Hi all,
Well, for only the second time in over fifty years of molding fiberglass and carbon fiber goodies, I really screwed up a mold!  I've used PVA mold release for several years with no problems, but this one didn't make it even close to releasing.
I had no problem removing the buck from the plaster mold, popped right out.  I sanded the inside of the female mold smooth, fixed all the little imperfections, and then finished it with Z-poxy. Well coated with PVA, then waxed and I thought it was ready.  This is the same procedure I've used for a long time.
When I laid up the glass, I cut my laminates, then saturated them while they lay on waxed paper, peeled them off and put them in place.  I pressed them in place, rubbing out all the bubbles, then let the rascal cure overnight.
The part is the cowling for my scale Tri-Pcaer, is quite large, and with a very natural release angle on the whole surface.  It was permanent, or so I thought.
I ended up breaking the plaster mold off, with at least 1/8 inch of plaster left clinging for dear life to the glass cowling.
I soaked it in a bucket of water over two days, then was able to peel the crud off with a knife.  When I got the blade under the PVA, it came off in large membranes with the plaster still attached.  I've since applied carbon tow inside in strips to further stiffen the beast and then post-cured it.  The CF was applied using Resin Services HTR250.  I have a good cowl, but don't have my female mold any more.  (Well, that's not quite true, it's still in my junk barrel in pieces.)
Do any of you have any suggestions on what I may have screwed up?  I sure wish I could still get the old Elmer's Slide-All for a release, it was fool proof!
Thanks in advance for the help, guys amd gals.
Will