What bad glue can do to the board

[lexwalker]

Re: What bad glue can do to the board

...

Sometimes pictures can tell a thousand words. Do these pictures tell the story? Once a while I would take some snapshots of degraded glue and the carnage...

[budm]

Re: What bad glue can do to the board

"One of my huge enemies as thinker repair man, is this tendency of some people about generalizing and jump in conclusions, based on very few experiences of their own."
It is obviously that you have not learn or done any more research abut this glue problem, more than one factories used these glue in the past.
From the article:
A Google search for “conductive brown glue” finds more than 100,000
references, some of which mention the glue’s role in various CRT display
problems and its use in consumer audio equipment. Searching for
“chloroprene adhesive,” Google finds 56,000 references, including one from a Sony division that contains the
following cautionary note: “The products…contain chloroprene rubber…. Prolonged standing in a high-temperature
environment…may cause thermal dechlorination, possibly resulting in the corrosion of metal parts nearby, or in a loss
of insulation resistance. Please be sure to avoid any use of these materials in electronic components that are to be
energized electrically to prevent tracking or similar problems.”
You also never use conformal coating since you claim "There is no issue with the glue it self, the one who placed it over the PCB he added too much, and caused a violation regarding the Creepage distance in a HV circuitry."
Time for you to change from "PRO" to "Knowledge seeker" and learn what the creepage and clearance are about.

From the Greek web site: "Due my unexplained insistence about perfect ness, and about learning new things almost daily, usually I can reach subjects close to the level of engineering. I have helped lots of trainees to advance fast in the job, by using the “Kiriakos teaching method”, which is to use small stories of unrelated examples, but with common essence. ( In a way, what Jesus did). " Just like Jesus eh!
http://www.ittsb.eu/about.html

[Kiriakos GR]

Re: What bad glue can do to the board

That's very incorrect. The degraded glue plague itself can cause problems (by being conductive and corrosive) and it does not have to be high voltage (for example, many audio amplifier and speaker systems suffers from this degraded glue causing malfunctions and brown outs)...

This glue is added as mechanical support over components which possibly are in risk due vibrations, which eventually will cause damage to their soldering leads.

One strong chemical reaction needs two hostile recipes in the mix.
The one recipe is the glue (chemical composition) the other is the varnish (chemical composition) which the manufacturer of one electronic part selected to use as additional protection against corrosion by humidity.

In manufacturing, tests regarding dielectric straight of chemical compositions, or if a part it does met it specifications regarding electrical isolation, it is in the hands of engineers.

If they do their job properly? Then there is no problem.
One of my huge enemies as thinker repair man, is this tendency of some people about generalizing and jump in conclusions, based on very few experiences of their own.

Even the industry of true hole resistors (for example) have update with out public notice the manufacturing process and materials, so the new components to become environmentally friendly.

And I am coming today to ask you all?
Which evidence and standards we are going to use so to come down in a conclusion?
1) The ones before 20 years?
2) The latest?
3) The work done in a single factory which did not comply to any manufacturing standard ( American or European ) regarding the use of safe parts and workmanship ?

Such important conversations have value if the participants qualify enough so to offer answers, instead of opinions.

[lexwalker]

Re: What bad glue can do to the board

Got 6 Samsung 245bw in, 3 were fixed by just removing bad glue, other 3 are badly damaged (will have to do more repair later).

More degraded glue horror stories. Have encountered plenty of such cases in many different equipment ranging from monitors, speakers to even everyday household appliances. The electronics industry is fond of them, and at least always gave us something (usually a mess) to work on (cleaning up and fixing that mess)...

There is no issue with the glue it self, the one who placed it over the PCB he added too much, and caused a violation regarding the Creepage distance in a HV circuitry.

That's very incorrect. The degraded glue plague itself can cause problems (by being conductive and corrosive) and it does not have to be high voltage (for example, many audio amplifier and speaker systems suffers from this degraded glue causing malfunctions and brown outs)...

[TechSuperDave]

Re: What bad glue can do to the board

Hot glue FTW.

That's what we use in my shop after repairs.

Never had an issue with it.

[c_hegge]

Re: What bad glue can do to the board

I don't agree... If soldering itself was enough to prevent cold joints due to oscillations, then it would never have been used in the first place... I'm aware that the adhesive is also used to keep components in place during flow soldering, but its main purpose is for high-frequency vibration absorption.

For the coils, maybe. But at least they usually have insulation around the wire, so conductive glue isn't much of an issue there. For capacitors and transistors, though, there is no need to glue them in place, as they don't vibrate (and they're not heavy enough to put much stress on the soldering either).

[Th3_uN1Qu3]

Re: What bad glue can do to the board

Hot glue FTW.

[mockingbird]

Re: What bad glue can do to the board

I don't agree... If soldering itself was enough to prevent cold joints due to oscillations, then it would never have been used in the first place... I'm aware that the adhesive is also used to keep components in place during flow soldering, but its main purpose is for high-frequency vibration absorption.

[c_hegge]

Re: What bad glue can do to the board

I just never use glue. There's really no need to IMO. The soldering is more than enough to hold the components in place (at least on the average TV/Monitor/PC PSU PCB).

[japlytic]

Re: What bad glue can do to the board

How about Star Brite Liquid Electrical Tape?

[budm]

Re: What bad glue can do to the board

Hi gootron, we are not that smart! You also notice that he changed the subject because he does not know how the glues are used and probably never herd of or use electronics grade Silicone RTV.

[goontron]

Re: What bad glue can do to the board

I think that the nerdy Greek strikes your PRIDE for another one time.

Yes it is PAINFUL for anonymous in forum heroes to accept the fact that they are not that smart.
And before some one even think to extend his bitching attempts, he must post first his own qualification degree scanned at 100% as is when it hands on his wall.

[budm]

Re: What bad glue can do to the board

I am not bitching, when I want a good laugh, I just read that post, some one else also laughing along when they read it.
"Yes it is PAINFUL for anonymous in forum heroes to accept the fact that they are not that smart" Not that smart eh? And you are SO SMART!
We already see how much you know about safety and creepage and clearance after working all these years and called yourself a pro.

[mockingbird]

Re: What bad glue can do to the board

Kiriakos - in this case, YOU were wrong... You incorrectly stated that adding too much stabilizing adhesive violates established rules pertaining to maintaining adequate creepage distance... budm correctly pointed out to you that not only were you wrong, but that to the contrary, high-quality adhesive enhances the quality of creepage distance.

[Kiriakos GR]

Re: What bad glue can do to the board

I think that the nerdy Greek strikes your PRIDE for another one time.

Yes it is PAINFUL for anonymous in forum heroes to accept the fact that they are not that smart.
And before some one even think to extend his bitching attempts, he must post first his own qualification degree scanned at 100% as is when it hands on his wall.

[budm]

Re: What bad glue can do to the board

I have dealt with this problem since the 70's (some of you were not even born yet, or not getting into electronics yet), it is the chemical in the glue being used, some Chinese companies still use this glue. If you have lots of experience, you will know why it has nothing to do with creepage and clearance. I also use conformer coating in my board design that are used in high moisture location. I also use potting compound on the whole board. BTW, our lab is UL and CSA certified for safety testing. Done lots of HI-POT test @> 3000V.
If the glue is not conductive, you actually increase the creepage distance.

PAGE 1-8.
But what do I know, I am just a kid playing on the keyboard:
https://www.badcaps.net/forum/showth...dge+tom&page=2

budm when you will update your ID from Knowledge Seeker to a Pro ( in 10 years) ,
then I will take you more seriously, for now you are just a kid playing with it keyboard.
By my opinion you do not own even half than the understanding of Tom regarding electronics.
From the other hand Tom goes by the book due his limited experiences which he will improve in time,
those additional experiences they will help him to improvise too by using the limits of hardware with out causing a disaster.

[goontron]

Re: What bad glue can do to the board

i can only assume that use of this glue is for planned failure now .
this stuff was eating traces off boards in 70's quasar tv crt socket boards in the mid-late 70's.

i found this glue in an apple Macintosh plus floppy drive too!

[kc8adu]

Re: What bad glue can do to the board

i can only assume that use of this glue is for planned failure now .
this stuff was eating traces off boards in 70's quasar tv crt socket boards in the mid-late 70's.

[mockingbird]

Re: What bad glue can do to the board

That's absurd... Conformal coating covers the entire board. The problem lies in the conductivity of the glue, not in "creepage distance".

[Kiriakos GR]

Re: What bad glue can do to the board

There is no issue with the glue it self, the one who placed it over the PCB he added too much, and caused a violation regarding the Creepage distance in a HV circuitry.