
the holes with new solder, re wick the holes. Sometimes the
re-filling process can reflow the whole joint instead of wicking out
the top half and the bottom never gets hot enough. Of course, not
perfect, and should be done on a scrap board.

Steve


maybe use some very low melting point solder like ChipQuik?
And a vacuum desoldering tool.

--
Jim Yanik
jyanik
at
kua.net

In article ,
"Michael A. Terrell" wrote:

Smitty Two wrote:

In article ,
"Michael A. Terrell" wrote:

"Ron(UK)" wrote:

Steve wrote:


I've often found that in a pinch, you can wick the solder out, re-fill
the holes with new solder, re wick the holes. Sometimes the
re-filling process can reflow the whole joint instead of wicking out
the top half and the bottom never gets hot enough. Of course, not
perfect, and should be done on a scrap board.

That`s true. One of the things novices do wrong is to wick off most of
the solder, but leave a little behind deep in the hole, that wont be
drawn up into the solder braid. Then they get impatient and try to rip
the component out damaging the board in the process.

There needs to be enough solder to easily wick up into the braid, and
the iron need to be hot enough to melt all the solder in the joint
through the braid or there`s a chance that pulling the braid away takes
some of the pad with it.

There`s as much an art to desoldering as there is to soldering. (IMO)

Ron(UK)



The solder used for wave soldering is 80/20 and has a higher melting
temperature. By removing what solder you can, then adding fresh 60/40
you move the melting point to somewhere in between, which then can be
either vacuum desoldered or removed with solder wick and a drop of
liquid rosin flux.

80/20 is used for wave soldering, because it has a very narrow
temperature range where it is in a plastic state. this reduces cold
solder joints, by not giving the leads a chance to move while the solder
passes through this state.

80/20? 60/40? What kind of solder are you talking about? Eutectic
tin/lead is 63/37 and used in both hand and automated soldering.


Really? I want proof. If 63/37 is the only solder used, please
explain to everyone WHY there are so many different solder alloys sold
for electronics. I have NEVER seen a wave solder machine filled with
eutectic solder. 80/20 was used in all the wave solder machines I've
seen because it has a higher melting temperature and goes from liquid to
solid almost immediately.

I shouldn't have included the reflow process, because there is too
damn many low temp plastics used in SMD components these days. Earlier
boards only had the resistors, capacitors and semiconductors reflowed,
which could use higher temperature solders. Now there are lots of
crappy SMD connectors, pots and relays that require a lot more work to
create a workable reflow profile for the oven. Every board design has
to be evaluated, and a custom profile created for that assembly. We had
over three hundred profiles stored on the Heller oven when I left
Microdyne, all sorted by assembly/stock number.

They kept changing the paste solder for reflow, and replaced the two
original ovens with the computer controlled Heller so I couldn't keep up
with all the variations in alloys, ball sizes and fluxes. It seemed
like as soon as we found paste solder that worked right, we couldn't get
more of it, and had to start looking again. I know that the solder I
used for rework was .015" 60/40.

http://www.kester.com/en-us/technical/alloy.aspx is a chart of alloys
currently available from Kester. They list 13 various tin/lead alloys.

Yes there are many alloys of solder. 60/40 was the standard for some
time but was replaced 20 years ago by 63/37. That is the only tin/lead
ratio that is eutectic and has been the industry standard for all
soldering AFAIK, for at least 20 years. You may have used 80/20 for some
reason, but it certainly isn't eutectic.

Smitty Two wrote:

Yes there are many alloys of solder. 60/40 was the standard for some
time but was replaced 20 years ago by 63/37. That is the only tin/lead
ratio that is eutectic and has been the industry standard for all
soldering AFAIK, for at least 20 years. You may have used 80/20 for some
reason, but it certainly isn't eutectic.


I never claimed that it was.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

In article ,
"Michael A. Terrell" wrote:

Smitty Two wrote:

Yes there are many alloys of solder. 60/40 was the standard for some
time but was replaced 20 years ago by 63/37. That is the only tin/lead
ratio that is eutectic and has been the industry standard for all
soldering AFAIK, for at least 20 years. You may have used 80/20 for some
reason, but it certainly isn't eutectic.


I never claimed that it was.

Well, you wrote:

"80/20 is used for wave soldering, because it has a very narrow
temperature range where it is in a plastic state. this reduces cold
solder joints, by not giving the leads a chance to move while the solder
passes through this state."



If that isn't the definition of eutectic, than you have my apology for
being wrong yet again.

In article
,
Smitty Two wrote:

In article ,
"Michael A. Terrell" wrote:

Smitty Two wrote:

Yes there are many alloys of solder. 60/40 was the standard for some
time but was replaced 20 years ago by 63/37. That is the only tin/lead
ratio that is eutectic and has been the industry standard for all
soldering AFAIK, for at least 20 years. You may have used 80/20 for some
reason, but it certainly isn't eutectic.


I never claimed that it was.

Well, you wrote:

"80/20 is used for wave soldering, because it has a very narrow
temperature range where it is in a plastic state. this reduces cold
solder joints, by not giving the leads a chance to move while the solder
passes through this state."



If that isn't the definition of eutectic, than you have my apology for
being wrong yet again.

Defintion of eutectic:

"The lowest temperature at which a mix of two materials will melt. Often
the temperature is an anomaly, that is, it is much lower than the
melting temperatures of only slightly different mixtures. Lead-tin
solder is an example. Lead melts at 327C, tin at 231C. The lowest
melting combination is 67 lead, 33 tin (180C). Non-eutectic mixtures
have a melting or softening range. Such mixtures do not flow well until
thoroughly heated past the softening range."

Jeesh, get a dictionary.

Al

"Al" wrote in message
...
Defintion of eutectic:

"The lowest temperature at which a mix of two materials will melt. Often
the temperature is an anomaly, that is, it is much lower than the
melting temperatures of only slightly different mixtures. Lead-tin
solder is an example. Lead melts at 327C, tin at 231C. The lowest
melting combination is 67 lead, 33 tin (180C). Non-eutectic mixtures
have a melting or softening range. Such mixtures do not flow well until
thoroughly heated past the softening range."

Jeesh, get a dictionary.

Al

I thought it was 67% TIN and 37% lead.

David

In article ,
Al wrote:

In article
,
Smitty Two wrote:

In article ,
"Michael A. Terrell" wrote:

Smitty Two wrote:

Yes there are many alloys of solder. 60/40 was the standard for some
time but was replaced 20 years ago by 63/37. That is the only tin/lead
ratio that is eutectic and has been the industry standard for all
soldering AFAIK, for at least 20 years. You may have used 80/20 for some
reason, but it certainly isn't eutectic.


I never claimed that it was.

Well, you wrote:

"80/20 is used for wave soldering, because it has a very narrow
temperature range where it is in a plastic state. this reduces cold
solder joints, by not giving the leads a chance to move while the solder
passes through this state."



If that isn't the definition of eutectic, than you have my apology for
being wrong yet again.

Defintion of eutectic:

"The lowest temperature at which a mix of two materials will melt. Often
the temperature is an anomaly, that is, it is much lower than the
melting temperatures of only slightly different mixtures. Lead-tin
solder is an example. Lead melts at 327C, tin at 231C. The lowest
melting combination is 67 lead, 33 tin (180C). Non-eutectic mixtures
have a melting or softening range. Such mixtures do not flow well until
thoroughly heated past the softening range."

Jeesh, get a dictionary.

Al


Exactly: "Non-eutectic mixtures have a melting or softening range." This
is what causes the "cold solder" problem when components are moved
slightly as the solder cools. In the eutectic (63/37) alloy of tin and
lead, the melting temperature and the freezing temperature are the same.
THAT is the relevant part of the definition as it relates to soldering.

Sheesh, learn how to read and comprehend your dictionary.

Jon

In article ,
"David" wrote:

"Al" wrote in message
...
Defintion of eutectic:

"The lowest temperature at which a mix of two materials will melt. Often
the temperature is an anomaly, that is, it is much lower than the
melting temperatures of only slightly different mixtures. Lead-tin
solder is an example. Lead melts at 327C, tin at 231C. The lowest
melting combination is 67 lead, 33 tin (180C). Non-eutectic mixtures
have a melting or softening range. Such mixtures do not flow well until
thoroughly heated past the softening range."

Jeesh, get a dictionary.

Al

I thought it was 67% TIN and 37% lead.

David

That's your high tech military alloy, 104% total. Not allowed for
commercial applications. But you're a lot closer than the dictionary
reader. 63 tin, 37 lead.

Smitty Two wrote in
news
In article ,
Al wrote:

In article
,
Smitty Two wrote:

In article ,
"Michael A. Terrell" wrote:

Smitty Two wrote:

Yes there are many alloys of solder. 60/40 was the standard for
some time but was replaced 20 years ago by 63/37. That is the
only tin/lead ratio that is eutectic and has been the industry
standard for all soldering AFAIK, for at least 20 years. You
may have used 80/20 for some reason, but it certainly isn't
eutectic.


I never claimed that it was.

Well, you wrote:

"80/20 is used for wave soldering, because it has a very narrow
temperature range where it is in a plastic state. this reduces
cold solder joints, by not giving the leads a chance to move while
the solder passes through this state."



If that isn't the definition of eutectic, than you have my apology
for being wrong yet again.

Defintion of eutectic:

"The lowest temperature at which a mix of two materials will melt.
Often the temperature is an anomaly, that is, it is much lower than
the melting temperatures of only slightly different mixtures.
Lead-tin solder is an example. Lead melts at 327C, tin at 231C. The
lowest melting combination is 67 lead, 33 tin (180C). Non-eutectic
mixtures have a melting or softening range. Such mixtures do not flow
well until thoroughly heated past the softening range."

Jeesh, get a dictionary.

Al


Exactly: "Non-eutectic mixtures have a melting or softening range."
This is what causes the "cold solder" problem when components are
moved slightly as the solder cools. In the eutectic (63/37) alloy of
tin and lead, the melting temperature and the freezing temperature are
the same. THAT is the relevant part of the definition as it relates to
soldering.

Sheesh, learn how to read and comprehend your dictionary.

Jon


That is how Tektronix explained it to it's techs when they converted from
60/40 to eutectic 63/37 solder.Eutectic has a narrower plastic range.
Now,that is for repair work,I do not know what TEK used in its
wavesoldering lines.it makes sense ot use a eutectic alloy on them,too,as
motion would have a greater effect on a partially soldified joint.

for REMOVING that relay,I'd use ChipQuik or similar alloy,the joint would
melt at around 200 something degrees F,MUCH less chance to apply too much
heat to the PCB.

You would think that solder makers would offer an alloy similar to ChipQuik
for this purpose,at a more reasonable price,maybe in a 1/2 lb spool.

--
Jim Yanik
jyanik
at
kua.net

I thought it was 67% TIN and 37% lead.

David

That's your high tech military alloy, 104% total. Not allowed for
commercial applications. But you're a lot closer than the dictionary
reader. 63 tin, 37 lead.

(Blushing) I guess spell checkers do not perform arithmetic checks. Thanks
for correcting this.

David

On May 30, 5:53 am, "N Cook" wrote:
wrote in message

oups.com...

I have an old project where a relay is oddly stuck in a state with the
common rail connected to the normally open contact. I can only assume
that the two connections fused together during a high-current
transient. The relay breaks a connection between an audio amplifier
circuit and a subwoofer. I think my only choice is to replace the
relay. There is however a problem where the pins of the relay are
soldered to plated through-holes. This is making the relay nearly
impossible to remove without risking damaging the pcb. Does anyone
have any neat tricks to remove such a component safely?
Thanks

Make up a pyramidal truncated frustrum (Google) out of 4 pieces of tin-
plate, wired together. Mask off that area around the relay, with the
frustrum temporarily wired to the board. Mount board firmly in vice, near
the relay. Pull and wriggle the relay when you apply heat from a hot-air gun
directed into the frustrum.
If you don't believe it will work try the technique with plated thru comps
on a scrap board first. The hotter the air and quicker you are the better,
if board starts to discolour there is probably some other mechanical
restraint.


We just usually use the hot air bonder. Sorry had to go there.
--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list onhttp://home.graffiti.net/diverse:graffiti.net/

On 3 Jun 2007 18:22:01 GMT, Jim Yanik wrote:

Steve wrote in
:

On Sun, 03 Jun 2007 14:04:16 +0100, "Ron(UK)"
wrote:

wrote:
On 2 Jun, 05:12, wrote:

Which bit do you use? A grinder or a saw bit



I've used a Dremel tool to remove relays, as well as other
components, by cutting them to pieces, carefully, of course. Then
I unsolder one pin at a time. Unless you need to do failure
analysis on the bad part.

Cutting off the relay is the hard bit, as many have quite hefty bits
of steel in them. A cutting wheel in a die grinder (aka dremel)
works, but can be slow.


My own method would be a good hot iron, plenty of solder braid and a
lot of patience.

Ron(UK)

I've often found that in a pinch, you can wick the solder out, re-fill
the holes with new solder, re wick the holes. Sometimes the
re-filling process can reflow the whole joint instead of wicking out
the top half and the bottom never gets hot enough. Of course, not
perfect, and should be done on a scrap board.

Steve


maybe use some very low melting point solder like ChipQuik?
And a vacuum desoldering tool.

I got lucky and we have a nice Pace desoldering station at work, makes
easy work for most items. But, I still have quite a few rolls of
different sized wicks for that fun special occasion, or SM work.

Steve wrote in
:

On 3 Jun 2007 18:22:01 GMT, Jim Yanik wrote:

Steve wrote in
m:

On Sun, 03 Jun 2007 14:04:16 +0100, "Ron(UK)"
wrote:

wrote:
On 2 Jun, 05:12, wrote:

Which bit do you use? A grinder or a saw bit



I've used a Dremel tool to remove relays, as well as other
components, by cutting them to pieces, carefully, of course. Then
I unsolder one pin at a time. Unless you need to do failure
analysis on the bad part.

Cutting off the relay is the hard bit, as many have quite hefty bits
of steel in them. A cutting wheel in a die grinder (aka dremel)
works, but can be slow.


My own method would be a good hot iron, plenty of solder braid and a
lot of patience.

Ron(UK)

I've often found that in a pinch, you can wick the solder out, re-fill
the holes with new solder, re wick the holes. Sometimes the
re-filling process can reflow the whole joint instead of wicking out
the top half and the bottom never gets hot enough. Of course, not
perfect, and should be done on a scrap board.

Steve


maybe use some very low melting point solder like ChipQuik?
And a vacuum desoldering tool.

I got lucky and we have a nice Pace desoldering station at work, makes
easy work for most items. But, I still have quite a few rolls of
different sized wicks for that fun special occasion, or SM work.


In TEK's SMD training class,we used a newer Pace desoldering system(than
what we had back at the field office),and were told use of wick(or
Soldapult) would lift pads,as wick requires more heat to be applied for a
longer time.
The Pace tip was a lot different for SMD desoldering work.

--
Jim Yanik
jyanik
at
kua.net

On 9 Jun 2007 17:46:29 GMT, Jim Yanik wrote:

Steve wrote in
:

On 3 Jun 2007 18:22:01 GMT, Jim Yanik wrote:

Steve wrote in
:

On Sun, 03 Jun 2007 14:04:16 +0100, "Ron(UK)"
wrote:

wrote:
On 2 Jun, 05:12, wrote:

Which bit do you use? A grinder or a saw bit



I've used a Dremel tool to remove relays, as well as other
components, by cutting them to pieces, carefully, of course. Then
I unsolder one pin at a time. Unless you need to do failure
analysis on the bad part.

Cutting off the relay is the hard bit, as many have quite hefty bits
of steel in them. A cutting wheel in a die grinder (aka dremel)
works, but can be slow.


My own method would be a good hot iron, plenty of solder braid and a
lot of patience.

Ron(UK)

I've often found that in a pinch, you can wick the solder out, re-fill
the holes with new solder, re wick the holes. Sometimes the
re-filling process can reflow the whole joint instead of wicking out
the top half and the bottom never gets hot enough. Of course, not
perfect, and should be done on a scrap board.

Steve


maybe use some very low melting point solder like ChipQuik?
And a vacuum desoldering tool.

I got lucky and we have a nice Pace desoldering station at work, makes
easy work for most items. But, I still have quite a few rolls of
different sized wicks for that fun special occasion, or SM work.


In TEK's SMD training class,we used a newer Pace desoldering system(than
what we had back at the field office),and were told use of wick(or
Soldapult) would lift pads,as wick requires more heat to be applied for a
longer time.
The Pace tip was a lot different for SMD desoldering work.

We have a very small budget where I work, the smd tip we have is just
a very fine point tip instead of one of the chip-size special tips. I
mainly use the desoldering tool for thru-hole items, especially
tedious ones like 40 pin IC's. I have lifted a few SM pads, but for
the most part as long as I'm careful the fine tip and good quality
wick do just fine. I've used tech-spray no clean wick with some good
results. I had quite a few rolls of some cheaper wick, and the flux
on the wick must have gone bad, the solder just doesn't flow to the
wick anymore. I've heard solder and wick have a shelf life, I guess I
didn't used to believe it until I saw it first-hand.

Steve

In article ,
Steve wrote:

On 9 Jun 2007 17:46:29 GMT, Jim Yanik wrote:

Steve wrote in
:

On 3 Jun 2007 18:22:01 GMT, Jim Yanik wrote:

Steve wrote in
:

On Sun, 03 Jun 2007 14:04:16 +0100, "Ron(UK)"
wrote:

wrote:
On 2 Jun, 05:12, wrote:

Which bit do you use? A grinder or a saw bit



I've used a Dremel tool to remove relays, as well as other
components, by cutting them to pieces, carefully, of course. Then
I unsolder one pin at a time. Unless you need to do failure
analysis on the bad part.

Cutting off the relay is the hard bit, as many have quite hefty bits
of steel in them. A cutting wheel in a die grinder (aka dremel)
works, but can be slow.


My own method would be a good hot iron, plenty of solder braid and a
lot of patience.

Ron(UK)

I've often found that in a pinch, you can wick the solder out, re-fill
the holes with new solder, re wick the holes. Sometimes the
re-filling process can reflow the whole joint instead of wicking out
the top half and the bottom never gets hot enough. Of course, not
perfect, and should be done on a scrap board.

Steve


maybe use some very low melting point solder like ChipQuik?
And a vacuum desoldering tool.

I got lucky and we have a nice Pace desoldering station at work, makes
easy work for most items. But, I still have quite a few rolls of
different sized wicks for that fun special occasion, or SM work.


In TEK's SMD training class,we used a newer Pace desoldering system(than
what we had back at the field office),and were told use of wick(or
Soldapult) would lift pads,as wick requires more heat to be applied for a
longer time.
The Pace tip was a lot different for SMD desoldering work.

We have a very small budget where I work, the smd tip we have is just
a very fine point tip instead of one of the chip-size special tips. I
mainly use the desoldering tool for thru-hole items, especially
tedious ones like 40 pin IC's. I have lifted a few SM pads, but for
the most part as long as I'm careful the fine tip and good quality
wick do just fine. I've used tech-spray no clean wick with some good
results. I had quite a few rolls of some cheaper wick, and the flux
on the wick must have gone bad, the solder just doesn't flow to the
wick anymore. I've heard solder and wick have a shelf life, I guess I
didn't used to believe it until I saw it first-hand.

Steve

You might be able to reactivate the wick using electronic grade
isopropyl alcohol. Just put a drop on a length, wipe it clean and try it
out on a scrap board.

Al

Al wrote:

You might be able to reactivate the wick using electronic grade
isopropyl alcohol. Just put a drop on a length, wipe it clean and try it
out on a scrap board.


All that will do is remove even more flux.

Get some good liquid RMA flux (I use Kester 1544) and wet wick it.
Touch the end of the wick to the flux, and use it that way. It will do
less damage than dry wicking. Also, leaving about 1/8" of used wick when
you trim it makes it work better.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

On Sun, 10 Jun 2007 18:00:35 GMT, "Michael A. Terrell"
wrote:

Al wrote:

You might be able to reactivate the wick using electronic grade
isopropyl alcohol. Just put a drop on a length, wipe it clean and try it
out on a scrap board.


All that will do is remove even more flux.

Get some good liquid RMA flux (I use Kester 1544) and wet wick it.
Touch the end of the wick to the flux, and use it that way. It will do
less damage than dry wicking. Also, leaving about 1/8" of used wick when
you trim it makes it work better.

I'll try it. May be worth a shot to save a few bucks.
Steve

Steve wrote:

On Sun, 10 Jun 2007 18:00:35 GMT, "Michael A. Terrell"
wrote:

Al wrote:

You might be able to reactivate the wick using electronic grade
isopropyl alcohol. Just put a drop on a length, wipe it clean and try it
out on a scrap board.


All that will do is remove even more flux.

Get some good liquid RMA flux (I use Kester 1544) and wet wick it.
Touch the end of the wick to the flux, and use it that way. It will do
less damage than dry wicking. Also, leaving about 1/8" of used wick when
you trim it makes it work better.

I'll try it. May be worth a shot to save a few bucks.
Steve


I've only bought about 15 feet of solder wick in the last 20 years
but I've made, and used, thousands of feet from scrapped bare copper
braided Cable TV converter cables that I replaced.

I could pull the two insulated wires and paper filler out of the
braid, then pull out the braid from a 21 foot cable. By the time it was
flattened out and wound on a spool, it was a little over 25 feet by
approx. 3/16". I had about 500 bad cables when I moved to Florida, 20
years ago.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

On May 30, 4:44 am, wrote:
I have an old project where a relay is oddly stuck in a state with the
common rail connected to the normally open contact. I can only assume
that the two connections fused together during a high-current
transient. The relay breaks a connection between an audio amplifier
circuit and a subwoofer. I think my only choice is to replace the
relay. There is however a problem where the pins of the relay are
soldered to plated through-holes. This is making the relay nearly
impossible to remove without risking damaging the pcb. Does anyone
have any neat tricks to remove such a component safely?
Thanks

Carefully destroy the relay without damaging the circuit board so that
you have the stubs of the leads still sticking out from the PC board,
then solder to them. if you're lucky, there'll be enough leads exposed
so that you can just cut them and leave enough stub.