Epoxy cure before paint

Is epoxy ready to paint as soon as it's hard enough to sand?  Or do I need to wait for "full cure" (using CLC supplied MAS slow hardening ~72 hr to full cure).  

If I can get the cockpit painted in short order, my son will still be in town to help me get the deck on!

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RE: Epoxy cure before paint

It's A Good Idea, yes.

The chemistry of epoxy is such that it can interfere with the chemistry of paint applied too soon.

Then there's the negative health aspects of sanding epoxy that's become hard enough yet not fully cured. That same chemistry that makes it so valuable for our projects can play hob with our bodies'.

Epoxy dust is not something you want to be inhaling or getting much of on your skin or other body parts. It's still reactive; you can become sensitized pretty much at any time even if you've worked 'safely' with it for years. And once that happens further exposure may increase your sensitivity, why it's important to wear at minumim a respirator equipped with the right filter cartridges when mixing, using as well as sanding epoxy.


RE: Epoxy cure before paint

@hspira:  Thanks!  I'll just wait out the requisite 72 hr and recruit other hands to help with the deck when my son is gone.  If there's one lesson this project teaches it's that you can't rush it!

And just to reassure you - I sand with a half mask respirator and P-100 filters, gloves, long sleeves and long pants dedicated to this work, work out of doors and have my random orbital hooked up to a shop vac with HEPA filter.  Don't like dust of any sort, toxic dust least of all.

RE: Epoxy cure before paint

Hi Andrew, 

it was spclark who answered your question and deserves the credit. 

i also follow the practice he shared.

i did also want to note that you mentioned painting then putting the deck on.....so i am a bit curious about what you were thinking.

in general, painting or varnish work is done after all the epoxy work is completed on a typical CLC boat.....so i was a bit curious what you were intending to paint before putting the deck on?

maybe you don't have to wait after all?


RE: Epoxy cure before paint

  Well, that was funny (careless) - mixing up two people I've never even met!

To your question - I was going to paint the cockpit.  Just seemed a lot easier to get that sanding and painting done before hiding so much with the deck.  Taking care to keep paint clear of and deck gluing surfaces (shear clamps, carlins, bulkhead edges, deck beam, upper edges of hanging knees) and associated filetting sites.  

If there's an argument against this, I'll jump right in and get the deck on before the end of the week.  Everything is ready, otherwise.

Your thoughts?

RE: Epoxy cure before paint

Hi Andrew, 

my perspective on paint on the interior is to avoid it. (by paint i mean the brightside single part polyurethane)

the main reason for paint or varnish on these kayaks is that you need to protect the epoxy from UV rays...or else the epoxy will break down.  paint and varnish are great for protecting epoxy from the sun's rays.

so it is clearly necessary anywhere on the exterior.   

inside compartments or any other place not exposed to sun, you don't need it.   so if you want paint inside a compartment, recognize it is just there for decoration.

i avoid paint or varnish inside of these areas becuase if i ever have to make a repair, paint or varnish is not compatible with epoxy repair and i would need to sand it off on the interior as part of a repair...making the repair more difficult.  further, paint can also deteriorate and or hide a problem that if left unpainted, would be more easily spotted (like water getting into the wood through damage to the epoxy).

my only exception to this general approach is i will varnish parts of the main cockpit that may see sunlight.  but this would only be parts that are also easily accessable so i would not need to do it in advance.

anyway, those are my thoughts.




RE: Epoxy cure before paint

   Thanks.  Gives me something to think about.  Getting the deck on and getting on with things has its appeal!

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