Count Down Fun! 5! Part 2, "You know . . ."

[I just discovered that this was saved as a draft last night when I fell asleep in my office chair!  So here's yesterday's second post ~ please just ignore any confusing tense usages and pretend that you're reading it yesterday  .  .  . ]

You know, there's a reason that casting is as much an art form as it is a science . . .

Pat test wearing our newest

Seasonal Botanicals in Sterling Silver !!!

This is another case of taking a break outside and really looking at the wonderful world around us.  I saw this amazing shape and knew that I just had to see what they would look like, and feel like, what they would be as a piece of jewelry.  How could anyone possibly improve on this form, this shape, these proportions???  You can't.

This is one of the first pairs of earrings that I had to try to cast (I think it was) last week (?) because of this inspiration.  (The days are beginning to blend together a little!)  And yes, if you saw my last post, these are actually seed pods from our Ipomoea guamoclit, or Hummingbird Vine.  These beautiful earrings began life as this beautiful flower:

Hummingbird Vine, also known as Star Glory or Cyprus Vine,

Ipomoea guamoclit.

Talk about a stretch your limits challenge!  The first test casting went well and I learned a number of things.  There was no way I could stop with just a couple.  So I had to make more!  But the clock is steadily ticking away and I just don't have time for experimenting ~ if something doesn't work the time and energy and effort is gone.  (But not wasted!  Sometime we have to learn certain lessons more than once . . .)

It was disappointing to take Tuesday night's castings out of the ultrasound and think I'd found shrinkage porosity last night.  I used a miniature cut off disc to desprue the castings today.  And I feel alot better.  Only a couple actually suffered from shrinkage porosity!  (Generally caused by too small a sprue supplying too little metal to too large a mass.  Which was exactly what happened here.)  The rest are perfect and we'll have them at the Guild Fair!  (Providing we find the time to get them all finished!)  I got them all de-sprued and rough ground for Pat today.  She finished up the forged rings so I've got them waiting in the que for grinding and buffing and final polishing.

Between our long dry spell and the cold nights we're having now these might just be the only Hummingbird Vine castings I can make this year.

Our chains haven't arrived from Italy yet, so I called today.  They should be here today or tomorrow.  As long as we have them by next Wednesday we'll be happy.

While I was minding the kiln today Pat got lots more finished up than I did.  Thank goodness!  (Why, oh why, do I still think I can get a dozen other things done when I'm casting???)

Ferns, waxed and ready for spruing*.

So I made dinner a little later than I probably should have tonight.  Pat offered to, but I was already so hungry-wired that I just wasn't being effective so it was better for me to stop working and get into the kitchen.  I made Pat flop on the couch with a good book.

So we ate and then I cast the Ferns at 7:27 tonight.  It was 56 degrees out, though because the kiln and Electro-Melt were running it was 65 in my casting area.  I charged the Electro-Melt with 59 grams (just a smidge under 2 ounces) of Everdur Silicon Bronze once it was preheated to 1850 degrees Fahrenheit.  The kiln and flask were at 950 degrees F.  Normally I'd cast Silicon Bronze with the flask at 900, but it was a cool evening and the ferns are delicate finely detailed pieces.  (Remember that:  "Delicate finely detailed pieces" . . .)

Here's tonight's 1 minute 30 second video of the pour.  If you want to skip ahead to see the four seconds it takes to pour 2 ounces of molten metal, the Fun Part starts at 54 seconds.  This is the make or break point of more than two very full very long days of work and another day spent burning out the flask . . .



Ten minutes later, because it was so cool, the button wasn't glowing and it was time to quench.  And I immediately knew I had problems.  Despite the extremely excessive spruing three of the five ferns completely failed to cast . . .

Gut-dropping, stomped flat, sick to the stomach about sums up how I felt when I first held the castings in my hand.  What ???  Sure, we all know ferns are too thin and too light to cast.  But I've done 'em before and . . .

When I first started casting [lets be polite and just say it was a couple of decades ago, okay?] everything that could go wrong did.  There are so many things that have to be just right to making a casting work, or not, that sometimes I couldn't figure out what had happened!  I wish I could find it now but, I wrote out a list of every single step involved and what might go wrong if you made a mistake at any step and what the affects would be on the casting.  For some reason the number 311 still jumps into my mind all these years later.  (It might've been 315.)

So by my, ancient, calculations from the wax stage to the final quench there are more than 300 hundred ways that you can completely mess up a casting . . .

But more importantly, just what the heck went wrong this time?!?  And how the heck have I messed up two castings in a row???  Am I really that tired???

The metal temp was at 1950 when I poured.  Silicon Bronze is, like DeOxidized Sterling Silver, kind of funny stuff to melt.  There's the melting point of the metal and then there's the liquidous point ~ and sometimes there's another altogether different temperature for the pouring point.  When Silicon Bronze first melts it looks like an antique mirror with a crackly crazzed surface; raise the temperature another 20 or 25 degrees and that affect disappears as the silicon is activated and you're good to pour.

Okay.  It looked good or I wouldn't've poured when I did.  But my first suspicion was the metal's temperature and even though I tried to allow for the ambient temperature that's where I looked first . . . 

Oh.

Here's what I forgot to allow for!!!  Yep, I poured at the correct temperature ~ for a dense heavy casting.  For light delicate ferns I should have poured when the Bronze was another 50 to 100 degrees higher!!!

There's nothing to do but make a note in my casting log and hope that I'll always remember to double-check in the future.  Then you turn the music on and smile and dance.

It's such a Beautiful World and there is always more to remember and to learn. 

So if that was the problem why did I say casting is as much an Art as it is a Science???

Because if I had listened to, and really heard, my own inner voice saying, "Um, it's not hot enough yet . . ." regardless of what the pyrometer said, I think they would have all turned out perfectly.

I didn't listen.  Now all I can do is dance and smile and laugh with the music.

If today is suddenly Friday it must be time for lists, or maybe it's time for bed   .   .   .

Sam & Ink again, late this July, just because.

*Gee, aother word that I seem to automatically misspell!  Sprueing should be spruing.  Though ti, er, it makes me feel better to see how many people have googled sprueing and landed on our blog!

Count Down Fun! 7! 6!! Catching Up, I Hope . . .

This is the morning of Count Down Fun Day 5, as I try catch you up on what we did on Days 7 & 6.  (Lets see if the video works!)

Last time I talked about investing the new Seasonal Botanicals.  On Day 7 they went into the preheated kiln at 300 F at 10 AM.  I spent the day waxing new Fern Seasonal Botanicals.  And waxing, and waxing, and minding the kiln.

It was a pretty well behaved burnout cycle.  There's always a lag between the kiln temperature and the actual temperature of the flask being burned out.  Especially at the lower temperatures, but once the water content has been forced out by the heat and you reach the 1000 degree point the flasks tend to be pretty responsive to temperature changes.  (Though just because of their size and weight there is still a bit of a lag in temperature changes.)  Anyway . . .

Because of the time/temperature lag I start counting down each stage of the burnout cycle once the kiln actually reaches the new temperature range.  For example, the main high temperature for a 3" by 3" flask is 1350 degrees F for three hours.  So when I go from the 2nd stage at 700 F I don't begin timing until the kiln is actually at 1350 F.  And that's the fiddly stage for my old electric kiln.  (An American Ceramics kiln that I dearly love and owe an awful lot to.)  An hour and a half into the 1350 F stage I'll pull the flask, rotate it approximately 90 degrees and turn it over so the sprue former pour cup is now facing up.  Then back in, make sure it's at 1350 F and time for another hour and a half.

The actual pour was at 6:30 PM.  Wait about 15 minutes to let the flask cool then quench.  Then you finally get an idea if all of the wax work and then the burnout and pour worked.

I don't have a way to edit video yet, so this 3 minute clip is a bit rough.  I tried setting the camera up facing my casting area.  From the camera what you see is:  my Vic 9 vacuum caster, my Kerr Maxi Electro-Melt  (100 oz capacity!), and behind that the side of the kiln.  The very loud noise you hear is the exhaust fan.  The even louder noise later is the vacuum caster when it's turned on.  It's dark, but wait till you see the molten metal flowing!!!

Here's a quick timeline:

.10 Charging the Maxi-Melt with 90 grams of Sterling Silver (3 oz) when it is at 1850 F
.30-.40 Rocking the Maxi-Melt to help mix the alloy and sometimes, if it's a lot of metal I can feel if it has begun to melt
.50 checking the melt. Nope, not ready.
1.40+ rocking the Maxi-Melt, feels good, lets check it!
1.50 quick stir with my quartz stirring rod to make sure the melt is complete & to mix it
2.04+ turn off the kiln, pull the flask and set it on the casting table, turn on the vacuum pump and check the vacuum gauge to make sure the flask is drawing a vacuum
2.19 the beginning of the pour & my very favorite part of casting. All the hours and days of work lead up to the next few seconds.

After the actual pour I dump any residual slag out onto my fire resistant base and make sure the graphite crucible is clean. Turn off the Maxi-Melt and unplug it.

The last bit is jumpy because I wanted to show what the flask looks like from my view as it is glowing at me.  Sorry 'bout that, but after the Fair I'll have time to work on editing some more videos.

After cooling a bit I quenched then put it into a glass jar to devest in the ultrasound.  Made dinner and we both decided that we were pretty much done for the evening.  Around midnight I transferred these castings to a pickle jar and left them in the ultrasound for the night.  I turned the ultrasound off when I went to bed around 2.

Just as a reminder, there's a reason I look like this when I'm casting!!!

• Full respirator ~ don't want to breath in any metal fumes!
• Casting glasses ~ I'm looking directly at and into 1850+ degrees F!
• Welding glove on my right hand ~ I use tongs to pull the flask out of a 1000 degree F kiln, and then I use my quartz rod to stabilize the 1850 degree F graphite crucible as I pour.

Yesterday, Day 6 I spent working on new Fern Botanicals.  And working on them, and working on them.  I have to admit I was in a groove and loving it.  They came along really well, but took a lot longer than I had meant them to.  (I thought I'd get them burned out and cast yesterday.  HA!  I just kept working on them.)  I left the earlier Botanicals in the ultrasound all day.  Just got distracted and left them running in fresh water.

Pat got a lot done on the production earrings for the spinner rack over the last few days.  Yesterday she finished the larger pendants that had been on the bench.

We stopped and I made us dinner around 7:30.  Then I went back to working on the Ferns.  I pulled the castings and dried them off . . .

And that was when I finally saw that some of them had shrinkage porosity and aren't usable.  Blankity-blank-blank-blank!!!  It was my own fault.  So there's nothing to do at this point except make a note in my casting log and remember to have a heavier sprue the next time . . .

So, of course, I stayed in the office working on the Ferns and boy did I overcompensate!  I began to actually spruesprue them up ~ after I completely over did their sprueing!  There is no way they will have any shrinkage porosity.

But what a pain they're going to be when it's time to de-sprue them . . .

So now it's the morning of Count Down Day 5!  In four days I'll be loading the display in the car.  In five days we'll be setting up at Booth #109 in the arena level of the Asheville Civic Center.  In six days the Fair will open at 10 AM and we'll be there, all set up and ready to go!

Counting the days  .  .  .





Count Down Fun! Day 8 . . . Seasonal Botanicals Invested [Yesterday's Post Tonight!]

Monday's are always a little off for us.  Once we've both had our wake up coffee-computer time I spend the morning running errands and going to the grocery store.  After we've eaten lunch Pat heads off for Jeannie's shop, The Jeweler's Workbench in Waynesville.  Today was no exception.  I spent another couple of hours on Guild business again before I got busy with our own work in the afternoon.  Once I was back at the office work table it took me a couple of minutes to I realize that something was missing   .   .   .

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 asked Inky.  No.  He's too innocent and cute.

Sammy?  No.  He's obviously on Guard Duty.

(Hmmm.)

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?)

Can you guess what I did today ???

With luck there may just be a video in tomorrow's post about today.

Day 9  posting on Day 10 that is!

Please feel free to let me know if you have any questions about investing, casting, or questioning cats about their nocturnal escapades!