Electrical Engineering

Author

Epoxy

Esther & Fester Bestertester

2008-03-20, 5:25 pm

See no n.g. for adhesives & epoxies, so if there's a better forum for this,
just point me to it.

I need an epoxy that is strong to the point of brittle. I want no flex; it
has to transmit vibration as close to 100% as possible.

Am I looking for a high Shore Hardness value? That's what Devcon uses in its
data sheets to specify hardness.

Is this something that I can achieve by changing the mix of the 2 parts? If
so, what do I lose if I use more hardener?

Any personal experiences with epoxies that you found to be harder than
others?

Thanks.
FBt

bpederso@ball.com

2008-03-20, 5:25 pm

On Mar 20, 3:09=A0pm, Esther & Fester Bestertester <n...@me.really>
wrote:
> See no n.g. for adhesives & epoxies, so if there's a better forum for this=
,
> just point me to it.
>
> I need an epoxy that is strong to the point of brittle. I want no flex; it=

> has to transmit vibration as close to 100% as possible.
>
> Am I looking for a high Shore Hardness value? That's what Devcon uses in i=
ts
> data sheets to specify hardness.
>
> Is this something that I can achieve by changing the mix of the 2 parts? I=
f
> so, what do I lose if I use more hardener?
>
> Any personal experiences with epoxies that you found to be harder than
> others?
>
> Thanks.
> FBt

For spacecraft vibration testing we use Dental cement. It's extremely
non-compliant so it is good for transmitting vibration from a
structure to an accelerometer. It is brittle so we remove them by
just taping them with a hammer and breaking them off the surface. We
first put a layer of thin tape on the surface to protect the surface.
the tape does not affect the vibration response.
bob

Martin Griffith

2008-03-20, 5:25 pm

On Thu, 20 Mar 2008 21:09:14 GMT, in sci.electronics.design Esther &
Fester Bestertester <not@me.really> wrote:

>See no n.g. for adhesives & epoxies, so if there's a better forum for this,
>just point me to it.
>
>I need an epoxy that is strong to the point of brittle. I want no flex; it
>has to transmit vibration as close to 100% as possible.
>
>Am I looking for a high Shore Hardness value? That's what Devcon uses in its
>data sheets to specify hardness.
>
>Is this something that I can achieve by changing the mix of the 2 parts? If
>so, what do I lose if I use more hardener?
>
>Any personal experiences with epoxies that you found to be harder than
>others?
>
>Thanks.
>FBt
try searching for
sci.engr.chem
or sci.engr.*

martin

John Popelish

2008-03-20, 5:25 pm

Esther & Fester Bestertester wrote:
> See no n.g. for adhesives & epoxies, so if there's a better forum for this,
> just point me to it.
>
> I need an epoxy that is strong to the point of brittle. I want no flex; it
> has to transmit vibration as close to 100% as possible.
>
> Am I looking for a high Shore Hardness value? That's what Devcon uses in its
> data sheets to specify hardness.
>
> Is this something that I can achieve by changing the mix of the 2 parts? If
> so, what do I lose if I use more hardener?
>
> Any personal experiences with epoxies that you found to be harder than
> others?

Filled epoxies (loaded with various mineral and glass bits)
are much more rigid than plain epoxy. But if you start with
a slow cure epoxy (30 minute versus 5 minute) the epoxy,
itself will also be a lot harder. Glass micro spheres are a
good filler if you want to lower the density, and glass
micro beads or aluminum oxide if you want to raise it. Even
adding talcum powder adds to the rigidity, but the gas
bubbles it entrains lowers it (foams are less rigid than
solids of the same material), so vacuum degassing increases
the rigidity.

A very rigid mineral filled epoxy is Hysol 1C:
http://www.gluguru.com/Hysol%20Data%20Sheets/1C.htm

A slighter harder aluminum filled formula is Hysol 9434:
http://www.gluguru.com/Hysol%20Data%20Sheets/9434.htm

But they make lots of variations:
http://www.gluguru.com/HyEpSelecGuide.htm

--
Regards,

John Popelish

Roy

2008-03-20, 5:25 pm

From: (Martin=A0Griffith)
On Thu, 20 Mar 2008 21:09:14 GMT, in sci.electronics.design
Esther & Fester Bestertester <worte>
See no n.g. for adhesives & epoxies, so if there's a better forum for
this, just point me to it.
I need an epoxy that is strong to the point of brittle. I want no flex;
it has to transmit vibration as close to 100% as possible.
Am I looking for a high Shore Hardness value? That's what Devcon uses in
its data sheets to specify hardness.
Is this something that I can achieve by changing the mix of the 2 parts?
If so, what do I lose if I use more hardener?
Any personal experiences with epoxies that you found to be harder than
others?
Thanks.
FBt
---------
try searching for
sci.engr.chem
or sci.engr.*
martin
-----------------------
Yep' epoxy is definetly chemical engr. it's electrical properties are
null here....., although, the atomic composition may have a place in
electronic engr..There is a 2 part putty that acheives Metallic like
strength & properties when hardened it's not brittle as is nor
recoverable, so I guess it could be formed thin enough with a machine
press that it'd crackle....

Roy Q.T. ~ US/NCU ~ E.E. Technician
[have tools, will travel]

Didi

2008-03-20, 8:26 pm

> Any personal experiences with epoxies that you found to be harder than
> others?

I cannot suggest a harder epoxy but you pressed a sensitive button on
me
so here I go.

Many years ago (1991, to be precise) I opted to epoxy-fill my first
5kV
coils I did for my then employer in Cologne, Germany. I used no
multiplier,
straight flyback @ 5kV; about 1000 windings on an RM8 core, winding
and insulation layers being an art of their own. I located some very
liquid
epoxy meant for that purpose, then the whole module went filled, using
vacuum to make sure there were no cavities. Everything worked fine,
the filling
was perfect - I got asked how come the space between the *windinds*
was
not filled (0.05 wire, mylar foil between each layer) by my then
employer...
Some years later I had founded TGI in Bulgaria and did the first HV
source
making the coil more or less the same. However, I used off-the-shelf
epoxy;
it did not get as hard (although it was by far not as liquid before
hardening),
and after some warmup it began to conduct just enough to make the
thing
noisy... I wasted more than one coil (wound with a lot of work) until
I
got what was going on, I spent days if not weeks on that nightmare...
Eventually I learned I needed no filling at all, just a few drops of
melted
silicon at the right spots did the job (still does) quite well.

And on another occasion I had a guy from a detector repairshop in
Sofia
use the same effect trying to cheat on me... The HPGe gamma detectors
are very sensitive things, the front FET is cooled to -90C or so for
lowest
noise. The bias is a few kV (3.5 in that case), and the HV input is
filtered
through a 1Gohm/0.47uF group. Well, he had had the detector in his
hands
to "check it" for me and had put a stripe of such epoxid along the
resistor
between its pins... (The resistor is a rectangle, say 20x5mm, 1mm
thick).
After some warmup - the preamp consumes not so little, they have not
changed its design for >20 years - the detector begins to behave like
when it needs repair. Well he did not get it for repair because I
looked
and discovered what he had done and cleaned the mess up -and the
detector
worked fine. A few years later he got the same detector in his hands
directly from customers and did the same, this time he had added a
stripe
across the capacitor, though, and had scratched the paint of the
resistor between the pins. Mind you, I had told him I knew what he had
done the first time and he had done it again. I guess the epoxy must
have
had braindamaging effect as well.... (and I had refused to believe
other
people telling me he was sabotaging detectors before I got burned, the
epoxy must have worked on my brain as well - perhaps while dealing
with my coils... :-).

Dimiter

------------------------------------------------------
Dimiter Popoff Transgalactic Instruments

http://www.tgi-sci.com
------------------------------------------------------
http://www.flickr.com/photos/didi_t...57600228621276/

Esther & Fester Bestertester wrote:
> See no n.g. for adhesives & epoxies, so if there's a better forum for this,
> just point me to it.
>
> I need an epoxy that is strong to the point of brittle. I want no flex; it
> has to transmit vibration as close to 100% as possible.
>
> Am I looking for a high Shore Hardness value? That's what Devcon uses in its
> data sheets to specify hardness.
>
> Is this something that I can achieve by changing the mix of the 2 parts? If
> so, what do I lose if I use more hardener?
>
> Any personal experiences with epoxies that you found to be harder than
> others?
>
> Thanks.
> FBt

Dave Platt

2008-03-20, 8:26 pm

>I need an epoxy that is strong to the point of brittle. I want no flex; it
>has to transmit vibration as close to 100% as possible.

Sounds to me as if you're actually looking for stiffness, not
necessarily strength?

I think you'd want to look for (or make) a filled epoxy. A
high-strength epoxy which is loaded up with (e.g.) chopped or milled
fiberglass would be very stiff.

--
Dave Platt <dplatt@radagast.org> AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

TT_Man

2008-03-20, 8:26 pm

"Esther & Fester Bestertester" <not@me.really> wrote in message
news:0001HW.C408208C00069F2AB01AD9AF@news.sf.sbcglobal.net...
> See no n.g. for adhesives & epoxies, so if there's a better forum for
> this,
> just point me to it.
>
> I need an epoxy that is strong to the point of brittle. I want no flex; it
> has to transmit vibration as close to 100% as possible.
>
> Am I looking for a high Shore Hardness value? That's what Devcon uses in
> its
> data sheets to specify hardness.
>
> Is this something that I can achieve by changing the mix of the 2 parts?
> If
> so, what do I lose if I use more hardener?
>
> Any personal experiences with epoxies that you found to be harder than
> others?
>
> Thanks.
> FBt
>
If you can afford it, Araldite 2014. 4-6 hrs grab, 24hr set.It's a grey
paste two part.-

The Last Mimsy

2008-03-20, 8:26 pm

On Thu, 20 Mar 2008 21:09:14 GMT, Esther & Fester Bestertester
<not@me.really> wrote:

>See no n.g. for adhesives & epoxies, so if there's a better forum for this,
>just point me to it.
>
>I need an epoxy that is strong to the point of brittle. I want no flex; it
>has to transmit vibration as close to 100% as possible.
>
>Am I looking for a high Shore Hardness value? That's what Devcon uses in its
>data sheets to specify hardness.
>
>Is this something that I can achieve by changing the mix of the 2 parts? If
>so, what do I lose if I use more hardener?
>
>Any personal experiences with epoxies that you found to be harder than
>others?
>
>Thanks.
>FBt

With the way you worded this, it would seem that a technical response
would go right over your head.

Epoxy mix ratios are NEVER meant to be altered. You need to find an
epoxy that matches your needs. The only time I ever saw mix ratio ranges
to alter behavior, it was with an epoxy branded as "stycast". Which,
would oddly meat your needs.

It will not likely be cheap, however.

Corbomite Carrie

2008-03-20, 8:26 pm

On Thu, 20 Mar 2008 17:52:40 -0400, ROYKEY@webtv.net (Roy) wrote:

>From: (Martin_Griffith)
>On Thu, 20 Mar 2008 21:09:14 GMT, in sci.electronics.design
>Esther & Fester Bestertester <worte>
>See no n.g. for adhesives & epoxies, so if there's a better forum for
>this, just point me to it.
>I need an epoxy that is strong to the point of brittle. I want no flex;
>it has to transmit vibration as close to 100% as possible.
>Am I looking for a high Shore Hardness value? That's what Devcon uses in
>its data sheets to specify hardness.
>Is this something that I can achieve by changing the mix of the 2 parts?
>If so, what do I lose if I use more hardener?
>Any personal experiences with epoxies that you found to be harder than
>others?
>Thanks.
>FBt
>---------
>try searching for
>sci.engr.chem
>or sci.engr.*
>martin
>-----------------------
>Yep' epoxy is definetly chemical engr.

As if the group needs your affirmation to know that.

You're an idiot, Roy.

> it's electrical properties are
>null here.....,

I think you have a problem even knowing what "electrical properties"
are. EVERYTHING has electrical properties, you idiot.

> although, the atomic composition may have a place in
>electronic engr..There is a 2 part putty that acheives Metallic like
>strength & properties when hardened it's not brittle as is nor
>recoverable, so I guess it could be formed thin enough with a machine
>press that it'd crackle....

That has to be one of the most retarded statements I have ever read in
this group.

Please, Roy... stay away for a few months longer this time, you
goddamned WebTV retard.

>
>Roy Q.T. ~ US/NCU ~ E.E. Technician
> [have tools, will travel]

Total bullshit.

2008-03-20, 9:25 pm

On Thu, 20 Mar 2008 21:09:14 +0000, Esther & Fester Bestertester wrote:

> See no n.g. for adhesives & epoxies, so if there's a better forum for
> this, just point me to it.
>
> I need an epoxy that is strong to the point of brittle. I want no flex;
> it has to transmit vibration as close to 100% as possible.
>
> Am I looking for a high Shore Hardness value? That's what Devcon uses in
> its data sheets to specify hardness.
>
> Is this something that I can achieve by changing the mix of the 2 parts?
> If so, what do I lose if I use more hardener?
>
> Any personal experiences with epoxies that you found to be harder than
> others?
>
> Thanks.
> FBt

sci.materials is good.

Al

Tam

2008-03-20, 9:25 pm

"Esther & Fester Bestertester" <not@me.really> wrote in message
news:0001HW.C408208C00069F2AB01AD9AF@news.sf.sbcglobal.net...
> See no n.g. for adhesives & epoxies, so if there's a better forum for
> this,
> just point me to it.
>
> I need an epoxy that is strong to the point of brittle. I want no flex; it
> has to transmit vibration as close to 100% as possible.
>
> Am I looking for a high Shore Hardness value? That's what Devcon uses in
> its
> data sheets to specify hardness.
>
> Is this something that I can achieve by changing the mix of the 2 parts?
> If
> so, what do I lose if I use more hardener?
>
> Any personal experiences with epoxies that you found to be harder than
> others?
>
> Thanks.
> FBt
>
If you have been letting it cure at room temperature, try about 15 minutes
at 160 F or so. It will get a lot harder.

Tam

myrealaddress@comic.com

2008-03-20, 9:25 pm

On Thu, 20 Mar 2008 21:09:14 GMT, Esther & Fester Bestertester
<not@me.really> wrote:

>See no n.g. for adhesives & epoxies, so if there's a better forum for this,
>just point me to it.
>
>I need an epoxy that is strong to the point of brittle. I want no flex; it
>has to transmit vibration as close to 100% as possible.
>
>Am I looking for a high Shore Hardness value? That's what Devcon uses in its
>data sheets to specify hardness.
>
>Is this something that I can achieve by changing the mix of the 2 parts? If
>so, what do I lose if I use more hardener?
>
>Any personal experiences with epoxies that you found to be harder than
>others?
>
>Thanks.
>FBt

Dunno if it's tough enough but I use GR epoxy glue from Industrial
Formulations.
24 hour cure. (Sometimes a pita.)
Here in BC.
http://www.indform.com/
"We have an epoxy system for almost any project".
Really?? :P

All I know is that GR epoxy has less flex than Lepage 2 page epoxy
(dual syringe) I got from the hardware store.

D from BC
British Columbia
Canada

myrealaddress@comic.com

2008-03-20, 9:25 pm

On Thu, 20 Mar 2008 19:03:05 -0800, myrealaddress@comic.com wrote:

>On Thu, 20 Mar 2008 21:09:14 GMT, Esther & Fester Bestertester
><not@me.really> wrote:
>
>
>Dunno if it's tough enough but I use GR epoxy glue from Industrial
>Formulations.
>24 hour cure. (Sometimes a pita.)
>Here in BC.
>http://www.indform.com/
>"We have an epoxy system for almost any project".
>Really?? :P
>
>All I know is that GR epoxy has less flex than Lepage 2 page epoxy
>(dual syringe) I got from the hardware store.
>
>
>D from BC
>British Columbia
>Canada

Nothing to add.. Just checking my usenet client settings.
Ignore this part..

D from BC
British Columbia
Canada

Tim Williams

2008-03-21, 3:25 am

"The Last Mimsy" <mimsy@TheOtherSideoftheLookingGlass.org> wrote in message
news:qlr5u3l692gqnhm4hnttvo0h9n9d7tqegj@4ax.com...
> Which, would oddly meat your needs.

Don't let your meat loaf ;-)

Tim

--
Deep Fryer: A very philosophical monk.
Website @ http://webpages.charter.net/dawill/tmoranwms

Esther & Fester Bestertester

2008-03-21, 3:25 am

> If you have been letting it cure at room temperature, try about 15 minutes
> at 160 F or so. It will get a lot harder.
>
> Tam

Does it matter when the heat is applied? Right away? Or after it seems to
have cured as much as it is going to at room temp?

Esther & Fester Bestertester

2008-03-21, 3:25 am

To those who offer help even to the misguided, thank you for the benefit of
your knowledge.

To those who offer directions to the appropriate forum, thanks for the
(index) finger. :-)

FBtf

Phil Hobbs

2008-03-21, 9:25 am

Esther & Fester Bestertester wrote:
> See no n.g. for adhesives & epoxies, so if there's a better forum for this,
> just point me to it.
>
> I need an epoxy that is strong to the point of brittle. I want no flex; it
> has to transmit vibration as close to 100% as possible.
>
> Am I looking for a high Shore Hardness value? That's what Devcon uses in its
> data sheets to specify hardness.
>
> Is this something that I can achieve by changing the mix of the 2 parts? If
> so, what do I lose if I use more hardener?
>
> Any personal experiences with epoxies that you found to be harder than
> others?
>
> Thanks.
> FBt
>

sci.polymers or sci.materials might be a better bet. There are two
general ways you can make a given epoxy harder: bake it (an hour at 100C
does wonders) or put filler in it.

If you're bonding hard materials, you might want to use a glass bead
filler. When you squeeze the bondline down, the spheres contact the
surface, and as the epoxy shrinks (1% or so), it applies a preload to
the glass/substrate interfaces. That's a pretty stiff joint.

If you're trying to do something in shear, e.g. attach a strain gauge,
glue is not your friend at all. You might be better off using solder or
indium bonding or something like that.

Cheers,

Phil Hobbs

Tam

2008-03-21, 1:25 pm

"Esther & Fester Bestertester" <not@me.really> wrote in message
news:0001HW.C408B6B10029D013B01AD9AF@news.sf.sbcglobal.net...
>
> Does it matter when the heat is applied? Right away? Or after it seems to
> have cured as much as it is going to at room temp?
>
I have been waiting a few minutes until the epoxy is no longer runny. I turn
the oven on to 200, but turn it off before it reaches temperature. Have also
used a heat gun on something that was part of a large stationary object
(toilet). I haven't bothered, but this information should be available from
the manufacturer.

Tam

Gerald Newton

2008-03-21, 5:25 pm

On Mar 20, 1:09=A0pm, Esther & Fester Bestertester <n...@me.really>
wrote:
> See no n.g. for adhesives & epoxies, so if there's a better forum for this=
,
> just point me to it.
>
> I need an epoxy that is strong to the point of brittle. I want no flex; it=

> has to transmit vibration as close to 100% as possible.
>
> Am I looking for a high Shore Hardness value? That's what Devcon uses in i=
ts
> data sheets to specify hardness.
>
> Is this something that I can achieve by changing the mix of the 2 parts? I=
f
> so, what do I lose if I use more hardener?
>
> Any personal experiences with epoxies that you found to be harder than
> others?
>
> Thanks.
> FBt

Rubinno cement made by Singer Kearfott in the 70's was used on
guidance systems for the Sram missile, PC3, and A7 navey fighter
jets. It is the best there is.

Esther & Fester Bestertester

2008-03-21, 5:25 pm

> Rubinno cement

Google turns up zero hits. Is the correct spelling? Any web references you
can give?

Thanks,
FBt

ChairmanOfTheBored

2008-03-21, 5:25 pm

On Fri, 21 Mar 2008 18:36:53 GMT, Esther & Fester Bestertester
<not@me.really> wrote:

>
>Google turns up zero hits. Is the correct spelling? Any web references you
>can give?
>
>Thanks,
>FBt

It is probably $50 a quart. Minimum.

Paul Hovnanian P.E.

2008-03-22, 3:25 am

Esther & Fester Bestertester wrote:
>
> See no n.g. for adhesives & epoxies, so if there's a better forum for this,
> just point me to it.
>
> I need an epoxy that is strong to the point of brittle. I want no flex; it
> has to transmit vibration as close to 100% as possible.
>
> Am I looking for a high Shore Hardness value? That's what Devcon uses in its
> data sheets to specify hardness.

I believe that (Shore) is a measure of resistance to indentation. In
other words, pressure. You might need something else, depending on which
direction the vibration is acting with respect to the surface. A
pressure wave will result in both pressure and tensile stresses on the
adhesive. A shear wave will result in (duh) shear stresses.

In addition, you need to define what you mean by 'transmit vibration'.
I'm not a mechanical guy, but I'd be willing to bet that the problem of
maximizing mechanical energy transmission is analogous to that of
maximizing electromagnetic energy transmission. That is: It is optimal
when the impedance (modulus of elasticity?) is closely matched and
energy reflection is minimized.

The strength of the adhesive only becomes important if the amplitude of
the vibration approaches the strength limit of the bond.

This appears to be the sort of problems that people designing sonar
transducers have to deal with.

--
Paul Hovnanian mailto:Paul@Hovnanian.com
------------------------------------------------------------------
What if no one ever asked a hypothetical question?

Esther & Fester Bestertester

2008-03-22, 3:25 am

> It is probably $50 a quart. Minimum.

But that doesn't help me know *where*.

FBt

ChairmanOfTheBored

2008-03-22, 3:25 am

On Sat, 22 Mar 2008 03:54:02 GMT, Esther & Fester Bestertester
<not@me.really> wrote:

>
>But that doesn't help me know *where*.
>
>FBt

Try this one:

EPOTEK

http://www.epotek.com/categories.asp?ID=1

There are several that would easily fit your needs, and some that are
sold at small qty tube level.

Paul Hovnanian P.E.

2008-03-22, 3:25 am

Gerald Newton wrote:
>
> On Mar 20, 1:09 pm, Esther & Fester Bestertester <n...@me.really>
> wrote:
>
> Rubinno cement made by Singer Kearfott in the 70's was used on
> guidance systems for the Sram missile, PC3, and A7 navey fighter
> jets. It is the best there is.

What exactly was it used for? For securing components in a high
vibration environment, that might damp the vibrations that the OP wants
to transmit.

--
Paul Hovnanian mailto:Paul@Hovnanian.com
------------------------------------------------------------------
During the next two hours, the system will be going up and down several
times, often with lin~po_~{po ~poz~ppo\~{ o n~po_~{o[po ~y oodsou>#w4ko

JeffM

2008-03-22, 3:25 am

Paul Hovnanian P.E. wrote:
>The strength of the adhesive only becomes important if
>the amplitude of the vibration approaches the strength limit of the bond.
>
>This appears to be the sort of problems
>that people designing sonar transducers have to deal with.

I saw something on Blue Whales the other day
that mentioned they are the loudest creature.
I looked it up and the figure is 188dB (like being next to a rocket)
....and there is great controversy about SONAR use
because it is thought (due to weird behavior
like healthy-appearing specimens beaching themselves)
that it is so loud that it damages the hearing of whales.

daestrom

2008-03-22, 5:25 pm

"Paul Hovnanian P.E." <paul@hovnanian.com> wrote in message
news:47E49147.3898C236@hovnanian.com...
> Esther & Fester Bestertester wrote:
>
> I believe that (Shore) is a measure of resistance to indentation. In
> other words, pressure. You might need something else, depending on which
> direction the vibration is acting with respect to the surface. A
> pressure wave will result in both pressure and tensile stresses on the
> adhesive. A shear wave will result in (duh) shear stresses.
>
> In addition, you need to define what you mean by 'transmit vibration'.
> I'm not a mechanical guy, but I'd be willing to bet that the problem of
> maximizing mechanical energy transmission is analogous to that of
> maximizing electromagnetic energy transmission. That is: It is optimal
> when the impedance (modulus of elasticity?) is closely matched and
> energy reflection is minimized.
>
> The strength of the adhesive only becomes important if the amplitude of
> the vibration approaches the strength limit of the bond.
>
> This appears to be the sort of problems that people designing sonar
> transducers have to deal with.
>

Well, we used an epoxy (simple two part) to 'glue' mounts for vibration
monitoring equipment. The accelerator was in a magnetic housing and we
epoxied steel rings (not much more than washers really) to rotating
equipment at key points of bearings etc...). The mounts/washers provided a
nice flat, properly oriented surface for the vibration pickup so we could do
'sound cuts'.

Two fold, 1) we wanted to know how much noise our equipment was making
(submarines live / die by sound levels transmitted into the water) and 2) we
could predict some equipment maintenance like simple balance, pump-motor
alignment, bearing problems.

Maybe that's what the OP is after. But as I said, we used a simple, two
part epoxy with quite good results.

daestrom

Paul Hovnanian P.E.

2008-03-23, 3:25 am

daestrom wrote:
>
> "Paul Hovnanian P.E." <paul@hovnanian.com> wrote in message
> news:47E49147.3898C236@hovnanian.com...
>
> Well, we used an epoxy (simple two part) to 'glue' mounts for vibration
> monitoring equipment. The accelerator was in a magnetic housing and we
> epoxied steel rings (not much more than washers really) to rotating
> equipment at key points of bearings etc...). The mounts/washers provided a
> nice flat, properly oriented surface for the vibration pickup so we could do
> 'sound cuts'.
>
> Two fold, 1) we wanted to know how much noise our equipment was making
> (submarines live / die by sound levels transmitted into the water) and 2) we
> could predict some equipment maintenance like simple balance, pump-motor
> alignment, bearing problems.
>
> Maybe that's what the OP is after. But as I said, we used a simple, two
> part epoxy with quite good results.

The selection of a suitable adhesive depends on how much energy one can
afford to lose in a sub-optimally coupled system. In your case, the
signal level of vibrating mechanical equipment is probably high enough
that some attenuation is tolerable.

The other thing to consider is the mass of the sensor, the flexibility
of the adhesive and the resulting natural frequency of the sensor
assembly. A massive sensor and/or flexible coupling will result in a
lower frequency and result in attenuation of signals above that point.

> daestrom

--
Paul Hovnanian mailto:Paul@Hovnanian.com
------------------------------------------------------------------
You can discover what your enemy fears most by observing the
means he uses to frighten you. -- Eric Hoffer

ChairmanOfTheBored

2008-03-23, 3:25 am

On Sat, 22 Mar 2008 20:12:13 -0800, "Paul Hovnanian P.E."
<paul@hovnanian.com> wrote:
[color=darkred]
>daestrom wrote:
>
>The selection of a suitable adhesive depends on how much energy one can
>afford to lose in a sub-optimally coupled system. In your case, the
>signal level of vibrating mechanical equipment is probably high enough
>that some attenuation is tolerable.
>
>The other thing to consider is the mass of the sensor, the flexibility
>of the adhesive and the resulting natural frequency of the sensor
>assembly. A massive sensor and/or flexible coupling will result in a
>lower frequency and result in attenuation of signals above that point.
>

Metal filled epoxies pass thermal as well as vibration quite well.

http://www.epotek.com/SSCDocs/datasheets/H20E.PDF

Esther & Fester Bestertester

2008-03-23, 3:25 am

> The other thing to consider is the mass of the sensor, the flexibility
> of the adhesive and the resulting natural frequency of the sensor
> assembly. A massive sensor and/or flexible coupling will result in a
> lower frequency and result in attenuation of signals above that point.

The "flexible coupling" provided by the epoxies I've tried is causing issues.

It's been suggested that I try silver-filled epoxy and potting compound.
Dental cement was also a suggestion. I'm looking at all of these.

FBt

MakeNoAttemptToAdjustYourSet

2008-03-23, 3:25 am

On Sat, 22 Mar 2008 22:49:16 -0700, Esther & Fester Bestertester
<not@me.really> wrote:

>
>The "flexible coupling" provided by the epoxies I've tried is causing issues.
>
>
>It's been suggested that I try silver-filled epoxy and potting compound.
>Dental cement was also a suggestion. I'm looking at all of these.
>
>FBt

The silver filled is used to attach IC chip dies to their heat sinks
inside the chip package.

It is quite firm... brittle even, and is also conductive.

Requires 4 hr 80 C cure, however.

There are cooler, longer schedules.

HapticZ

2008-03-23, 5:25 pm

hand held hair dryers work fine

let epxy cure to near solid, then heat

else it will reliquify and run with gravity, messy!!

my work once required magnets to be epoxied to core pieces in meter
movements, they went thru ovens after primary cure for abt 15 minutes at 200
deg F

that was before engneering started using cryanoacrylite type adhesives, they
seemed much better and harder with less work time, never had a release
either.

preparation is key to good results

cryo is avail in gel or near gooy form

Loctite corporation has tons of alternatives available

"Tam" <t-tammaru@comcast.net> wrote in message
news:5eednSppS42jR37anZ2dnUVZ_oSunZ2d@comcast.com...
>
> "Esther & Fester Bestertester" <not@me.really> wrote in message
> news:0001HW.C408B6B10029D013B01AD9AF@news.sf.sbcglobal.net...
to[color=darkred]
> I have been waiting a few minutes until the epoxy is no longer runny. I
turn
> the oven on to 200, but turn it off before it reaches temperature. Have
also
> used a heat gun on something that was part of a large stationary object
> (toilet). I haven't bothered, but this information should be available
from
> the manufacturer.
>
> Tam
>

MakeNoAttemptToAdjustYourSet

2008-03-23, 5:25 pm

On Sun, 23 Mar 2008 20:15:46 GMT, "HapticZ" <hapticz@sbcglobal.net>
wrote:

>else it will reliquify and run with gravity, messy!!

Wrong. There are plenty of epoxies that stay right where they are put.

Not only that, but capillary attraction will hold most in place.

Also, the extremely high temp a hair dryer or heat gun puts out is too
much. It needs to be in an oven at a known temperature to cure correctly.

Esther & Fester Bestertester

2008-03-23, 9:25 pm

How does CA (cyanoacrylate) stack up against epoxy?

William Sommerwerck

2008-03-23, 9:25 pm

CA has high "pulling" strength, but is easily cracked by lateral forces.

Paul Hovnanian P.E.

2008-03-23, 9:25 pm

Esther & Fester Bestertester wrote:
>
>
> The "flexible coupling" provided by the epoxies I've tried is causing issues.

Can you quantify thos issues?

> It's been suggested that I try silver-filled epoxy and potting compound.
> Dental cement was also a suggestion. I'm looking at all of these.

Perhaps. I suppose you could keep trying stuff until the system appears
to work better.

> FBt

--
Paul Hovnanian mailto:Paul@Hovnanian.com
------------------------------------------------------------------
First they ignore you, then they ridicule you, then they fight you,
then you win. -Gandhi

UltimatePatriot

2008-03-23, 9:25 pm

On Sun, 23 Mar 2008 18:33:00 -0700, Esther & Fester Bestertester
<not@me.really> wrote:

>How does CA (cyanoacrylate) stack up against epoxy?

Poor thermal, poor vibration. Not epoxy.

Gerald Newton

2008-03-23, 9:25 pm

On Mar 21, 10:36=A0am, Esther & Fester Bestertester <n...@me.really>
wrote:
>
> Google turns up zero hits. Is the correct spelling? Any web references you=

> can give?
>
> Thanks,
> FBt

Try:
Kearfott Guidance & Navigation Corporation
1150 McBride Avenue
Little Falls, New Jersey 07424-2500, USA

root114@gmail.com

2008-03-24, 9:25 am

On 3=D4=C221=C8=D5, =C9=CF=CE=E75=CA=B109=B7=D6, Esther & Fester Besterteste=
r <n...@me.really>
wrote:
> See no n.g. for adhesives & epoxies, so if there's a better forum for this=
,
> just point me to it.
>
> I need an epoxy that is strong to the point of brittle. I want no flex; it=

> has to transmit vibration as close to 100% as possible.
>
> Am I looking for a high Shore Hardness value? That's what Devcon uses in i=
ts
> data sheets to specify hardness.
>
> Is this something that I can achieve by changing the mix of the 2 parts? I=
f
> so, what do I lose if I use more hardener?
>
> Any personal experiences with epoxies that you found to be harder than
> others?
>
> Thanks.
> FBt

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amdx

2008-03-24, 9:25 am

"TT_Man" <Someone@ntlworld.com> wrote in message
news:IbCEj.862$4f4.645@newsfe6-win.ntli.net...
>
> "Esther & Fester Bestertester" <not@me.really> wrote in message
> news:0001HW.C408208C00069F2AB01AD9AF@news.sf.sbcglobal.net...
> If you can afford it, Araldite 2014. 4-6 hrs grab, 24hr set.It's a grey
> paste two part.-
>
I like Araldite 10, fast cure, 10 minutes to set, 1hr cure. The last time
I ordered it it came as Huntsman 10. You should be able to find a spec.
sheet online.
Huntsman Advanced Materials Americas Inc.
4917 Dawn Ave.
East Lansing Mi. 48823-5691
517-351-5900
Mike

root114@gmail.com

2008-03-24, 1:25 pm

Rich Grise

2008-03-24, 9:25 pm

On Thu, 20 Mar 2008 16:19:07 -0700, The Last Mimsy wrote:
> On Thu, 20 Mar 2008 21:09:14 GMT, Esther & Fester Bestertester
>
>
> With the way you worded this, it would seem that a technical response
> would go right over your head.
>
> Epoxy mix ratios are NEVER meant to be altered. You need to find an
> epoxy that matches your needs. The only time I ever saw mix ratio ranges
> to alter behavior, it was with an epoxy branded as "stycast". Which,
> would oddly meat your needs.
>
> It will not likely be cheap, however.

Just FYI, when I was a kid, my Dad (RIP) got a two-bottle set of one of
the first epoxies, and its instructions gave one ratio for a rigid bond,
and another for "flexible".

I haven't seen anything like that lately, probably because so few
people would have the right measuring stuff. :-)

Thanks,
Rich

stratus46@yahoo.com

2008-03-24, 9:25 pm

On Mar 22, 9:49=A0pm, Esther & Fester Bestertester <n...@me.really>
wrote:
flexibility[color=darkred]
in a[color=darkred]
point.[color=darkred]
>
> The "flexible coupling" provided by the epoxies I've tried is
causing issues.
>
> It's been suggested that I try silver-filled epoxy and potting
compound.
> Dental cement was also a suggestion. I'm looking at all of these.
>
> FBt

Devcon Plastic Welder or Stabilit Express are methacrylates that are
much harder and stronger than the hardware store epoxies and cheap
enough to try.

http://www.hobby-lobby.com/adhesive.htm

http://www.ellsworth.com/plastic_welder.html

GG

The Last Mimsy

2008-03-25, 3:25 am

On Tue, 25 Mar 2008 01:40:00 GMT, Rich Grise <rich@example.net> wrote:

>On Thu, 20 Mar 2008 16:19:07 -0700, The Last Mimsy wrote:
>
>Just FYI, when I was a kid, my Dad (RIP) got a two-bottle set of one of
>the first epoxies, and its instructions gave one ratio for a rigid bond,
>and another for "flexible".
>
>I haven't seen anything like that lately, probably because so few
>people would have the right measuring stuff. :-)
>
>Thanks,
>Rich

There are some epoxies that give different characteristics with a
different mix ratio, but not many, and NONE of those that do not should
be manipulated in such a way.

The "stycast" I mentioned has about four different hardening schedules,
and uses about three different hardening medias. All yield differing
results for heat resistance, high temp softening after cure, etc.

When it is several grams of base media, and a few drops of "hardener",
I call it barely qualified to be called epoxy.

When the mix is closer to 50 50, one will find it is more stringently
adhered to as both constituents are critical to the finished medium.

Some mixes have to be accurate to within 0.1 grams or 0.1%.

Glen Walpert

2008-03-25, 1:25 pm

On Mon, 24 Mar 2008 19:27:09 -0700, The Last Mimsy
<mimsy@TheOtherSideoftheLookingGlass.org> wrote:

>On Tue, 25 Mar 2008 01:40:00 GMT, Rich Grise <rich@example.net> wrote:
>
>
>
> There are some epoxies that give different characteristics with a
>different mix ratio, but not many, and NONE of those that do not should
>be manipulated in such a way.

Curious, I have been using epoxies for more than 40 years and have
read many articles on epoxies in for instance Adhesives and Sealants
magazine, and I have never once seen or heard of any epoxy whose
properties do not depend on mix ratio; although in many cases exact
mix ratio is not critical.

> The "stycast" I mentioned has about four different hardening schedules,
>and uses about three different hardening medias. All yield differing
>results for heat resistance, high temp softening after cure, etc.
>
> When it is several grams of base media, and a few drops of "hardener",
>I call it barely qualified to be called epoxy.
>
> When the mix is closer to 50 50, one will find it is more stringently
>adhered to as both constituents are critical to the finished medium.
>
> Some mixes have to be accurate to within 0.1 grams or 0.1%.

"Epoxy" is not an adhesive, it is a family of adhesives that includes
many different specific chemistries. All high strength epoxies are
multi-functional, that is, they are a blend of two or more of the
basic epoxy chemistries. In any critical application it is foolish
not to discuss your specific requirements with one or more epoxy
formulators to obtain a blend closely optimized to your needs, and
then to qualify the materials and application process with testing.
Master Bond is one supplier of specialty epoxies with good tech
support.

On the other hand, for hobby applications, you can get good variation
in hardness with mix ratio with any nominally 5:1 ratio marine epoxy.
These epoxies are normally available with slow or fast hardeners in
order to allow reasonable working time in cool (use fast hardener) to
hot (use slow hardener) conditions. More hardener results in more
flexibility with lower strength and hardness. I mostly use "The West
System" with pump dispensers for easy measurement - one stroke of each
is 5:1, for small amounts I count drops. With the addition of fumed
silica (available from the same marine suppliers as the epoxy) it can
be thickened into a non-running paste very easily, or with the
addition of fine wood dust as a filler you can make epoxy foam.

BTW, by far the most common reason for lower than normal strength
epoxy is inadequate mixing, especially in the filled, pasty
formulations. It is best to consider the point where the epoxy
appears to be completely mixed to be the half way point in mixing. If
you actually measure the strength or hardness of the cured epoxy the
additional mixing will almost always result in better and more
consistent properties.

HapticZ

2008-03-25, 1:25 pm

for epoxies available over the counter ( not commercial specialty) most are
two part resin based, to be mixed like a liquid initially

this appeals to small , unique and one time fixes.

thin applications are ideal, as most ofthese areNOT meant to be filler
types, unless specificcaly stated

thin narrow space between parts creates incredible strength when properly
epoxied, never 'rely' on the epoxy to become strong like the materials you
are joining

except someepoxy may be actualy stronger,, then you just end up breakin the
fixed part in some other place when it is used badly agaon!

filled and putty type epoxies , granted they do not 'run' when applied.
technically diferent formulations

silicone sealants when cured wil offer high strength when used correctly
( thin, well prepared)

acrylic based fillers provide similar opportuinites.

polymers come in many shades of performance and coloration,

dont get hung upon 'the same old thing', the chemists are busy as we sit on
asses typing ...................................

"MakeNoAttemptToAdjustYourSet" <DoNotAttemptToAdjustYourSet@anytime.org>
wrote in message news:82hdu3hjn9emj7a40rdcp6616qqbvjif2m@4ax.com...
> On Sun, 23 Mar 2008 20:15:46 GMT, "HapticZ" <hapticz@sbcglobal.net>
> wrote:
>
>
>
> Wrong. There are plenty of epoxies that stay right where they are put.
>
> Not only that, but capillary attraction will hold most in place.
>
> Also, the extremely high temp a hair dryer or heat gun puts out is too
> much. It needs to be in an oven at a known temperature to cure correctly.

The Last Mimsy

2008-03-25, 5:25 pm

On Tue, 25 Mar 2008 15:49:55 GMT, Glen Walpert <nospam@null.void> wrote:

> All high strength epoxies are
>multi-functional, that is, they are a blend of two or more of the
>basic epoxy chemistries.

Two. Epoxy, by definition is a two part mix.

James Sweet

2008-03-25, 5:25 pm

"The Last Mimsy" <mimsy@TheOtherSideoftheLookingGlass.org> wrote in message
news:d7iiu3t2sdj6h2cg1sh8tpina61o10b7md@4ax.com...
> On Tue, 25 Mar 2008 15:49:55 GMT, Glen Walpert <nospam@null.void> wrote:
>
>
>
> Two. Epoxy, by definition is a two part mix.

You're talking about different things. Epoxy is a two part mix when you buy
it, but that doesn't mean that each part is not made of multiple compounds
mixed inmanufacture.

HapticZ

2008-03-26, 3:25 am

Loctite Corp also has a slew of stuff .

<stratus46@yahoo.com> wrote in message
news:f690642e-fe9b-48f9-a9cc-1c1f887901fb@e23g2000prf.googlegroups.com...
On Mar 22, 9:49 pm, Esther & Fester Bestertester <n...@me.really>
wrote:
flexibility[color=darkred]
in a[color=darkred]
point.[color=darkred]
>
> The "flexible coupling" provided by the epoxies I've tried is
causing issues.
>
> It's been suggested that I try silver-filled epoxy and potting
compound.
> Dental cement was also a suggestion. I'm looking at all of these.
>
> FBt

Devcon Plastic Welder or Stabilit Express are methacrylates that are
much harder and stronger than the hardware store epoxies and cheap
enough to try.

http://www.hobby-lobby.com/adhesive.htm

http://www.ellsworth.com/plastic_welder.html

GG

Esther & Fester Bestertester

2008-03-27, 5:25 pm

And the winner is...

Silver conductive epoxy:

<http://mgchemicals.com/products/8331.html>

Conductive wasn't a requirement, but it's the toughest in my small battery of
tests.

Thanks to all who contributed.

FBt

Roy

2008-04-03, 3:25 am

From: Cromholemite@maneuver.org (Crubholemite=A0Carrie)
On Thu, 20 Mar 2008 17:52:40 -0400, ROYKEY@webtv.net (Roy) wrote:
From: (Martin=A0Griffith)
On Thu, 20 Mar 2008 21:09:14 GMT, in sci.electronics.design Esther &
Fester Bestertester <worte>
See no n.g. for adhesives & epoxies, so if there's a better forum for
this, just point me to it.
I need an epoxy that is strong to the point of brittle. I want no flex;
it has to transmit vibration as close to 100% as possible. Am I looking
for a high Shore Hardness value? That's what Devcon uses in its data
sheets to specify hardness.
Is this something that I can achieve by changing the mix of the 2 parts?
If so, what do I lose if I use more hardener? Any personal experiences
with epoxies that you found to be harder than others?
Thanks.
FBt
---------
try searching for
sci.engr.chem
or sci.engr.*
martin
-----------------------
Yep' epoxy is definetly chemical engr.
As if the group needs your affirmation to know that.
=A0=A0=A0=A0You're an idiot, Roy.
=A0=A0it's electrical properties are
null here.....,
=A0=A0=A0=A0I think you have a problem even knowing what "electrical
properties" are. EVERYTHING has electrical properties, you idiot.
[[[here you are Relecting yourself]]]
{it will not condcut electricity - your XXX has electrical properties
shut it off.}

=A0=A0although, the atomic composition may have a place in electronic
engr..There is a 2 part putty that acheives Metallic like strength &
properties when hardened it's not brittle as is nor recoverable, so I
guess it could be formed thin enough with a machine press that it'd
crackle....

=A0=A0=A0=A0That has to be one of the most retarded statements I have
ever read in this group.
=A0=A0=A0=A0Please, Roy... stay away for a few months longer this time,
you goddamned WebTV retard.
[[Envy, You Infectuos Rat., that's all you can do]]

Roy Q.T. ~ US/NCU ~ E.E. Technician
=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0[have tools, will travel]
=A0=A0Total bullshit.
[[if it were from you]]

TO THE GROUP: THIS MORON THINKS HE CAN HIDE THE SUN FROM THE OTHERS WITH
HIS HAND BUT HE ONLY KEEPS HIMSELF FROM SEEING IT>>>

FOR THE CRUMHOLE MORON: FUCK YOU ! SCUM FOR BRAINS ! YOU'RE A STINKIN
XXXXXXX So, EAT SHIT & DIE BIGGOT....YOU CAN SHOVE YOUR ENVIOUS BERATING
COMMENTS UP YOUR WANNABE XXX...FOWLER.

Response; If you thin the putty out enough., when it dries it will be
brittle as the OP seeks..so shut up and stay of my case....You Stunk !

LinkBot