Carbon Fiber Cut lines

Anyone has experience with carbon fiber cut lines?  Looking for advice, pictures, hints.  I have 6 oz. carbon fiber and was planning on vaccumm bagging it and later glass 4 oz clear over it.  I am only going to do the bottom and rails with carbon.  Thank you in advance. 

I’m building a kiteboard right now with the same appearance & was worried about that same thing. I ended up purchasing a “carbon veil” (fake carbon) which is a cloth with the carbon printed on it and will be trying that in the next couple days when I lam my bottom. This stuff is only 2 oz so it should wrap the rails well.

Just reread you post.Do you mean Cut laps wih vaccum bagging? If so, please check the archives as I previously posted how I do cut laps when vacuum bagging.

What’s the title of your post.  I came up nada.  Thanks,

The thread I was thinking of is called “Cut Lap with Vacuum Bag Lamination(Epoxy)?”. I just reread it and it doesn’t have my process so I must have made the comments on someone else’s thread ( & I can’t remember which one).

It’s actually pretty simple though.

  1. Mark out the cut lap lines on the foam.
  2. Tape off this line with a good qualiy masking tape.
  3. Tape off on top of the masking tape with Stucco tape (the red plastic tape that stucco contractors use to mask off windows b4 plastering a building). You **don't** want to use the Stucco Tape directly against the foam. It can tear off some of the foam.
  4. Tape & mask off the remainder of the top deck & then "bag" your board.
  5. After the epoxy hardens, I use a combination single edge razor blade & a small die grinder. I start sanding with the DG until "Red" starts showing. You can then try to fold up the dried cloth & cut it with a single edge razor blade (like a normal cut lap). Or you may find it easier to just continue sanding with the DG around the entire cut lap.

Good Luck!

Uncle D, I have no real answer to your question. I recently started vacuum bagging myself, just doing small things mostly fins. If you need/want I am more than willing to help out with the process, both to help out and to gain the experience. PM me if you need/want my weekends are usually open.

Aloha Dennis,

I usually have a CF patch on my ‘rowboats’ (SUP’s).

Here are some pics of a hand lam CF+ fiberglass hand trimmed with a razor. This one was unique in that the rest of the board was still raw EPS.

I do not see why vacuum would not work, I think the key would be using good tape and timing the trim after the resin is set hard enough not to be sticky or peelable but soft enough to bend for cutting the lap. If you know that ‘feel’ already you are golden. Were you thinking peel ply along with the bagging?

I have done them ‘grindlap’ too but sanding CF make a black dusty mess that gets into the other weaves and pores and is hard to get out.

Let us know how it goes-



I do all my boards with pigmented lam and grind lap tech with 10oz Stitch fiber or 8oz carbon tape rails, works really well, use at least two layers of masking tape, first wide other can be thinner, easier if not same color. When dry, mark where masking tape end should be according widthe of first tape sand carrefully up to it in small area (easier at center of board) to see where it’s really then go all around, sanding up to masking tape edge of first layer on foam.

Really easy, even more when lam is well compacted on tape, as vaccum bag lam would be.

Small grinder disk and vaccum attachement is a must here.

The plaster red tape and a die grinder get my vote.  I’ve been doing a lot of Vector Net lately.  Full deck and sometimes deck and bottom.  I cut it at the rail apex with a layer of 4 or 6oz over.  I use my Carbon Fiber serrated shears. Then clean them with acetone.  I always tint the layer of cloth over the Net.  Usually what a painter would call “semi-opaque” not “semi-transparent” .  The cut at the apex is not noticeable.

Got some good tips!  I will post pictures.