Thanks, guys. Let me think about this for a while. One of my problems has been that Smooth-On's molding compounds seem to change names over time, especially if I buy them from a different supplier. I'm away from home, so I can't read the labels off the tubs. I'm having much better luck with the "30" soft materials, which are blue, and seem not to need a release agent. Before that I tried the "60" brown harder materials, as I thought they would give longer mold life--but my definition of severe undercuts (i.e., hulls) was obviously far more lenient that theirs. That is, I considered hulls as mild undercuts, but I think Smooth-On might consider them severe. I am in no way criticizing Smooth-On, just relating how I reacted to their web site descriptions, and their descriptions of mold flexibility.
I'm dealing with big molds and castings. The large freighter bow took 52 oz. of molding materials, and each cast takes 27 oz. of casting materials. Later on I can thin the hull walls down from 6 mm to 3 mm, which would reduce the casting materials a bit (and increase the molding materials). So the molds are pretty expensive. I've been using mold release agents to ensure that get maximum life out of the molds. But then cleaning them up, and having paint failures, is defeating any cost benefit from not using release agents.
I just might be pushing the envelope of expertise here, as N scale casting is usually in pretty small quantities. I'm having no problems whatsoever with winches, hatches, rescue boats, small hulls--in fact, anything up to about 10 oz. I think the smaller hulls are no problem because I actually sand off any of the oily residue when trimming them up.
I've tried to talk to the two firms that I know make fine art ship models with resin, but haven't received any technical advice yet, and rather doubt I will.
So--onward! I do have the Santa Fe Tug announcement ready and will post it shortly, which is marketing-speak for when I actually have the seven ships of the first run nearly ready for shipping. Actually, they are ready now, but do I dare?
Oh, I should have a photo of an Active-class with the post 1967 racing stripes tomorrow--I only know of two of the class that received them--the Cuyahoga and the Alert.
