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My Cat Mold

September 22:

I’ve been surprised at how long it’s taken to get this thing ready for its bath. Last weekend I cleaned up the surface and then made some sprues. It took a long time to roll little wax turds and then stick them together. I should have bought wax rods. They don’t cost much.

Today, finally, I expected to get the cat in its plaster mold. That didn’t happen. Above, you can see how I plan to mount this thing. At first I was going to stick a rectangular piece of was to the foot and bolt that down. It didn’t look right. Now, I plan to stick this part through the base plate and weld it underneath.

If you look closely, you can see my mark. I’m getting pretty sloppy. It’s like I really don’t care anymore.

I cut the cat in half with a sawzall blade. You can see some thin parts, like at the seams. I painted more wax in all these parts. That took some time. I was careful, but got some wax on the outside. I’ll have to clean that off.

I made the flasks too small. Just as I finished making them, I realized that they should be two inches bigger all the way around. The wax will be within about an inch of the flask. They recommend 2”. This won’t leave any room for drift. I should probably make new flasks, but I want to see if I can get away with this.

The tubing is bolted through the sheet steel in two places. I left the bolts long. I plan to hook on to them with the crane. I hope I can easily turn these things over that way when I put them in and out of the kiln.

I reduced the sprue diameter close to the pattern to make it easier to break out later. We’ll see. I actually don’t know what to expect. I am using three gates to fill in from above, to fill any holes that develop by freezing metal. (I hope.) I tapered them to let the metal flow past until the level reaches them.

Nice fit. My concern is that the sprue will crack away down in there. In that case, a film of plaster will close the passage. I ran wax down in there, getting some on the outside. I’ll have to clean that off.

I sure didn’t have to make that sprue so long. I was thinking it had to reach almost to the bottom of the flask.

Here’s the back end. That’s beech sand in the pails. I plan to mix it 2 to 1 with the plaster.

I cut the sprue off and attached a pouring basin (cup) and vents.

I stuck the vents to the cup, just to strengthen them. Half that cup will be sticking out of the plaster. The vents, too. I wasn’t thinking when I stuck one of the vents on and got wax all over the outside. It’ll take a while getting that off.

And, here’s the back end. That’s as far as I got tonight. I’m hoping Michelle will help me tomorrow. I plan to get it in plaster. I might actually be pouring this next week.

September 24:
It's like I'll never get this cat in the flask. I got the thing ready to go - meaning that I cleaned up the surface and gave the sprue structure a final check. Then I started to ponder the difficulties I might have with the plaster. This has been on my mind a lot.

There's no room for error, with the flasks so small. I know from experience that the wax will work hard to float out of the plaster. If I hold it down from above, the bottom will rotate until it bumps against the wall of the flask, which will be only about 1" away. To add to the trouble, I will want to run my hand against the surface after it's submerged, to brush bubbles off. Otherwise the metal will be covered with little bumps, each of which I'll need to chisel away.

I thought I had a good idea for holding the wax pattern in place: running 1/8" wire straight through the flask and the pattern in two places. I planned to use pins through the wax anyway, to hold the core in place after the wax is gone. I figured that I'd make the pins a foot long and use them to hold the wax stationary while I filled the flask with plaster. I wondered how I could be so inventive, and why I hadn't read about this anywhere. It seemed to make sense. You guessed: it didn't work.

I propped the butt end of the cat (easier to work with than the head end) on a plastic top to a spray paint can, to keep it about the right height off the floor. I was going to mark where to drill for the wire pin. The thing immediately fell off the plastic and down to the garage floor, with a loud crack.

You can see the large flake that split off. I stuck it back on and worked it over with patching wax.

Not so bad. Just time lost.

Then I drilled the flask and marked where to drill the wax. After poking through, I had trouble deciding where to drill the other side. I wished I had a 6" bit. I would have bought one but time was running out. (I have other things in my life to do.) I set an old phone book on my knee and gently tapped the wire through the wax from the other side. I was patient. But look what happened.

I never have done much with wax, so I didn't know how tough this would be to fix.

Right about now is when I decided to fuck the idea of long rods through both the flask and wax. Even if I had the holes all lined up, it would be way too hard to get the wire through everything way down in that can.

It wasn't that hard to patch. It took maybe fifteen minutes.

This is what I'm going to use for core pins. I read that some people use nails, but that they're sometimes hard to get out of the metal. Some people use stainless steel pins. I figured if nails work, (the ubiquitous) 3" drywall screw would too. Maybe they'll turn out of the metal after casting. I used three of them.

This is where time ran out. Michelle had the idea of tying on to these screws and securing the wax from below. I think that might work. She said she'd help me, but probably not until Wednesday. I won't like waiting. I also have a hunch this might be worse than trying to teach your wife to drive, or to play golf. I might be in such a rotten mood with all the hassles and urgency of setting plaster, that she might perish, or leave me immediately.

Tune in next time for (believe it) more in the long life of Waxton.

October 7, A Good Cat Day

I made some bigger flasks. It made sense, since I was no longer in a great big hurry.

I made them the same way, but now I wish I used something stronger than that square tubing. I remember that that stuff burns up and is pretty weak after enduring multiple days in the hot kiln. I might do something different, still.

I have my foot in the picture for proportions. This would be very expensive if I was using the jewelry investment I used to use.

Things went smooth today, with Michelle's help. Here, she's showing us the ready cat with core pins and reinforcing wire. There's a total of four pins (3" drywall screws).

I'm using this wire to reinforce the core in his head and legs. It would be bad for pieces of that core to break off during burnout or pouring.

I was surprised how smoothly things went today. I'm using plaster and sand now, instead of that expensive investment, and I have a new process for mixing. I use coffee cans: 1 of water, 1 of plaster, 2 of sand. It makes for real fast mixing. It took less than three bags of plaster for both these molds. We'll see how it works in the foundry.

Michelle is inscribing the number of pounds of wax in that mold, and a "hex mark". I understand the hex mark is a traditional way to ask the supernatural forces for good luck.

You see the three. The other mold has four pounds of wax in it. The hex mark Michelle chose is the Celtic knot; her favorite. Our wedding rings are composed of Celtic knots.

I'm guessing the plaster mold weighs 150 lb. We'll find out tomorrow, after they set.

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