I’d use some resin, pour it and fill the gap beetwen the two separate layers, usually works for me, sometimes i use a different kind of epoxy wich remains more “gummy” but i cann’t suggest you a brand name, europeans do it different :oP
chipfish, is this a wood fin with glass over it? It looks like it in the pic, what I believe has happened, if it is wood, the natural resins have awakened from the heat of sanding and the bond was lost between wood and resin. The choice is, sand away the delam’d part, re-glass or start a new sheet.
Then , because it wasn’t thick enough for fcs plugs , I layed up another 10 layers of 5oz… which started “splitting” after I cut out the fins.
I’m thinking maybe I should have cut out the fins from the “too thin” panel , foiled them , THEN glassed on the extra 10 layers of 5oz …[maybe laminating a layer at a time ?..would doing it that way have prevented this delam happening , you think ?]
I always saved all the trimmings from cutting out cloth to lam boards. But in Florida, a near daily rain bout can happen instantly and with a leaky factory, cloth can get wet.
I had sheets with the cloth all white in one layer. I usually was doing black layups and started using epoxy appliance spray can paint for the gloss finish. It covered the crap cloth and gave it a clean look
It happened several times to me, with motorbike fairings, when i don’t have time i just fill the gap, but for a fin it’s better to redoo, cause it needs strenght.
Quote:
I’m thinking maybe I should have cut out the fins from the “too thin” panel , foiled them , THEN glassed on the extra 10 layers of 5oz …[maybe laminating a layer at a time ?..would doing it that way have prevented this delam happening , you think ?]
Well i think it wouldn’t work, there’s no chemical bond between the two layers, and also poor mechanical, the first panel was maybe too smooth, or maybe it was a bit oily, have you touched it with your hands? have you used the same resin?
chipfish, I have learned a lesson with epoxy. In adding glass, ALWAYS give an alcohol rub-down before adding new layers to set layers, and don’t touch it after the alcohol cleaning. Sand it rough, clean with alcohol, and then apply epoxy. I’d probably rip the old layers off.
Dave, how many layers did you add / laminate at a time , when you added" to an existing fin ?
I went through a troubling time getting an undersized fin tab built up and canted properly. Ultimately I decided 5 layers of 6 oz on each size was a nice size to add, cleaned thoroughly with alcohol first, and ground off enough near the base of the fin to allow the new layers to hold. I failed probably 5 times before I got the details needed to make it work (overlap size, number of layers, cleaning protocol, etc).
BTW, if you want to make a thin fin, I’d recommend laying up a glass stack thin enough that two layers of carbon would make it complete. Then, foil the fin as thin as you want minus two layers of carbon. The carbon layers go on the outside, the place where you want to put more material to keep it stiff.
Putting a few layers of carbon on the spine just doesn’t add much strength or stiffness. The outside of the fin is where the strength and stiffness come from. Make it a glass fin, then add carbon on the outside.
oh, now I see. okay, this is what you need to do. try to seperate each layer of carbon fiber and spread a thin film of epoxy resin betwixt them. Then clamp it all together.
