Removing rubbery potting compound

S

Sam Goldwasser

Guest
This type is usually dark gray and soft - about the consistency of a pencil
eraser, maybe a bit tougher. It can be removed laboriously with knives,
picks, and elbow grease. But the question is whether there is some easier
way to do this that would leave the underlying components undamaged.
This stuff is used in a variety of places including PCBs and laser
tube assemblies. Both of these are of interest to me. Modest heat
has no effect including immersing in boiling water - it's not hot-melt glue.

Thanks!

--
sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
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| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

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Sam Goldwasser <sam@ampersand.seas.upenn.edu> wrote in
news:6wws755z1c.fsf@ampersand.seas.upenn.edu:

This type is usually dark gray and soft - about the consistency of a
pencil eraser, maybe a bit tougher. It can be removed laboriously with
knives, picks, and elbow grease. But the question is whether there is
some easier way to do this that would leave the underlying components
undamaged. This stuff is used in a variety of places including PCBs and
laser tube assemblies. Both of these are of interest to me. Modest
heat has no effect including immersing in boiling water - it's not
hot-melt glue.
Click to expand...
I think you need a tin of grey rubbery stuff remover.
 
Lostgallifreyan <no-one@nowhere.net> writes:

Sam Goldwasser <sam@ampersand.seas.upenn.edu> wrote in
news:6wws755z1c.fsf@ampersand.seas.upenn.edu:

This type is usually dark gray and soft - about the consistency of a
pencil eraser, maybe a bit tougher. It can be removed laboriously with
knives, picks, and elbow grease. But the question is whether there is
some easier way to do this that would leave the underlying components
undamaged. This stuff is used in a variety of places including PCBs and
laser tube assemblies. Both of these are of interest to me. Modest
heat has no effect including immersing in boiling water - it's not
hot-melt glue.


I think you need a tin of grey rubbery stuff remover.
Click to expand...
HeHeHe... Do you charge BIG BUCKs for that advice, huh? :)

And, it probably rots internal organs.....

--
sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/
 
Sam Goldwasser <sam@ampersand.seas.upenn.edu> wrote in message
news:6wws755z1c.fsf@ampersand.seas.upenn.edu...
This type is usually dark gray and soft - about the consistency of a
pencil
eraser, maybe a bit tougher. It can be removed laboriously with knives,
picks, and elbow grease. But the question is whether there is some easier
way to do this that would leave the underlying components undamaged.
This stuff is used in a variety of places including PCBs and laser
tube assemblies. Both of these are of interest to me. Modest heat
has no effect including immersing in boiling water - it's not hot-melt
glue.

Thanks!

--
sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above
is
ignored unless my full name AND either lasers or electronics is included
in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.
Click to expand...

I seem to remember using a 1/8 inch ball mill in a Dremmel for that sort of
stuff, localised heat and tugging action hepled in removing from surfaces,
.. But still time consuming and you have to know there is no little vital
stuff buiried within it.


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/
 
Sam Goldwasser <sam@ampersand.seas.upenn.edu> wrote in
news:6wljnl5oxj.fsf@ampersand.seas.upenn.edu:

Lostgallifreyan <no-one@nowhere.net> writes:

Sam Goldwasser <sam@ampersand.seas.upenn.edu> wrote in
news:6wws755z1c.fsf@ampersand.seas.upenn.edu:

This type is usually dark gray and soft - about the consistency of a
pencil eraser, maybe a bit tougher. It can be removed laboriously with
knives, picks, and elbow grease. But the question is whether there is
some easier way to do this that would leave the underlying components
undamaged. This stuff is used in a variety of places including PCBs and
laser tube assemblies. Both of these are of interest to me. Modest
heat has no effect including immersing in boiling water - it's not
hot-melt glue.


I think you need a tin of grey rubbery stuff remover.

HeHeHe... Do you charge BIG BUCKs for that advice, huh? :)
Click to expand...
Oh yeah, I should, given what anything seems to cost the moment I need it...

Here's some for free though. Try snagging a bit and burning it, melting it,
putting it in chemicals, and comparing to some knowns. If it's silicone
you're SOL but a lot of other stuff might be attacked while the rest of the
parts sit looking as if they enjoy it because a lot of PCB washes are strong
stuff and most parts are designed to resist a lot. If you find something that
can edge its way between the stuff and the parts, you might be able to peel
it off. And if it's based on actual rubber try ozone to perish it fast so it
will crumble away.

And, it probably rots internal organs.....
Click to expand...
And what did you think the grey goop was made of? >:) Thpthpthp (That being
my best Hannibal Lecter impersonation, feeble though it may be).
 
Lostgallifreyan <no-one@nowhere.net> wrote in
news:Xns9C31E597F7238zoodlewurdle@216.196.109.145:

And if it's based on actual rubber try ozone to perish it fast so it
will crumble away.
Click to expand...
Likewise, strong shortwave UV might also help degrade it so it's easy to
remove.
 
"William Sommerwerck" <grizzledgeezer@comcast.net> wrote in
news:h1m3kv$pp3$1@news.eternal-september.org:

I think you need a tin of grey rubbery stuff remover.

Go back to your TARDIS.
Click to expand...
I would but I don't think it will have me.
 
"N_Cook" <diverse@tcp.co.uk> writes:

Sam Goldwasser <sam@ampersand.seas.upenn.edu> wrote in message
news:6wws755z1c.fsf@ampersand.seas.upenn.edu...
This type is usually dark gray and soft - about the consistency of a
pencil
eraser, maybe a bit tougher. It can be removed laboriously with knives,
picks, and elbow grease. But the question is whether there is some easier
way to do this that would leave the underlying components undamaged.
This stuff is used in a variety of places including PCBs and laser
tube assemblies. Both of these are of interest to me. Modest heat
has no effect including immersing in boiling water - it's not hot-melt
glue.

Thanks!

--
sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/

I seem to remember using a 1/8 inch ball mill in a Dremmel for that sort of
stuff, localised heat and tugging action hepled in removing from surfaces,
. But still time consuming and you have to know there is no little vital
stuff buiried within it.
Click to expand...
I've been using the mechanical approach. It is tedious and risky as
you note. But does work:

http://repairfaq.cis.upenn.edu/Misc/vmi373p1.jpg

However, some components were damaged (a graphics editing program
can work wonders!) and for what I really want, it is trickier
as the part being removed is a glass laser tube and much of the
potting material is in a space 2 or 3 mm thick surrounding the
tube, and running its entire length.

Thanks!

--
sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/
Click to expand...
 
De-Solv-It hardware stores
Eposolve, mcmaster carr is your friend.

Steve
 
Sam Goldwasser wrote:
This type is usually dark gray and soft - about the consistency of a pencil
eraser, maybe a bit tougher. It can be removed laboriously with knives,
picks, and elbow grease. But the question is whether there is some easier
way to do this that would leave the underlying components undamaged.
This stuff is used in a variety of places including PCBs and laser
tube assemblies. Both of these are of interest to me. Modest heat
has no effect including immersing in boiling water - it's not hot-melt glue.

Thanks!
Click to expand...

The best luck I've had is with simply picking the stuff off, you're
right though that it's no fun. I suspect it would become brittle at some
temperature, can you get your hands on some liquid nitrogen? If so, give
it a soak and smack it with something, hoping the components within do
not shatter as well. I'm curious to hear the results.
 
Sam Goldwasser <sam@ampersand.seas.upenn.edu> wrote in message
news:6w3a9t18ej.fsf@ampersand.seas.upenn.edu...
"N_Cook" <diverse@tcp.co.uk> writes:

Sam Goldwasser <sam@ampersand.seas.upenn.edu> wrote in message
news:6wws755z1c.fsf@ampersand.seas.upenn.edu...
This type is usually dark gray and soft - about the consistency of a
pencil
eraser, maybe a bit tougher. It can be removed laboriously with
knives,
picks, and elbow grease. But the question is whether there is some
easier
way to do this that would leave the underlying components undamaged.
This stuff is used in a variety of places including PCBs and laser
tube assemblies. Both of these are of interest to me. Modest heat
has no effect including immersing in boiling water - it's not hot-melt
glue.

Thanks!

--
sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/

I seem to remember using a 1/8 inch ball mill in a Dremmel for that
sort of
stuff, localised heat and tugging action hepled in removing from
surfaces,
. But still time consuming and you have to know there is no little vital
stuff buiried within it.

I've been using the mechanical approach. It is tedious and risky as
you note. But does work:

http://repairfaq.cis.upenn.edu/Misc/vmi373p1.jpg

However, some components were damaged (a graphics editing program
can work wonders!) and for what I really want, it is trickier
as the part being removed is a glass laser tube and much of the
potting material is in a space 2 or 3 mm thick surrounding the
tube, and running its entire length.

Thanks!

--
sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

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

What is the output level of the Cockcroft Walton circuit ?


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/
 
On Jun 21, 10:32 pm, James Sweet <jamesswe...@trashmail.net> wrote:
Sam Goldwasser wrote:
This type is usually dark gray and soft - about the consistency of a pencil
eraser, maybe a bit tougher.  It can be removed laboriously with knives,
picks, and elbow grease.  But the question is whether there is some easier
way to do this that would leave the underlying components undamaged.
This stuff is used in a variety of places including PCBs and laser
tube assemblies.  Both of these are of interest to me.  Modest heat
has no effect including immersing in boiling water - it's not hot-melt glue.  

Thanks!

The best luck I've had is with simply picking the stuff off, you're
right though that it's no fun. I suspect it would become brittle at some
temperature, can you get your hands on some liquid nitrogen? If so, give
it a soak and smack it with something, hoping the components within do
not shatter as well. I'm curious to hear the results.
Click to expand...
The rubbery tarry stuff that is used in older hene tube heads
dissolves in dichloromethane (DCM) used in paint strippers, The
silicone stuff is pretty impervious to all but mechanical attack.
 
heruursciences wrote:
The rubbery tarry stuff that is used in older hene tube heads
dissolves in dichloromethane (DCM) used in paint strippers, The
silicone stuff is pretty impervious to all but mechanical attack.
Click to expand...
FWIW There is a home decorating product called 'silicone eater' designed
for removing sealant from hard surfaces by dissolving it a little.

<http://www.cglass.co.uk/everbuild-everflex-silicone-eater-pr-17657.html>

--
Adrian C
 
James Sweet <jamessweet1@trashmail.net> writes:

Sam Goldwasser wrote:
This type is usually dark gray and soft - about the consistency of a pencil
eraser, maybe a bit tougher. It can be removed laboriously with knives,
picks, and elbow grease. But the question is whether there is some easier
way to do this that would leave the underlying components undamaged.
This stuff is used in a variety of places including PCBs and laser
tube assemblies. Both of these are of interest to me. Modest heat
has no effect including immersing in boiling water - it's not
hot-melt glue.

Thanks!

The best luck I've had is with simply picking the stuff off, you're
right though that it's no fun. I suspect it would become brittle at
some temperature, can you get your hands on some liquid nitrogen? If
so, give it a soak and smack it with something, hoping the components
within do not shatter as well. I'm curious to hear the results.
Click to expand...
That might work for the PCBs, though what will it do to the components?

However, what I really need to remove it from are special HeNe laser tube
assemblies. Not the common laser heads, but ones where the tube is totally
surrounded by the stuff as well as in front and back. So, the tube will
still be stuck inside surrounded by brittle hard stuff. :)

Thanks for thinking about it!

--
sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.
 
"N_Cook" <diverse@tcp.co.uk> writes:

Sam Goldwasser <sam@ampersand.seas.upenn.edu> wrote in message
news:6w3a9t18ej.fsf@ampersand.seas.upenn.edu...
"N_Cook" <diverse@tcp.co.uk> writes:

Sam Goldwasser <sam@ampersand.seas.upenn.edu> wrote in message
news:6wws755z1c.fsf@ampersand.seas.upenn.edu...
This type is usually dark gray and soft - about the consistency of a
pencil
eraser, maybe a bit tougher. It can be removed laboriously with
knives,
picks, and elbow grease. But the question is whether there is some
easier
way to do this that would leave the underlying components undamaged.
This stuff is used in a variety of places including PCBs and laser
tube assemblies. Both of these are of interest to me. Modest heat
has no effect including immersing in boiling water - it's not hot-melt
glue.

Thanks!

--
sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/

I seem to remember using a 1/8 inch ball mill in a Dremmel for that
sort of
stuff, localised heat and tugging action hepled in removing from
surfaces,
. But still time consuming and you have to know there is no little vital
stuff buiried within it.

I've been using the mechanical approach. It is tedious and risky as
you note. But does work:

http://repairfaq.cis.upenn.edu/Misc/vmi373p1.jpg

However, some components were damaged (a graphics editing program
can work wonders!) and for what I really want, it is trickier
as the part being removed is a glass laser tube and much of the
potting material is in a space 2 or 3 mm thick surrounding the
tube, and running its entire length.

Thanks!

--
sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/

What is the output level of the Cockcroft Walton circuit ?
Click to expand...
Greater than 10 kV but the current is very low since it only needs to drive
an open circuit, then is bypassed once the main current flows. Nearly
every HeNe laser power supply has a circuit like that.

--
sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.
 
Whatever this stuf is, common sense suggests it was designed not to be
easily removed, especially by chemical means. Otherwise, there would be
little point to it.
 
Bruce Esquibel <bje@ripco.com> writes:

In sci.electronics.repair Sam Goldwasser <sam@ampersand.seas.upenn.edu> wrote:

This type is usually dark gray and soft - about the consistency of a pencil
eraser, maybe a bit tougher. It can be removed laboriously with knives,
picks, and elbow grease. But the question is whether there is some easier
way to do this that would leave the underlying components undamaged.
This stuff is used in a variety of places including PCBs and laser
tube assemblies. Both of these are of interest to me. Modest heat
has no effect including immersing in boiling water - it's not hot-melt glue.

This probably isn't much help but we used to use a chemical called
Eccostrip 93 made by Emerson and Cuming (or cumming or cummings).

I don't know if it's sold anymore, probably on every EPA hazard chemical
list by now but I believe the main purpose of it was to attack something in
the resin.

It wasn't a miracle worker, but did it's job eventually. Generally you
needed to apply it with a glass eyedropper to keep the area wet, then
periodically using a acid brush, dust off the powder, reapply.

As far as component damage, yeah, some carbon film resistors, the bodies
would flake off but I don't remember anything else. Even ic's (chips) that I
thought had some epoxy holding them together were no worse for wear even
soaking in the stuff.
Click to expand...
Yeah, for the real application I have in mind, this is probably going to
take about 1,423 years (give or take a century). :)

The PCB was just an example. But where this is needed is to remove
the stuff surrounding a glass laser tube - about 6 inches in length
and a space of 2 or 3 mm between the tube and the cylinder it's in.
Both the cylinder and tube need to come out undamaged.

Thanks.

--
sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.


-bruce
bje@ripco.com
Click to expand...
 
On Sun, 21 Jun 2009 12:31:27 -0400, Sam Goldwasser
<sam@ampersand.seas.upenn.edu> wrote:

This type is usually dark gray and soft - about the consistency of a pencil
eraser, maybe a bit tougher. It can be removed laboriously with knives,
picks, and elbow grease. But the question is whether there is some easier
way to do this that would leave the underlying components undamaged.
This stuff is used in a variety of places including PCBs and laser
tube assemblies. Both of these are of interest to me. Modest heat
has no effect including immersing in boiling water - it's not hot-melt glue.

Thanks!
Click to expand...

Go to a good hardware store, and see if they have silicone tub caulk
remover. Try that and see if it works.
 
Sam Goldwasser <sam@minus.seas.upenn.edu> wrote in message
news:6wk5348n3g.fsf@minus.seas.upenn.edu...
Bruce Esquibel <bje@ripco.com> writes:

In sci.electronics.repair Sam Goldwasser <sam@ampersand.seas.upenn.edu
wrote:

This type is usually dark gray and soft - about the consistency of a
pencil
eraser, maybe a bit tougher. It can be removed laboriously with
knives,
picks, and elbow grease. But the question is whether there is some
easier
way to do this that would leave the underlying components undamaged.
This stuff is used in a variety of places including PCBs and laser
tube assemblies. Both of these are of interest to me. Modest heat
has no effect including immersing in boiling water - it's not hot-melt
glue.

This probably isn't much help but we used to use a chemical called
Eccostrip 93 made by Emerson and Cuming (or cumming or cummings).

I don't know if it's sold anymore, probably on every EPA hazard chemical
list by now but I believe the main purpose of it was to attack something
in
the resin.

It wasn't a miracle worker, but did it's job eventually. Generally you
needed to apply it with a glass eyedropper to keep the area wet, then
periodically using a acid brush, dust off the powder, reapply.

As far as component damage, yeah, some carbon film resistors, the bodies
would flake off but I don't remember anything else. Even ic's (chips)
that I
thought had some epoxy holding them together were no worse for wear even
soaking in the stuff.

Yeah, for the real application I have in mind, this is probably going to
take about 1,423 years (give or take a century). :)

The PCB was just an example. But where this is needed is to remove
the stuff surrounding a glass laser tube - about 6 inches in length
and a space of 2 or 3 mm between the tube and the cylinder it's in.
Both the cylinder and tube need to come out undamaged.

Thanks.

--
sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above
is
ignored unless my full name AND either lasers or electronics is included
in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.


-bruce
bje@ripco.com
Click to expand...
Can you make a pilot hole with a thin steel rod, chisel ground at the end.
Then pass through it one of those carbide covered wire saw , garotte type
things, or even a coping saw blade, kept under tension. Would some scratch
damage matter? If so then perhaps spaced , glued-on, guard rings along the
blade


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