Keeping edges straight on a shape with organic contours can be challenging, but here is a simple tip to avoid over cutting parts while maintaining consistent part shape and straight edges. A scribe tool can be used to etch into many different surfaces. It is very helpful for clearly indicating where a part line ends. When trimming by hand, clearly mark your trim lines with sharpie or scribe. Avoid trimming along the line, instead trim between 1/16th and 1/8th of an inch from the true edge. When your largest cuts are complete, clean up what you can or what you feel comfortable with by using a 90 degree die grinder. You can always remove more material later if your cut is not close enough, but you cannot add more back.
A crucial tip for blocking your edges is to use a very hard straight block with a rough grit, between 36 and 80, to bring it all the way down to your etched part line. If time is of the essence, a die grinder will make quick work of this, but always be sure to follow with a good hard blocking. The Perma-Grit hard block is a great tool for this purpose.
A hard aluminum block with 36-80 grit paper works like this Perma-Grit block
These steps will ensure that the parts you produce have clean, straight edges that anyone would want to showoff. If you have run into wobbly trimming and have your own successful solutions to share, include your questions or advice in the comment field below (make sure to include your email) and we will share your questions and advice in our troubleshooting posts. Remember to check our other DIY Blogs as well for resources and expertise for future carbon fiber projects. Good luck!