Keeping the fibres away from the perimeter is good advice. Like everyone said cutting Kevlar is difficult. My best method may not suit everyone but I use a box cutter with a brand new blade and trim the part just when it's gone past the green stage. It may require opening the vac bag etc but it beats all the other futile attempts at a fully cured part.

whew! i learned something today. it wasnt a total waste then
i would NEVER have thought to try this.
.....quietly scribbles note on paper and stuffs into pocket....

Sorry Fred, Perspex is a trade name here in the U.K. It is clear Acrylic sheet. You can often find it used in picture frames in a bargain store (2mm thick) 

You can cut kevlar with a decent pair of composite scissors its a slow process, an inch at a time but it does work. If you wet sand edges with 1200's you can get nearly as good a finish as with normal carbon. For drilling I clamp the part between two pieces of perspex, grind the drill bit at a similar angle to that required for sheet metal ie quite steep/pointed.

you can get the correct scissors to cut kevlar cloth,

some here http://www.shopmaninc.com/cutters.html

Kevlar is nothing short of a nightmare to trim. You have the same chance of sanding a burlap bag to a high gloss finish as you would with kevlar.

When you embed kevlar try never to have it reach the perimeter where you will actually do the trimming of you carbon panel.

If you do get fibers exposed the only way I have found to push them down is to wet them with resin and then use plastic sheet over the area and tape down firmly with clear packaging tape. Build up resin over the area once cured and you have removed the tape. (light scotch bright first, but do not expose the fibers) Carefully flat out the resin. If you break through your toast again and will have to do the whole thing over again.

If anyone knows how to cut kevlar or better yet drilling a clean whole through it I would really like to know how myself.

Fred

I have found that cutting Kevlar by all the normal means is extremely difficult.  Worse than that trimming and finishing edges of vacuum bagged parts containing kevlar has never been satifactory.  Kevlar edges always seem to get fuzzy and never look right.  Does anyone have some advice on a) cutting kevlar to produce a clean edge and b) (most importantly) trimming and finishing kevlar edges?


Thank you.

-Kingsley