No trim ideas

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#1

I was thinking how on all the molds I have previously made, how I had to trim the rough edges off with a bandsaw or dremel tool.

Some ideas on building FRP molds that do not need trimming after building? Perhaps building a vertical flange off of the horizontal flange, outer edge, that provides a “dam” to keep laminates snug up against the end edge of the flange?

I’m trying to eliminate trimming the mold. I don’t like flying glass or carbon dust, spending an hour or so trimming, all the associated noise of said trimming.

#2

You mean green trimming a open mold part in the mold? Yes, real easy if you get the right timing when to use a hook blade knife along the edge of the mold to trim the part down.

#3

Net shape tooling. After you lay in your prepreg, come back through with a razor/preg knife and trim the part prior to cure. Keep the trim off and cure it along with the part. This gives you a test coupon.

#4

That’s a good idea for prepreg tooling, but what about a wet lay up tooling that uses epoxy resin and fiberglass and carbon fiber cloth?

Certainly not discounting or putting down anyones ideas :slight_smile:

About green trimming - anyone got a photo of a hook knife?

#5

Maybe you could wrap the horizontal flange with pvc pipe that has a slit cut in it. Like that wire loom stuff.

#6

it works for prepregs almost, but look for silicone foam tape. cut the pieces as perfect as you can, and use the tape as an edge dam. Maybe only a slight sanding to get the flash off.
Else, make the tooling with a flat vert. edge on the end of flange, and just butt everything up to that.
Again, some flash trimming might be needed, since you will never create a PERFECT flat edge, there will be some resin pushed up the side of the edge.

#7

If your razor is sharp enough this will work for wet layup pas well. (unless using infusion)
Wet cloth, trim cloth, bag it. Curse because you got resin in places where you were going to put bag sealant tape. Clean areas with resin. Panic because your outlife clock is running. Seal bag, fight leaks, curse some more, get vacuum at last, remember to put masking tape on bag seal tape areas next time.
The tape idea is nice. If you slimed areas you wanted dry, pull the masking tape and the area under that is without slime.