I'm doing a Monogram 1/48 DC-3 and decided that I'd try the Wally Patented Resin Window method on it. I used some thin shim brass bent to shape to seal the openings, then mixed and poured the resin (Barnes Clear Casting Resin). Everything went according to plan until I pulled the tape and brass off the fuselage, when I found this:
The striated areas have gone quite soft and sticky, and still remain so 48 hours after the resin was poured. It's happened on both fuselage halves. The windows themselves have come out perfectly, and the resin is now fully cured and ready to be sanded down and polished. A Heller C-121 on which I did the windows at the same time has not shown this problem at all.
The resin catalyst is MEK but the proportion is only 1.5% by weight, which is hardly going to affect the plastic. I used scales accurate to 0.001g, so the mixing proportions should be pretty close to spot-on. Besides, the softening has only occurred in certain places, all in areas behind where I put tape onto the fuselage before taping down the shim brass but not everywhere the tape went down.
Anyone got any ideas about what's going on, or how it can be fixed? All suggestions thankfully received ...
A man can't have too many flying boats ...
Looks like you may have got some raw MEK on those areas, ie. not from the mixed resin, but spilt, or on fingers etc.
I would also reccomend you use epoxy resin and not polyester, as polyester does dry green, and takes years to fully cure.
Creative Models Australia