While this is not strictly metal related, I'm sure I will get some
good advice here.

I need to stick tiny (about 1/8th inch dia) rare earth magnets to
plastic film (think laminated paper) and I am looking for a glue to do
the job. The result needs to be fairly difficult to break.Tried CA,
but I can break the bond with some effort. Same with Araldite
(epoxy).

Any suggestions? Any tips to get it to work better?

TIA - I'm back to lurking now
Gautham

wrote in message
...
While this is not strictly metal related, I'm sure I will get some
good advice here.

I need to stick tiny (about 1/8th inch dia) rare earth magnets to
plastic film (think laminated paper) and I am looking for a glue to do
the job. The result needs to be fairly difficult to break.Tried CA,
but I can break the bond with some effort. Same with Araldite
(epoxy).

Any suggestions? Any tips to get it to work better?

TIA - I'm back to lurking now
Gautham

It depends entirely on what kind of plastic film you're dealing with. In
some cases, there is no adhesive that will produce more than a superficial
bond.

You really have to know what the plastic is. There's no getting around it.

--
Ed Huntress

Just used some of this stuff to glue a magnet to some "King Board" in my
trailer, double sided acrylic body trim tape didn't stick at all but this
seems to be holding so far:

http://www3.towerhobbies.com/cgi-bin...&I=LXCX69&P=SM

Think it's the same family of adhesives as "shoo goo". It's a little
flexible but should do the job...



"Ed Huntress" wrote in message
...

wrote in message
...
While this is not strictly metal related, I'm sure I will get some
good advice here.

I need to stick tiny (about 1/8th inch dia) rare earth magnets to
plastic film (think laminated paper) and I am looking for a glue to do
the job. The result needs to be fairly difficult to break.Tried CA,
but I can break the bond with some effort. Same with Araldite
(epoxy).

Any suggestions? Any tips to get it to work better?

TIA - I'm back to lurking now
Gautham

It depends entirely on what kind of plastic film you're dealing with. In
some cases, there is no adhesive that will produce more than a superficial
bond.

You really have to know what the plastic is. There's no getting around it.

--
Ed Huntress

On May 13, 5:21 pm, wrote:
While this is not strictly metal related, I'm sure I will get some
good advice here.

I need to stick tiny (about 1/8th inch dia) rare earth magnets to
plastic film (think laminated paper) and I am looking for a glue to do
the job. The result needs to be fairly difficult to break.Tried CA,
but I can break the bond with some effort. Same with Araldite
(epoxy).

Any suggestions? Any tips to get it to work better?

TIA - I'm back to lurking now
Gautham

I'd ask 3M
http://solutions.3m.com/wps/portal/3...ing-Solutions/

Karl

On May 14, 6:13*am, " wrote:
On May 13, 5:21 pm, wrote:

While this is not strictly metal related, I'm sure I will get some
good advice here.

I need to stick tiny (about 1/8th inch dia) rare earth magnets to
plastic film (think laminated paper) and I am looking for a glue to do
the job. *The result needs to be fairly difficult to break.Tried CA,
but I can break the bond with some effort. Same with Araldite
(epoxy).

Any suggestions? Any tips to get it to work better?

TIA - I'm back to lurking now
Gautham

I'd ask 3Mhttp://solutions.3m.com/wps/portal/3M/en_US/Manufacturing/Industry/Pr...

Karl

There may be a problem that is more difficult than adhesive. When you
say "rare earth magnet" I assume you are using Neodymium-Iron-Boron
magnets. I used these to make refrigerator magnets with epoxy for a
while. The neo oxidizes very badly. When you bond with epoxy it is
strong for a while and then a film of oxide forms between the magnet
and the adhesive. Then the magnet falls off. You need to get an
airtight coating on the magnet before bonding. I have seen plating
that lasts well.

The problem is the Neodymium, it is the material that makes sparks in
cigarette lighter flints. It is very oxidizable (flammable in powder
form).

I never solved the problem. By the way I still have hundreds of
magnets to sell. They are about .2 dia x .4 inches long.

Good luck.
Bob

On Tue, 13 May 2008 23:32:24 -0400, Ed Huntress wrote:

wrote in message
...
While this is not strictly metal related, I'm sure I will get some good
advice here.

I need to stick tiny (about 1/8th inch dia) rare earth magnets to
plastic film (think laminated paper) and I am looking for a glue to do
the job. The result needs to be fairly difficult to break.Tried CA,
but I can break the bond with some effort. Same with Araldite (epoxy).

Any suggestions? Any tips to get it to work better?

TIA - I'm back to lurking now
Gautham

It depends entirely on what kind of plastic film you're dealing with. In
some cases, there is no adhesive that will produce more than a
superficial bond.

You really have to know what the plastic is. There's no getting around
it.

And the magnet. The rare-earth alloys are highly prone to rust, and many
of the magnets are chrome plated. In addition to the difficulty of
sticking to the plastic, you may need a glue that can handle the chrome
plating.

OP: Are these magnets chromed? Are you having trouble with the bond to
the magnet, or the bond to the plastic/paper?

--
Tim Wescott
Control systems and communications consulting
http://www.wescottdesign.com

Need to learn how to apply control theory in your embedded system?
"Applied Control Theory for Embedded Systems" by Tim Wescott
Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html

On Tue, 13 May 2008 20:21:55 -0700 (PDT),
wrote:

While this is not strictly metal related, I'm sure I will get some
good advice here.

I need to stick tiny (about 1/8th inch dia) rare earth magnets to
plastic film (think laminated paper) and I am looking for a glue to do
the job. The result needs to be fairly difficult to break.Tried CA,
but I can break the bond with some effort. Same with Araldite
(epoxy).

Any suggestions? Any tips to get it to work better?

TIA - I'm back to lurking now
Gautham
==========\
I would try using a hot melt glue gun while you are waiting for
information. As fast as the hot melt sets up, your biggest
problem may be positioning the magnets. Make a trial for 2.97$US
+SHT click on
http://www.lowes.com/lowes/lkn?actio...300&lpage=none

for more info see
http://www.glu-stix.com/
http://www.glu-stix.com/shop/page/Polyamide_Glue.html
and for metal/plastic bonding see
http://www.glu-stix.com/shop/page/pr...ece2b38b7.html
also see
http://www.hotstik.com/store/pc/HS-3...er-Lb-6p43.htm





Unka' George [George McDuffee]
-------------------------------------------
He that will not apply new remedies,
must expect new evils:
for Time is the greatest innovator: and
if Time, of course, alter things to the worse,
and wisdom and counsel shall not alter them to the better,
what shall be the end?

Francis Bacon (1561-1626), English philosopher, essayist, statesman.
Essays, "Of Innovations" (1597-1625).

Where's the bond part, from the magnet or the plastic? Divide &
conquer, so to speak.

Hul

wrote:
While this is not strictly metal related, I'm sure I will get some
good advice here.

I need to stick tiny (about 1/8th inch dia) rare earth magnets to
plastic film (think laminated paper) and I am looking for a glue to do
the job. The result needs to be fairly difficult to break.Tried CA,
but I can break the bond with some effort. Same with Araldite
(epoxy).

Any suggestions? Any tips to get it to work better?

TIA - I'm back to lurking now
Gautham

On Wed, 14 May 2008 10:41:15 -0500, Tim Wescott
wrote:


wrote in message
...
While this is not strictly metal related, I'm sure I will get some good
advice here.

I need to stick tiny (about 1/8th inch dia) rare earth magnets to
plastic film (think laminated paper) and I am looking for a glue to do
the job. The result needs to be fairly difficult to break.Tried CA,
but I can break the bond with some effort. Same with Araldite (epoxy).

Any suggestions? Any tips to get it to work better?

TIA - I'm back to lurking now
Gautham

How about placing a "twin" magnet on each "side" of the plastic, with
say some glue under each. That should almost double the strain
required to remove one.

Will try those hotmelt varieties.

The bond seems to give up on the plastic side i.e. there is adhesive
on the magnet which seems difficult to get off but the plastic surface
is clean.

Wondering if roughing up the plastic film with a bit of sandpaper will
make any difference.

Thanks, Gautham

On Thu, 15 May 2008 02:55:23 -0700 (PDT),
wrote:

Will try those hotmelt varieties.

The bond seems to give up on the plastic side i.e. there is adhesive
on the magnet which seems difficult to get off but the plastic surface
is clean.

Wondering if roughing up the plastic film with a bit of sandpaper will
make any difference.

Thanks, Gautham
===========
Be sure to let the group know how things work out [enquiring
minds want to know...]


Unka' George [George McDuffee]
-------------------------------------------
He that will not apply new remedies,
must expect new evils:
for Time is the greatest innovator: and
if Time, of course, alter things to the worse,
and wisdom and counsel shall not alter them to the better,
what shall be the end?

Francis Bacon (1561-1626), English philosopher, essayist, statesman.
Essays, "Of Innovations" (1597-1625).

On Thu, 15 May 2008 02:55:23 -0700, gautham.vanya wrote:
Will try those hotmelt varieties.

The bond seems to give up on the plastic side i.e. there is adhesive on
the magnet which seems difficult to get off but the plastic surface is
clean.

Wondering if roughing up the plastic film with a bit of sandpaper will
make any difference.

While it makes a difference, other methods are more effective. From page
355 at the end of section D, "Surface Grafting" of "Adhesives in Joining
Plastics", a chapter in Patrick and Minford's "Treatise on adhesion and
adhesives": "increases in adhesion were seen" (by abrading under epoxy
vs abrading in air) but "failure surfaces of the adhesive bonds were
apparently adhesion failure" vs. "Yamakawa's work in which grafted
surfaces exhibited primarily substrate failure in practical adhesion
testing." Yamakawa grafted saponified methyl acrylate on PE, PTFE,
and PCTFE surfaces, via Co60 radiation -- impractical to try unless
you work in a hospital with a radiation-therapy department.

http://www.corotec.com/techinfo/pape...l?id=997131402 describes
high voltage RF plasma techniques that are commonly used to prepare
PE surfaces for printing and gluing. Also see the chemical surface
preps (for metals but maybe relevant to some plastics) described in
http://www.wmrc.uiuc.edu/info/librar...gs/surface.htm
many of which are practical at home.

-jiw

Keywords:
In article , wrote:
Will try those hotmelt varieties.

The bond seems to give up on the plastic side i.e. there is adhesive
on the magnet which seems difficult to get off but the plastic surface
is clean.

Wondering if roughing up the plastic film with a bit of sandpaper will
make any difference.

I came in on the middle of this thread, so I'm not sure what sort of
plastic you are working with. There areseveral possible contributing
reasons why adhesives don't stick to plastic:

1) Residual monomers. These can be oily, and prevent the adhesive from
attaching to anything structural. The right solvent can clean off a lot
of this.

2) Too smooth a surface. The adhesive just can't hang on to anything.
Thsi is where roughing it up will help.

3) No molecules on the surface that want to hook up with the glue. If
all of the ploymers in the plastic are long chains happily hooked
together, the adhesive can't find anything to chemically bond with. This
is sort of like 2, only at the molecular level. Chewing it up with
abrasive may help, but chemically etching the surface to break up the
long polymer chains is best. Sometimes you can achieve soemthtign
similar by lightly scorching the surface. The chemicals required to etch
some plastics are pretty nasty.

For most things, I use some sandpaper & then give it a good cleaning with
a solvent.

I haven't used it myself, but I've heard good things about the Cyanopoxy
system:

http://www.coolchem.com/index.cfm?fuseaction=cyanopoxy

Doug White