Colloidal Silica ~ Reducing the Volume

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Forum topic by John Smith posted 06-12-2019 02:20 PM 483 views 0 times favorited 7 replies Add to Favorites Watch
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John Smith

2858 posts in 1169 days

06-12-2019 02:20 PM

I have a few large bags of epoxy thickener, colloidal silica, fairing filler,
microbead fairing filler, or whatever you want to call it. (similar to West 407).
I am trying to vacuum out as much air as possible to make it economical
to ship a one gallon amount in the standard USPS Small Flat Rate box.
I have tried several layers of stocking material with a slight vacuum from
the shopvac and the stuff just goes through the filter material with a lot of waste.
I know this is something that is probably never done in the common shops.
(I know that I have never had a need to do it ~ until now).
I just need to find a way to make it affordable for members here that would like to
purchase some. If you have ever worked with this material, you know how freely
it moves around with the slightest puff of air.
The manufacturing data is: “Goldenwest M15 Filler” if you want to look it up.
I have a vacuum pump but I really don’t want this material inside of it.


-- there is no educational alternative to having a front row seat in the School of Hard Knocks. --

7 replies so far

View Lazyman's profile


6628 posts in 2394 days

#1 posted 06-12-2019 03:15 PM

How about a large ziplock bag inside a large ziplock bag inside a large ziploc bag? Just leave the innermost bag just slightly open and have the open ends on opposite ends. Once the air is sucked out, you should be able to close the innermost bag without releasing suction. Another option would be to put a couple of nested ziplock bags in a much larger space bag. With the ziplocks as far away from the suction valve as possible, you should get minimal material escaping and getting sucked into the vacuum.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

View CaptainKlutz's profile (online now)


4134 posts in 2501 days

#2 posted 06-12-2019 05:47 PM

Worked with silica fillers for decades. Highly doubt you will be successful reducing the volume significantly?

Colloidal silica is micro powder. The size ranges in commercially available fillers are measured in sub-micron to ~100 microns. It will be very hard to filter material out of any vacuum system to reduce the volume for shipping.
Also by using a vacuum to remove air, you will be filtering out the smaller particles and the filler will not behave same afterwards. Vacuum filtering is common technique used for particle size separation and classification operations producing the fillers.

Fine particle silica also a very dangerous carcinogen. Not only is the compound dangerous for you., but the ends of the crystalline shapes for the silica particles is like a barbed snowflake. If you inhale it, it seldom dislodges from airways/lungs, and usually becomes a permanent part of you. Exposure is cumulative over your life time and can not be reduced without surgical removal of tissue. Silica dust has been determined as major contributing factor to many lung diseases, especially those experienced by miners or people exposed to dust in construction industries.
ALWAYS, ALWAYS wear respirator when using or handling colloidal or fumed silica fillers.

Sorry to be health nut.
Silica powders scare me more than handling pyrophoric (flammable in oxygen) or explosive materials that I produce on occasion.

Be safe, not sorry.

-- If it wasn't for bad luck, I wouldn't have no luck at all, - Albert King - Born Under a Bad Sign released 1967

View fly2low's profile


88 posts in 1103 days

#3 posted 06-12-2019 07:07 PM

agree on the dangers
look up silicosis. Not a fun way to die

-- Rich Gig Harbor, WA

View runswithscissors's profile


3128 posts in 3032 days

#4 posted 06-15-2019 07:27 AM

Just wondering if a Seal-a-meal might work?

-- I admit to being an adrenaline junky; fortunately, I'm very easily frightened

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John Smith

2858 posts in 1169 days

#5 posted 06-15-2019 12:47 PM

thanks for the feedback.
I tried the bag in a bag trick and it doesn’t work.
what I found that once most of the air has been removed
from a zip-top bag, that is far as it will go, size wise.
honestly, I don’t know what “type” of thickener I have.
when I worked for a gov. contractor back in the ‘80s, they were
cleaning house one day and they tossed 4 big paper bags in the dumpster
that I recognized right away as the epoxy thickener that I have been
buying from Goldenwest so I absconded them. it “could be” silica or
glass micro-balloons. but I treat it as the most hazardous, for safety.
each bag contained 4 cubic feet of material. I have one big bag left and
I will never use it all in my life time. so I need to reduce it down to
the more manageable sized quart bags and get rid of it.
as noted, this is not a material that a novice craftsman should be
messing around with in large quantities without respiratory protection.
I got the little red tube that goes on an aerosol can like WD-40.
put the tip in the corner of the bag and held the shopvac hose in my
hand to allow a very light controlled suction and it works “okay”.
then I can store it, box it and ship it safely and economically.

I am very much aware of the potential health hazards of silicosis.
a copy of the MSDS will be provided with each bag for the recipient.
[I have had my head in a hood sandblasting with silica sand for many more
years than I have have been using epoxy thickeners].
and no; a foodsaver vac will not work – it will suck the material into the machine.

thank you all for your input.



-- there is no educational alternative to having a front row seat in the School of Hard Knocks. --

View MrRon's profile


5994 posts in 4250 days

#6 posted 06-16-2019 02:51 AM

Hi John, You may want to check if sending thickener by the post or UPS might violate shipping hazardous materials. I would consider that as hazardous as asbestos fibers. The GG1 project is still ongoing. I work slow so as not to make any big mistakes.

View Rich's profile


6519 posts in 1596 days

#7 posted 06-16-2019 10:23 PM

A chamber vac will work since the pressure inside and outside the bag remains equal during sealing, there is no tendency for the material to move. You can even seal up a bag of water with one.

-- Half of what we read or hear about finishing is right. We just don’t know which half! — Bob Flexner

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