prem Posted February 12, 2016 Share Posted February 12, 2016 I was perusing trilobites on e-bay and came across this gem: the seller makes no bones about the fact that it is a resin cast of a Phacops mortality plate. What is interesting is the level of detail of the cast, including individual lenses on the schizochroal eyes. Most of the websites discussing trilobite fakes indicate that if you see details like terrace lines and individual eye facets, there is a very good chance that it is not a fake (at least those parts of the trilobite). This cast changes those rules, it seems. In the close-up views, you can see bubbles from the setting resin (another tell-tale sign of a resin cast). So, in conclusion...be watchful...the level of detail in resin casts has just gone up a notch. ---Prem 3 Link to comment Share on other sites More sharing options...
BrookeTrout Posted February 12, 2016 Share Posted February 12, 2016 That looks fantastic! Definitely fooled me. It's sad that people feel the need to create all of these fakes and try to pass them off as authentic... :/ Thanks for the heads up, you've got a great eye. Link to comment Share on other sites More sharing options...
Ludwigia Posted February 12, 2016 Share Posted February 12, 2016 As long as the seller says that it's a cast, then that's fine with me. No need to look twice there, although it's so well done that it looks genuine even at second and third glance. Greetings from the Lake of Constance. Roger http://www.steinkern.de/ Link to comment Share on other sites More sharing options...
RJB Posted February 12, 2016 Share Posted February 12, 2016 Wow, would have fooled me. Im assuming that if it is made of resin, then actually picking it up may give it away? RB Link to comment Share on other sites More sharing options...
prem Posted February 12, 2016 Author Share Posted February 12, 2016 Well, had the seller not said it was a resin cast, I would have been easily fooled with all the eye detail...that's usually the first thing I look at when examining a potential trilobite purchase - that, along with matrix cracks, and general imperfections in the trilobite point to a real bug as opposed to a fake. ---Prem Link to comment Share on other sites More sharing options...
jpc Posted February 12, 2016 Share Posted February 12, 2016 Bad trilobite eyes in 'fakes' is probably a sign that it is carved or molded in plaster. Resin casts are incredibly accurate when molded with quality silicone and cast in resin, especially if they use some sort of vacuum to cast the resin. Meanwhile, this guy is selling it as a cast, so you really can't call it a 'fake'. It is a museum quality cast. Extra points for the seller. 1 Link to comment Share on other sites More sharing options...
amour 25 Posted February 12, 2016 Share Posted February 12, 2016 (edited) Bad trilobite eyes in 'fakes' is probably a sign that it is carved or molded in plaster. Resin casts are incredibly accurate when molded with quality silicone and cast in resin, especially if they use some sort of vacuum to cast the resin. Meanwhile, this guy is selling it as a cast, so you really can't call it a 'fake'. It is a museum quality cast. Extra points for the seller. Bingo I cast stuff ,and JPC hit it , I use a vacuum chamber, be hard to tell master from copy. Not fossils though. LOL Edited February 12, 2016 by amour 25 Jeff Link to comment Share on other sites More sharing options...
jpc Posted February 12, 2016 Share Posted February 12, 2016 Bingo I cast stuff ,and JPC hit it , I use a vacuum chamber, be hard to tell master from copy. Not fossils though. LOL OK.. I will ask... what then do you cast if not fossils? Aren't fossils the only thing worth casting? (Kidding). Link to comment Share on other sites More sharing options...
DinoMike Posted February 13, 2016 Share Posted February 13, 2016 Deaerating resin & mold rubber via vacuum is one way to go. Another is pressure casting. After the liquid rubber is poured to make the mold, the whole assembly is put into a pressure chamber and cranked up to around 40 psi or so. This eliminates air "voids" in the rubber. When resin is then poured into the cured mold to make a copy, the whole deal is again put into the pressure chamber & cranked up to 40 psi. This forces the resin into any voids, pretty much eliminating any air bubbles. It's a common practice among those who manufacture resin model kits, and the gear isn't that expensive. I have the whole setup myself, from back when I made an abortive attempt to manufacture model kits. Costs less than $1000 to get a full setup. Something to bear in mind when looking at "fossils" on eBay. Granted, fragile specimens & crumbly matrix wouldn't take too well to the pressurizing. 1 Link to comment Share on other sites More sharing options...
aplomado Posted February 15, 2016 Share Posted February 15, 2016 Would make a great wall hanger... Link to comment Share on other sites More sharing options...
Auspex Posted February 15, 2016 Share Posted February 15, 2016 Would make a great wall hanger... ...or 'landscape' for the bottom of an aquarium! "There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant “Try to learn something about everything and everything about something.” - Thomas Henry Huxley >Paleontology is an evolving science. >May your wonders never cease! Link to comment Share on other sites More sharing options...
Mike Pocock Posted February 16, 2016 Share Posted February 16, 2016 Or a plaque in the garden Regards Mike Link to comment Share on other sites More sharing options...
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