Cyano & Epoxy: Marriage made in heaven, or...?

Discussion in 'Techniques' started by Curtis Enlow, Apr 15, 2019.

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  1. Apr 15, 2019 #1

    Curtis Enlow

    Curtis Enlow

    Curtis Enlow

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    I love how thin cyano seeps into tight joints (which epoxy does not handle well) and so am tempted to use both to combine their various strengths & advantages, but am concerned as to whether or not cyano affects the bond of epoxy. For example, allowing cyano to seep into and bond a tight fitting bulkhead and following up with a fillet of epoxy. Does the existing cyano affect the epoxy in your experiences?

    Thanks,

    C
     
  2. Apr 15, 2019 #2

    Steve Shannon

    Steve Shannon

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    I don’t mix them, but if I have a tight joint I’ll use laminating epoxy. It can wick into a tight joint.
     
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  3. Apr 15, 2019 #3

    TimothyG

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    I use very small amounts of Cyano to "tack" parts in place in hard to stabilize situations when setting up for epoxy. I've had great luck so far but haven't really pushed things to hard.
     
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  4. Apr 15, 2019 #4

    JohnCoker

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    I'm with TimothyG; CyA is great for tacking things in place so they don't move around when trying to create a good bond.
     
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  5. Apr 15, 2019 #5

    heada

    heada

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    The thin CA will seal the surface and so any other adhesive (epoxy or otherwise) can only give a surface bond. Thin epoxy can seep into the substrate (wood fins, paper tube, etc.) and give a better bond than a surface bond only.

    Use CA to tack in place but not to seal the surface and then try to bond on top with something else.
     
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  6. Apr 15, 2019 #6

    dr wogz

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    some epoxies seep better than others. Some are thinner, and some take longer to cure.

    West systems is fairly runny, and takes a good long time to cure. That gives it time to seep into crooks & crannies to give a good bond.
    BSI 5 minute is thick and gels within the 5 minute window. So, little to no chance to seep in in either scenario..

    heating up epoxy will also make it runnier, but will speed up its cure time. (A better method than thinning it with Alcohol)

    Use a dot of CA to tack the part in place.
     
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  7. Apr 15, 2019 #7

    Jim Hinton

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    I've used epoxy over CA many times, I've never had a reaction between the two. Always a good idea to make sure that the CA is completely cured before covering it. The biggest issue I've had with A is that some formulae of accelerator will attack plastics. The reaction usually doesn't show up for a while.

    Jim
     
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  8. Apr 15, 2019 #8

    Curtis Enlow

    Curtis Enlow

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    Thanks, everyone. Everything you've said makes perfect sense. I was worried about it affecting the chemical bond and never really considered pre-sealing the surface. I almost always use thin CA so it always feels textured and rough, but at a micro level it's clear that it's an issue.

    Thanks, again,

    C
     
  9. Apr 16, 2019 #9

    BABAR

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    Kinda what I was thinking. Seems like you would want to be careful to only use a small amount of CA to tack, so you don’t compromise/waste much surface area for your epoxy.
     

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