Can you recommend an epoxy resin that does not react with EPS foam? I'm undertaking simple repair of a Stand up Paddle board which has an EPS core.

I will be mixing the resin with Micro filler balls to reduce the density of the repair.  Max repair depth will be  20mm X    area 30X30mm. Can this the cured in one application?

 

 

That's a very thick repair, can't you pack out the depth with epoxied in foam to reduce the epoxy thickness?

I would not try to do this in one go ..

use ordinary Epoxy, mixed with an amount of microballon filler, just to make it thick enough to not run or drip, use this to glue in one or more pieces of foam, then make up some micro-ballon filled epoxy thich enough to be used as a stiff filler on top.. but leave it a bit low.  Wait until the "filling reaches "tack" then fill the rest up with a high density/fibre filled epoxy and let it all cure.
When fully cured sand smooth.

Does the board have some sort of outside "wrap" of glass or textile or resin coat ?

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