I have done a good few boards now, note I said a good few boards, not a few good boards. bwaaa haaa haa.
Anyway… getting better for sure but I still struggle to avoid bubbles just on the sharp tail rail. I just glassed another board with 6oz plus 6oz tail fin area patch (not round rails), so not too much glass this time, and I squeegeed it damn hard to pull everything super tight. I went back to see if cut lap was ready to cut, and notice some bubbles along the sharp tail edge. It got me wondering… should I not be sanding the black to a sharp 90 degree edge on the tail, maybe it should be slightly rounded and then add the sharp edge using the hotcoat?
slightly rounded. resin bead sand back to flat
Shape your blank with a hard/sharp edge in the tail. Then very lightly round that hard edge off with one light pass of a soft shaping block and 120 grit. fiberglass is hard to wrap around a super hard edge like in the tail of a surfboard. putting a slight radius on it allows the glass to wrap easier. Then put a tape dam around the tail when hotcoating and brush the resin up against that tape dam, but not too much because then you will have to do a lot of sanding. Sand the hard edge back into the tail by sanding that resin. When you wrap the laps of your board walk around and double check the tail area that it is all pressed firmly down.
I do it in the foam.
Thanks everyone. Sounds like the pros CAN do it in the foam, but easier option is a slight rounding so I will try that, as no matter how many times I try, I just don’t seem to be a pro 
Pretty sure it makes a difference which glass you are using.
4oz is easier to turn the corner than 6oz, E glass is easier than S glass, etc…
But, like was said above, I get the best results when I slightly round the corner then add the edge back in hotcoat/sanding…
BTW if you are using epoxy and doing a tail or nose with sharp corners and the glass is raising off the very tips. Wait until the resin is just past the stringy stage (so when you touch it with a stir stick or the corner of your squeegee, it doesn’t pull/stretch off the board) and then use some masking tape pulled tight around the corner to force the glass to lay down. When the board finishes kicking, if you timed it right, the tape will pull off cleanly and the glass will have cured down tight around the corner. Then it’s just on to the next step.
If you want to leave the sharp edge on the foam give it a rub. Take the back of your thumb nail and drag it along the hard edge of the foam. This should round it enough to allow the glass to wrap yet still make a crisp edge once you build it back up with the hotcoat.
Thanks, sorry I should have said. 6 oz glass, PUPE
Masking tape is a great idea, but I can imagine how important it is to time it right!! Thanks
thats a good idea too, just enough to compress maybe 1-2mm of the corner. i will remember that, thanks
Some glassers use wetted out fin roving along the tail edge to produce the sharp edge. This minimizes cracking along the edge that only using resin does. Extra work but better edge longevity.
Good point, I don’t like the idea of building up with pure resin as we know that cracks up easily, I may give that a try, I bet it takes some skill!
thanks
That’s what I’ve been doing. On some boards I blunt the nose and tail tips by maybe 1/8th before glassing and then come back and add a finrope-based fill to reinforce those areas. Whether it’s for an edge or a tip, I add it and then shape it back down prior to hotcoating.
Sounds like a great idea, especially on the nose if the tip is small, they take such a bashing even with careful users. Thanks
Aloha! I shape a nice crisp edge around the tail, then I use the ‘thumbnail technique’ when I lay up the bottom (6oz. on all my styros). One thing to check is the length of your lap in that area. I stretch my cloth out nice and flat, and the glass likes to pull back from the edge when the side is setting up. If your lap is a little longer, it’ll stick to the rail shape better, and not let the airs in. Tape dam on the bottom hot coat, sands out sharp. Mahalo…RH
Thanks