This thing may actually may be use full for something. Presorvac 5
Cycle Marinater

http://woot.com/!

"Usual suspect" wrote in message
...
This thing may actually may be use full for something. Presorvac 5
Cycle Marinater

http://woot.com/!

How about an epoxy mixer that doesn't add any bubbles to begin with.
http://www.japanunix.co.jp/ju_en/pro...err_video.html

"anorton" wrote in message
...

"Usual suspect" wrote in message
...
This thing may actually may be use full for something. Presorvac 5
Cycle Marinater

http://woot.com/!

How about an epoxy mixer that doesn't add any bubbles to begin with.
http://www.japanunix.co.jp/ju_en/pro...err_video.html

AN:

I followed your link. The machine looks pricey. Have you ever used
one?
I'm looking for something to "de-bubbelize" thickened and pigmented
polyester
resin.

Regards,

EH

Edward Hennessey wrote:
"anorton" wrote in message
...
"Usual suspect" wrote in message
...
This thing may actually may be use full for something. Presorvac 5
Cycle Marinater

http://woot.com/!
How about an epoxy mixer that doesn't add any bubbles to begin with.
http://www.japanunix.co.jp/ju_en/pro...err_video.html

AN:

I followed your link. The machine looks pricey. Have you ever used
one?
I'm looking for something to "de-bubbelize" thickened and pigmented
polyester
resin.

Regards,

EH




Casting or laminating resin?

(sorry, hadn't been following closely)

--

Richard Lamb
email me:
web site: www.home.earthlink.net/~cavelamb

"Edward Hennessey" wrote in message
m...

"anorton" wrote in message
...

"Usual suspect" wrote in message
...
This thing may actually may be use full for something. Presorvac 5
Cycle Marinater

http://woot.com/!

How about an epoxy mixer that doesn't add any bubbles to begin with.
http://www.japanunix.co.jp/ju_en/pro...err_video.html

AN:

I followed your link. The machine looks pricey. Have you ever used one?
I'm looking for something to "de-bubbelize" thickened and pigmented
polyester
resin.

Regards,

EH

I have not used one or priced it, But I saw the video a while ago and
thought it would be very useful. These are made by several places, search
for centrifugal mixer.
http://www.speedmixer.com/
http://www.nmtronics.com/smt/thinky-...ugal-mixer.htm
http://www.ewkaufmann.com/product.as...ific=jncooqene

Here is an article describing it. Looks like it would not be hard to make
if you were so inclined.
http://www.adhesivesmag.com/Articles...00000000853210

My current method for removing bubbles from mixed epoxy is to spread it out
very thin on something smooth with a spatula, wait for the bubbles to pop,
then scrape it back onto the spatula for application.

"CaveLamb" wrote in message
m...
Edward Hennessey wrote:
"anorton" wrote in message
...
"Usual suspect" wrote in message
...
This thing may actually may be use full for something. Presorvac
5
Cycle Marinater

http://woot.com/!
How about an epoxy mixer that doesn't add any bubbles to begin
with.
http://www.japanunix.co.jp/ju_en/pro...err_video.html

AN:

I followed your link. The machine looks pricey. Have you ever used
one?
I'm looking for something to "de-bubbelize" thickened and pigmented
polyester
resin.

Regards,

EH


Casting or laminating resin?

(sorry, hadn't been following closely)

--

Richard Lamb
email me:
web site: www.home.earthlink.net/~cavelamb


RL:

I'm using casting resin in a surface application to simulate shell in
fossil
restoration. Aside from the wax already in the polyester, thixotropic
powdered
glass is added so the material doesn't obey gravity in creeping off
the curvature
of the specimens. I usually add a single colored pigment or
composition of them
in the mix for a base color, catalyze that and pour it on the
specimen. If--and
that "if" occurs often--there is detailed color pattern in the
adjacent shell, I will
"paint" different pigment patterns into the pour before the catalyst
has a chance
to set. Once set, the repair gets sanded and polished. The difference
between
the shell and the original material can sometimes be very difficult to
discern when
all is done.

My problem appears to be the thixotropic material trapping air.
Bubbles form three
ways: in the mixing process; when air is trapped in specimen surface
irregularities on
resin application; and when additional colorant is daubed in once the
resin is in place.
The last wave of bubbles constitute the smallest number and, I think,
are probably
just something you have to understandably live with.

Glass works better than microballoons as a thickening agent but
because of the amount of
material necessary to keep the liquid from creeping off the rock, the
viscosity of the mix
prevents bubbles from easily migrating out.

A vaccuum pump and chamber recently arrived and next time out, they
will get a
trial. But other approaches and thoughts are always welcome.

Regards,

EH

"anorton" wrote in message
m...

"Edward Hennessey" wrote in message
m...

"anorton" wrote in message
...

"Usual suspect" wrote in message
...
This thing may actually may be use full for something. Presorvac
5
Cycle Marinater

http://woot.com/!

How about an epoxy mixer that doesn't add any bubbles to begin
with.
http://www.japanunix.co.jp/ju_en/pro...err_video.html

AN:

I followed your link. The machine looks pricey. Have you ever used
one?
I'm looking for something to "de-bubbelize" thickened and pigmented
polyester
resin.

Regards,

EH


AN:

I have not used one or priced it, But I saw the video a while ago
and thought it would be very useful. These are made by several
places, search for centrifugal mixer.
http://www.speedmixer.com/
http://www.nmtronics.com/smt/thinky-...ugal-mixer.htm
http://www.ewkaufmann.com/product.as...ific=jncooqene

Here is an article describing it. Looks like it would not be hard
to make if you were so inclined.
http://www.adhesivesmag.com/Articles...00000000853210


Thank you very much for the above. I'll check it out when I'm newly
awake.

My current method for removing bubbles from mixed epoxy is to spread
it out very thin on something smooth with a spatula, wait for the
bubbles to pop, then scrape it back onto the spatula for
application.


If you'll forgive me for referring you to what I wrote to Richard Lamb
above in detail,
the short story of my primary problem seems to be the thickening agent
trapping bubbles.
I've tried compressing the resin as you suggest but the "lumpiness" of
the material both retains
bubbles well and gathers some more when I try to scrape it into a
pourable mass.

Regards,

EH

Edward,

Thanks for the details.

I haven't used much casting resin.
Way back in once-upon-a-time time when I was putting ships in bottles...

There are other fillers as well - talc for instance, wood flour, colloidal
silica (cabosil), cotton flox, etc.

I've had some "interesting" results using glass in epoxy.
They seem to help contain the exothermic heat in the cup and cause a run away
situation. It rises like bread and overflows the mixing cup!

But back to your issue...

I'd almost suggest that microbaloons are the wrong material for what your
work entails.

Perhaps a quick experiment with other stuff might be useful as I've not
had much problem with it developing bubbles in the mix.

West 406 (blended? colloidal silica) is good stuff, but it's available form
other sources cheaper.

Aircraft Spruce or Wicks Aircraft both carry it.

For my serious work I often mix silica and cotton.
Silica to thicken the resin and cotton to make it hard as a rock.
Balancing those two can produce a wide range of physical properties.

For what it's worth, cotton can be "dyed" before mixing.
It has possibilities...

The other question with composites is always - "how big"?
Smaller batches may show more variation in properties, but are more
controllable.

If you don't really need the transparency's of casting resin, perhaps
an epoxy? When fresh most epoxies are pretty much clear (well, not ALL).
West, for instance, is really clear when fresh, nut turns dark as the
catalyst ages.

Wish I could see what you are up to.
It sounds interesting.

Richard


http://www.maddyhome.com/canardpages...20%20micro.pdf

http://www.fiberglasssupply.com/Prod...s/fillers.html

http://www.favonius.com/soaring/additives/additive.htm

http://www.aircraftspruce.com/catalo...es/bubbles.php

http://www.wicksaircraft.com/catalog...423/index.html

Edward Hennessey wrote:

If you'll forgive me for referring you to what I wrote to Richard Lamb
above in detail,
the short story of my primary problem seems to be the thickening agent
trapping bubbles.
I've tried compressing the resin as you suggest but the "lumpiness" of
the material both retains
bubbles well and gathers some more when I try to scrape it into a
pourable mass.

Regards,

EH




A CLUE!

Ed, take a fine strainer and run the filler through it before mixing.
Use your fingers to rub it through the strainer.
(and wear a mask!)

It Should NOT be lumpy!

Most likely the air making the bubbles is mechanically trapped in the lumps.

--

Richard Lamb
email me:
web site: www.home.earthlink.net/~cavelamb

In article ,
"Edward Hennessey" wrote:

Glass works better than microballoons as a thickening agent but
because of the amount of
material necessary to keep the liquid from creeping off the rock, the
viscosity of the mix
prevents bubbles from easily migrating out.

A vaccuum pump and chamber recently arrived and next time out, they
will get a
trial. But other approaches and thoughts are always welcome.

Spread it out as thin as possible in your vacuum chamber (ie, a bunch of
petri dishes would be much better than a beaker, say) and give it some
time under vacuum. My personal analysis of the best way to do this has
always proved more complex to implement than has been worth it anywhere
I've needed to do this - that would be to pour the epoxy from one
container to another (or directly into the mold in the case of molded
parts) while under vacuum, and thus gets into mechanical seals and or
electrical apparatus to facilitate pouring while under vacuum. Can be
done, just more money and bother than has been desired to expend on this
detail.

--
Cats, coffee, chocolate...vices to live by

In article
,
Ecnerwal wrote:

In article ,
"Edward Hennessey" wrote:

Glass works better than microballoons as a thickening agent but
because of the amount of
material necessary to keep the liquid from creeping off the rock, the
viscosity of the mix
prevents bubbles from easily migrating out.

A vaccuum pump and chamber recently arrived and next time out, they
will get a
trial. But other approaches and thoughts are always welcome.

Spread it out as thin as possible in your vacuum chamber (ie, a bunch of
petri dishes would be much better than a beaker, say) and give it some
time under vacuum. My personal analysis of the best way to do this has
always proved more complex to implement than has been worth it anywhere
I've needed to do this - that would be to pour the epoxy from one
container to another (or directly into the mold in the case of molded
parts) while under vacuum, and thus gets into mechanical seals and or
electrical apparatus to facilitate pouring while under vacuum. Can be
done, just more money and bother than has been desired to expend on this
detail.

In the late 1960s I worked as a summer hire at RCA in Burlington, MA, in
the Plastics Lab, where were were potting modules for the US space
program. These modules were in fact going to the Moon, and many did.

The modules were cordwoods, which have a pair of glass-epoxy circuit
boards with axial-lead components strung between and soldered to the
boards. One board had solder terminals and the other board was potted
with alumina-loaded epoxy.

Degassing was done twice. First, the just-mixed epoxy was degassed in a
vacuum chamber. The mold was then filled, and the entire mold with
cordwood and uncured epoxy was again degassed under vacuum.

I assume that the centrifugal mixer had not been invented, because we
did not have one, and it would have been a great improvement on the
manual mixing we used.

Joe Gwinn

"CaveLamb" wrote in message
m...
Edward Hennessey wrote:

If you'll forgive me for referring you to what I wrote to Richard
Lamb above in detail,
the short story of my primary problem seems to be the thickening
agent trapping bubbles.
I've tried compressing the resin as you suggest but the "lumpiness"
of the material both retains
bubbles well and gathers some more when I try to scrape it into a
pourable mass.

Regards,

EH


A CLUE!

Ed, take a fine strainer and run the filler through it before
mixing.
Use your fingers to rub it through the strainer.
(and wear a mask!)

It Should NOT be lumpy!

Most likely the air making the bubbles is mechanically trapped in
the lumps.

--

Richard Lamb
email me:
web site: www.home.earthlink.net/~cavelamb


RL:

"Turgidity" is a word that would have been much better used. Another
unmentioned reason for using a thickener like powdered glass (or
cabosil
which has so far come in a near second) is that it allows pigments to
appear
opaque in very thin sections (@ 3/32" or ). I've tried using more of
the pigments
but they are innately soft and don't allow the harder and more
polished finish
you get with the named thickeners.

As to safety, a respirator, Devo suit (Tyvek) and gloves come with
the use of
pigments, particularly when sanding the cured material comes up. The
suit
suggested itself the first time there was an inopportune spill of
catalyzing polyester.
"Cold Pants On Fire" could have been the theme song for the ensuing
striptease.

Regards,

EH

"Ecnerwal" wrote in
message
...
In article ,
"Edward Hennessey" wrote:

Glass works better than microballoons as a thickening agent but
because of the amount of
material necessary to keep the liquid from creeping off the rock,
the
viscosity of the mix
prevents bubbles from easily migrating out.

A vaccuum pump and chamber recently arrived and next time out, they
will get a
trial. But other approaches and thoughts are always welcome.

Spread it out as thin as possible in your vacuum chamber (ie, a
bunch of
petri dishes would be much better than a beaker, say) and give it
some
time under vacuum. My personal analysis of the best way to do this
has
always proved more complex to implement than has been worth it
anywhere
I've needed to do this - that would be to pour the epoxy from one
container to another (or directly into the mold in the case of
molded
parts) while under vacuum, and thus gets into mechanical seals and
or
electrical apparatus to facilitate pouring while under vacuum. Can
be
done, just more money and bother than has been desired to expend on
this
detail.

--

E:

Vacuum degassing the resin in a flat dish would be possible. Any hint
at the level
of vacuum best used?

Because the fossil substrate that takes the pour is very large, the
prospect of building
a sizeable air-tight chamber is not one preferably contemplated.

Regards,

EH

Edward Hennessey wrote:
"CaveLamb" wrote in message
m...

Edward Hennessey wrote:

"anorton" wrote in message
...

"Usual suspect" wrote in message
...

This thing may actually may be use full for something. Presorvac
5
Cycle Marinater

http://woot.com/!

How about an epoxy mixer that doesn't add any bubbles to begin
with.
http://www.japanunix.co.jp/ju_en/pro...err_video.html

AN:

I followed your link. The machine looks pricey. Have you ever used
one?
I'm looking for something to "de-bubbelize" thickened and pigmented
polyester
resin.

Regards,

EH

Casting or laminating resin?

(sorry, hadn't been following closely)

--

Richard Lamb
email me:
web site: www.home.earthlink.net/~cavelamb



RL:

I'm using casting resin in a surface application to simulate shell in
fossil
restoration. Aside from the wax already in the polyester, thixotropic
powdered
glass is added so the material doesn't obey gravity in creeping off
the curvature
of the specimens. I usually add a single colored pigment or
composition of them
in the mix for a base color, catalyze that and pour it on the
specimen. If--and
that "if" occurs often--there is detailed color pattern in the
adjacent shell, I will
"paint" different pigment patterns into the pour before the catalyst
has a chance
to set. Once set, the repair gets sanded and polished. The difference
between
the shell and the original material can sometimes be very difficult to
discern when
all is done.

My problem appears to be the thixotropic material trapping air.
Bubbles form three
ways: in the mixing process; when air is trapped in specimen surface
irregularities on
resin application; and when additional colorant is daubed in once the
resin is in place.
The last wave of bubbles constitute the smallest number and, I think,
are probably
just something you have to understandably live with.

Glass works better than microballoons as a thickening agent but
because of the amount of
material necessary to keep the liquid from creeping off the rock, the
viscosity of the mix
prevents bubbles from easily migrating out.

A vaccuum pump and chamber recently arrived and next time out, they
will get a
trial. But other approaches and thoughts are always welcome.

Regards,

EH




I've not de-gassed epoxy but have done so with a silicon rubber mould
making material, it seems to work very well and the material is fairly
thick. Be aware that the mix can bubble up to 3 or 4 times the volume
when the bubbles start to come out initially so make sure you have
sufficient volume to contain that in your container. In my case I got a
cheap polycarbonate bell jar from a lab supply house and initially used
a venturi vacuum generator which would produce about 90% vacuum, I've
subsequently acquired an electric vacuum pump which is more efficient
than using large quantities of compressed air to produce the vacumm.

A vaccuum pump and chamber recently arrived and next time out, they
will get a
trial. But other approaches and thoughts are always welcome.

Regards,

I'd expect that to do it (obviously you may have to experiment a bit).
Remove the vacuum before the resin sets, so that air pressure collapses the
remaining bubbles.

On Sat, 30 Oct 2010 23:06:48 +0100, newshound wrote:

A vaccuum pump and chamber recently arrived and next time out, they
will get a
trial. But other approaches and thoughts are always welcome.

Regards,

I'd expect that to do it (obviously you may have to experiment a bit).
Remove the vacuum before the resin sets, so that air pressure collapses the
remaining bubbles.

If you'd pumped it down properly, there shouldn't _be_ any remaining
bubbles. What would be in them?

Thanks,
Rich

In article ,
"Edward Hennessey" wrote:

Vacuum degassing the resin in a flat dish would be possible. Any hint
at the level
of vacuum best used?

On a dial gauge, 0 (or 30, if it's reading inches of mercury). You may
wish to pause briefly on the way down for some of the larger bubble/foam
events before that point. Not really an application that calls for
thermocouple or ionization gauges, though you might get to the point
that a TC gauge would register. Basically whatever your mechanical
vacuum pump can manage, and there should be no call for a diff pump or
cryo pump (though I have diff pumped epoxy, it was mostly to play with
the disused diff pump that happened to be attached to the chamber we
generally used for degassing epoxy, normally without ever turning that
on.)

Because the fossil substrate that takes the pour is very large, the
prospect of building
a sizeable air-tight chamber is not one preferably contemplated.

I expect your application as described will be fine with the mix
degassed. We did a lot of fairly fussy stuff without actually degassing
the final cast, just the mixed resin.

--
Cats, coffee, chocolate...vices to live by

I've used vacuum degassing for polyurethane rubber casting and it works
well, but when I tried to degas epoxy it was so viscous the air bubbles
could not migrate out. I was trying to do it in the mold, did not think of
spreading it out in a very thin layer first. I use a mechanical vacuum pump
that reaches 0 or 30 inches of Hg (depending on how the gauge scale is set
up; actually about 30 mtorr on a thermocouple gauge) but I think anything
under about 1 torr is enough (for polyurethane, anyway). The other way to
go is to apply about 100 psi of air pressure after you paint on or pour the
epoxy, and leave it under pressure until it cures. That compresses the
bubbles so they are basically invisible. You just have to come up with the
pressure vessel :-). There are usually a few vacuum degassing setups for
sale on ebay, made from a large stock pot or bain marie pot and a flat
acrylic lid with an oring and connection to the pump and vent valve. I
don't think you gave the max size you need to deal with but if it would fit
into a 10 or 12" id pot the ebay units would be a simple, cheap way to go.
I was going to make a pressure vessel from 6" black iron pipe with caps
threaded on each end, but the vacuum worked so well for what I was doing
that I never bothered.

-----
Regards,
Carl Ijames

"Edward Hennessey" wrote in message
...

"Ecnerwal" wrote in message
...
In article ,
"Edward Hennessey" wrote:

Glass works better than microballoons as a thickening agent but
because of the amount of
material necessary to keep the liquid from creeping off the rock, the
viscosity of the mix
prevents bubbles from easily migrating out.

A vaccuum pump and chamber recently arrived and next time out, they
will get a
trial. But other approaches and thoughts are always welcome.

Spread it out as thin as possible in your vacuum chamber (ie, a bunch of
petri dishes would be much better than a beaker, say) and give it some
time under vacuum. My personal analysis of the best way to do this has
always proved more complex to implement than has been worth it anywhere
I've needed to do this - that would be to pour the epoxy from one
container to another (or directly into the mold in the case of molded
parts) while under vacuum, and thus gets into mechanical seals and or
electrical apparatus to facilitate pouring while under vacuum. Can be
done, just more money and bother than has been desired to expend on this
detail.

--

E:

Vacuum degassing the resin in a flat dish would be possible. Any hint at
the level
of vacuum best used?

Because the fossil substrate that takes the pour is very large, the
prospect of building
a sizeable air-tight chamber is not one preferably contemplated.

Regards,

EH

"Carl Ijames" wrote in message
...
I've used vacuum degassing for polyurethane rubber casting and it
works well, but when I tried to degas epoxy it was so viscous the
air bubbles could not migrate out. I was trying to do it in the
mold, did not think of spreading it out in a very thin layer first.
I use a mechanical vacuum pump that reaches 0 or 30 inches of Hg
(depending on how the gauge scale is set up; actually about 30 mtorr
on a thermocouple gauge) but I think anything under about 1 torr is
enough (for polyurethane, anyway). The other way to go is to apply
about 100 psi of air pressure after you paint on or pour the epoxy,
and leave it under pressure until it cures. That compresses the
bubbles so they are basically invisible. You just have to come up
with the pressure vessel :-). There are usually a few vacuum
degassing setups for sale on ebay, made from a large stock pot or
bain marie pot and a flat acrylic lid with an oring and connection
to the pump and vent valve. I don't think you gave the max size you
need to deal with but if it would fit into a 10 or 12" id pot the
ebay units would be a simple, cheap way to go. I was going to make a
pressure vessel from 6" black iron pipe with caps threaded on each
end, but the vacuum worked so well for what I was doing that I never
bothered.

-----
Regards,
Carl Ijames


CJ:

The specimens at hand are large, in the range of 20-26" in diameter
and about 12"
high, resembling a large snail shell. All surfaces are curved, which
mandates the
thixotropic additive to keep the resin from traveling.

Obviously, this application is unusual and it seems that the next step
is to test
some of the ideas you and others have been so kind to outline. Thanks.

Regards,

EH