joining carbon sheet.

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#1

hey all,

right so we are thinking of using our new near perfect mould to make a part. but as its quite a large part (hood/bonnet) the carbon we have isnt big enough to just lay one sheet of cloth over the mould.

we were thinking that if there has to be a join that we might as well make it part of the design of the bonnet. e.g. a nice stright line join up the middle of the part.

how can we prepare the carbon so that the join is need and stright with a good weave?
we have a spare flat mould to try out some ideas on but any tips for joining the carbon before we start would help us out a lot… thanks

L.

#2

so no one has ever joined 2 bits of carbon then? i’m going to be the first person in the world eh? :wink:

its the top surface i’m thinking about, i dont care what the back of the part looks like. my supplier can only get 92cm wide carbon roll (36"). if i want bigger i think i’ll have to order from the states and pay to have it shipped to the uk. i think that may bump the price up a fair bit :?

so with 36" roll i have to have a join on a part that is about 50" square.
any tips people?

thanks

L.

#3

I dont know if this will work but might be worth a shot on small try out piece. Lay the carbon front to front and run or have your wife run it down the sewing machine to stitch it together, That way you will end up with a nice straight seam ( if you or your wife can sew straight), Im’ not sure of how the weave will take the stitching so some experimenting my be in order on scraps before you try a large piece. make sure you reinforce teh seam from behind of course.

#4

have you tried these guys?
http://www.carrreinforcements.com/

#5

yeh i spotted them before. not tried them yet. 1250 is still a bit short as most of our parts are about 1450mm wide and around 1200-1300 long.

but if i could make a mould that was only 1200xwhatever then i could lay the carbon accross that in one part.

after reading about the ‘V’ join that EMI anted to get i was thinking about stiching in a seam.
no wife :frowning: so i’ll have to learn myself. but my mother has a machine and could prolly teach me how to do it. its defo worth a try.
we are also playing with lots of small samples to try out a few wet la options. just to see how it comes out. i’ll post up pics once we are done next week.

the further i get into this carbon stuff, the more respect i have for the people that make wonderful looking parts!

L.

#6

For the top layer, I have created an artificial “V” pattern using two 50" pieces of carbon. Just as a process note, I was also using a layer of clear gel coat and infusing with VER. You could do the same with epoxy and tack spray. First, find the center line of the piece. Then, I cut a piece of peel ply in a straight line that acts as a mask for the side opposite where you are going to lay down the first side. I then make sure the carbon, 2x2 twill in this case, is oriented in the desired direction (flaring from center out, front to rear) and lay it down over side “A” (the first side for lack of something better to call it). The gel coat or tack spray will hold the piece in place and it will not stick to the other side because you have the peel ply there. When I lay the piece down, I also make sure that it overlaps the center line so that I can fold the material back over itself. When folding it back, you need to pay particular attention to getting the seam or fold as straight as possible or it will not look as good. You can use tack spray to hold the flap down flat. Then, remove the peel ply and lay the second piece down with a mirror of the opposite side. You dont have to worry about folding it back over itself because you will not be able to see anything from the other side. If I use an analogy, its kind of like folding a paper airplane if you get what I mean. Hope that helps and did not totally confuse you.

#7

yeh sorta sounds useful. i’m trying some ideas out over the weekend including trying to stich the carbon myself with a machine. i’ll add you idea to the list of tests, thanks

L.