Iffin you REALLY wanted to be sure that a nut won't fall off a screw, or a
screw will loosen, wouldn't plain ole 2-part epoxy be the best bet?

Also, if an epoxied screw/nut did have to come off, wouldn't a little heat
do it?
--
EA

On Mon, 14 May 2012 22:28:13 -0400, "Existential Angst"
wrote:

Iffin you REALLY wanted to be sure that a nut won't fall off a screw, or a
screw will loosen, wouldn't plain ole 2-part epoxy be the best bet?

There are epoxy thread-lockers made for volume production. They're
hollow phenolic beads, half of them filled with resin and half of them
with hardener. The threads are dipped in a weak adhesive and then in
the beads, whereupon they can be stored for as long as you want. When
you tighten the nut the beads crush, the epoxy and hardener mix, and
the mess hardens.

For non-production use, Loctite is much more convenient.


Also, if an epoxied screw/nut did have to come off, wouldn't a little heat
do it?

A fair amount of heat. And the epoxy doesn't melt. It may get soft,
but it chars.

Five-minute epoxies can handle less heat than the slow-cure types.

--
Ed Huntress

"Ed Huntress" wrote
On Mon, 14 May 2012 22:28:13 -0400, "Existential Angst"
wrote:

Iffin you REALLY wanted to be sure that a nut won't fall off a
screw, or a
screw will loosen, wouldn't plain ole 2-part epoxy be the best bet?

There are epoxy thread-lockers made for volume production. They're
hollow phenolic beads, half of them filled with resin and half of
them
with hardener. The threads are dipped in a weak adhesive and then in
the beads, whereupon they can be stored for as long as you want.
When
you tighten the nut the beads crush, the epoxy and hardener mix, and
the mess hardens.

For non-production use, Loctite is much more convenient.


Also, if an epoxied screw/nut did have to come off, wouldn't a
little heat
do it?

A fair amount of heat. And the epoxy doesn't melt. It may get soft,
but it chars.

Five-minute epoxies can handle less heat than the slow-cure types.


What Ed wrote, but also..

Split Lock washers DO NOT work and should not be used. Steve W.'s link
http://www.boltscience.com/index.htm has a graph showing that they
fail quicker under vibration than a straight bolted conection.
Basicaly when fully compressed they act as a flat washer giving two
surfaces that can slip. Once slightly released, they activly permote
the rotation of the bolt or nut.

Star washers I think work as long as the conection is tight enough to
actualy cut into the two surfaces.

Look at how cars are put together now. IIRC for critical areas they
use belvel washers with embosed squares or stars that alow for higher
clamping force upon compression.

--
Stephen B.

"Ed Huntress" wrote in message
...
On Mon, 14 May 2012 22:28:13 -0400, "Existential Angst"
wrote:

Iffin you REALLY wanted to be sure that a nut won't fall off a screw, or a
screw will loosen, wouldn't plain ole 2-part epoxy be the best bet?

There are epoxy thread-lockers made for volume production. They're
hollow phenolic beads, half of them filled with resin and half of them
with hardener. The threads are dipped in a weak adhesive and then in
the beads, whereupon they can be stored for as long as you want. When
you tighten the nut the beads crush, the epoxy and hardener mix, and
the mess hardens.

For non-production use, Loctite is much more convenient.


Also, if an epoxied screw/nut did have to come off, wouldn't a little heat
do it?

A fair amount of heat. And the epoxy doesn't melt. It may get soft,
but it chars.

Five-minute epoxies can handle less heat than the slow-cure types.

--
Ed Huntress

Even with heat, removing bolts with epoxy on the threads is not very easy.
Epoxy just dribbled around the outside of a bolt does not work well.

The army uses this stuff in the turret of the Abrams tank.
http://www.vibra-tite.com/vc3.php
They found it is the only removable thread locker that can withstand the
shock and vibration they get there.

You apply it to the male threads and let it dry. It is the consistency of
soft plastic. It cold flows into the threads when assembled to fill all the
gaps. It is also great for screws that have to be adjusted and then stay
put.

You can also use castle nuts and cotter pins or tie wires.

"anorton" wrote in message
m...

"Ed Huntress" wrote in message
...
On Mon, 14 May 2012 22:28:13 -0400, "Existential Angst"
wrote:

Iffin you REALLY wanted to be sure that a nut won't fall off a screw, or
a
screw will loosen, wouldn't plain ole 2-part epoxy be the best bet?

There are epoxy thread-lockers made for volume production. They're
hollow phenolic beads, half of them filled with resin and half of them
with hardener. The threads are dipped in a weak adhesive and then in
the beads, whereupon they can be stored for as long as you want. When
you tighten the nut the beads crush, the epoxy and hardener mix, and
the mess hardens.

For non-production use, Loctite is much more convenient.


Also, if an epoxied screw/nut did have to come off, wouldn't a little
heat
do it?

A fair amount of heat. And the epoxy doesn't melt. It may get soft,
but it chars.

Five-minute epoxies can handle less heat than the slow-cure types.

--
Ed Huntress

Even with heat, removing bolts with epoxy on the threads is not very easy.
Epoxy just dribbled around the outside of a bolt does not work well.

The army uses this stuff in the turret of the Abrams tank.
http://www.vibra-tite.com/vc3.php
They found it is the only removable thread locker that can withstand the
shock and vibration they get there.

You apply it to the male threads and let it dry. It is the consistency of
soft plastic. It cold flows into the threads when assembled to fill all
the gaps. It is also great for screws that have to be adjusted and then
stay put.

You can also use castle nuts and cotter pins or tie wires.

Well, apropos of Ed's 5 min epoxy, of which I have quite a bit (and which HF
sells dert cheap), if I applied that well to the threads, would it do an
effective job? At least until I figger out exactly what direction I want to
take.
--
EA

"Existential Angst" wrote in message
...
"anorton" wrote in message
m...

"Ed Huntress" wrote in message
...
On Mon, 14 May 2012 22:28:13 -0400, "Existential Angst"
wrote:

Iffin you REALLY wanted to be sure that a nut won't fall off a screw, or
a
screw will loosen, wouldn't plain ole 2-part epoxy be the best bet?

There are epoxy thread-lockers made for volume production. They're
hollow phenolic beads, half of them filled with resin and half of them
with hardener. The threads are dipped in a weak adhesive and then in
the beads, whereupon they can be stored for as long as you want. When
you tighten the nut the beads crush, the epoxy and hardener mix, and
the mess hardens.

For non-production use, Loctite is much more convenient.


Also, if an epoxied screw/nut did have to come off, wouldn't a little
heat
do it?

A fair amount of heat. And the epoxy doesn't melt. It may get soft,
but it chars.

Five-minute epoxies can handle less heat than the slow-cure types.

--
Ed Huntress

Even with heat, removing bolts with epoxy on the threads is not very
easy. Epoxy just dribbled around the outside of a bolt does not work
well.

The army uses this stuff in the turret of the Abrams tank.
http://www.vibra-tite.com/vc3.php
They found it is the only removable thread locker that can withstand the
shock and vibration they get there.

You apply it to the male threads and let it dry. It is the consistency of
soft plastic. It cold flows into the threads when assembled to fill all
the gaps. It is also great for screws that have to be adjusted and then
stay put.

You can also use castle nuts and cotter pins or tie wires.

Well, apropos of Ed's 5 min epoxy, of which I have quite a bit (and which
HF sells dert cheap), if I applied that well to the threads, would it do
an effective job? At least until I figger out exactly what direction I
want to take.
--
EA




A small bottle of Loctite which was designed for the job would probably be
just as cost effective. No mixing or faffing about - one drip & its done
properly. One little bottle goes a looong way.

Aye.. and Loctites are also available as tape/film or stick forms. The tape
is supplied on a small spool like thread sealer, and the stick type is
similar to a wax stick/chapstick.

Either product is available as blue or red/permanent types.

--
WB
..........


"Dennis" wrote in message
. au...


A small bottle of Loctite which was designed for the job would probably be
just as cost effective. No mixing or faffing about - one drip & its done
properly. One little bottle goes a looong way.

I dunno why anyone would want to mix and apply 2-part products when Loctite
formulas will do an excellent/proven job.

Numerous fasteners are available with an epoxy-type product already applied
for numerous applications from nails/staples to more heavy duty steel
fabrication fasteners.. generally considered OTU one-time-use permanent
fasteners, not removed for maintenance/service.

Screws and nuts are available as nyloc types which will essentially insure
that the fastener won't separate from vibration, such as a nyloc nut mounted
on a screw acting as a pin, but I dunno about (doubt) the effectiveness at
maintaining a specified torque.
The mil-spec and aviation self-locking nuts with synthetic inserts may hold
to a specified torque when used as specified for one-time-use only.

To insure that a nut doesn't come off with general hardware, the screw
threads can be distorted/smashed after the nut's in place to ensure that the
screw will need to be broken to separate the pieces.. or use stainless steel
for intentional gall/seizing of the threads.

And rust is still considered fairly effective.

As far as a "little heat" being effective at loosening epoxied hardware (or
red Loctite), a soldering iron may be useful for small fasteners up to maybe
1/8" but not enough heat for anything larger, assuming the heat can be
applied to a nut on a screw, not heating a screw length imbedded in
heat-sinking material.

--
WB
..........


"Existential Angst" wrote in message
...
Iffin you REALLY wanted to be sure that a nut won't fall off a screw, or a
screw will loosen, wouldn't plain ole 2-part epoxy be the best bet?

Also, if an epoxied screw/nut did have to come off, wouldn't a little heat
do it?
--
EA

"Wild_Bill" wrote in message
...
Aye.. and Loctites are also available as tape/film or stick forms. The
tape is supplied on a small spool like thread sealer, and the stick type
is similar to a wax stick/chapstick.

Either product is available as blue or red/permanent types.

--
WB
.........


Interesting - I was only aware of the liquid in the little dripper bottles.

"Wild_Bill" wrote in message
...
I dunno why anyone would want to mix and apply 2-part products when
Loctite formulas will do an excellent/proven job.

Numerous fasteners are available with an epoxy-type product already
applied for numerous applications from nails/staples to more heavy
duty steel fabrication fasteners.. generally considered OTU
one-time-use permanent fasteners, not removed for
maintenance/service.

Segways are assembled with screws with pre-applied threadlocker. In
the lab we just re-used them on in-house-only machines. They still
took some force to install or remove and AFAIK none of them ever
loosened.

When I had to remove a batch of particularly reluctant screws
installed with permanent Loctite I heated them with a soldering iron
in a blob of solder in the socket recess.

On 5/14/2012 10:28 PM, Existential Angst wrote:
Iffin you REALLY wanted to be sure that a nut won't fall off a screw, or a
screw will loosen, wouldn't plain ole 2-part epoxy be the best bet?

Also, if an epoxied screw/nut did have to come off, wouldn't a little heat
do it?


Have you ever heard of "Stoverized" nuts? Those are the ticket!

On May 14, 8:28*pm, "Existential Angst" wrote:
Iffin you REALLY wanted to be sure that a nut won't fall off a screw, or a
screw will loosen, wouldn't plain ole 2-part epoxy be the best bet?

Also, if an epoxied screw/nut did have to come off, wouldn't a little heat
do it?
--
EA

Nylon insert nuts or deformed locking nut will do it, if you ever have
to get it apart. A nut with a check nut will work as well. Could
drill and wire, too. Castle nut with a cotter pin works for car hubs.
If you NEVER have to remove the fastener, just rivet the joint.

Threadlockers are really meant for bolts or studs going into tapped
holes, there are nuts designed for locking duty, see above. Epoxies
really suck at holding shear forces, which is what you get with a nut
unscrewing.

Stan

In article ,
says...

Iffin you REALLY wanted to be sure that a nut won't fall off a screw, or a
screw will loosen, wouldn't plain ole 2-part epoxy be the best bet?

Also, if an epoxied screw/nut did have to come off, wouldn't a little heat
do it?

If you really want to be sure, hit it with an arc welder.

On Tue, 15 May 2012 19:51:23 -0400, "J. Clarke"
wrote:

In article ,
says...

Iffin you REALLY wanted to be sure that a nut won't fall off a screw, or a
screw will loosen, wouldn't plain ole 2-part epoxy be the best bet?

Also, if an epoxied screw/nut did have to come off, wouldn't a little heat
do it?

If you really want to be sure, hit it with an arc welder.

Prevailing torque nuts do the job extremely well (stovers). And
drilling and safety wiring them is just icing on the cake.

On Tue, 15 May 2012 09:03:51 -0700 (PDT), Stanley Schaefer
wrote:

On May 14, 8:28*pm, "Existential Angst" wrote:
Iffin you REALLY wanted to be sure that a nut won't fall off a screw, or a
screw will loosen, wouldn't plain ole 2-part epoxy be the best bet?

Also, if an epoxied screw/nut did have to come off, wouldn't a little heat
do it?
--
EA

Nylon insert nuts or deformed locking nut will do it, if you ever have
to get it apart. A nut with a check nut will work as well. Could
drill and wire, too. Castle nut with a cotter pin works for car hubs.
If you NEVER have to remove the fastener, just rivet the joint.

Threadlockers are really meant for bolts or studs going into tapped
holes, there are nuts designed for locking duty, see above. Epoxies
really suck at holding shear forces, which is what you get with a nut
unscrewing.

I am not sure how epoxy behaves on threads but in a "shaft-in-a-hole"
application when epoxy fails it is a catastrophic failure and the
shaft then moves quite freely. If one uses a retaining compound
similar to a threadlocker (Loctite 680 or Vibratite equivalent) the
shaft may move if enough force is applied but once the level of force
drops the shaft is stuck in this new position and one needs almost an
equal amount of force to shift it again.

Michael Koblic,
Campbell River, BC

On May 15, 12:36*am, "anorton"
wrote:

....

The army uses this stuff in the turret of the Abrams tank.http://www.vibra-tite.com/vc3.php
They found it is the only removable thread locker that can withstand the....

The web page says that the solvent is MEK and a plastic like substance
is deposited.

So, I guess, the obvious question is "What plastic dissolves in MEK" ?

DOC


Something about inquiring minds...




....

I believe you'll find that numerous plastics "melt" with MEK.. it's an
ingredient in PVC-ABS plumbing fitting cement.

If a solvent is hot enough that it "burns" a plastic (melts the surface on
contact), the plastic material will typically continue to soften as more of
the solvent comes into contact with it.
Hot solvents such as acetone, lacquer thinner and toluene will generally
melt hard plastic compounds and styrene, or many of the rigid plastic
compounds that don't bend easily/aren't typically flexible, but also foams
such as styrofoam.

--
WB
..........


"doc" wrote in message
...
On May 15, 12:36 am, "anorton"
wrote:

....

The army uses this stuff in the turret of the Abrams
tank.http://www.vibra-tite.com/vc3.php
They found it is the only removable thread locker that can withstand
the...

The web page says that the solvent is MEK and a plastic like substance
is deposited.

So, I guess, the obvious question is "What plastic dissolves in MEK" ?

DOC


Something about inquiring minds...




....