Delft clay casting pt.2: dealing with gas porosity, ring band moulds, and something akin to progress.

I spent another week learning how to cast metal. And today got pretty close to obtaining satisfying results. I'm not quite there yet, but I saw the light at the end of the tunnel, so to speak.
Last week I've ordered 20g of pure silver casting grain, to make more of my 30%silver 70%copper shibuichi alloy. I made about 5g (as I already had 10g of alloy, and I didn't want to melt all of it at once) more, and tried to cast something presentable.

It was a right amount for the wolf model, but I was still getting loads of porosity. Yes, I learned that those bubbles I was getting in the casts are result of gas porosity: apparently, gas can dissolve in molten metal. That was news for me. And using flux is supposed to eliminate it. However, I was using flux, and still getting the bubbles in my pieces.

So I went back to browsing the web, and at some forum (I really don't know where, sorry) read that if there is even a little bit of solder on the metal you melt, it will behave terribly in castings.

That got me thinking. I melted art clay pieces that I just gave up on. I did my best to clean them, but it was possible that some solder made it into the alloy. So I made another 15g from scratch, using only the casting grain and well-cleaned copper. And that actually helped a bit.
See here:

It's so tantalizingly close to good cast, I don't even know if I'm happy or frustrated.

 Sorry about the picture. But you can see that there are almost no pores here: apart from that huge one between the ears, and one on the paw, and, I think, some tiny ones on the snout.
I wouldn't mind the one on the leg that much, actually, but that one smack right between the ears just won't do. Next time I'm casting this piece, I'm going to add a bit more flux and see if that helps. There are more bubbles on the back, but that can be dealt with. But on the front I have very limited options for clean up available. Still, it's progress.

I also have to work on my ring band moulds, as I can't seem to find a good way of making them, and the metal solidifies in the funnel, without filling the mould itself. I, again, searched the net for pictures of how others make their moulds, and found one approach I didn't tried yet. I hope this one will work for me.

Apart from casting, that takes up huge chunks of my time, I also decided to make another cuff, and made project for another one. I could really use guillotine cutter, or good metal shears, because, even though I'm getting comfortable with using my saw, and getting to even like it (and that's a huge surprise for me, let me tell you), I absolutely abhor cutting through such thick sheet. I mean, it takes up to 15min to cut out 15cm x 2.5cm blank for the cuff! And after passing some length mark ( somewhere between 5 and 10cm ), my saw frame gets in the way, and bangs against the sheet, and keeping it going in straight line is tricky.
Anyway, here's how the cuff looks right now:

Unfinished cuff

It's close to finished, but I need to clean the etching up a little bit, and then of course oxidise it. I formed it, and then slapped myself in the forehead very hard, because I need to use gravers somehow on the etching! That means I need to flatten it again. I get overexcited sometimes, adding myself more work. But that's minor issue.

I also almost finished those lockets I've been working on for forever now. I have to clean them up, add all the finishing touches... and figure out what to do about a teeny-tiny slit that appeared in one joint on the raven locket. That's major reason as to why I haven't finished them yet.

So, that's it for now. I hope I'll have finished, nice castings next week!
Till the next time!
Kasia.