It bothers me that so many can’t glass the butt with enough glass to evenly cover the foam. Because of the arc of the cut fiberglass, the glass doesn’t cover the crack evenly unless you add some extra glass. You see this clearly on cutlap fish butts. Here is a pic of one way to do it. Start with a square piece of cloth about 4 inches by 4 inches. Cut it about 3 inches down the middle. Then spread it as shown. I do this on both the top and the bottom.
yeah you have to add a little glass there to make it right.
why do people call it a butt crack? Surfboards dont have butts and its a notch or an indentation its not a crack. Some things will just never make sense to me I guess 
thanks for posting - nice looking work as usual mr tate.
Thanks Greg
I’m gonna use that
Me too. I have a shaped fish sitting in my shed awaiting glass and resin. Patch will now be added as per the picture above.
Thanks for the tip Mr Tate but what about when doing a resin tint? As you said, that’s when it really shows up and I believe this method would look a big ugly with tint. Got any resin tint crack tips? Cheers
I broke to many fish tails off and gave up on them. Now I am into shaping diamond tails. I go through a cycle. Perhaps in 5 years I’ll fall in love with fish tails again but for now, NADA!
That’s a nice clean method, Greg. I don’t wrap the glass around the edges in the crack anymore. I drape it and cut/sand it flush after curing(zip lap?). From the bottom I use roving around the the edge, almost like a bit of a fin halo. Come back and add some glass strips inside the crack to cover any exposed foam and reinforce that area against a leash if I put a leash loop across the crack. Sand it all smooth then hotcoat. So, if you re doing tint or pigment I do the ‘zip lap’ method with my color. When I reinforce the area I just use clear resin. Hope that makes sense. It’s pretty easy, really. Mike
Excellent Mike. Thanks
All the best
Great info thank you guys. Would you use a similar method to reinforce Bat, Moon tails etc?
bat tails are like mini fish tails so the same should work. moon tails are a little different, you’ll have to make some relief cuts that will become a void on the flip side, I would think you could probably just fill in with some acute triangle shaped scraps.
Excellent Huck
…and thanks for a fast responce
Did Greg Tates trick on the bottom lam and it worked great. Tried this on the deck and it works pretty well too. Diamond shape with slits on top and bottom
Yes Greg’s method is about all one can do to insure No Exsposed Foam. But; Cabosil and or Milled Fiber applied properly will do the trick as well.
Love that Burllster. Great idea.