Got myself some uni carbon material from shapers for reinforcing tail areas and running as a stringer for stringerless builds. First board i lammed with it i lammed it with 2 layers of 6 oz on top. When it was dried, and even after first hot coat, there is a noticable edge/bump around the edge of the uni tape material. Does anyone have any techniques to avoid this bump? would it be better or worse if i lammed it between the 2 layers of glass?
I'd like to know the same thing. I've used carcon fiber cloth to do a whole deck cut to the bottom edge of the rail, but never done strips or patches. I know some bulders are using strips in the manner you are speaking of and have wondered if the edge was a problem. If you go to a lighter weight fabric and glass over it; Does that reduce or eliminate the edge or "bump"?
Uni-carbon looks the goods, But your right! you get that bump.
After the deck lam has gone off you can paint a thick lam coat around and over it to fair it in, but that sux, Just added weight for a cosmetic reason.
I have found those uni-carbon strips on the tail often cause more haste then they are worth, another layer of 6oz (especially under a 2x6 oz) would be fine.
No matter which way you apply the carbon uni I have found they cause a weak point where the carbon ends. There’s just no flex in the stuff.
I have found this stuff great because it’s really thin and has some give on the edges, You have to cut your desired patch with a blade and template but its good.
4.01 oz from http://www.solarcomposites.com/composites/carbon%20fiber%20uni-fabric.html
Just a ques, but it looks like the same stuff Al Merric uses-mostly on the Slater Boards??? But I’m an Aussie and have never seen one first hand.
My thoughts on this based on what I've learned from boat construction. Don't know if the concept of Hard Spots has ever come up here. Basically, when working in fiberglass you want to avoid creating hard spots. A spot where the laminate is stiffer than the surrounding laminate. This can create a hinge effect at the transition. That is the spot where failure of the laminate will occur.
When I look at the boards on the market where they put the carbon patches on the tail its my theory that they are just moving the spot where the board will break up just a bit. If I were doing it I would make the strips longer and taper them out to spread the stresses out more evenly.
How about a tail patch running from rail to rail of six ounce or Volan? Maybe from the tail forward one foot or the rear foot area in general?
Mako224
"Don’t know if the concept of Hard Spots has ever come up here.
Basically, when working in fiberglass you want to avoid creating hard
spots. A spot where the laminate is stiffer than the surrounding
laminate. This can create a hinge effect at the transition. That is
the spot where failure of the laminate will occur."
Did you read the post before yours? didn’t I just say that?? lol
Some of you guys crack me up!
''Stress riser'' is the proper term, in structural-speak. Tapering makes a lot more sense than some of the applications I see from the status-quo companies who are using the toe/heel strips. What really cracks me up is when they say it's ''enhancing the flex''. In reality, putting the stiffest possible material on the compression side isn't going to do anything but stiffen the tail.
And if you wanna get rid of the bump, you need to vac all that stuff down tight.
Forget the extra hot coat resin. You still have a bump, just spread out a little more. Extra weight, with no strength. You dont need the vacuum either. Here is how I do it. Shape a depression into the blank where the carbon goes, Put your carbon in the low spot, then glass over it. If you are doing colors, first do a single four oz laminate with color. Pull the lam tight, so you keep the depression. Lam the carbon into the low spot, then do the second four oz. Never vacuum carbon under peel ply only. It will suck out too much resin, and the carbon will look hazy, rather than gloss black
if you use 50k like seen on this board then you have to spread it out and flatten it out. the tow will soke up lots of resin so you will have to press it down as the lam kicks. you will also have to lay a heavy fill coat then sand it down to get a flat finish. I raised prices on my boards and switched to uni tape , for looks and a flatter surface.
The gridlox I posted about doesn’t leave a ridge at all and wets out under both layers of cloth