Capacitor glue?
- Thread starter ncgrant
- Start date
merrylander
AK Member
The major reason for gluing down the bigger electrolytics was wave soldering. The circuit boards get populated with components and then are sent across a bath of liquid solder, pre heated before hitting the molten solder and cooled down afterward. If you look closely you will note that most of the smaller components have the leads bent over to secure them in place, the bigger caps can't do this, so in comes the glue. Yes it gets corrosive over time, case in point the Sansui Au series amplifiers.
Well, being quick to pickup on the word "California" (Duncan Industries happens to be located in California) doesn't make up for being wrong :nono:. Neither does not looking at any of the reference sources.
Solvents are substances that are capable of dissolving or dispersing one or more other substances. Organic solvents are carbon-based solvents (i.e., they contain hexavalent carbon in their molecular structure) and they readily breakdown many substances. Tetrachloroethylene is an organic solvent. Liquid Nails products also contain organic solvents. The solvent's ability to readily disperse susbtances is exactly what makes it not only useful, but also dangerous (to caps & humans). Smearing an adhesive containing tetrachloroethylene solvent around the rubber seal at the capacitor base and leaving it there for hours until the solvent evaporates has no chance of improving the seal but a very good chance of damaging it. This is well known. That anyone would suggest doing this is really difficult to comprehend - their motive or knowledge must be called into question.
I've provided 3 sources stating that the use of halogenated hydrocarbon based cleaners and adhesives are to be avoided with electrolytic capacitors. I provided a source that recommends RTV162 for bonding capacitors and calls out compliance to MIL-A-46146B. Please extend beyond personal experience and provide one legimate source (e.g. capacitor manufacturer, electronics component distributor even the adhesive manufacturer) that recommends tetrachloroethylene based adhesives (or "Liquid Nails" for that matter) for bonding electrolytic capacitors. Short of that, any further contribution is simply nonsense.
Regarding the "California" comment: EPA, Center for Disease Control & National Institutes of Health have all concluded that tetrachloroethylene can damage human organs and that it is a reasonably probable carcinogen. Their conclusions are based on research :thmbsp: - not personal anecdote :thumbsdn:. Remember I'm not addressing the health aspect here - it's simply that the chemical properties of the solvent that cause human tissue damage are those responsible for damage to the cap seal and insulation.
Solvents are substances that are capable of dissolving or dispersing one or more other substances. Organic solvents are carbon-based solvents (i.e., they contain hexavalent carbon in their molecular structure) and they readily breakdown many substances. Tetrachloroethylene is an organic solvent. Liquid Nails products also contain organic solvents. The solvent's ability to readily disperse susbtances is exactly what makes it not only useful, but also dangerous (to caps & humans). Smearing an adhesive containing tetrachloroethylene solvent around the rubber seal at the capacitor base and leaving it there for hours until the solvent evaporates has no chance of improving the seal but a very good chance of damaging it. This is well known. That anyone would suggest doing this is really difficult to comprehend - their motive or knowledge must be called into question.
I've provided 3 sources stating that the use of halogenated hydrocarbon based cleaners and adhesives are to be avoided with electrolytic capacitors. I provided a source that recommends RTV162 for bonding capacitors and calls out compliance to MIL-A-46146B. Please extend beyond personal experience and provide one legimate source (e.g. capacitor manufacturer, electronics component distributor even the adhesive manufacturer) that recommends tetrachloroethylene based adhesives (or "Liquid Nails" for that matter) for bonding electrolytic capacitors. Short of that, any further contribution is simply nonsense.
Regarding the "California" comment: EPA, Center for Disease Control & National Institutes of Health have all concluded that tetrachloroethylene can damage human organs and that it is a reasonably probable carcinogen. Their conclusions are based on research :thmbsp: - not personal anecdote :thumbsdn:. Remember I'm not addressing the health aspect here - it's simply that the chemical properties of the solvent that cause human tissue damage are those responsible for damage to the cap seal and insulation.
qboneus
Senior Member
Dude are you just coming here to start a fight and attempt to belittle people?
I read back and hate to take the wind from your sails but NO ONE BUT YOU has been addressing electrolytics specifically, other than Rob and he was simply stating why the manufacturers did what they did in assembly.
When "I" rebuild an XO I use polypros/foil capacitors in the XO, I NEVER mentioned electro's.
I would also like to take this opportunity to remind you that my 100LB per speaker polk SDA's are NOT scheduled to depart on a lunar mission until 2012 and by then I'm sure I will have pulled that offensive Kimber Kap for some other 'flavor of the month'.
This is not a courtroom where sources are cited and discoveries are launched and argued; no one is going to get disbarred.
I'm still not questioning the 'facts'
This is the school-of-hard-knocks where experience speaks louder than text.
It appears no one here has experienced or repaired damage or a failure from foam tape or RTV or hot glue or TRUST me on this; they WOULD come forward and say so..
This is the internet where we can ALL have a podium and Mic.
Just MY 'nonsense' .02 cents in return.
warmest wishes,
tal
shelly_d
Not An Audiophool
I did not see in the original post if this was a circuit board mounted crossover or point to point on a support - such as wood.
If wood I would use 2 cable ties around each cap and 2 around each inductor. Haven't built on a circuit board so I don't know for that.
Good Luck.
If wood I would use 2 cable ties around each cap and 2 around each inductor. Haven't built on a circuit board so I don't know for that.
Good Luck.
Gizmologist
Member
The biggest health concern we have is cancer warnings.
Many of my 40+ years in the audio visual presentation business have been providing and operating all types of AV equipment for all types of meetings- hundreds of which were medical in nature. This runs from the small room PA systems to full scale video projection and distribution including national and international broadcast networks.
These include numerous presentations at NIH in Bethesda, MD, Bethesda Naval Hospital, Mayo Clinic in AZ, National Association of Allergy and Immunology, National Assoc. of Anesthesiologists, Symposium of Multiple Chemical Sensitivity, International Symposium on Animal Research Procedures, Ethics, and Protocols, etc. This list goes on and on.
During many of those conventions and break out sessions I was exposed to a great deal of behind the scenes study and research data.
One of the overriding factors in a great deal of the research was the concentration and exposure time frame that lab animals were subjected to in all sorts of experiments from medical research and drug trials, industrial liquids, gases, cosmetics, food additives and foodstuff concentrates, temperature and social stress factors on lab research animals, genetic similarities and differences between species and genus in relation to correlating test procedures and results in empirical and double blind studies.
In an overwhelming number of discussions, it was determined and accepted that the concentrations frequently used in sensitivity tests for all sorts of products and pharmacological agents were quite often used and or administered in completely unreasonable concentrations and over time frames that would in many cases be lethal to any living thing. This frequently results in erroneous publication of public health warnings not at all based on real life occurrences under normal use. So I always keep in mind that trace amounts of most any OTC chemical sold to the general public are tolerable in normal use and that warnings about toxicity are all too often based on unrealistic scenarios.
As I and others mentioned, many different substances can and have been used quite successfully for the purpose of anchoring components to circuit boards. I don't recall anyone in my lifetime having to replace a cap because it was sealed to the PCB with RTV, hot glue, Liquid nail, silicone, foam tape, rubber cement, epoxy, etc.
That is not to say that these chemical concoctions do not off gas, but in the quantity and concentration they are used in, you would think some of us would have run across a few caps where the device was rendered useless and had to be replaced.
I had someone here tell me that internal mechanical disconnection of the leads on a large electrolytic axial caps was not possible and I responded that I should have saved some of the hundred or so from the last ten years.
The same holds true here. Let us see some actual examples (chemically verified by an independent lab) that the outer casing was breached and therefore the internal structure were damaged or destroyed by being exposed to a small amount of ANY of the adhesives of preference mentioned here.
Otherwise, let it go.
Many of my 40+ years in the audio visual presentation business have been providing and operating all types of AV equipment for all types of meetings- hundreds of which were medical in nature. This runs from the small room PA systems to full scale video projection and distribution including national and international broadcast networks.
These include numerous presentations at NIH in Bethesda, MD, Bethesda Naval Hospital, Mayo Clinic in AZ, National Association of Allergy and Immunology, National Assoc. of Anesthesiologists, Symposium of Multiple Chemical Sensitivity, International Symposium on Animal Research Procedures, Ethics, and Protocols, etc. This list goes on and on.
During many of those conventions and break out sessions I was exposed to a great deal of behind the scenes study and research data.
One of the overriding factors in a great deal of the research was the concentration and exposure time frame that lab animals were subjected to in all sorts of experiments from medical research and drug trials, industrial liquids, gases, cosmetics, food additives and foodstuff concentrates, temperature and social stress factors on lab research animals, genetic similarities and differences between species and genus in relation to correlating test procedures and results in empirical and double blind studies.
In an overwhelming number of discussions, it was determined and accepted that the concentrations frequently used in sensitivity tests for all sorts of products and pharmacological agents were quite often used and or administered in completely unreasonable concentrations and over time frames that would in many cases be lethal to any living thing. This frequently results in erroneous publication of public health warnings not at all based on real life occurrences under normal use. So I always keep in mind that trace amounts of most any OTC chemical sold to the general public are tolerable in normal use and that warnings about toxicity are all too often based on unrealistic scenarios.
As I and others mentioned, many different substances can and have been used quite successfully for the purpose of anchoring components to circuit boards. I don't recall anyone in my lifetime having to replace a cap because it was sealed to the PCB with RTV, hot glue, Liquid nail, silicone, foam tape, rubber cement, epoxy, etc.
That is not to say that these chemical concoctions do not off gas, but in the quantity and concentration they are used in, you would think some of us would have run across a few caps where the device was rendered useless and had to be replaced.
I had someone here tell me that internal mechanical disconnection of the leads on a large electrolytic axial caps was not possible and I responded that I should have saved some of the hundred or so from the last ten years.
The same holds true here. Let us see some actual examples (chemically verified by an independent lab) that the outer casing was breached and therefore the internal structure were damaged or destroyed by being exposed to a small amount of ANY of the adhesives of preference mentioned here.
Otherwise, let it go.
Yes, I am focused on aluminum electrolytic capacitors because they are the components most likely to require replacement over time and the larger snap-in's require bonding to the PCB - so this topic has great relevance on this forum.
Maybe I should have started with a discussion on how aluminum electrolytic capacitors fail. This is known in industry as FEMA (Failure Modes Effects Analysis). What are the aluminum electrolytic capacitor failure modes? Let’s do some research.
Sources:
Rubycon: Aluminum Electrolytic Capacitors - Typical failure modes and their factors
Panasonic: Reliability of Aluminum Electrolytic Capacitors
Pansonic and Rubycon have deterimed these failure modes:
1) capacitance reduction
2) tan d increase
3) leakage current increase
4) short circuit
5) open
6) failure to components on the capacitor periphery
Thus, the mode of capacitor failure isn’t always catastrophic in a very obvious way (i.e. open or short) but rather there are degradation failure modes where the capacitor or proximate circuit performance changes from the specified value. In degradation failure the stage at which the capacitor is judged as “failed” varies with the performance of the electronic device. For this purpose of this audiokarma forum, let’s assume that we are interested in obtaining the best audio performance possible from an electronic device.
Adhesives containing halogenated hydrocarbons have been identified as application factor cause of failure in both of the above FEMAs. These following capacitor makers caution against their use:
Nichicon: Application Guidelines for Aluminum Electrolytic Capacitors
“2-10-3 Fixing Material and Coating Material
1) Do not use any affixing or coating materials, which
contain halide substance.”
Elna: Cautions for Using Aluminum Electrolytic Capacitors
“Please read product specifications before using ELNA products.
The following cautions should be observed when using our aluminum electrolytic capacitors to assure their maximum stability and performance. When your application design conditions or operating conditions exceed the limit of the product specification, please contact us. If used under conditions beyond the limit of our specifications, it may cause defects such as short circuit, open circuit, leakage, explosion or combustion.”
“6. Fixing adhesives and coating materials.
(1)Do not use fixing adhesive or coating material
containing halogen-based solvent.”
Rubycon: CAUTION FOR PROPER USE OF ALUMINUM ELECTROLYTIC CAPACITORS
“9) ADHESIVES AND COATING MATERIALS
Do not use halogenated adhesives and coatings to fix aluminum electrolytic capacitors.”
Cornell Dublier Application Guide, Aluminum Electrolytic Capacitors
“Potting and gluing
Be certain that varnishing, coating, lacquering, embedding or gluing near the capacitors’ seals are halogen free. And be sure all constituent parts including base material, thinners, binders, reacting agents, propellants and additives are halogen free. If the printed circuit board has been cleaned with halogenated solvent, be sure it’s fully dry before installation of capacitors.”
EPCOS Aluminum Electrolytic Capacitors, General Technical Information
Because of this, measures must be taken to prevent electrolytic capacitors from coming into contact with the solvents when using halogenated hydrocarbon solvents to clean printed circuit boards after soldering the components, or to remove flux residues. If it is not possible to prevent the electrolytic capacitors from being wetted by the solvent, halogen-free solvents must be used in order to eliminate the possibility of damage."
Elcon: Capacitor Handling Techniques
“2.9 Mounting Adhesives and Coating Agents
When using mounting adhesives or coating agents to control humidity, avoid using materials containing halogenated solvents. Also, avoid the use of chloroprene based polymers.
*After applying adhesives or coatings, dry thoroughly to prevent residual solvents from being trapped between the capacitor and the circuit board.”
Shenzhen BoXinYuan Electronics Company: Precaution and Guidelines for Aluminum Electrolytic Capacitors
“Fixing Adhesives and Coating Materials
- Do not use adhesive or coating materials containing halogen-based solvent. ”
Reliability of Aluminum Electrolytic Capacitors
There are more, I'm tired of pasting them in.
OK. Some of the best audio-grade capacitor manufacturers (with far, far more collective experience than anyone on this forum) have concluded that adhesives containing halogenated hydrocarbons have been identified as application factor cause of degradation failure. If it isn't clear that you shouldn't use adhesive or coating materials containing halogen-based solvents, then facts are irrelevant to you and further reading will not benefit you.
Clearly the manufacturers’ FEMAs indicate that adhesives misuse may not result in an immediate catastrophic failure. This may align with your experience. But the FEMAs also indicate that the effects of adhesives misuse are degradation failure modes where the audio circuit performance will be effected. How would you know if your amp doesn't sound as good as it's design potential?
Why spend money on Elna Muse, Silmic II, Nichicon Hi-Sound electrolytics only to ignore the manufacturer’s adhesive application recommendations and risk degrading them? It doesn’t make any sense. Some may call this "the school of hard-knocks" but it's more "the school of self-inflicted wounds." I'm just trying to help others avoid pitfalls - it's astounding when some point to their own experience as proof that they could not possibly be wrong.
It’s not that I have some way of putting it. It’s just the way it is.
Maybe I should have started with a discussion on how aluminum electrolytic capacitors fail. This is known in industry as FEMA (Failure Modes Effects Analysis). What are the aluminum electrolytic capacitor failure modes? Let’s do some research.
Sources:
Rubycon: Aluminum Electrolytic Capacitors - Typical failure modes and their factors
Panasonic: Reliability of Aluminum Electrolytic Capacitors
Pansonic and Rubycon have deterimed these failure modes:
1) capacitance reduction
2) tan d increase
3) leakage current increase
4) short circuit
5) open
6) failure to components on the capacitor periphery
Thus, the mode of capacitor failure isn’t always catastrophic in a very obvious way (i.e. open or short) but rather there are degradation failure modes where the capacitor or proximate circuit performance changes from the specified value. In degradation failure the stage at which the capacitor is judged as “failed” varies with the performance of the electronic device. For this purpose of this audiokarma forum, let’s assume that we are interested in obtaining the best audio performance possible from an electronic device.
Adhesives containing halogenated hydrocarbons have been identified as application factor cause of failure in both of the above FEMAs. These following capacitor makers caution against their use:
Nichicon: Application Guidelines for Aluminum Electrolytic Capacitors
“2-10-3 Fixing Material and Coating Material
1) Do not use any affixing or coating materials, which
contain halide substance.”
Elna: Cautions for Using Aluminum Electrolytic Capacitors
“Please read product specifications before using ELNA products.
The following cautions should be observed when using our aluminum electrolytic capacitors to assure their maximum stability and performance. When your application design conditions or operating conditions exceed the limit of the product specification, please contact us. If used under conditions beyond the limit of our specifications, it may cause defects such as short circuit, open circuit, leakage, explosion or combustion.”
“6. Fixing adhesives and coating materials.
(1)Do not use fixing adhesive or coating material
containing halogen-based solvent.”
Rubycon: CAUTION FOR PROPER USE OF ALUMINUM ELECTROLYTIC CAPACITORS
“9) ADHESIVES AND COATING MATERIALS
Do not use halogenated adhesives and coatings to fix aluminum electrolytic capacitors.”
Cornell Dublier Application Guide, Aluminum Electrolytic Capacitors
“Potting and gluing
Be certain that varnishing, coating, lacquering, embedding or gluing near the capacitors’ seals are halogen free. And be sure all constituent parts including base material, thinners, binders, reacting agents, propellants and additives are halogen free. If the printed circuit board has been cleaned with halogenated solvent, be sure it’s fully dry before installation of capacitors.”
EPCOS Aluminum Electrolytic Capacitors, General Technical Information
Because of this, measures must be taken to prevent electrolytic capacitors from coming into contact with the solvents when using halogenated hydrocarbon solvents to clean printed circuit boards after soldering the components, or to remove flux residues. If it is not possible to prevent the electrolytic capacitors from being wetted by the solvent, halogen-free solvents must be used in order to eliminate the possibility of damage."
Elcon: Capacitor Handling Techniques
“2.9 Mounting Adhesives and Coating Agents
When using mounting adhesives or coating agents to control humidity, avoid using materials containing halogenated solvents. Also, avoid the use of chloroprene based polymers.
*After applying adhesives or coatings, dry thoroughly to prevent residual solvents from being trapped between the capacitor and the circuit board.”
Shenzhen BoXinYuan Electronics Company: Precaution and Guidelines for Aluminum Electrolytic Capacitors
“Fixing Adhesives and Coating Materials
- Do not use adhesive or coating materials containing halogen-based solvent. ”
Reliability of Aluminum Electrolytic Capacitors
There are more, I'm tired of pasting them in.
OK. Some of the best audio-grade capacitor manufacturers (with far, far more collective experience than anyone on this forum) have concluded that adhesives containing halogenated hydrocarbons have been identified as application factor cause of degradation failure. If it isn't clear that you shouldn't use adhesive or coating materials containing halogen-based solvents, then facts are irrelevant to you and further reading will not benefit you.
Clearly the manufacturers’ FEMAs indicate that adhesives misuse may not result in an immediate catastrophic failure. This may align with your experience. But the FEMAs also indicate that the effects of adhesives misuse are degradation failure modes where the audio circuit performance will be effected. How would you know if your amp doesn't sound as good as it's design potential?
Why spend money on Elna Muse, Silmic II, Nichicon Hi-Sound electrolytics only to ignore the manufacturer’s adhesive application recommendations and risk degrading them? It doesn’t make any sense. Some may call this "the school of hard-knocks" but it's more "the school of self-inflicted wounds." I'm just trying to help others avoid pitfalls - it's astounding when some point to their own experience as proof that they could not possibly be wrong.
It’s not that I have some way of putting it. It’s just the way it is.
Gizmologist
Member
I applaud your bibliographical skills
HOWEVER it does not change the evidence that no one here has ever had to replace a component under normal use, cleaning and /or construction techniques that has not been subjected to gross physical damage due to the demonstrated and proven effect of halogenated solvents and no other reason.
For that proof to be forthcoming, complete operational calibrated lab tests would need to be run and the results published in double blind tests. All other components in the circuit would have to be within spec'd tolerances so no other cause - electrical or chemical-of a specific component (i.e. electrolytic caps) failure could be identified.
This would also require an internal core inspection of the electrolytic structure and chemical analysis probably using a mass spectrometer to identify the concentration of halogen gaseous residue or the corrosive or other effects directly attributable to Halogenated compounds and no other substance.
That is not say that on rare occasions such damage may have occurred, but I am just looking for ONE verifiable case in the real world. So far, none have been found by anyone I know of.
Don't forget also that the very packaging this equipment comes in (styrofoam, plastic bags cardboard boxes sealed with hot glue or other adhesives) must be factored in as well if a claim that ONLY the adhesives used around capacitors to secure them to a specific circuit board is the ONLY possible cause for any detectable damage.
And now for something completely different.
HOWEVER it does not change the evidence that no one here has ever had to replace a component under normal use, cleaning and /or construction techniques that has not been subjected to gross physical damage due to the demonstrated and proven effect of halogenated solvents and no other reason.
For that proof to be forthcoming, complete operational calibrated lab tests would need to be run and the results published in double blind tests. All other components in the circuit would have to be within spec'd tolerances so no other cause - electrical or chemical-of a specific component (i.e. electrolytic caps) failure could be identified.
This would also require an internal core inspection of the electrolytic structure and chemical analysis probably using a mass spectrometer to identify the concentration of halogen gaseous residue or the corrosive or other effects directly attributable to Halogenated compounds and no other substance.
That is not say that on rare occasions such damage may have occurred, but I am just looking for ONE verifiable case in the real world. So far, none have been found by anyone I know of.
Don't forget also that the very packaging this equipment comes in (styrofoam, plastic bags cardboard boxes sealed with hot glue or other adhesives) must be factored in as well if a claim that ONLY the adhesives used around capacitors to secure them to a specific circuit board is the ONLY possible cause for any detectable damage.
And now for something completely different.
That was completely different...
Evidence. What evidence? "That no one on this forum here has ever had to replace a component under normal use, blah, blah..."
Your "evidence" reads like this:
"No one that I or my family knows has ever had health problems from smoking cigarettes. Therefore cigarettes must be safe. I can safely ignore published medical data and the warnings that cigarette manufacturers place on cigarette packs until a smoker whom we know actually dies. And even then complete lab tests would need to be run and the results published in double blind tests. All other possible factors in the individual's life would have to be known within spec'd tolerances so no other cause - biological or chemical could be identified. This would also require an autopsy of the body and chemical analysis probably using a mass spectrometer to identify the concentration of nicotine, CO and tobacco biproducts or the carcinogen directly attributable to tobacco smoke compounds and no other substance. That is not say that on rare occasions health problems due to cigarette smoking may have occurred, but I am just looking for ONE verifiable case in my world. So far, none have been found by anyone I know of."
That's not evidence, it's a fallacious argument.
Um, dude, the capacitor manufacturers have done the research and published the data and the warnings.
If by applauding my bibliographical skills you mean that you think I got my facts right - thanks, but I don't think the facts helped you.
Gizmologist
Member
Aren't you glad
I wasn't asking for your help?
Coffee time!
I wasn't asking for your help?
Coffee time!
Characterization and reliability of electrolytic capacitors exposedto halogenated solvents
MaSaitis, R.L.; Muller, A.J.; Opila, R.L.; Psota-Kelty, L.A.; Daoud, S.
Electronic Components and Technology Conference, 1992. Proceedings., 42nd
Volume , Issue , 18-20 May 1992 Page(s):611 - 616
Digital Object Identifier 10.1109/ECTC.1992.204266
Summary:To determine the effect of exposure to halogenated solvents on electrolytic-capacitor lifetime, populations of these capacitors were exposed to accelerated testing. It is shown that halogenated solvents cause electrolytic capacitors to fail open at the anode. The electrolytic corrosion, which dissolves the passivating oxide layer on the anodically biased aluminum and exposes a clean aluminum surface, is the rate limiting step in the failures. Halogenated solvents then readily react with the aluminum surface and erode the electrode until the solvent is consumed. The increase in pressure inside the capacitor can cause the capacitor to vent, further accelerating failure. Accelerated life testing of one of the capacitor types considered suggests that it may fail at normal operating conditions in 2-3 years. Monitoring of capacitor characteristics during the accelerated life test shows that changes in these characteristic parameters cannot be used to predict failure
feeding the troll:
One hundred capacitors, fifty of each type, were exposed to
halogenated solvents in a two part process. Each capacitor was
fist vapor degreased with Freon TMS+ for a total exposure of 15-
20 seconds. Freon TMS+ is 91.5% 1,1,2-trichloro-1,2,2-
trifluoroethane, 4% ethanol, 4% methanol, and 0.5% nitromethane.
The capacitors were then immersed in a mixture containing 41%
l,l,l-trichloroethane, 32% toluene, and 27% soluble inert solids
for 80-100 seconds and dried to simulate a capacitor coating
process.
Again unrealistic scenarios. Companies have to state what you are buying into because they need to cover their ass from all liability.
I'm even kind enough to download the study and post free of charge. PSh... don't tell ieeex.
MaSaitis, R.L.; Muller, A.J.; Opila, R.L.; Psota-Kelty, L.A.; Daoud, S.
Electronic Components and Technology Conference, 1992. Proceedings., 42nd
Volume , Issue , 18-20 May 1992 Page(s):611 - 616
Digital Object Identifier 10.1109/ECTC.1992.204266
Summary:To determine the effect of exposure to halogenated solvents on electrolytic-capacitor lifetime, populations of these capacitors were exposed to accelerated testing. It is shown that halogenated solvents cause electrolytic capacitors to fail open at the anode. The electrolytic corrosion, which dissolves the passivating oxide layer on the anodically biased aluminum and exposes a clean aluminum surface, is the rate limiting step in the failures. Halogenated solvents then readily react with the aluminum surface and erode the electrode until the solvent is consumed. The increase in pressure inside the capacitor can cause the capacitor to vent, further accelerating failure. Accelerated life testing of one of the capacitor types considered suggests that it may fail at normal operating conditions in 2-3 years. Monitoring of capacitor characteristics during the accelerated life test shows that changes in these characteristic parameters cannot be used to predict failure
feeding the troll:
One hundred capacitors, fifty of each type, were exposed to
halogenated solvents in a two part process. Each capacitor was
fist vapor degreased with Freon TMS+ for a total exposure of 15-
20 seconds. Freon TMS+ is 91.5% 1,1,2-trichloro-1,2,2-
trifluoroethane, 4% ethanol, 4% methanol, and 0.5% nitromethane.
The capacitors were then immersed in a mixture containing 41%
l,l,l-trichloroethane, 32% toluene, and 27% soluble inert solids
for 80-100 seconds and dried to simulate a capacitor coating
process.
Again unrealistic scenarios. Companies have to state what you are buying into because they need to cover their ass from all liability.
I'm even kind enough to download the study and post free of charge. PSh... don't tell ieeex.
Study contradicts your statements. If by your statement, you are looking to get the best audio performance, then you'll get quality components and if so, read on:
Capacitors from two vendors were randomly distributed
between the four cells from Type B. One vendor's capacitors
proved to be significantly more reliable than the other vendor's;
only 3 failures were observed for the good vendor from 20
capacitors distributed throughout the four cells. The less vulnerable
capacitors were not analyzed further. Since these capacitors are
significantly more expensive than the more vulnerable capacitor
and the more vulnerable capacitors perform adequately when not
exposed to halogenated solvents, the less vulnerable capacitors are
no longer purchased. However, they were analyzed to determine
why they were relatively invulnerable with respect to exposure to
halogenated solvents and these results will be discussed below.
In the accelerated testing, one vendor's capacitors appeared
to be much more reliable after exposure to halogenated solvents.
These capacitors were analyzed and their reliability was attributed
to two factors. First, the seal between the gasket and the electrode
leads was much better, thereby limiting the amount of halogenated
solvent that entered the capacitor. In addition, large quantities of
Cd were found on the anode riser. Cd plate is occasionally used to
passivate aluminum surfaces with respect to electrolytic corrosion
[9]. If the electrolytic reaction is unable to dissolve the aluminum
oxide, the organometallic reaction will not proceed. Thus, by
limiting the diffusion of solvent into the capacitor and by
passivating the electrode surface, a more reliable capacitor is
produced.
Since this is audiokarma and not avsforums, everyone uses quality components and your shananigans thus not apply...
Q.E.D.
Chingon: thanks for the link to the study. The study introduction states the thesis:
"Aluminum electrolytic capacitors are a common component in electronic equipment, yet can fail catastrophically if inadvertently exposed to halogenated solvents. Although the attack of halogenated hydrocarbons on bare aluminum has been recognized for some time [1,2]. the detailed mechanism of this corrosion, especially in the case of aluminum electrolytic capacitors, has received little attention. In this work, we use the results of both accelerated life test experiments and chemical analysis of failed capacitors to determine the failure mechanism of electrolytic capacitors exposed to halogenated solvents." That is exactly my point.
It is not correct to say that accelerated life testing (ALT) is an unrealistic scenario: the purpose of ALT is to induce field failure modes in the laboratory but at a much faster rate so that the field failure rate can be known in advance. In ALT the device is expected to fail in the lab just as it would in the field - but in much less time. ALT permits failure modes to be discovered and failure rates to be predicted.
Some study conclusions:
- Accelerated life testing of Type B (120uF/60V operating at 51V) capacitors suggests that Type B may fail at normal operating conditions in 2-3 years.!
- "The 95% confidence bounds for the extrapolation predict that at 1 year between 0.02 and 99.7% of the capacitors will fail and at 11 years between 0.3 and 100% will fail." The study shows plots of the cumulative failure distributions versus time. Every plot shows at least a 10% failure at 500 hours! No wonder the cap makers warn against using adhesives with halogenated hydrocarbons.
In industry we would use this data to predict warranty costs. My reading of the study suggests that one should avoid adhesives with halogenated hydrocarbons unless the cost-savings of the adhesive is sufficiently large enough to more than cover the predicted warranty expenses. With failures somewhere between 0.02% and 99.7% this is "halogenated hydrocarbon" roulette.
BTW the for the more reliable caps in the study "large quantities of Cd were found on the anode riser." Cd is cadmium. For RoHS the maximum concentration value by weight is 0.01%. I wouldn't expect to find large quantities of Cd in current mass-production caps.
The study supports capacitor manufacturer warnings. Thanks for weighing in.
"Aluminum electrolytic capacitors are a common component in electronic equipment, yet can fail catastrophically if inadvertently exposed to halogenated solvents. Although the attack of halogenated hydrocarbons on bare aluminum has been recognized for some time [1,2]. the detailed mechanism of this corrosion, especially in the case of aluminum electrolytic capacitors, has received little attention. In this work, we use the results of both accelerated life test experiments and chemical analysis of failed capacitors to determine the failure mechanism of electrolytic capacitors exposed to halogenated solvents." That is exactly my point.
It is not correct to say that accelerated life testing (ALT) is an unrealistic scenario: the purpose of ALT is to induce field failure modes in the laboratory but at a much faster rate so that the field failure rate can be known in advance. In ALT the device is expected to fail in the lab just as it would in the field - but in much less time. ALT permits failure modes to be discovered and failure rates to be predicted.
Some study conclusions:
- Accelerated life testing of Type B (120uF/60V operating at 51V) capacitors suggests that Type B may fail at normal operating conditions in 2-3 years.!
- "The 95% confidence bounds for the extrapolation predict that at 1 year between 0.02 and 99.7% of the capacitors will fail and at 11 years between 0.3 and 100% will fail." The study shows plots of the cumulative failure distributions versus time. Every plot shows at least a 10% failure at 500 hours! No wonder the cap makers warn against using adhesives with halogenated hydrocarbons.
In industry we would use this data to predict warranty costs. My reading of the study suggests that one should avoid adhesives with halogenated hydrocarbons unless the cost-savings of the adhesive is sufficiently large enough to more than cover the predicted warranty expenses. With failures somewhere between 0.02% and 99.7% this is "halogenated hydrocarbon" roulette.
BTW the for the more reliable caps in the study "large quantities of Cd were found on the anode riser." Cd is cadmium. For RoHS the maximum concentration value by weight is 0.01%. I wouldn't expect to find large quantities of Cd in current mass-production caps.
The study supports capacitor manufacturer warnings. Thanks for weighing in.
davesnewTT
justdavesTT
"The 95% confidence bounds for the extrapolation predict that at 1 year between 0.02 and 99.7% of the capacitors will fail and at 11 years between 0.3 and 100% will fail."
So they can confidently predict that the number of failures will be between none and all? Well, that's cleared everything right up.
So they can confidently predict that the number of failures will be between none and all? Well, that's cleared everything right up.
"The 95% confidence bounds for the extrapolation predict that at 1 year between 0.02 and 99.7% of the capacitors will fail and at 11 years between 0.3 and 100% will fail."
So they can confidently predict that the number of failures will be between none and all? Well, that's cleared everything right up.
:lmao::lmao::lmao:
"The 95% confidence bounds for the extrapolation predict that at 1 year between 0.02 and 99.7% of the capacitors will fail and at 11 years between 0.3 and 100% will fail."
So they can confidently predict that the number of failures will be between none and all? Well, that's cleared everything right up.
Here's how to read this study statement: it is 95% certain that the true percentage of capacitors that will fail at 1 year is between 0.02% and 99.7% and it is 95% certain that the true percentage of capacitors that will fail at 11 years is between 0.3% and 99.7%.
Think of it this way: imagine that you are a manufacturing engineer at Arcam and you have the above data, including the warnings from manufacturers. Would you select an adhesive that will (to a statistical certainty) induce between 0.02% and 99.7% failures at 1 year? Or would you select an adhesive that is statistically not known to cause failures?
There is no benefit in recommending a halogenated hydrocarbon adhesive. The downside risk is too great - potentially high enough to put a product line out of business :tears:.
This same decision-making process applies to members of this forum; only the stakes are a lot lower.
Hope this helps.
Gizmologist
Member
Hey guys
We forgot about the one product that works for everything and is available everywhere-- DUCK tape (not duct tape as that is metalized and we will start this whole silliness all over again)
OR as a back-up Juicy Fruit or Doublemint.
heading over to Lowe's now to buy some LIQUID NAIL.
We forgot about the one product that works for everything and is available everywhere-- DUCK tape (not duct tape as that is metalized and we will start this whole silliness all over again)
OR as a back-up Juicy Fruit or Doublemint.
heading over to Lowe's now to buy some LIQUID NAIL.