# Vacuum explanation

## Main Question or Discussion Point

Hi everyone!

I need help about understanding the Vacuum process, where can I find some information about it? and also

The weight of a material (liquid) change after a vacuum process?

I mean if the weight will be the same if I measure the material before and after the vacuum process?

## Answers and Replies

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Gokul43201
Staff Emeritus
Gold Member
It sounds like you have heard something from someone about this, but you've misunderstood the idea.

"Vacuum Process" is not some specific process. There are several processes that involve operation under vacuum conditions, and all of these are refered to as vacuum processes.

If you have a specific vacuum process in mind, you must describe exactly what this process is, because the generic term "vacuum process" can be used for any of several different processes (eg: contact evaporation, crystal cleavage, STM measurement, cryogenic cooling).

By "vacuum process" if you simply mean subjecting something to high vacuum, then yes, the mass of a liquid under vacuum could be different from outside because of the removal of dissolved gases.

Some links for further reading (preferably, read in the order listed) :

http://www.mcallister.com/vacuum2.html
http://en.wikipedia.org/wiki/Vacuum

more details

Thanks for your advice Gokul43201!!! and for the links they were very useful

I just wanted to know more about the "vacuum process" in general; in order to understand the physical principles behind it.

About the question... specifically I am using a Vacuum Oven with a mechanical vacuum pump, part of my epoxy rubber manufacturing process consist in making vacuum to an specific container of 5 gallons. So i have the doubt if the container weight less after the vacuum process.

I suppose that it is the only way to know if the epoxy rubber was vaccumed?

am i right? or there is another way to know ?

http://www.lesker.com/CFDOCS/newweb/Technical_Info/BasicVacuum.cfm [Broken]
http://www.rawbw.com/~rwaits/NCCAVS/effects.pdf [Broken]

Last edited by a moderator:
Integral
Staff Emeritus
Gold Member
The purpose of drawing a vacuum over epoxy rubber mixtures is to draw out entrapped air. There should be a small weight change, proportional to the amount of air removed from the mixture. You might try a before and after measurement but you will need a pretty sensitive scale to see the change.

Integral,

Thanks for you answer

I will do a weight test before and after the vacuum process to see what happens.

I hope that there is a significant variation so I will be able to determine if whether or not the epoxy rubber mixture go through a vacuum process.