Fumed silica substitute

Discussion in 'Materials' started by Hunter25, May 13, 2011.

  1. Hunter25
    Joined: Mar 2006
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    Hunter25 Senior Member

    Can corn starch be used as a silica substitute? It would be a lower cost thixotropic additive in alkaline mixtures like epoxy. Would is also impart the adhesive properties that silica has? Would wheat or corn flour be as effective as wood flour as an additive? Wood flour is common in fillets, just looking for an inexpensive substitute. Any other filler substitutes?
  2. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    No. Silica has a very low humidity content. Wood flour, unless it comes from a species that is low in oil and rosin can be a problem too. Silica is quite cheap, also it is thixotropic as you say. Other fillers, including wood flour, are not. That makes for a drier mix.
  3. TeddyDiver
    Joined: Dec 2007
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    Location: Finland/Norway

    TeddyDiver Gollywobbler

    Yes it can be used, but isn't as good as silica. As wheat or corn flour instead of wood grit. You can use pretty much anything dry enough with epoxy but you don't know how it affects to the physical properties of the mix, so better stay with known additives..

  4. CatBuilder

    CatBuilder Previous Member

    Buy your silica nearby from bateau.com in Vero Beach. It costs next to nothing.
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