Fill whole with epi glue .vasoline screw .( or dab screw in glue before insert ) you don't need much.
then unscrew and screw in and out ,a few times when glue is half set making it own thread

leave screw in till it sets .make sure the grubs screw can full screw out .

you can use resin .but it's messy .epi glue is thick and gos off quicker .Araldite works too.
worked for me .

The best way by far is to just use a bigger (wider) screw, with the same keyhole so you still use the same key.

I know Gong sells them, but I am sure they are easy to find in places still using the imperial system (OZ,US,UK, ...)

http://gongsupshop.com/epages/box1707.sf/en_GB/?ViewObjectPath=%2FShops%2Fbox1707%2FProducts%2FGON4SAVVISFOIRE

If you must use glue, my trick:
- rough the hole so that the glue can stick better. try to make grooves lengthwise as the main risk is the glue rotating with the key
- use something that really get hard when curing: actual epoxy resin rather than epoxy glue for instance
- use microspheres to make the result very hard. Loz79 solution is microspheres that you wet with cyanolate, and it works quite well
- let it cure thourougly. heating to 40C (no more) helps. Epoxy cures as much in an hour at 40C than a week ar 20C
- drill, take care of drilling at the exact original angle. Insert a stick in the other hole to visually guide you
- tap. Use a lubrifiant to tap and for the first time inserting the screw, agian to minimize the risk of rotating the glue.

But using wider screws is so much better. Everyone should have spare ones.

I solved this by buying a load of screws that were a little longer- works a treat

If it's not to loose otherwise Loz, Colas and others solutions can work there is a solution of the "Teflon tape" . That stuff is used by plumb man to seal piping screw.

Roll 2 or 3 times around the screw the " Teflon tape" Then screw in back the plug . Do it gently .
That trick can be a quick repair

colas said..

mybrosweeper said..
this has to be the biggest drama with most FCS boxes. Ive had it happen with a well known expensive brand of board, but just one board after having 4x others with no drama.

In my experience, most of the time it is a manufacturing blunder: typically some worker will remove what was put to fill the screw holes during the glassing of fin boxes with a drill without taking any care, and thus making screw holes too big. It tends to happen in factories with no surf culture where work on fins is seen as a second-rate job and are given to rookies or mediocre workers.

Yes.... its what we call in Australia "a Friday job" meaning it is rushed without care to get it done before the w/end. Funny when I bitched to retailer who then went up chain to Aust. supplier, they were very aware of the issues and sent me a set of larger grub screws and a tap(which was too big)
Lots of "screwing around" for something that should have been sorted in the 90's... not 2017
If Im paying them HUGEEE $$$ I just want to go surfing not stuffing around doing repairs to their manufacturing faults..... come on guys get your sh@t together!!!