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	[Parent Directory]	-	Sat May 23 11:18:18 2009
	Silicon Mold Initial Result	-	Mon Feb 15 12:04:53 2010
	Getting ready to create the initial silicone mold layer with a coin pressed into a thin wax layer. Given that I’ve never worked with the Smooth-On Oomo 25 silicon before, having something go wrong was sort of expected, so I didn’t spend too much effort on including sprue and vent channels in the first molding attempt. If it worked, I would have cut them later. I did, however, include the registration marks since those would be difficult to add later. Oh, and I should probably also point out here that the coin being molded here is real 1735 George II penny (or half penny, I’m not 100% sure) and not one of the copies I bought last year. The first layer separated from molding container. The initial mix and pour for the fist half of the mold went well and there were no problems demolding. The final product was soft and deformable under light finger pressure, though this was expected. I suspect this might eventually be an issue when it comes time to do an actual casting. The coin and first layer of the mold made ready for the second layer of silicone. The actual problem didn’t come until poring the second half of the mold. Not knowing if the second half would stick to the first. I brushed the first half with a light oil and decided to see what would happen. The result of the first silicone mold attempt - a solid block of silicone. Now, in case anyone was wondering, yes, I did have both petroleum jelly and talc on hand but I wanted to see if a brushing of oil would be sufficient to keep the two mold halves from sticking together. As it turns out, it was not. The second layer of the silicone stuck to itself so completely it could not be separated from the first. In fact, the layers were so well bonded, there was no real indication where one layer ended and another began. This is actually very useful information for later should I attempt to pour two part mold layers that are not completely flat, like an “L” shape layer for example. Unable to separate the layers of silicone, the only option left was to cut the coin out. So, the next step is to try the whole again with petroleum jelly to see what happens. Also, I will probably use about 1/2 of the amount of silicone in the next mold after seeing how deformable the larger blocks are. I had hoped to avoid having to create something like a plaster backing for the silicone, but it seems that even the larger blocks with probably still require some extra support to keep the mold cavity from deforming when the two halves are are clamped together for the casting. Filed under: Coin, Pewter Casting. No comments.
	January Posts	-	Thu Feb 04 20:36:05 2010
	In case anyone is bothering to read this I’m still in the process of cleaning up a few January unposted entries that may or may not appear in the near future. Rather than let this hold things up, I’ve decided to proceed with newer posts and fix the old ones later. It’s not like I’ve been doing anything interesting last month, so you are not missing much. Filed under: Online. No comments.