Explanation of Hazardous Labels
Important Message:
SPI Supplies has been appointed the exclusive and sole distributor for Vacseal
® products worldwide.
All of the original Vacseal
® products are again available, including
Vacseal® II Clear (but not Vacseal
® II Blue)
and we are now able to once again ship from stock
to customers as orders are placed. We do not know at this point when, or even if,
the Vacseal
® II Blue product will be produced in the future.
Products described on this page:
The products listed below are what sometimes are referred to as "original Vacseal".
The other part of the product line consisted of the Vacseal
® II products but presently, of that
family, only Vacseal
® Clear is available.
Hence, there is no reason to be using any "substitutes" or alternative products that do not
have the desirable properties of the Vacseal
® family of vacuum leak sealants. No product exists that comes close to the
UHV compatibility as Vacseal. And no product has had the "acceptance" in as many different laboratories as Vacseal.
Vacseal
® is a silicone based liquid resin system developed
primarily for sealing leaks in high and UHV systems. It was recently
reformulated to contain no Class 1 ozone depleting chemicals. Vacseal
® will
seal leaks as large as 4 micron liters per second on systems under
evacuation. The sealant will repair larger leaks if the system is at
atmospheric pressure.
Weight loss
and
vapor pressure characteristics
are truly outstanding. Vacseal
® is extremely useful as a cement for sealing
all kinds of optical windows and CRT glass to wire feed throughs. It will
substantially reduce the IR reflectivity of metals and will produce higher
emissivity levels for better heat transfer. The product can be used for the
sealing of Brewster windows for lasers. And it can be used for more mundane
applications such as the repairing of gauge tubes and also vacuum feed
throughs. Vacseal, when sprayed on a surface, "dries" to a film that is
optically transparent and exhibiting optical properties generally
characteristic of clear silicone polymers.
The use of this product almost always results in reduced downtime, in some
cases eliminates the need for expensive "permanent" repairs, and on occasion
has been known to save an experiment in progress (an argument for keeping
some on hand, "just in case"). Vacseal
® has major potential for application
as an adhesive at cryogenic temperatures as well as good radiation
resistance. The sealant's durability will survive the environment of space
without adverse effect on the product or the spacecraft itself. For vacuum
systems, just about where there is any kind of a joint is a potential
application for Vacseal.
Applications in space:
We are often times asked if Vacseal
® is "qualified for use in space". We
wish we had a solid unambiguous answer to that question. Certainly, even
after long periods of time, there is no weight loss of Vacseal. We have
been told that Vacseal
® currently is being used in space applications, such
as on board satellites. We are told that it has been "approved" by some of
the major firms in the aerospace industry. We are told it has been used on
manned spacecraft. However, we do not have any specific documentation to
which we could point where such usage has been documented. If you know of
any such documentation, we would be greatly appreciative if you could share
it with us, because we would be quite fast to put that additional
information up for others to read and derive benefit. So in the mean time,
if you are contemplating the use of Vacseal
® in a space application, be sure
you do the appropriate level of testing to make certain that Vacseal
® would
indeed work in your particular application.
Temperature Extremes
One can assume product use to be in the temperature range of -200 to 450°C.
At or about 400°C, in air, Vacseal
® will start to oxidize, ultimately leaving
only a white powder, but in vacuum, where there is no oxygen, it can be expected
to operate up to about 450°C. We do not recommend taking the material to such
extremes, but we have been told that others have found success, even at those
temperatures. As with any other materials selection, some amount of testing
must be done on the customer's end to validate that the product will indeed
work in your specific application. We don't want this to sound like a major
disclaimer, but we feel we can not over-stress the importance of the customer
making the final decision as to suitability, a decision being the result of
your own testing.
The high temperature characteristics reported for Vacseal are possible because
the product is a unique silicone and is not an epoxy or other organic based
system which would degrade at far lower temperatures.
VacsealŪ has application as an adhesive at cryogenic temperatures as
well as good radiation resistance. The sealant's durability will survive
the environment of space without adverse effect on the product or the
spacecraft itself. The dried product will withstand repeated temperature
cycling from liquid helium to 450°C.
Adhesion considerations:
Vacseal
® will adhere literally to everything.....except, as we like to say, "running water".
Obviously, there are differences in adhesion between different materials, but for the most part,
the adhesion is quite good on virtually all solid surfaces. But again, we have not tested the
adhesion parameters on different materials quantitatively, so if adhesion is an important issue,
be sure you devise your own kind of system-specific test to make sure that Vacseal
® is indeed
going to be the appropriate solution for your particular application.
Just remember that Vacseal
®
was formulated to be a vacuum leak sealant, not specifically as an adhesive,
but as we have learned over the years, a significant number of our customers
are indeed using it as an adhesive. Unfortunately, because of the wide
diversity of applications, we really don't have further information on the
use of Vacseal
® as an adhesive. If you think you have such an application, we
can only suggest that you might want to try it and after the appropriate
testing, make some determination if it is the right "solution" for your
specific case.
Use with hydrogen:
Vacseal
® has been used to make seals for hydrogen gas and it has also be used
to contain liquid hydrogen. The real question though is now well it does do
this and on that point we have difficulty giving an unambiguous answer.
With any container there will be some kind of leak rate, and this is going
to be no exception, but in at least some applications, the use of Vacseal
®
seems to be quite acceptable.
Use in threaded joints:
Assuming the application is with a UHV (ultra high vacuum) system, and of
course, the use of such joints in a UHV system is generally discouraged, in
theory it could be used. Indeed Vacseal
® has been used with threaded joints
but not for UHV applications. The connection must be made "wet" and once
the Vacseal
® has started to cure, making the joint will become all that much
more difficult, and the end result will probably be found to be less than
satisfactory. The reason is that Vacseal
® cures by evaporation of the
solvent, yet some amount of solvent is required to make the polymer flow
as a liquid into the crevices of the joint. High vacuum joints pose
particularly frustrating issues, since the tendency is for the curing to
begin at the outside and progress inward. The cured portion of the joint
then acts as a barrier to the further evaporation of the solvent, and the
result is that there is a very slow rate of solvent evaporation for a very
long time, possibly years.
Curing conditions
Vacseal
® can be
cured
under a wide range of conditions.
Removal of Vacseal:
Unlike other vacuum sealing products, the resulting polymer formed can be
removed with a number of hydrocarbon solvents. The uncured polymer can be
wiped away or other wise removed with toluene, where as the cured polymer
requires something stronger, such as methyl ethyl ketone (MEK), or in
extreme cases, methylene chloride. For applications not requiring high
cleanliness, many common paint or lacquer thinners will work equally as
well. However, common sense must always prevail, and if the Vacseal
® is to
be removed from a plastic substrate, for example, then some careful testing
must be done first, in order to make sure that the solvent does not damage
the underlying plastic.
Finding the leak:
Various and expensive leak detection equipment can be used to find vacuum
leaks. One "quick and dirty" solution which can be done in a matter of
minutes and without spending a huge amount of money for an expensive leak
detection system is to take advantage of the
surface chemical properties of
Liqui-Nox which can be used in conjunction with the easily understood "bubble test".
Product shelf-life and stability:
Vacseal
® has a limited shelf life. On the shelf while still in unopened bottles, and being
stored at room temperature and out of direct sunlight, the shelf life could be expected to
be a minimum of three years. However the liquid product in quart cans has a shelf life of only
three months. Hence be sure to give serious thought to the purchase Vacseal
® in bulk quantities.
Unless the product is destined for use almost immediately, we would
recommend the purchase of the smaller bottles instead of the individual larger bottles or bulk cans.
Shelf life of the product in aerosol cans is less than that in bottles.
Vacseal
® is available in two forms, as an aerosol can and also in bottles.
The product can withstand repeated temperature cycling from liquid helium
temperatures to 450° C over long intervals of time.
Original Vacseal® products
Storage Conditions:
Room temperature
Hazardous from the standpoint of shipping
Aerosol, Non-Flammable N. O. S.
UN 1950
UN Class: 2.2
Packing Group III
The product in aerosol form is undoubtedly the most popular form of
this product because of the ease of application and also, it is presumed
that the product is in its most effective form when applied this way.
However, the shelf-life of the aerosol can is less than that when packaged
in liquid form and in addition, for international shipments, the shipping
costs are usually higher because it is always considered to be Dangerous
Goods.
|
|
Storage Conditions:
Room temperature
Hazardous from the stand point of shipping
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Tuesday October 07, 2008
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