Getting CF to comform to mold

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#1

1st post and I have a problem,
I’m trying to replicate some motorcycle body work via infusion CF,
I have done a rear hugger which turned out great as a 1st attempt but now I am having difficulty getting the twill mat to conform to my mold shape without the individual
strands spreading apart when it goes around corners.
I tried a light spray of 3m super77 and a clean paint brush on the back to gently smooth it down progressively but this eventually stuffs up as the glue holds too strong in some places and rips up the PVA coat
Then I tried lightly gluing some woven fibreglass mat I had lying around to the back of the CF twill in the hope it will keep the strands in place but it makes the mat to stiff to go round corners.

Any hints as to how I can do this better?

Pic of bike before I started resto, the bodywork is an original I made out of FG and its the mold (2 piece) I used to do that which I’m now trying to use with the CF.
Will post some pics of the mold later.

#2

When using a gelcoat you wil not rip the pva off. And don’t use the 3M 77 or super7. Use another one.

#3

So you are saying apply an epoxy gel coat let that dry? or apply the mat while its still tacky
I don’t have spray equipment, how would I get the gel coat at an even thickness.

With the rear guard/hugger I just laid the layers of mat in the mold, made the bag checked for vacuum leaks and then infused with infusion grade slow cure epoxy resin,
The surface finish was acceptable, this project is for lightness not cosmetic appearance, though a good finish would be nice.

This is my first infusion project so forgive me if Im asking basic questions

#4

get rid of the PVA and use semi-permanent release.

#5

The challenge you’re facing isn’t with your gelcoat or your fabric placement.

Your issue is simple physics: the fabric has physical limitations as to how it can traverse a mold. In looking at the mold(s), I’d recommend you start making some templates for the hard corners of that rectangular area that sticks out.

You can’t get a clean lay out of the fabric there and get it all done in a single piece. The curves are too tight and the rest of the piece is too round/curvy.

The fabric is either going to pull up or End up a snarled mess that you’ll hate to look at.

I’d recommend a single piece of carbon fiber for the main piece of the mold, and a separate thin rectangle for the other area. Personally, I like to make paper templates, since you can get an exact shape from it as what you’ll need to fit the part.

Lay down the main piece first, with it trimmed so it creeps about half way around the corner that curves from the main area of the part up to the sides of the raised triangle area. (seaming in a curve will h elp hide it.

Once that’s done, lay down the rectangle “cap” over the raised area, then bag and infuse.

Easier than it sounds, I promise. :slight_smile:

We make these out of 4 individual pieces of carbon laid into the mold separately.