I have Skullcandy Crusher headphones and the hinge plastic broke. It's a
really common problem with them. I don't need a hinge, I'd like to epoxy
the hinge joint in the fully open position as it would be when being
worn. I tried using 2 part epoxy to hold it together, but it wasn't
plastic rated epoxy and it held perfectly for about 4 minutes, it was
easy to pry off of the plastic and it was clear it didn't adhere well at
all. I remember making plastic model cars and planes as a kid, the glue
seemed like it melted the plastic pieces into one another for a really
good joint, like a weld in metal. I don't know what grade the plastic
they used for the joints is and I don't know how to find that
information. Is there an all purpose adhesive or epoxy that I can use to
make one big solid mass of plastic? Or do I pretty much have to try the
various adhesives used for different grades of plastic?

This amazon ad says

Loctite Super Glue Plastics Bonding System with Activator 2-Gram (681925)

Bonds plastics such as Plexiglas, polycarbonate, polystyrene, PVC,
polyethylene, polypropylene and polytetrafluoroethylene (PTFE)/Teflon.
Plus rubber, leather, cork, paper, cardboard, wood, chipboard, fabric,
metal and ceramic.

https://www.amazon.com/Loctite-Plast.../dp/B000Y3LHXW


Loctite sells 2 different adhesives for these two different types of plastic

The easiest way to identify a plastic type is by its label, commonly a
recycling symbol. Plastics marked with a 6 or €œPS€� are polystyrenes.
These are used for simple items like disposable cutlery, plastic bowls,
or fashion bags. For these, the best glue is a poly cement such as
Loctite Plastic Bonder.

Other types of plastic are used for tougher industrial or construction
uses, such as drainpipes. Special plastics are even used for medical
applications and bulletproof vests. For gluing these plastics, try
Loctite Plastics Bonding System, which creates a powerful bond with just
one drop.

https://www.loctiteproducts.com/en/k...stic-glue.html


JB Weld PlasticWeld comes with this note:

While this product works beautifully with most varieties of plastic,
please be aware that there are certain types - including polyethylene
and polypropylene sheet - that it will not adhere to.

https://www.acplasticsinc.com/inform...s-for-plastics

On Tuesday, April 14, 2020 at 9:07:42 PM UTC-7, Mike S wrote:
I have Skullcandy Crusher headphones and the hinge plastic broke. It's a
really common problem with them. I don't need a hinge, I'd like to epoxy
the hinge joint in the fully open position as it would be when being
worn. I tried using 2 part epoxy to hold it together, but it wasn't
plastic rated epoxy and it held perfectly for about 4 minutes, it was
easy to pry off of the plastic and it was clear it didn't adhere well at
all. I remember making plastic model cars and planes as a kid, the glue
seemed like it melted the plastic pieces into one another for a really
good joint, like a weld in metal. I don't know what grade the plastic
they used for the joints is and I don't know how to find that
information. Is there an all purpose adhesive or epoxy that I can use to
make one big solid mass of plastic? Or do I pretty much have to try the
various adhesives used for different grades of plastic?

This amazon ad says

Loctite Super Glue Plastics Bonding System with Activator 2-Gram (681925)

Bonds plastics such as Plexiglas, polycarbonate, polystyrene, PVC,
polyethylene, polypropylene and polytetrafluoroethylene (PTFE)/Teflon.
Plus rubber, leather, cork, paper, cardboard, wood, chipboard, fabric,
metal and ceramic.

https://www.amazon.com/Loctite-Plast.../dp/B000Y3LHXW


Loctite sells 2 different adhesives for these two different types of plastic

The easiest way to identify a plastic type is by its label, commonly a
recycling symbol. Plastics marked with a 6 or €œPS€� are polystyrenes.
These are used for simple items like disposable cutlery, plastic bowls,
or fashion bags. For these, the best glue is a poly cement such as
Loctite Plastic Bonder.

Other types of plastic are used for tougher industrial or construction
uses, such as drainpipes. Special plastics are even used for medical
applications and bulletproof vests. For gluing these plastics, try
Loctite Plastics Bonding System, which creates a powerful bond with just
one drop.

https://www.loctiteproducts.com/en/k...stic-glue.html


JB Weld PlasticWeld comes with this note:

While this product works beautifully with most varieties of plastic,
please be aware that there are certain types - including polyethylene
and polypropylene sheet - that it will not adhere to.

https://www.acplasticsinc.com/inform...s-for-plastics

I use Weld*On products with lexan and acrylics. It is a solvent as you describe. I imagine that they have products for your plastic. https://weldon.com/

Good luck.

On Tue, 14 Apr 2020 21:07:38 -0700, Mike S wrote:

Loctite Super Glue Plastics Bonding System with Activator 2-Gram (681925)

Bonds plastics such as Plexiglas, polycarbonate, polystyrene, PVC,
polyethylene, polypropylene and polytetrafluoroethylene (PTFE)/Teflon.
Plus rubber, leather, cork, paper, cardboard, wood, chipboard, fabric,
metal and ceramic.

https://www.amazon.com/Loctite-Plast.../dp/B000Y3LHXW

That's what I use for gluing problem plastics. Seems to work with all
the hard plastics and some soft (flexible) plastics. It's a
cyanoacrylate adhesive, with some hexane added to soften the plastic.
Note that it's not very good at filling gap. With flexible plastics,
it does well if the glue joint is very thin and therefore flexible.
With a thicker glue line, it will crack and eventually crumble.

Another glue that I've found that works well with hard plastics is
Zap-It. It's also a cyanoacrylate adhesive with some manner of
solvent to soften the plastic. What I like most about it is that if I
use the UV light to cure the joint, I don't need to wait until it
hardens. I'll know if I have a decent joint in seconds.
https://supergluecorp.com/product/zap-it/
One catch is that it works best on transparent plastics, where the UV
light can penetrate. However, if the plastic is opaque, just slop on
some glue which leaks outside of the joint, harden what's visible with
the UV light, and let it sit for about an hour. Even without the UV
light, the cyanoacrylate adhesive will harden in less than an hour.

"ZAP IT® Glue"
https://www.youtube.com/watch?v=Pg1zRNQISyU

No clue on the other stuff you mentioned as I haven't tried those.

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

Mike S wrote:

Loctite sells 2 different adhesives for these two different types of
plastic

Try the 'burn test' to identify the plastic if its type isn't marked on it

https://www.boedeker.com/Technical-Resources/Technical-Library/Plastic-Identification

if it's a low surface energy type, there is Scotchweld DP8005, but it's
not cheap

On 4/14/2020 11:47 PM, Andy Burns wrote:
Mike S wrote:

Loctite sells 2 different adhesives for these two different types of
plastic

Try the 'burn test' to identify the plastic if its type isn't marked on it

https://www.boedeker.com/Technical-Resources/Technical-Library/Plastic-Identification


if it's a low surface energy type, there is Scotchweld DP8005, but it's
not cheap

Thanks very much b23sunwoodllc, Jef Liebermann, and Andy Burns,

the burn test is great, I'll make a purchase based on those results.

On Tue, 14 Apr 2020 21:07:38 -0700, Mike S wrote:

Is there an all purpose adhesive or epoxy that I can use to
make one big solid mass of plastic?

No, unfortunately there is not. Plastics is a huge group of materials
with large differences in properties.

If at all possible, find out which type(s) of plastic you are dealing
with. Larger plastic parts usually have mark, in a normally invisible
location, that indicates plastic type.

If you can't find out, the job is merely a matter of trying different
things until you run out of patience.

I do not have personal experience with the products you mention, but
if it claims to be able to glue plastics such as PP and PTFE, it might
be well worth a try. Those plastics, along with PA (PolyAmid / Nylon),
are usually considered practically ungluable.

Your application is a high stress one, so it is possible a glue joint
will not be able to last, even with a glue that works. Sometimes, a
mechanical repair can be used. Some sort of bracket or clip that is
screwed in place, for example.

In article , Mike S wrote:
I have Skullcandy Crusher headphones and the hinge plastic broke. It's a
really common problem with them. I don't need a hinge, I'd like to epoxy
the hinge joint in the fully open position as it would be when being
worn. I tried using 2 part epoxy to hold it together, but it wasn't
plastic rated epoxy and it held perfectly for about 4 minutes, it was
easy to pry off of the plastic and it was clear it didn't adhere well at
all. I remember making plastic model cars and planes as a kid, the glue
seemed like it melted the plastic pieces into one another for a really
good joint, like a weld in metal. I don't know what grade the plastic
they used for the joints is and I don't know how to find that
information. Is there an all purpose adhesive or epoxy that I can use to
make one big solid mass of plastic? Or do I pretty much have to try the
various adhesives used for different grades of plastic?

Plastics can be tricky. The broken surfaces tend to be fairly smooth,
which doesn't give epoxy much opportunity to "grab" onto it and make a
good mechanical bond.

Also, some common plastics have a "low surface energy" issue - put
simplistically (and not quite correctly) this means that the surface
of the plastic has relatively few chemically-reactive sites on it, to
which the epoxy resin could create a chemical bond.

So, without good mechanical or chemical bonds, you end up with a glue
joint that's not held together very strongly, and it breaks apart
easily.

I've had good luck on plastics using a thickened epoxy called G-Flex
655. It's sold by West System (a.k.a. West Marine) specifically for
use in repairing plastic and fiberglass boats. In my experience it's
an excellent all-around repair epoxy for most materials. A friend of
mine used it to bond steel pipes and flanges to sheets of granite,
after roughing up the granite surface with some emery paper. When he
tested it by banging sideways on the pipe with a sledgehammer, the
epoxy didn't fail... instead, the granite itself "tore apart" - the
rock pulled apart into separate crystals. This stuff has become my
"go-to" repair epoxy.

There are two tricks you can/should use when bonding difficult
plastics. The first is to roughen the surfaces with some sandpaper,
giving the material some "tooth" into which the epoxy can flow and
then harden - this gives you a better mechanical bond.

The second is flaming. Take a propane and butane torch set on a
fairly low flame. *Quickly* pass the very tip of the flame over the
area to be bonded. You don't want to heat the plastic up enough that
it melts, or even starts to soften... you simply want to let the tip
of the flame oxidize the very surface of the plastic. This helps deal
with the "low surface energy" issue, by creating reactive sites to
which the epoxy resin can create a chemical bond.

If you buy the West System G-Flex 655 boat-repair kit, you get two
very generous tubes of epoxy, some sandpaper, gloves, and "plastic
boat repair" instructions which goes through the above procedures in
detail. You can buy just the epoxy (without the extras) for a bit
less money. It's a more expensive initial purchase than the little
tubes you'll find at a hardware store, but it'll be enough to last you
for years.

On Wed, 15 Apr 2020 11:44:44 -0700, (Dave
Platt) wrote:
If you buy the West System G-Flex 655 boat-repair kit, you get two
very generous tubes of epoxy, some sandpaper, gloves, and "plastic
boat repair" instructions which goes through the above procedures in
detail. You can buy just the epoxy (without the extras) for a bit
less money. It's a more expensive initial purchase than the little
tubes you'll find at a hardware store, but it'll be enough to last you
for years.

G/Flex 650 is the less viscous mix.
https://www.westsystem.com/specialty-epoxies/gflex-650-toughened-epoxy/

G/Flex 655 is the thickened mixture.
https://www.westsystem.com/specialty-epoxies/gflex-655-thickened-epoxy-adhesive/

G/FLex 650 can be converted into the thicker G/Flex 655 by adding 406
Colloidal Silica:
https://www.westsystem.com/406-colloidal-silica/
However, I've never tried it.

Both epoxies require some form of surface preparation.
https://www.westsystem.com/specialty-epoxies/gflex-epoxy-adhesion-data/
Notice that the adhesion strength increases substantially with
sandpapering, alcohol wipe, and flame treating.

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

On 4/15/2020 4:19 AM, HW wrote:
On Tue, 14 Apr 2020 21:07:38 -0700, Mike S wrote:

Is there an all purpose adhesive or epoxy that I can use to
make one big solid mass of plastic?

No, unfortunately there is not. Plastics is a huge group of materials
with large differences in properties.

If at all possible, find out which type(s) of plastic you are dealing
with. Larger plastic parts usually have mark, in a normally invisible
location, that indicates plastic type.

If you can't find out, the job is merely a matter of trying different
things until you run out of patience.

I do not have personal experience with the products you mention, but
if it claims to be able to glue plastics such as PP and PTFE, it might
be well worth a try. Those plastics, along with PA (PolyAmid / Nylon),
are usually considered practically ungluable.

Your application is a high stress one, so it is possible a glue joint
will not be able to last, even with a glue that works. Sometimes, a
mechanical repair can be used. Some sort of bracket or clip that is
screwed in place, for example.

Thanks, and I agree, I think I'll glue it and then wrap an aluminum
brace around the perimeter to add additional strength.

On 4/15/2020 11:44 AM, Dave Platt wrote:
In article , Mike S wrote:
I have Skullcandy Crusher headphones and the hinge plastic broke. It's a
really common problem with them. I don't need a hinge, I'd like to epoxy
the hinge joint in the fully open position as it would be when being
worn. I tried using 2 part epoxy to hold it together, but it wasn't
plastic rated epoxy and it held perfectly for about 4 minutes, it was
easy to pry off of the plastic and it was clear it didn't adhere well at
all. I remember making plastic model cars and planes as a kid, the glue
seemed like it melted the plastic pieces into one another for a really
good joint, like a weld in metal. I don't know what grade the plastic
they used for the joints is and I don't know how to find that
information. Is there an all purpose adhesive or epoxy that I can use to
make one big solid mass of plastic? Or do I pretty much have to try the
various adhesives used for different grades of plastic?

Plastics can be tricky. The broken surfaces tend to be fairly smooth,
which doesn't give epoxy much opportunity to "grab" onto it and make a
good mechanical bond.

Also, some common plastics have a "low surface energy" issue - put
simplistically (and not quite correctly) this means that the surface
of the plastic has relatively few chemically-reactive sites on it, to
which the epoxy resin could create a chemical bond.

So, without good mechanical or chemical bonds, you end up with a glue
joint that's not held together very strongly, and it breaks apart
easily.

I've had good luck on plastics using a thickened epoxy called G-Flex
655. It's sold by West System (a.k.a. West Marine) specifically for
use in repairing plastic and fiberglass boats. In my experience it's
an excellent all-around repair epoxy for most materials. A friend of
mine used it to bond steel pipes and flanges to sheets of granite,
after roughing up the granite surface with some emery paper. When he
tested it by banging sideways on the pipe with a sledgehammer, the
epoxy didn't fail... instead, the granite itself "tore apart" - the
rock pulled apart into separate crystals. This stuff has become my
"go-to" repair epoxy.

There are two tricks you can/should use when bonding difficult
plastics. The first is to roughen the surfaces with some sandpaper,
giving the material some "tooth" into which the epoxy can flow and
then harden - this gives you a better mechanical bond.

The second is flaming. Take a propane and butane torch set on a
fairly low flame. *Quickly* pass the very tip of the flame over the
area to be bonded. You don't want to heat the plastic up enough that
it melts, or even starts to soften... you simply want to let the tip
of the flame oxidize the very surface of the plastic. This helps deal
with the "low surface energy" issue, by creating reactive sites to
which the epoxy resin can create a chemical bond.

If you buy the West System G-Flex 655 boat-repair kit, you get two
very generous tubes of epoxy, some sandpaper, gloves, and "plastic
boat repair" instructions which goes through the above procedures in
detail. You can buy just the epoxy (without the extras) for a bit
less money. It's a more expensive initial purchase than the little
tubes you'll find at a hardware store, but it'll be enough to last you
for years.

Thanks Dave.

On 4/15/2020 5:11 PM, Jeff Liebermann wrote:
On Wed, 15 Apr 2020 11:44:44 -0700, (Dave
Platt) wrote:
If you buy the West System G-Flex 655 boat-repair kit, you get two
very generous tubes of epoxy, some sandpaper, gloves, and "plastic
boat repair" instructions which goes through the above procedures in
detail. You can buy just the epoxy (without the extras) for a bit
less money. It's a more expensive initial purchase than the little
tubes you'll find at a hardware store, but it'll be enough to last you
for years.

G/Flex 650 is the less viscous mix.
https://www.westsystem.com/specialty-epoxies/gflex-650-toughened-epoxy/

G/Flex 655 is the thickened mixture.
https://www.westsystem.com/specialty-epoxies/gflex-655-thickened-epoxy-adhesive/

G/FLex 650 can be converted into the thicker G/Flex 655 by adding 406
Colloidal Silica:
https://www.westsystem.com/406-colloidal-silica/
However, I've never tried it.

Both epoxies require some form of surface preparation.
https://www.westsystem.com/specialty-epoxies/gflex-epoxy-adhesion-data/
Notice that the adhesion strength increases substantially with
sandpapering, alcohol wipe, and flame treating.

Thanks Jeff,
their video is funny and impressive.
https://www.youtube.com/watch?time_c...ature=emb_logo

On 4/14/2020 11:07 PM, Mike S wrote:
I have Skullcandy Crusher headphones and the hinge plastic broke. It's a
really common problem with them. I don't need a hinge, I'd like to epoxy
the hinge joint in the fully open position as it would be when being
worn.Â* I tried using 2 part epoxy to hold it together, but it wasn't
plastic rated epoxy and it held perfectly for about 4 minutes, it was
easy to pry off of the plastic and it was clear it didn't adhere well at
all. I remember making plastic model cars and planes as a kid, the glue
seemed like it melted the plastic pieces into one another for a really
good joint, like a weld in metal. I don't know what grade the plastic
they used for the joints is and I don't know how to find that
information. Is there an all purpose adhesive or epoxy that I can use to
make one big solid mass of plastic? Or do I pretty much have to try the
various adhesives used for different grades of plastic?

This amazon ad says

Loctite Super Glue Plastics Bonding System with Activator 2-Gram (681925)

Bonds plastics such as Plexiglas, polycarbonate, polystyrene, PVC,
polyethylene, polypropylene and polytetrafluoroethylene (PTFE)/Teflon.
Plus rubber, leather, cork, paper, cardboard, wood, chipboard, fabric,
metal and ceramic.

https://www.amazon.com/Loctite-Plast.../dp/B000Y3LHXW



Loctite sells 2 different adhesives for these two different types of
plastic

The easiest way to identify a plastic type is by its label, commonly a
recycling symbol. Plastics marked with a 6 or €œPS€� are polystyrenes.
These are used for simple items like disposable cutlery, plastic bowls,
or fashion bags. For these, the best glue is a poly cement such as
Loctite Plastic Bonder.

Other types of plastic are used for tougher industrial or construction
uses, such as drainpipes. Special plastics are even used for medical
applications and bulletproof vests. For gluing these plastics, try
Loctite Plastics Bonding System, which creates a powerful bond with just
one drop.

https://www.loctiteproducts.com/en/k...stic-glue.html


JB Weld PlasticWeld comes with this note:

While this product works beautifully with most varieties of plastic,
please be aware that there are certain types - including polyethylene
and polypropylene sheet - that it will not adhere to.

https://www.acplasticsinc.com/inform...s-for-plastics






On many of my plastic repairs, I strengthen them be drilling and
inserting a 0.025" steel rod that I glue in place. Sometimes two, if it
is large enough. Sometimes I temporarily glue it in place to get proper
alignment while drilling. It has saved me a lot of time waiting for
parts. I also have a drill and tap for a 1-72 screw if that is needed.
As you are aware, it breaks where at the point where it needs the
most reinforcement.

Mikek

On 4/14/2020 11:36 PM, Jeff Liebermann wrote:
On Tue, 14 Apr 2020 21:07:38 -0700, Mike S wrote:

Loctite Super Glue Plastics Bonding System with Activator 2-Gram (681925)

Bonds plastics such as Plexiglas, polycarbonate, polystyrene, PVC,
polyethylene, polypropylene and polytetrafluoroethylene (PTFE)/Teflon.
Plus rubber, leather, cork, paper, cardboard, wood, chipboard, fabric,
metal and ceramic.

https://www.amazon.com/Loctite-Plast.../dp/B000Y3LHXW

That's what I use for gluing problem plastics. Seems to work with all
the hard plastics and some soft (flexible) plastics. It's a
cyanoacrylate adhesive, with some hexane added to soften the plastic.
Note that it's not very good at filling gap. With flexible plastics,
it does well if the glue joint is very thin and therefore flexible.
With a thicker glue line, it will crack and eventually crumble.
snip

Jeff,

Thanks again, I tried the Loctite above based on your recommendation and
the price and it worked great, exactly as you said - it is a great glue
for close-fitting parts! I added a 3/4" wide strip of aluminum cut from
a rain gutter and screwed that into place around the joint for extra
support, covered that with black tape, used the headphones several
times, problem solved and it's not too noticeable. Thanks for your
detailed reply.

snip
Â*On many of my plastic repairs, I strengthen them be drilling and
inserting a 0.025" steel rod that I glue in place. Sometimes two, if it
is large enough. Sometimes I temporarily glue it in place to get proper
alignment while drilling. It has saved me a lot of time waiting for
parts. I also have a drill and tap for a 1-72 screw if that is needed.
Â* As you are aware, it breaks where at the point where it needs the
most reinforcement.

Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* Mikek

Thanks Mikek, that would make for a very strong joint, if my current fix
breaks I'll see if there's enough plastic material to support this
approach. Cheers.

On Thu, 16 Apr 2020 08:08:09 -0500, amdx wrote:

On many of my plastic repairs, I strengthen them be drilling and
inserting a 0.025" steel rod that I glue in place. Sometimes two, if it
is large enough. Sometimes I temporarily glue it in place to get proper
alignment while drilling. It has saved me a lot of time waiting for
parts. I also have a drill and tap for a 1-72 screw if that is needed.

I do something similar when desperate. Instead of drill and pin, I
use a flexible sewing pin (not a needle) and my soldering iron. I put
some gouges in the surface of the pin, heat the pen head, shove the
pin into the parts that I want to glue, and wait for the plastic to
harden. When done, I cut off the head of the pin with flush cutting
diagonal cutters or a Dremel tool with a cutoff disk. If I need pull
strength, I use a straightened paper clip instead of a pin. The paper
clip metal is softer, so I can use my wire cutters to roughen the
surface of the paper clip. I heat instead of glue to assemble the
parts because the hole is usually in some inaccessible location that
can be reached with a soldering iron, but not a Dremel drill tool.

Another alternative is plastic welding.
https://www.harborfreight.com/plastic-welding-kit-with-air-motor-and-temperature-adjustment-96712.html
https://www.harborfreight.com/plastic-welding-kit-with-adjustable-temperature-96464.html
I modified a spare tip for my SMD hot air desoldering tool by adding a
smaller nozzle suitable for plastic welding. So far, it's worked
nicely for parts about the diameter of a pencil. However, my attempts
at plastic welding small parts usually result in a blob of plastic or
a cloud of plastic smog. The next time I get a laptop in the shop to
fix, with the usual ultra-thin standoffs broken off by the threaded
brass inserts, I'll give plastic welding another try.

As you are aware, it breaks where at the point where it needs the
most reinforcement.

Yep. However, my usual problem is finding the broken off plastic
piece.


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

On 4/19/2020 1:19 AM, Mike S wrote:
On 4/14/2020 11:36 PM, Jeff Liebermann wrote:
On Tue, 14 Apr 2020 21:07:38 -0700, Mike S wrote:

Loctite Super Glue Plastics Bonding System with Activator 2-Gram
(681925)

Bonds plastics such as Plexiglas, polycarbonate, polystyrene, PVC,
polyethylene, polypropylene and polytetrafluoroethylene (PTFE)/Teflon.
Plus rubber, leather, cork, paper, cardboard, wood, chipboard, fabric,
metal and ceramic.

https://www.amazon.com/Loctite-Plast.../dp/B000Y3LHXW


That's what I use for gluing problem plastics.Â* Seems to work with all
the hard plastics and some soft (flexible) plastics.Â* It's a
cyanoacrylate adhesive, with some hexane added to soften the plastic.
Note that it's not very good at filling gap.Â* With flexible plastics,
it does well if the glue joint is very thin and therefore flexible.
With a thicker glue line, it will crack and eventually crumble.
snip

Jeff,

Thanks again, I tried the Loctite above based on your recommendation and
the price and it worked great, exactly as you said - it is a great glue
for close-fitting parts! I added a 3/4" wide strip of aluminum cut from
a rain gutter and screwed that into place around the joint for extra
support, covered that with black tape, used the headphones several
times, problem solved and it's not too noticeable. Thanks for your
detailed reply.


I visited my daughter last week and her Shark vacuum had broke at the
neck of the beater bar. (something about gravity and a stairway) No real
material to get any screws or pins into it. I used the Super Glue as
listed above,
https://www.amazon.com/Loctite-Plast.../dp/B000Y3LHXW

to preliminarily hold the parts in position. Then after spending the
time necessary to sand all the areas where I was to apply the two part
epoxy made for plastic.
https://www.amazon.com/J-B-Weld-5013...s%2C352&sr=1-1


I epoxied as much area as I could. After a full days cure, she vacuumed
the whole house and it survived. I left specific instructions to let me
know if it breaks. If it holds up, I'll call the glue and epoxy winners,
because that is a high stress point of the vacuum.
Mikek

On 4/29/2020 12:06 PM, amdx wrote:
On 4/19/2020 1:19 AM, Mike S wrote:
On 4/14/2020 11:36 PM, Jeff Liebermann wrote:
On Tue, 14 Apr 2020 21:07:38 -0700, Mike S wrote:

Loctite Super Glue Plastics Bonding System with Activator 2-Gram
(681925)

Bonds plastics such as Plexiglas, polycarbonate, polystyrene, PVC,
polyethylene, polypropylene and polytetrafluoroethylene (PTFE)/Teflon.
Plus rubber, leather, cork, paper, cardboard, wood, chipboard, fabric,
metal and ceramic.

https://www.amazon.com/Loctite-Plast.../dp/B000Y3LHXW


That's what I use for gluing problem plastics.Â* Seems to work with all
the hard plastics and some soft (flexible) plastics.Â* It's a
cyanoacrylate adhesive, with some hexane added to soften the plastic.
Note that it's not very good at filling gap.Â* With flexible plastics,
it does well if the glue joint is very thin and therefore flexible.
With a thicker glue line, it will crack and eventually crumble.
snip

Jeff,

Thanks again, I tried the Loctite above based on your recommendation
and the price and it worked great, exactly as you said - it is a great
glue for close-fitting parts! I added a 3/4" wide strip of aluminum
cut from a rain gutter and screwed that into place around the joint
for extra support, covered that with black tape, used the headphones
several times, problem solved and it's not too noticeable. Thanks for
your detailed reply.


Â*I visited my daughter last week and her Shark vacuum had broke at the
neck of the beater bar. (something about gravity and a stairway) No real
material to get any screws or pins into it. I used the Super Glue as
listed above,
https://www.amazon.com/Loctite-Plast.../dp/B000Y3LHXW

to preliminarily hold the parts in position. Then after spending the
time necessary to sand all the areas where I was to apply the two part
epoxy made for plastic.
https://www.amazon.com/J-B-Weld-5013...s%2C352&sr=1-1



I epoxied as much area as I could. After a full days cure, she vacuumed
the whole house and it survived. I left specific instructions to let me
know if it breaks. If it holds up, I'll call the glue and epoxy winners,
because that is a high stress point of the vacuum.
Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* Â*Â*Â*Â* Mikek

Nice! (gravity and a stairway : lol)

On 4/15/2020 1:47 AM, Andy Burns wrote:
Mike S wrote:

Loctite sells 2 different adhesives for these two different types of
plastic

Try the 'burn test' to identify the plastic if its type isn't marked on it

https://www.boedeker.com/Technical-Resources/Technical-Library/Plastic-Identification


if it's a low surface energy type, there is Scotchweld DP8005, but it's
not cheap

I've done the burn test, but find I have more confidence if I have a
known sample to compare aroma's.
Mikek

For those interested in bonding polypropylene.


https://www.adhesivesmag.com/article...-polypropylene

Mikek

On Wed, 6 May 2020 05:20:38 -0500, amdx wrote:

For those interested in bonding polypropylene.
https://www.adhesivesmag.com/article...-polypropylene
Mikek

For those into something more mundane for polypropylene:
https://www.loctiteproducts.com/en/products/fix/super-glue/loctite_plasticsbondingsystem.html
"The activator primes hard-to-bond surfaces such as polypropylene
and polyethylene"

https://dm.henkel-dam.com/is/content/henkel/TDS-681925-US-Loctite-Plastics-Bonding-System-Carded-4-ml-2-g-2016-08-26pdf
Cyanoacrylate adhesive with Heptane solvent for surface preparation
(activator). I'm rather surprised that it works as most surface
activators (used to increase surface energy and therefore chemical
reactivity of low energy plastics) require elevated temperatures.

One big problem for me has been shelf life. I bought a few tubes of
the stuff from a local hardware store, only to find that it was near
the end of its shelf life. It died in the tube (unopened) a few
months later:
Shelf Life. From date of manufacture (unopened):
30 months Stored at 36-46°F
18 months Stored at 68°F

I suggest you check the self destruct date when buying:

Lot Code Explanation: #YDDDX Printed on crimped end on tube
# = Disregard
Y = Last digit of year of manufacture
DDD = Day of manufacture based on 365 days in a year
X = Disregard
Example: 6061 = 61st day of 2016 = March 2, 2016

https://www.homedepot.com/p/Loctite-Plastics-Bonding-System-2g-Super-Glue-681925/100371829







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