Expansion of rubber after vac
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Expansion of rubber after vac
Does anyone know the expansion % of RTV when you put it in a vacuum? I've been molding some stuff and I can't help but feel like I'm just wasting expensive rubber by not putting it under a vacuum. Any rough estimates?
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Umi_Ryuzuki
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I don't think you are wasting RTV at all.
The Vacuum process "de-airs" the RTV. This pulls all of the large and small air bubbles that get mixed into the RTV as you stir it.
Once you take it out of the vacuum, it cures a bit denser, and stronger.
If you pressure cast, any tiny air bubbles caught in the RTV will compress, and make a "pimple" on the model surface. This is the reason to put the RTV in a vacuum for de-airing, not to save RTV.
The Vacuum process "de-airs" the RTV. This pulls all of the large and small air bubbles that get mixed into the RTV as you stir it.
Once you take it out of the vacuum, it cures a bit denser, and stronger.
If you pressure cast, any tiny air bubbles caught in the RTV will compress, and make a "pimple" on the model surface. This is the reason to put the RTV in a vacuum for de-airing, not to save RTV.
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Antenociti
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Re: Expansion of rubber after vac
As Umi says it wont save you any RTV it will "just" remove bubbles. (which, if you think about it, will *technically* reduce the overall volume!)bobbyfett wrote:Does anyone know the expansion % of RTV when you put it in a vacuum? I've been molding some stuff and I can't help but feel like I'm just wasting expensive rubber by not putting it under a vacuum. Any rough estimates?