Epoxying over chip numbers?

[John Muchow]

We have several prototypes being built over the next few weeks and
wanted to hide the chip numbers of some of the glue logic. We've
sanded them off up to now, but that's an awful and time consuming way
to do it. A search of the sci.electronics groups came up
empty....amazingly.

Does anyone have any recommendations for covering up the numbers on
plastic and ceramic DIP packages? Loctite's black Prism 410 adhesive
looks good, but we're not sure if it will stick well enough or if it
can be pried off like a "pancake".

Or is sanding still the best option for doing this?

Thanks!

John Muchow
-- remove SPAMMENOT for e-mail responses --

 

[Jim Thompson]

On Fri, 02 Jul 2004 21:48:58 GMT, John Muchow
<jmuchow@SPAMMENOTcamlight.com> wrote:

We have several prototypes being built over the next few weeks and
wanted to hide the chip numbers of some of the glue logic. We've
sanded them off up to now, but that's an awful and time consuming way
to do it. A search of the sci.electronics groups came up
empty....amazingly.

Does anyone have any recommendations for covering up the numbers on
plastic and ceramic DIP packages? Loctite's black Prism 410 adhesive
looks good, but we're not sure if it will stick well enough or if it
can be pried off like a "pancake".

Or is sanding still the best option for doing this?

Thanks!

John Muchow
-- remove SPAMMENOT for e-mail responses --

Electric eraser with "ink" type insert... very quick.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Dennis Clark]

In sci.electronics.misc John Muchow <jmuchow@spammenotcamlight.com> wrote:

You're wasting your time. Anyone that would be interested in figuring
it out will anyway, and those that aren't won't anyway.

IMO,
DLC

: We have several prototypes being built over the next few weeks and
: wanted to hide the chip numbers of some of the glue logic. We've
: sanded them off up to now, but that's an awful and time consuming way
: to do it. A search of the sci.electronics groups came up
: empty....amazingly.

: Does anyone have any recommendations for covering up the numbers on
: plastic and ceramic DIP packages? Loctite's black Prism 410 adhesive
: looks good, but we're not sure if it will stick well enough or if it
: can be pried off like a "pancake".

: Or is sanding still the best option for doing this?

: Thanks!

: John Muchow
: -- remove SPAMMENOT for e-mail responses --

--
============================================================================
* Dennis Clark dlc@frii.com www.techtoystoday.com *
* "Programming and Customizing the OOPic Microcontroller" Mcgraw-Hill 2003 *
============================================================================

 

[Franc Zabkar]

On Fri, 02 Jul 2004 21:48:58 GMT, John Muchow
<jmuchow@SPAMMENOTcamlight.com> put finger to keyboard and composed:

We have several prototypes being built over the next few weeks and
wanted to hide the chip numbers of some of the glue logic. We've
sanded them off up to now, but that's an awful and time consuming way
to do it. A search of the sci.electronics groups came up
empty....amazingly.

It doesn't amaze me at all. If I knew how to do it, I wouldn't tell
you. It's an abhorrent practice.

Does anyone have any recommendations for covering up the numbers on
plastic and ceramic DIP packages?

Please don't do it. I've spent hours reverse engineering products such
as alarm panels and electric wheelchairs (for repair reasons), only to
discover that they use garden variety ICs costing around $1.


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

 

[Zak]

Dennis Clark wrote:

You're wasting your time. Anyone that would be interested in figuring
it out will anyway, and those that aren't won't anyway.

Unless the device is trivial and the buyers have trivial skills.

Or if the device is 'magic' - golden ear audio comes to mind. Audio
reviewers do not have great technical skills usually. Hmm... reminds me
of a product that had the 'advantage' of no resistors in the signal
path... great invention.


Thomas

 

[Mark (UK)]

Hi!

Don't bother for standard LS/4xxx logic - anyone interested would
desolder it and chuck it in a digital chip tester, and it will come back
what the chip number is.

If you've got some flip flops in there, put a chip or two of those into
a GAL and secure it - that will stop all but the most hardened design
theives. Even better, put as much of the logic as possible into a CPLD,
again securing it.

Yours, Mark.

John Muchow wrote:

We have several prototypes being built over the next few weeks and
wanted to hide the chip numbers of some of the glue logic. We've
sanded them off up to now, but that's an awful and time consuming way
to do it. A search of the sci.electronics groups came up
empty....amazingly.

Does anyone have any recommendations for covering up the numbers on
plastic and ceramic DIP packages? Loctite's black Prism 410 adhesive
looks good, but we're not sure if it will stick well enough or if it
can be pried off like a "pancake".

Or is sanding still the best option for doing this?

Thanks!

John Muchow
-- remove SPAMMENOT for e-mail responses --

 

[CWatters]

How are you doing the sanding? Try using different tools in a dremel.


"John Muchow" <jmuchow@SPAMMENOTcamlight.com> wrote in message
news:smlbe0htvcgnojnpuof8j2o0kmphjk0fvu@4ax.com...

We have several prototypes being built over the next few weeks and
wanted to hide the chip numbers of some of the glue logic. We've
sanded them off up to now, but that's an awful and time consuming way
to do it. A search of the sci.electronics groups came up
empty....amazingly.

Does anyone have any recommendations for covering up the numbers on
plastic and ceramic DIP packages? Loctite's black Prism 410 adhesive
looks good, but we're not sure if it will stick well enough or if it
can be pried off like a "pancake".

Or is sanding still the best option for doing this?

Thanks!

John Muchow
-- remove SPAMMENOT for e-mail responses --

 

[Impmon]

On Fri, 02 Jul 2004 21:48:58 GMT, John Muchow
<jmuchow@SPAMMENOTcamlight.com> wrote:

Does anyone have any recommendations for covering up the numbers on
plastic and ceramic DIP packages? Loctite's black Prism 410 adhesive
looks good, but we're not sure if it will stick well enough or if it
can be pried off like a "pancake".

Or is sanding still the best option for doing this?

Epoxy can be removed one way or another. I've seen some chips whose
number was hidden under black marks (permanet marker) but it can be
cleaned off with some effort. Sanding is still a foolproof option.

If you have dremmel, try using that. It can sand off number in a
pinch but don't overdo or the chip might get too hot or worse, you
might sand the case clean off and expose the chip.
--
To reply, replace digi.mon with tds.net

 

[Al]

In article <8sobe051ct2p3ic9vjua9cj64saopqs2cl@4ax.com>,
Jim Thompson <thegreatone@example.com> wrote:

On Fri, 02 Jul 2004 21:48:58 GMT, John Muchow
jmuchow@SPAMMENOTcamlight.com> wrote:

We have several prototypes being built over the next few weeks and
wanted to hide the chip numbers of some of the glue logic. We've
sanded them off up to now, but that's an awful and time consuming way
to do it. A search of the sci.electronics groups came up
empty....amazingly.

Does anyone have any recommendations for covering up the numbers on
plastic and ceramic DIP packages? Loctite's black Prism 410 adhesive
looks good, but we're not sure if it will stick well enough or if it
can be pried off like a "pancake".

Or is sanding still the best option for doing this?

Thanks!

John Muchow
-- remove SPAMMENOT for e-mail responses --

Electric eraser with "ink" type insert... very quick.

...Jim Thompson

Does that work on laser scribed devices also?

Al

 

[Jim Thompson]

On Sat, 03 Jul 2004 15:40:15 GMT, Al <no.spam@wanted.com> wrote:

In article <8sobe051ct2p3ic9vjua9cj64saopqs2cl@4ax.com>,
Jim Thompson <thegreatone@example.com> wrote:

On Fri, 02 Jul 2004 21:48:58 GMT, John Muchow
jmuchow@SPAMMENOTcamlight.com> wrote:

We have several prototypes being built over the next few weeks and
wanted to hide the chip numbers of some of the glue logic. We've
sanded them off up to now, but that's an awful and time consuming way
to do it. A search of the sci.electronics groups came up
empty....amazingly.

Does anyone have any recommendations for covering up the numbers on
plastic and ceramic DIP packages? Loctite's black Prism 410 adhesive
looks good, but we're not sure if it will stick well enough or if it
can be pried off like a "pancake".

Or is sanding still the best option for doing this?

Thanks!

John Muchow
-- remove SPAMMENOT for e-mail responses --

Electric eraser with "ink" type insert... very quick.

...Jim Thompson

Does that work on laser scribed devices also?

Al

I haven't done it in years... I was last "hands-on-discrete" in 1987,
but I'd think so, the "ink" type insert is actually abrasive.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Dave Platt]

You're wasting your time. Anyone that would be interested in figuring
it out will anyway, and those that aren't won't anyway.

Unless the device is trivial and the buyers have trivial skills.

Or if the device is 'magic' - golden ear audio comes to mind. Audio
reviewers do not have great technical skills usually. Hmm... reminds me
of a product that had the 'advantage' of no resistors in the signal
path... great invention.

For an interesting "golden ear" story relevant to this issue, see:

http://groups.google.com/groups?selm=8m6rh402d2r%40news2.newsguy.com

--
Dave Platt <dplatt@radagast.org> AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

 

[Don Bruder]

In article <smlbe0htvcgnojnpuof8j2o0kmphjk0fvu@4ax.com>,
John Muchow <jmuchow@SPAMMENOTcamlight.com> wrote:

We have several prototypes being built over the next few weeks and
wanted to hide the chip numbers of some of the glue logic. We've
sanded them off up to now, but that's an awful and time consuming way
to do it. A search of the sci.electronics groups came up
empty....amazingly.

Does anyone have any recommendations for covering up the numbers on
plastic and ceramic DIP packages? Loctite's black Prism 410 adhesive
looks good, but we're not sure if it will stick well enough or if it
can be pried off like a "pancake".

Or is sanding still the best option for doing this?

For my nickel:
Any manufacturer who grinds chips (and therefore makes it impossible for
me to service the device, whatever it might be, but replacing chips that
die (they do that eventually, yknow) is a manufacturer who will never
again receive any money from me.

--
Don Bruder - dakidd@sonic.net - New Email policy in effect as of Feb. 21, 2004.
I respond to Email as quick as humanly possible. If you Email me and get no
response, see <http://www.sonic.net/~dakidd/main/contact.html> Short
form: I'm trashing EVERYTHING that doesn't contain a password in the subject.

 

[Jamie]

acetone


John Muchow wrote:

We have several prototypes being built over the next few weeks and
wanted to hide the chip numbers of some of the glue logic. We've
sanded them off up to now, but that's an awful and time consuming way
to do it. A search of the sci.electronics groups came up
empty....amazingly.

Does anyone have any recommendations for covering up the numbers on
plastic and ceramic DIP packages? Loctite's black Prism 410 adhesive
looks good, but we're not sure if it will stick well enough or if it
can be pried off like a "pancake".

Or is sanding still the best option for doing this?

Thanks!

John Muchow
-- remove SPAMMENOT for e-mail responses --

 

[Franc Zabkar]

On 03 Jul 2004 05:30:27 GMT, Dennis Clark <dlc@io.frii.com> put finger
to keyboard and composed:

In sci.electronics.misc John Muchow <jmuchow@spammenotcamlight.com> wrote:

You're wasting your time. Anyone that would be interested in figuring
it out will anyway, and those that aren't won't anyway.

Exactly. In the case of one alarm panel, it took me only a few hours
to determine that all the ICs were 4000 series CMOS. For someone
intending to steal the design, these few hours could easily be
amortised over a large production run. However, for a repairer such as
myself, this labour cost must be passed on to the customer. The only
thing the manufacturer has achieved in this case is to generate
animosity towards his brand.

IMO,
DLC

: We have several prototypes being built over the next few weeks and
: wanted to hide the chip numbers of some of the glue logic. We've
: sanded them off up to now, but that's an awful and time consuming way
: to do it. A search of the sci.electronics groups came up
: empty....amazingly.

: Does anyone have any recommendations for covering up the numbers on
: plastic and ceramic DIP packages? Loctite's black Prism 410 adhesive
: looks good, but we're not sure if it will stick well enough or if it
: can be pried off like a "pancake".

: Or is sanding still the best option for doing this?

: Thanks!

: John Muchow
: -- remove SPAMMENOT for e-mail responses --

- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

 

[Franc Zabkar]

On 3 Jul 2004 13:38:11 -0500, Don Bruder <dakidd@sonic.net> put finger
to keyboard and composed:

In article <smlbe0htvcgnojnpuof8j2o0kmphjk0fvu@4ax.com>,
John Muchow <jmuchow@SPAMMENOTcamlight.com> wrote:

We have several prototypes being built over the next few weeks and
wanted to hide the chip numbers of some of the glue logic. We've
sanded them off up to now, but that's an awful and time consuming way
to do it. A search of the sci.electronics groups came up
empty....amazingly.

Does anyone have any recommendations for covering up the numbers on
plastic and ceramic DIP packages? Loctite's black Prism 410 adhesive
looks good, but we're not sure if it will stick well enough or if it
can be pried off like a "pancake".

Or is sanding still the best option for doing this?

For my nickel:
Any manufacturer who grinds chips (and therefore makes it impossible for
me to service the device, whatever it might be, but replacing chips that
die (they do that eventually, yknow) is a manufacturer who will never
again receive any money from me.

I also despise the practice of relabelling chips with obscure in-house
numbers. HP and Ford Motor Company are two bad examples that come to
mind. I also recall junking a swimming pool solar heater controller
because the manufacturer refused to supply a replacement
field-programmable pre-programmed CPU. Instead I was offered an
uneconomically priced replacement module. What hurt even more was that
the original faulty CPU's code would have been retrievable had its
security bit not been set.


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

 

[Robert Baer]

John Muchow wrote:

We have several prototypes being built over the next few weeks and
wanted to hide the chip numbers of some of the glue logic. We've
sanded them off up to now, but that's an awful and time consuming way
to do it. A search of the sci.electronics groups came up
empty....amazingly.

Does anyone have any recommendations for covering up the numbers on
plastic and ceramic DIP packages? Loctite's black Prism 410 adhesive
looks good, but we're not sure if it will stick well enough or if it
can be pried off like a "pancake".

Or is sanding still the best option for doing this?

Thanks!

John Muchow
-- remove SPAMMENOT for e-mail responses --

Abrasion does the trick: sanding, milling, laser.
However, anyone can still find out what chips you used, so why bother?
No other company i know of does something as infantile as hiding part
numbers.

 

[Robert Baer]

Dennis Clark wrote:

In sci.electronics.misc John Muchow <jmuchow@spammenotcamlight.com> wrote:

You're wasting your time. Anyone that would be interested in figuring
it out will anyway, and those that aren't won't anyway.

IMO,
DLC

: We have several prototypes being built over the next few weeks and
: wanted to hide the chip numbers of some of the glue logic. We've
: sanded them off up to now, but that's an awful and time consuming way
: to do it. A search of the sci.electronics groups came up
: empty....amazingly.

: Does anyone have any recommendations for covering up the numbers on
: plastic and ceramic DIP packages? Loctite's black Prism 410 adhesive
: looks good, but we're not sure if it will stick well enough or if it
: can be pried off like a "pancake".

: Or is sanding still the best option for doing this?

: Thanks!

: John Muchow
: -- remove SPAMMENOT for e-mail responses --

--
============================================================================
* Dennis Clark dlc@frii.com www.techtoystoday.com *
* "Programming and Customizing the OOPic Microcontroller" Mcgraw-Hill 2003 *
============================================================================

*EXACTLY* !!

 

[Robert Baer]

Jamie wrote:

acetone

John Muchow wrote:

We have several prototypes being built over the next few weeks and
wanted to hide the chip numbers of some of the glue logic. We've
sanded them off up to now, but that's an awful and time consuming way
to do it. A search of the sci.electronics groups came up
empty....amazingly.

Does anyone have any recommendations for covering up the numbers on
plastic and ceramic DIP packages? Loctite's black Prism 410 adhesive
looks good, but we're not sure if it will stick well enough or if it
can be pried off like a "pancake".

Or is sanding still the best option for doing this?

Thanks!

John Muchow
-- remove SPAMMENOT for e-mail responses --

Nope; hasn't worked since the mid 1980s...

 

[John Muchow]

Electric eraser with "ink" type insert... very quick.

That's a great idea!
Too much like using a Dremel (with the rubberized wheel) though...what
we're doing now. I was hoping to just put a drop of epoxy on the chip
and go. After thinking about it, I'm pretty sure it won't stick well
enough to the ceramic packages. But, it would be nice if it could
work with PDIPs.


John Muchow
-- remove SPAMMENOT for e-mail responses --

 

[John Muchow]

You're wasting your time. Anyone that would be interested in figuring
it out will anyway, and those that aren't won't anyway.

You're probably right, but we're just trying to keep things in our
pocket until the prototype testing is done.


John Muchow
-- remove SPAMMENOT for e-mail responses --