I am a begineer lifecaster and have read about airpockets being present in pouring a casting. Taking a tip from the construction industry, they use a massive vibrating device to take air out when pouring concrete. Could we use some kind of vibrating table to allow the air to rise out of a casting when being poured? This could be made by a simple DIY method. Any comments?

That is true for concrete and some plasters. Depends on what material you are casting with and if it's going to be a solid casting. It could definately be useful for casting hands and feet that are solid. And yes, I do think you could use something simple to make a vibration table. It even helps to hold a vibrating object against the edge of the mold with plaster in it to help release the bubbles.
~ Niki

It all depends on the shape of the mould and if the air has a path to excape. For hands and feet I like to pour some of the plaster into the mould and turn the mould around, upside down etc to try and coat the surface of the mould. Then pour the plaster back out before pouring it all back in. This also helps get and little bits of loose aglinate back out of the mould.

I have heard of using a washing machine on spin cycle as a vibrating table.

For smaller parts you can use an electric sander to vibrate the mould.

Be aware that vibrating, which will help degass the plaster in general, probably wont much help with trapped air pockets in undercuts or upturned fingers. Try putting a plastic bottle open end first into a bucket of water. You need to turn the bottle on its side to let the air out and the water in.

So when pouring the cast, you need to consider where the plaster has to go, and how the air is going to get out.

Regards
Ray Hope
www.bimmortal.com

In the studio I work in we use a everyday Sander used to sand wood and we ductape it to the table and turn in on for a bit and it does the trick.