Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Default What is the shelf life of common adhesives?

I've been in the repair biz for too long. I can tell because some of
the adhesives in my disorganized collection are at least 10 years old.
Yesterday, I had to glue an HP Envy m6-1125dx laptop hinge mount back
together after the left a lump of something on the keyboard, and
closed the LCD lid. The weak spot was where HP had glued the metal
attachment point for the hinge to the aluminum cover and plastic
frame. Miserable design and crappy workmanship, but I can't complain
because that's why I'm still in business.

I tried cyanoacrylate adhesive, 5 minute epoxy, 24 hr epoxy, RTV,
Elmers contact cement, and Duco cement. Nothing worked. The glues
either remained tacky after 24 hrs, hardened in the tube, or crumbled
when stressed. Hardening in the tube is an obvious sign of old age,
but I've never had Duco cement turn to powder when it hardens.

Yes, I cleaned off the old glue between applications and carefully
removed any residue and oils with acetone.

So, I walked to the nearest hardware store, and bought a few
overpriced tubes of epoxy and other adhesives. Right now, I'm trying
some J-B Weld KwikWeld (sets in 6 minutes). Watching glue dry didn't
seem very productive, so I thought I would ask a few questions instead
of Googling for the answers.

Few of the package, bottles, or tubes, show an expiration date for
either shelf life, or shelf life after the bottle is opened. The
exception is RTV, which is formulated to harden in the tube after
about 1 year whether new or opened. Gorilla Glue seems to harden in
the tube about 3 months after the tube is first used.

So, in your experience, what are the approximate shelf lives of these
common adhesives?
Devcon or Ace 5 minute epoxy
Devcon or Ace 24 hr epoxy
Devcon or Ace Plastic repair epoxy
JB-Weld KwikWeld
JB-Weld
Gorrila Glue (water activated polyurethane)
Elmer's or Weldwood Contact Cement
Duco cement
RTV sealant
Barge Cement
Super Glue (cyanoacrylate)
Super Glue Gel
Elmer's white glue
Elmer's wood glue
Elmer's Craft Bond Rubber cement

Back to watching the glue dry... Thanks.

--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
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Default What is the shelf life of common adhesives?

I'd bet the manufacturers web sites would have information on shelf life. Double what they claim, and you'll have a more realistic number.

Refrigeration extends the working life of most adhesives.
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Default What is the shelf life of common adhesives?

Terry Schwartz wrote:

----------------------


I'd bet the manufacturers web sites would have information on shelf
life. Double what they claim, and you'll have a more realistic number.


** Double ??

Refrigeration extends the working life of most adhesives.



** A local supermarket store was offering a nice discount on 100gm tubes of famous brand silicone adhesive, the "neutral cure" type that is useful in electronics.

I bought two tubes and soon found they had been filled with "acid cure " material - no use at all as the acetic acid vapour corrodes any copper it gets near.

The warehouse asked me to send them the bad tubes for appraisal and shortly afterwards a parcel arrived with 12 tubes of the correct "neutral cure" type.

Unfortunately, most of the 12 tubes had gone rock hard they were so old.


..... Phil
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Default What is the shelf life of common adhesives?

On Thu, 25 Jan 2018 19:09:47 -0800 (PST), Terry Schwartz
wrote:

I'd bet the manufacturers web sites would have information
on shelf life. Double what they claim, and you'll have
a more realistic number.


Double of what claim? I can't seem to find shelf life, or how long it
lasts after it's opened, for most adhesives. Have you actually
experienced double an unstated shelf life?

Refrigeration extends the working life of most adhesives.


As Phil mentioned, that doesn't work. I've tried the same thing with
RTV (silicone seal) caulk tubes. It's about the same with or without
refrigeration. It lasts about a year no matter what I tried. For
example:
http://www.accumetricinc.com/uplimg/dynatex/tds/49274.pdf
"When stored in the original unopened containers
at or below 90F (32C), Dynatex Clear
Silicone Adhesive/Sealant has a shelf life of 12 months
from date of shipment."
That means if it's been sitting around collecting dust at the hardware
store for 6 months, you might have 6 months of useful life. If you've
used the tube, it's likely to be less than 6 months.

I appreciate your comments, but it would be more helpful if you
provided your experience with adhesive shelf life and lifetimes rather
than guessing what it might be under contrived circumstances.

Update: The JB Weld KwikWeld didn't hold. Instead of drying hard as
the proverbial rock, it dried into something more like hard rubber.
Apply a bit of force to the hinges and it fell apart. I also bought
some Devcon 2 ton epoxy. However, when I tried to squeeze out the
resin, I found it to be crystallized in the tube. I mixed it anyway
to see what would happen. The result was something that looked like
hard styrofoam, full of air/gas bubbles. Useless.

I just found a "new" tube of Ace Hardware 24 hr epoxy that looks good.
Hopefully, it will hold together. This is getting ridiculous.


--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
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Default What is the shelf life of common adhesives?

On 2018/01/25 5:27 PM, Jeff Liebermann wrote:
I've been in the repair biz for too long. I can tell because some of
the adhesives in my disorganized collection are at least 10 years old.
Yesterday, I had to glue an HP Envy m6-1125dx laptop hinge mount back
together after the left a lump of something on the keyboard, and
closed the LCD lid. The weak spot was where HP had glued the metal
attachment point for the hinge to the aluminum cover and plastic
frame. Miserable design and crappy workmanship, but I can't complain
because that's why I'm still in business.

I tried cyanoacrylate adhesive, 5 minute epoxy, 24 hr epoxy, RTV,
Elmers contact cement, and Duco cement. Nothing worked. The glues
either remained tacky after 24 hrs, hardened in the tube, or crumbled
when stressed. Hardening in the tube is an obvious sign of old age,
but I've never had Duco cement turn to powder when it hardens.

Yes, I cleaned off the old glue between applications and carefully
removed any residue and oils with acetone.

So, I walked to the nearest hardware store, and bought a few
overpriced tubes of epoxy and other adhesives. Right now, I'm trying
some J-B Weld KwikWeld (sets in 6 minutes). Watching glue dry didn't
seem very productive, so I thought I would ask a few questions instead
of Googling for the answers.

Few of the package, bottles, or tubes, show an expiration date for
either shelf life, or shelf life after the bottle is opened. The
exception is RTV, which is formulated to harden in the tube after
about 1 year whether new or opened. Gorilla Glue seems to harden in
the tube about 3 months after the tube is first used.

So, in your experience, what are the approximate shelf lives of these
common adhesives?
Devcon or Ace 5 minute epoxy
Devcon or Ace 24 hr epoxy
Devcon or Ace Plastic repair epoxy
JB-Weld KwikWeld
JB-Weld
Gorrila Glue (water activated polyurethane)
Elmer's or Weldwood Contact Cement
Duco cement
RTV sealant
Barge Cement
Super Glue (cyanoacrylate)
Super Glue Gel
Elmer's white glue
Elmer's wood glue
Elmer's Craft Bond Rubber cement

Back to watching the glue dry... Thanks.


Just about all epoxies have a shelf life of one to three years. Same if
opened.

Gorilla epoxy seems to last the same.

Cyanoacrylates if opened last only up to a year at most, otherwise a
year or two in the sealed tube. Gels don't last as long as the liquids.

White/wood (Carpenters grade is what we use) glue lasts a long time as
long as it is sealed, we have a bottle that is at least five years old
and it works just fine.

Rubber cement hardens in the can after about five years if sealed, one
year if ever opened.

RTV seems to last a few years if sealed and only a few months if the
tube is ever opened.

Gluing metal to metal is difficult at the best of times. Any chance you
can use silver solder? I yet to find a suitable consumer grade glue that
secures metal to metal reliably.

John :-#(#

--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd.
MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
(604)872-5757 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."


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Default What is the shelf life of common adhesives?

On 26/01/2018 01:27, Jeff Liebermann wrote:
I've been in the repair biz for too long. I can tell because some of
the adhesives in my disorganized collection are at least 10 years old.
Yesterday, I had to glue an HP Envy m6-1125dx laptop hinge mount back
together after the left a lump of something on the keyboard, and
closed the LCD lid. The weak spot was where HP had glued the metal
attachment point for the hinge to the aluminum cover and plastic
frame. Miserable design and crappy workmanship, but I can't complain
because that's why I'm still in business.

I tried cyanoacrylate adhesive, 5 minute epoxy, 24 hr epoxy, RTV,
Elmers contact cement, and Duco cement. Nothing worked. The glues
either remained tacky after 24 hrs, hardened in the tube, or crumbled
when stressed. Hardening in the tube is an obvious sign of old age,
but I've never had Duco cement turn to powder when it hardens.

Yes, I cleaned off the old glue between applications and carefully
removed any residue and oils with acetone.

So, I walked to the nearest hardware store, and bought a few
overpriced tubes of epoxy and other adhesives. Right now, I'm trying
some J-B Weld KwikWeld (sets in 6 minutes). Watching glue dry didn't
seem very productive, so I thought I would ask a few questions instead
of Googling for the answers.

Few of the package, bottles, or tubes, show an expiration date for
either shelf life, or shelf life after the bottle is opened. The
exception is RTV, which is formulated to harden in the tube after
about 1 year whether new or opened. Gorilla Glue seems to harden in
the tube about 3 months after the tube is first used.

So, in your experience, what are the approximate shelf lives of these
common adhesives?
Devcon or Ace 5 minute epoxy
Devcon or Ace 24 hr epoxy
Devcon or Ace Plastic repair epoxy
JB-Weld KwikWeld
JB-Weld
Gorrila Glue (water activated polyurethane)
Elmer's or Weldwood Contact Cement
Duco cement
RTV sealant
Barge Cement
Super Glue (cyanoacrylate)
Super Glue Gel
Elmer's white glue
Elmer's wood glue
Elmer's Craft Bond Rubber cement

Back to watching the glue dry... Thanks.


Store superglue in sealed jamjars with a transparent sachet of activated
silica gel or if in a sachet thensome loose crystals in the jar also ,no
trouble after 5 years.
Use gel with a colour indicator for dry/damp, not too obvious with plain
white/off-white colour of damp/dry silica crystals
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Default What is the shelf life of common adhesives?

Phil Allison wrote:
Terry Schwartz wrote:

----------------------


I'd bet the manufacturers web sites would have information on shelf
life. Double what they claim, and you'll have a more realistic number.


** Double ??

Refrigeration extends the working life of most adhesives.



** A local supermarket store was offering a nice discount on 100gm tubes
of famous brand silicone adhesive, the "neutral cure" type that is useful in electronics.

I bought two tubes and soon found they had been filled with "acid cure "
material - no use at all as the acetic acid vapour corrodes any copper it gets near.

The warehouse asked me to send them the bad tubes for appraisal and
shortly afterwards a parcel arrived with 12 tubes of the correct "neutral cure" type.

Unfortunately, most of the 12 tubes had gone rock hard they were so old.


.... Phil


I never found acid cure do much of anything to copper. I put some on
circuit board to test. Contrary to reading, i believe the stuff passes
moisture and corrode metal underneath.

Greg
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Default What is the shelf life of common adhesives?

Jeff Liebermann wrote:
I've been in the repair biz for too long. I can tell because some of
the adhesives in my disorganized collection are at least 10 years old.
Yesterday, I had to glue an HP Envy m6-1125dx laptop hinge mount back
together after the left a lump of something on the keyboard, and
closed the LCD lid. The weak spot was where HP had glued the metal
attachment point for the hinge to the aluminum cover and plastic
frame. Miserable design and crappy workmanship, but I can't complain
because that's why I'm still in business.

I tried cyanoacrylate adhesive, 5 minute epoxy, 24 hr epoxy, RTV,
Elmers contact cement, and Duco cement. Nothing worked. The glues
either remained tacky after 24 hrs, hardened in the tube, or crumbled
when stressed. Hardening in the tube is an obvious sign of old age,
but I've never had Duco cement turn to powder when it hardens.

Yes, I cleaned off the old glue between applications and carefully
removed any residue and oils with acetone.

So, I walked to the nearest hardware store, and bought a few
overpriced tubes of epoxy and other adhesives. Right now, I'm trying
some J-B Weld KwikWeld (sets in 6 minutes). Watching glue dry didn't
seem very productive, so I thought I would ask a few questions instead
of Googling for the answers.

Few of the package, bottles, or tubes, show an expiration date for
either shelf life, or shelf life after the bottle is opened. The
exception is RTV, which is formulated to harden in the tube after
about 1 year whether new or opened. Gorilla Glue seems to harden in
the tube about 3 months after the tube is first used.

So, in your experience, what are the approximate shelf lives of these
common adhesives?
Devcon or Ace 5 minute epoxy
Devcon or Ace 24 hr epoxy
Devcon or Ace Plastic repair epoxy
JB-Weld KwikWeld
JB-Weld
Gorrila Glue (water activated polyurethane)
Elmer's or Weldwood Contact Cement
Duco cement
RTV sealant
Barge Cement
Super Glue (cyanoacrylate)
Super Glue Gel
Elmer's white glue
Elmer's wood glue
Elmer's Craft Bond Rubber cement

Back to watching the glue dry... Thanks.


I often use GOOP as it's tuff, sticks well, slightly flexible. Also similar
E6000. takes some days to fully dry. Stuff evaporates from tube if put on
wrong.


Greg
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Default What is the shelf life of common adhesives?

On Friday, 26 January 2018 01:27:23 UTC, Jeff Liebermann wrote:
I've been in the repair biz for too long. I can tell because some of
the adhesives in my disorganized collection are at least 10 years old.
Yesterday, I had to glue an HP Envy m6-1125dx laptop hinge mount back
together after the left a lump of something on the keyboard, and
closed the LCD lid. The weak spot was where HP had glued the metal
attachment point for the hinge to the aluminum cover and plastic
frame. Miserable design and crappy workmanship, but I can't complain
because that's why I'm still in business.

I tried cyanoacrylate adhesive, 5 minute epoxy, 24 hr epoxy, RTV,
Elmers contact cement, and Duco cement. Nothing worked. The glues
either remained tacky after 24 hrs, hardened in the tube, or crumbled
when stressed. Hardening in the tube is an obvious sign of old age,
but I've never had Duco cement turn to powder when it hardens.

Yes, I cleaned off the old glue between applications and carefully
removed any residue and oils with acetone.

So, I walked to the nearest hardware store, and bought a few
overpriced tubes of epoxy and other adhesives. Right now, I'm trying
some J-B Weld KwikWeld (sets in 6 minutes). Watching glue dry didn't
seem very productive, so I thought I would ask a few questions instead
of Googling for the answers.

Few of the package, bottles, or tubes, show an expiration date for
either shelf life, or shelf life after the bottle is opened. The
exception is RTV, which is formulated to harden in the tube after
about 1 year whether new or opened. Gorilla Glue seems to harden in
the tube about 3 months after the tube is first used.

So, in your experience, what are the approximate shelf lives of these
common adhesives?
Devcon or Ace 5 minute epoxy
Devcon or Ace 24 hr epoxy
Devcon or Ace Plastic repair epoxy
JB-Weld KwikWeld
JB-Weld
Gorrila Glue (water activated polyurethane)
Elmer's or Weldwood Contact Cement
Duco cement
RTV sealant
Barge Cement
Super Glue (cyanoacrylate)
Super Glue Gel
Elmer's white glue
Elmer's wood glue
Elmer's Craft Bond Rubber cement

Back to watching the glue dry... Thanks.


I've got epoxy in plastic tubes bought somewhere around 15 years ago, it's still fine.

The rest probably is nothing new...
Cyanoacrylate never keeps well, but I've not tried anything special with it.
Glues generally last best afer opening if capped off with ali foil, for containers that have no lid. Plastic film just doesn't do it.
White pva lasts over a decade no problem, but some can moulder in the gallon container.
Bitumen glue lasts well if the solvent doesn't disappear, it can always be redissolved with paraffin/kerosene. Never use diesel.


NT
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Default What is the shelf life of common adhesives?

Jeff, you ARE the authority on most everything, so I probably should bow to your expertise. (But I won't) After all, you have been in the repair biz too long.

Re-read Phils post -- he did not mention refrigeration "not working". He said the replacement tubes were "so old".

Double unstated? What does that even mean? Obviously if it's unstated, even 1 day is potentially double that.

YES I've had success refrigerating adhesives and silicones. Cold always slows chemical reactions, it's basic chemistry. I've had sealed tubes of caulk last 5 years in my garage fridge. Please be cautious about accusing me of "contriving" anything.

I also refrigerate batteries, and I've got some Panasonic industrial C cells that are still at full cell voltage after more than 10 years.

So you did find something regarding shelf life? Or not? Which is it?

Unopened tubes of adhesive, if well manufactured and packaged, seem to last a long time. I've had silicones and cyanoacrylates last for many years. I have limited experience with epoxies, but one tube of plastic-specific epoxy has lasted at least two years -- even after being opened.

I almost always seem to be able to find a manufacture date on the tube, either printed or on a crimp. Not so much on the tiny drugstore "superglue" packages. Reputable manufacturers commonly publish a short number for shelf life, (sometimes you have to actually ask for it) as you saw, 12 months, but in reality, that is a CYA number so that the consumer will 1) not be disappointed when his 2 year past date product goes bad, and 2) feel the need to buy another tube and when the stuff only *might* be bad. Helps revenue.

I've found 3+ year old product on the shelves in the orange big box home stores. Caveat Emptor. Their warehouses do not have a FIFO system, and are not climate controlled.


I appreciate your comments, but it would be more helpful if you
provided your experience with adhesive shelf life and lifetimes rather
than guessing what it might be under contrived circumstances.




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On Friday, 26 January 2018 13:32:19 UTC, Terry Schwartz wrote:

I also refrigerate batteries, and I've got some Panasonic industrial C cells that are still at full cell voltage after more than 10 years.


I've still got some unrefrigerated ZnC & alkaline cells almost twice that age, so yours should last a long time yet. What I notice is that while most keep, a minority go from full to zero at some point. It's as if some sort of fault occurs internally and they then drain out.


NT
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On Thu, 25 Jan 2018 17:27:13 -0800, Jeff Liebermann wrote:
So, in your experience, what are the approximate shelf lives of these
common adhesives?
RTV sealant


REF: https://groups.google.com/forum/#!topic/sci.electronics.repair/t5xXvDn_T-U

I have ten year old unopened Toyota FIPG (aka RTV) that I "hope" to use for
a valve cover gasket. I "hope" it's still good.

I do know that the tube of Home Depot gray-putty-like two-part
"tootsie-roll" epoxy (with the cream in the middle) does NOT last more than
about 5 years (ask me how I know).

The epoxy still works, but once opened, and half used, the rest dries out
easily (I didn't re-wrap it though).

Likewise with "opened" cyanoacrylate ... I buy the *smallest* tubes I can
find, because, to me, they're single-use only. They may last a few weeks
once opened, maybe even a few months ... but not more than that.

The bigger bottles get runny ... like water ... and never stick, in my
experience.
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On Thu, 25 Jan 2018 17:27:13 -0800, Jeff Liebermann
wrote:

I've been in the repair biz for too long. I can tell because some of
the adhesives in my disorganized collection are at least 10 years old.
Yesterday, I had to glue an HP Envy m6-1125dx laptop hinge mount back
together after the left a lump of something on the keyboard, and
closed the LCD lid. The weak spot was where HP had glued the metal
attachment point for the hinge to the aluminum cover and plastic
frame. Miserable design and crappy workmanship, but I can't complain
because that's why I'm still in business.

I tried cyanoacrylate adhesive, 5 minute epoxy, 24 hr epoxy, RTV,
Elmers contact cement, and Duco cement. Nothing worked. The glues
either remained tacky after 24 hrs, hardened in the tube, or crumbled
when stressed. Hardening in the tube is an obvious sign of old age,
but I've never had Duco cement turn to powder when it hardens.

Yes, I cleaned off the old glue between applications and carefully
removed any residue and oils with acetone.

So, I walked to the nearest hardware store, and bought a few
overpriced tubes of epoxy and other adhesives. Right now, I'm trying
some J-B Weld KwikWeld (sets in 6 minutes). Watching glue dry didn't
seem very productive, so I thought I would ask a few questions instead
of Googling for the answers.

Few of the package, bottles, or tubes, show an expiration date for
either shelf life, or shelf life after the bottle is opened. The
exception is RTV, which is formulated to harden in the tube after
about 1 year whether new or opened. Gorilla Glue seems to harden in
the tube about 3 months after the tube is first used.

So, in your experience, what are the approximate shelf lives of these
common adhesives?
Devcon or Ace 5 minute epoxy
Devcon or Ace 24 hr epoxy
Devcon or Ace Plastic repair epoxy
JB-Weld KwikWeld
JB-Weld
Gorrila Glue (water activated polyurethane)
Elmer's or Weldwood Contact Cement
Duco cement
RTV sealant
Barge Cement
Super Glue (cyanoacrylate)
Super Glue Gel
Elmer's white glue
Elmer's wood glue
Elmer's Craft Bond Rubber cement

Back to watching the glue dry... Thanks.

Greetings Jeff,
I don't know about the shelf life but I do know about bonding metals
with epoxies. Aluminum can be especially hard to get a good bond on
because of the oxide coat. But this problem is fairly easily overcome.
Apply the epoxy to a clean oil and grease free surface. Then use a
small stainless wire brush to scrub the epoxy covered surface. Using
this method keeps oxygen away from the aluminum during the scrubbing
and the scrubbing action removes the super thin oxide coat. The
particles of aluminum oxide just get mixed into the epoxy. The epoxy
will wet the now oxide free aluminum surface. This process also works
when trying to solder aluminum. I have had to prove to a couple people
while they watched that this method works.
Eric
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Default What is the shelf life of common adhesives?

On Thursday, January 25, 2018 at 8:27:23 PM UTC-5, Jeff Liebermann wrote:
I've been in the repair biz for too long. I can tell because some of
the adhesives in my disorganized collection are at least 10 years old.
Yesterday, I had to glue an HP Envy m6-1125dx laptop hinge mount back
together after the left a lump of something on the keyboard, and
closed the LCD lid. The weak spot was where HP had glued the metal
attachment point for the hinge to the aluminum cover and plastic
frame. Miserable design and crappy workmanship, but I can't complain
because that's why I'm still in business.

I tried cyanoacrylate adhesive, 5 minute epoxy, 24 hr epoxy, RTV,
Elmers contact cement, and Duco cement. Nothing worked. The glues
either remained tacky after 24 hrs, hardened in the tube, or crumbled
when stressed. Hardening in the tube is an obvious sign of old age,
but I've never had Duco cement turn to powder when it hardens.

Yes, I cleaned off the old glue between applications and carefully
removed any residue and oils with acetone.

So, I walked to the nearest hardware store, and bought a few
overpriced tubes of epoxy and other adhesives. Right now, I'm trying
some J-B Weld KwikWeld (sets in 6 minutes). Watching glue dry didn't
seem very productive, so I thought I would ask a few questions instead
of Googling for the answers.

Few of the package, bottles, or tubes, show an expiration date for
either shelf life, or shelf life after the bottle is opened. The
exception is RTV, which is formulated to harden in the tube after
about 1 year whether new or opened. Gorilla Glue seems to harden in
the tube about 3 months after the tube is first used.

So, in your experience, what are the approximate shelf lives of these
common adhesives?
Devcon or Ace 5 minute epoxy
Devcon or Ace 24 hr epoxy
Devcon or Ace Plastic repair epoxy
JB-Weld KwikWeld
JB-Weld
Gorrila Glue (water activated polyurethane)
Elmer's or Weldwood Contact Cement
Duco cement
RTV sealant
Barge Cement
Super Glue (cyanoacrylate)
Super Glue Gel
Elmer's white glue
Elmer's wood glue
Elmer's Craft Bond Rubber cement

Back to watching the glue dry... Thanks.

--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558




Nothing specific Jeff, but a couple of observations of various glues..

Cyanoacrylates: I've bought stuff brand new that was crap. There are no dates that I can discern (well, with my eyes anyway) on the package so it's a crap shoot. If you buy from a high turnover store, it should be fresh. The way I test it is to put a *tiny* drop of glue on the tip of my index finger and immediately push my thumb into it and hold for a full second. If it comes apart, the glue is crap. If it sticks tight, it's still good.

RTV: Permatex makes all sorts of RTVs, but unless you use the entire tube immediately, it's gonna be junk soon. The reason is that the plastic caps that Permatex uses split. If you put the cap on too loose, air gets under the cap and you get a rubber plug in the neck. Too snug and it splits and you have a ruined tube.

I bought some RTV at Harbor Freight for half of what Permatex sells for anywhere else, it's made in the U.S., works just like the Permatex stuff and the caps don't split. Cheap and I can reuse it. Double win for me.
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Default What is the shelf life of common adhesives?

On Thursday, January 25, 2018 at 5:27:23 PM UTC-8, Jeff Liebermann wrote:
I've been in the repair biz for too long. I can tell because some of
the adhesives in my disorganized collection are at least 10 years old....

So, in your experience, what are the approximate shelf lives


RTV sealant

Circa 5 years, and it's generally water-catalyzed, so a paint can
sealed tightly, with some CaSO4 dessicant, can keep it fresh for an
extra year or two, even if the cap is gone. I did this for a tube that split open,
it stayed fresh for months.

Super Glue (cyanoacrylate)
Super Glue Gel

Those are best kept in a refrigerator. I've got a little wood-block with blind
holes in the top as a stand, so the tiny tubes can sit upright (and to hold a leak).
Unopened, I dunno how long.


Elmer's white glue
Elmer's wood glue

Very sensitive to cold, do NOT let it freeze. Otherwise, I'm pretty sure a useful
bond can be made from 20-year-old (but it may need water added). It's inexpensive,
for a big project just buy fresh glue.


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Default What is the shelf life of common adhesives?

On 2018/01/26 5:32 AM, Terry Schwartz wrote:
Jeff, you ARE the authority on most everything, so I probably should bow to your expertise. (But I won't) After all, you have been in the repair biz too long.

Re-read Phils post -- he did not mention refrigeration "not working". He said the replacement tubes were "so old".

....
I also refrigerate batteries, and I've got some Panasonic industrial C cells that are still at full cell voltage after more than 10 years.


I had some EverReady and Duracell AA batteries from 1980 that still
seemed fully charged in 2006 (voltage reading of 3.67 over 3 cells in
series) - found when I unpacked a group of new old stock pinball and
video arcade games that used them for the battery backup. Some batteries
had leakage, but not many. I should still have those batteries around
here somewhere...so 26 years (1980 to 2006) wasn't bad, if I find them
I'll see if they still hold up after 38 years.

Photo of testing the batteries in 2006:

ftp://flippers.com//usr/www/users/fl...sGOOD72DPI.JPG

These batteries were not refrigerated by the way - sitting in a (50F to
80F depending on time of year) warehouse in downtown Vancouver, BC for
most of their life.

John :-#)#

--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd.
MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
(604)872-5757 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."
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Default What is the shelf life of common adhesives?

Jeff Liebermann wrote:
I've been in the repair biz for too long. I can tell because some of
the adhesives in my disorganized collection are at least 10 years old.
Yesterday, I had to glue an HP Envy m6-1125dx laptop hinge mount back
together after the left a lump of something on the keyboard, and
closed the LCD lid. The weak spot was where HP had glued the metal
attachment point for the hinge to the aluminum cover and plastic
frame. Miserable design and crappy workmanship, but I can't complain
because that's why I'm still in business.

I tried cyanoacrylate adhesive, 5 minute epoxy, 24 hr epoxy, RTV,
Elmers contact cement, and Duco cement. Nothing worked. The glues
either remained tacky after 24 hrs, hardened in the tube, or crumbled
when stressed. Hardening in the tube is an obvious sign of old age,
but I've never had Duco cement turn to powder when it hardens.

Yes, I cleaned off the old glue between applications and carefully
removed any residue and oils with acetone.

So, I walked to the nearest hardware store, and bought a few
overpriced tubes of epoxy and other adhesives. Right now, I'm trying
some J-B Weld KwikWeld (sets in 6 minutes). Watching glue dry didn't
seem very productive, so I thought I would ask a few questions instead
of Googling for the answers.

Few of the package, bottles, or tubes, show an expiration date for
either shelf life, or shelf life after the bottle is opened. The
exception is RTV, which is formulated to harden in the tube after
about 1 year whether new or opened. Gorilla Glue seems to harden in
the tube about 3 months after the tube is first used.

So, in your experience, what are the approximate shelf lives of these
common adhesives?
Devcon or Ace 5 minute epoxy
Devcon or Ace 24 hr epoxy
Devcon or Ace Plastic repair epoxy
JB-Weld KwikWeld
JB-Weld
Gorrila Glue (water activated polyurethane)
Elmer's or Weldwood Contact Cement
Duco cement
RTV sealant
Barge Cement
Super Glue (cyanoacrylate)
Super Glue Gel
Elmer's white glue
Elmer's wood glue
Elmer's Craft Bond Rubber cement

Back to watching the glue dry... Thanks.

In my experience the rubbery, not really hardened epoxy has been due
to inadequate mixing. I've found that you need to really mix the epoxy
well. For even a small amount I mix for at least 30 seconds, sometimes
more. As for age, as long as the resin hasn't solidified/crystallized,
it still works.
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I have used a two part epoxy since the middle 80s and I have kept it
10 years without degradation. The only down fall, but no way a deal
breaker, is it comes as two 4.5 oz toothpaste type tubes, after 10 years
it's bound to sprout a leak. I'm just careful how I squeeze and roll it
up. I brought a partially used package with me when I moved from
Michigan to Fl. in 1994, I used that and have bought two packages since
then. All that said, the manufacturer says 12 month shelf life. ( maybe
for NASA) The package I have now was manufactured 1-30-15 and still
works as new. I keep it in my climate controlled home
A little goes a long way, most of my repairs are 3/8" lines and then
that is to much, but easier to get equal amounts when squeezing and
eyeballing equal amounts.
I see 10 minute set advertised, I find it is quicker. Maybe I'm just
having so much fun time goes fast. :-)

It was originally called Araldite by Ciba-Geigy.
Now it is owned by Huntsman and is called Fastweld 10.
Here's a good explanation.
https://krayden.com/fastweld-10-ab/


Here's a seller. Not sure it is the best price.
http://www.skygeek.com/huntsman-fast...weld10kit.html


Here a couple dollars cheaper.
http://www.uscomposites.com/adhesives.html


I doubt your mileage will vary. :-)

Mikek

Datasheet,
https://krayden.com/wp-content/plugi...openfile=false











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Default What is the shelf life of common adhesives?

Let's cut to the chase:

a) Shelf-Life is not uniform. Factors such as heat, humidity, temperature cycling, even altitude and more must be included in the process.
b) The nature of the adhesives are factor.
c) That some components will separate into separate ingredients depending on temperature is a factor.
d) That some cures are catalytic is a factor - and that once started, will continue until complete.
e) That some cures require exterior stimulus is a factor.
f) And some low-end epoxies will crystallize, one part especially, even when fresh with a single exposure to low temperatures.

During the summer, my hobby room will undergo pretty wild temperature swings. It has windows on three walls, the center of which faces south. That is a factor.

I use some slightly exotic cyanoacrylates. They do not like temp.cycling and last about a week when after opening - and I do refrigerate them for that reason. They will last about 90 days (refrigerated) if not opened, and are dated as such. These I purchase when I am about to begin a project, not before.

It depends on many things:

Storage
Use factors
Specific needs

If I am fixing something as basic as a Bakelite knob for a radio, pretty much any run-of-the-mill super-glue will do the trick. If I am setting the ballast-release on a $3,500 submarine, not so much.

What is on the label, you can be pretty assured, is what the manufacturer is willing to support against unknown users with unknown habits and unknown storage conditions. Nor will they guarantee the workpiece against failure, just the cost of a tube of glue.

Let yourself be the judge, and take risks against aged product and potential failure on your own.

Peter Wieck
Melrose Park, PA
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One more thing I've noted.

Some manufacturers really have their sh*t together better than others, and it shows. I have had unopened tubes of sealant fail, and in a couple cases I cut them open out of curiosity.

What I found is that the failure inevitably stems from a bad seal or crimp. You can literally see and feel the substance harden starting from a specific point. On metal tubes, it's been the bottom crimp. Poor or worn tooling will create a stress point in the crimp that can cause a seal breach. This is where air and moisture enters, and you can follow the hardened material from that point further into the tube. Plastic squeeze tubes can suffer a similar failure from the heat crimp.

On caulk tubes, the failure is usually at the bottom, the insert that gets pushed in by the caulk gun. Run your finger around the inside of the tube -- if you feel ridges or rough spots, this is where the seal can breach. Often the caulk hardens there and then the tube will no longer be usable -- can't push it in -- even though the majority of the material in the tube is still viable.

I've even had tubes rupture when I tried to push past the cured material. And I've ruined a cheap caulk gun that way.

The all plastic tubes seem more prone to fail than the foil lined cardboard tubes, at least as far as product going bad. It doesn't make sense, those tubes are one piece. But I think the interior surfaces are not as smooth.


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On Friday, January 26, 2018 at 12:39:19 PM UTC-5, wrote:
I don't know about the shelf life but I do know about bonding metals
with epoxies. Aluminum can be especially hard to get a good bond on
because of the oxide coat. But this problem is fairly easily overcome.
Apply the epoxy to a clean oil and grease free surface. Then use a
small stainless wire brush to scrub the epoxy covered surface. Using
this method keeps oxygen away from the aluminum during the scrubbing
and the scrubbing action removes the super thin oxide coat. The
particles of aluminum oxide just get mixed into the epoxy. The epoxy
will wet the now oxide free aluminum surface. This process also works
when trying to solder aluminum. I have had to prove to a couple people
while they watched that this method works.
Eric


About ten years ago I repaired a broken solder joint on a small bracket, between two pieces of brass. This part is used every day and gets a fair amount of mechanical force applied. I used JBWeld but I was scrupulous about removing all the solder and getting down to bright clean metal on both pieces. So far it is holding. I also wired it in place until completely set.

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Default What is the shelf life of common adhesives?

On Saturday, January 27, 2018 at 5:47:27 PM UTC-5, wrote:
Let's cut to the chase:

a) Shelf-Life is not uniform. Factors such as heat, humidity, temperature cycling, even altitude and more must be included in the process.
b) The nature of the adhesives are factor.
c) That some components will separate into separate ingredients depending on temperature is a factor.
d) That some cures are catalytic is a factor - and that once started, will continue until complete.
e) That some cures require exterior stimulus is a factor.
f) And some low-end epoxies will crystallize, one part especially, even when fresh with a single exposure to low temperatures.

During the summer, my hobby room will undergo pretty wild temperature swings.


That sounds almost like the direct opposite of a wine cellar, which is kept at a certain temperature year-round for years. Even decades.
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