Clay Wallower

I'm very new to the game, and for a first project I set out to make a set of floor tiles. After some thrashing I can now use porcelain slip (Seattle Pottery SP930 Swan) to cast tiles. The resulting tiles seem to be ok after I send them off for ^04 bisque fire. The current problem is glazing. I played with some colors in the Mayco Stoneware family (too bright!), and decided I wanted the Amaco PC-48 (Art Deco Grean) and eventually a couple of other colors from the family. The picture on their website suggested "slightly heavy" coating of the glaze. I made some test tiles and sent them off for firing (^5). They came back not at all like what I expected. I'm after the nice green with spots as shown on the glaze page and the sample tile in the shop, not the dark brown with hints of green I got. My result is matte, and I expected gloss. The closest result I can find looks like the picture on the Amaco site showing how the PC-48 looks on various clay bodies -- specifically on the Clay Body 11-M ("A-mix white stone ware"). The glaze looks better on other clay Amaco clay bodies, but they don't show my porcelain. The hoped for effect is something like the right hand tile in the image here. I got something more like the upper left cup here. How do I troubleshoot this? is this a bad clay-glaze pairing? I am reluctant to change clay now that I have a system to cast my pieces, but I also don't want to buy lots more glazes looking for one that might work. Does the idea of two clays being "similar" even mean anything here? I don't know what SP930 actually is beyond the "recommended" porcelain from the Seattle Pottery store. Did I fire at the wrong temp? I just sent the tiles off to the local shop and asked for mid-fire and they said that was ^5. Are there other variables here and do I need to bribe the kiln operator to be more specific? go a little hotter? Did I put the glaze on wrong? Too thick? Too thin? Wrong phase of the moon? I know there so many combinations of glaze, clay, and temp that I could spend a year just making test pieces, and at that point I will have a large collection of almost full jars of glaze and still not have my 20 sq ft of tile that I need. Is there a search method I can use to find a similar glaze on this clay? Please take a look at the attached picture and see if there is something obvious....or do I just need to buy more glazes and make more test tiles. The two small rhombs have either 1 and 2 or 3 and 4 coats of glaze. there is not much difference between 3 and 4. The large rhomb has 3 coats. tile edges are about 4" long. CW

I was using maple pieces as my masters to make molds. I poured a plaster mold and let it sit overnight to harden and dry. In the morning the wood had absorbed enough water to swell and split off a side of the mold. I decided that I could not find the perfect balance between a wooden master that sits a long time (swells and breaks the mold) and pulled off the mold early (damaging the soft plaster). The way that crack runs I would be suspicious that the wood absorbed the water in the plaster after it cured and swelled (5%-10%) -- pop. The current technique I'm trying is HDPE masters.