Absolutely correct. Timing is everything! If the timing is correct, it is
very easy to do a beautiful job. There is a point in time for the curing
process that the lay-up is quite stiff, but can be cut very cleanly with a
utility knife. I end up with cuts that require almost no sanding, or filing at
all. Just beautiful straight cuts. Also, the direction of the cut is
important. Always cut toward the surface the lay-up in on, using the edge of
the surface.
I usually do a two stage process. After a few hours (maybe 4 or 5?) I cut the
bulk off with the scissors. Then I go out hourly and test for the proper
cutting results. If the epoxy clogs the utility knife, even a brand new one,
you are too early.
Jeff
Tony Krzyzewski wrote:
> What is the secret to knife trimming? I am using a utility knife to trim at
> the leather stage. Try as I may, I am unable to make a clean cut without
> ripping the fibers or lifting the cloth.
>
> You are cutting too early which is causing the tearing.
>
> You have to time it right. Once it has lost it's tack leave it for another
> hour and then try. At the right stage the knife will slice through it like
> butter leaving a really clean edge. If you leave it too late of course then
> it's hacksaw time!
>
> Tony
>
|