Best way to fix this?

F’d up the routing on this twin.  Just jam it with resin and fiber clippings, a wedge of spare foam?

Small piece of foam is what I would do.

I would not pool resin underneath a fin box in EPS, an exotherm could melt the surounding foam and the box will not be solid.

I would thicken my resin with Cabosil.  Brush it in and around the cavity and install the box.  Put a small football shaped piece of cloth over the top of the box.  Do this in two stages.  First the box install and then the patch.  When you install the box make sure you get enough resin slurry in the cavity so that it will come up through the slots in the Futures Box.  Wipe off the excess with a plastic squeegee or your finger and then cap.  If you use “Slow” Hardener, Exotherm shouldn’t be an issue.  However if you are concerned or uneasy about it. Lay a zip-lock baggie of ice on top of the box until it sets.  Then cap with the football patch.  It’s not a big deal and I doubt if you will even notice the repair.

Depend your epoxy and temp but if it’s cool temp (around 20°C) with a standard fast epoxy, not those hyper fast set with really high exotherm, you can “glue like always” your box with thickened epoxy. As McDing I use cabosil to increase visco and for plugs under glass I had some micro in the mix too, small weight reduction and easier to sand before lam if needed. 

Lemat confirms.  The key is using a thickener.  Cabosil is best because it’s clear.  If you do the whole thing at once(install and football patches) the Cabosil will blend right into the surrounding Epoxy resin.  Just like a normal lamination and fin install.   Use of Cabosil is a trick I learned from watching the Epoxy 101 dvd done by Greg Loehr.  I highly recommend Greg’s Epoxy 101.  Chucked full of tricks, methods and instruction.

mcding is as right as a mensa member from lowell highschool

dont worry you execution of ''FIN BOX INSTALL IS STILL ‘’

in the 85%ile go man …ride it saturday…


q cell for looks, milled fiber for strength. 


Or between, you have “microfibers” also call “flock” , add strengh, but less than milled fiber, add kind of whitness, but less than qcell, add tixotropy a bit like cabosil, find it a good additive for gluing with epoxy.