Sure enough! I must have left the office door open Sunday night. Apparently somehow someone knocked all of my ready to sprue waxes onto the floor at some point ~ right into a large previously unknown dust bunny. I wonder who the culprit could be . . . ???
I think I said something about importance of thinking and planning ahead yesterday? Well, um, obviously I wasn't thinking or planing! If I had I would have reversed yesterday and today's work and be a little further along, instead of half a day behind where I'd like to be right now . . . .
Today I harvested and cleaned more of the new Seasonal Botanicals that I first test-cast last week. I was able to match up and sprue eighteen of them; enough for nine pairs of earrings. (There are some more detailed notes on sprueing here if you are interested.)
Since someone asked, here's more detail about how I invest a sprued flask to get it ready to cast. I use Kerr's Satin Cast 20 Investment, and have for as far back as I can remember. It's that good and that dependable a formula. I use Satin Cast 20 for casting karat Gold, Sterling Silver, Bronze, and Pewter. The instructions are clear, understandable, and easy to follow. I don't bake much, but Pat tells me that mixing investment is a lot like mixing a baking recipe.
So how do I do it? Well . . .
The flask's width and heigth determine the amount of investment and water to use. Today's flask of Seasonal Botanicals is 3" Wide by 3" Tall (allowing 1/2" extra heigth above the pieces). So Kerr's chart tells me I need 194 ml of water and 18 oz of investment.
Once my investing area and equipment (more on what I use as we go) is set up and I'm ready (full respirator on and wet paper towels nearby) it's time to turn the active exhaust ventilation on and invest!
Pat always calls to let me know when she is heading home from Waynesville, so I had the house mobile clipped on and ready. (I even had a grocery store bag nearby in case I had investment on my hands and the phone rang.)
So I measured 194 mil of distilled water and poured it into a stainless mixing bowl. (I use distilled water for consistency). Next I weigh out 18 oz, 1 lb 2 oz, of investment and wiped my hands down with a wet paper towel. Now it gets fun and you have to pay very close attention to time. I have a clock and Kerr's mixing chart set up at my eye level so I can keep track of everything I'm doing in the next ten minutes.
I mentally note the time and wait for the second hand to hit 12 before quickly and smoothly pouring the investment into the water. (You don't want to raise a cloud of investment dust.) Today it was 6:02 PM when I added the investment to the water. I've found that the easiest way for me to keep track of the time is to yell out each passing minute. (Hey, I'm wearing a respirator with a large noisy exhaust fan running, I've got to be able to hear myself!)
Mix the investment into the water by hand for 30 seconds. I use an old Hamilton Beach hand blender that Pat's Mother gave her decades ago, manually moving the beaters around. At 6:02:30 I turn the mixer on to low and mix for another 3 and a 1/2 minutes. Back and forth, spinning the bowl as I go counting each passing minute out loud.
I actually stop 15 seconds early, so I have enough time to put the mixing bowl on the vacuum table at the 4 minute mark. (I forgot to mention that I've already double-checked that my old Vic 9 Vacuum Caster's switch is in the investing position and that I've checked the vacuum pump's oil level gauge before even measuring the water.) I put the vacuum dome in place and turn the power switch on.
Now the time keeping gets a little tricky.
I keep an eye on the pressure gauge as I take the beaters out of the mixer and put them into the bowl for the scale that I weighted the investment in. I know that my Vic 9 takes about 20 seconds to draw a vacuum. Sure enough, this evening it hit 25 psi at 6:06:20. Time to put the blender away and wipe my hands down again.
Satin Cast 20 needs to be vacuumed for 1 1/2 minutes in the mixing bowl, and should not be vacuumed for more than 2 minutes total. Keeping an eye on the time I vigorously agitate the investment mixture by rocking the vacuum dome. (The vacuum table is essentially mounted on springs at each corner.) I move the flask into place to be ready, then, at 6:07:50 I turn the switch to cast and turn the power off.
Once the vacuum dome has re-pressurized (about ten or so seconds) I can break the seal and lift the dome. I pull the investment bowl with my right hand and pick up the flask with my left. I tilt the flask at about 45 degrees and pour the investment into it quickly and smoothly, aiming for the flask's lower wall. As the flask fills I gradually tip it back up to it's vertical position. You do not want to pour the investment directly onto your pieces; investment is heavy and dense enough that it could well collapse them or knock one of them out of place.
The flask goes onto the vacuum table, the dome goes down. The switch is moved to vacuum and then the power is turned on. I watch the pressure gauge until it's pulling a vacuum. 6:08:25 PM tonight. I scrap any extra investment out of the mixing bowl with a silicon spatula on a stainless handle (less to wash up in a few minutes), and agitate the vacuum table ~ basically rocking it back and forth.
At 6:10 PM I moved the switch to cast and turn the power off. Once the vacuum seal is broken I remove the vacuum dome and began to clean up. Wet paper towels to wipe my hands down.
Just as I was finishing washing up all of my equipment Pat called. Perfect timing! Time to change out of my investing clothes, wash myself up and get started on dinner.
We ate not long after she came home and caught each other up on our days.
I forgot to ask her about the waxes on the office floor . . . ;-D
(I wrote this on the laptop late last night while trying to keep our Count Down on track. But I was too done in to finish and post it. So, hmmm, now I'm a day behind on the countdown. Photos of The Boyz are from last year just because they look so sweet and innocnet. Right?)