Thursday, August 26, 2010
There was no question that I would need to cast Elsie's tail separately. What I hoped was that once I cut it free from the sculpture, I could find some kind of angle that would simplify the shape for mold-making. As it turns out, there wasn't a magic angle. It was a shape that didn't work well from any angle, and I was stumped about where to draw the mold lines.
I finally decided that I'd clay up one side, pour the first side piece and figure out what to do from there. I had high hopes that the planes would suddenly make sense once one was covered, but I also knew that I had rapidly degenerating rubber components. Polyurethane prepolymer (rubber Part A) degrades after it has been exposed to air, so I needed to use what I had left quickly. Experimenting seemed like a good idea.
The process did work, though there really wasn't a simple answer. The strands of the tail move in too many directions for anything but a fairly complex mold. Right now I think it will be a five piece mold, though the area that fits inside the bend may work better broken from the rest of that piece. That's five, possibly six, pieces and we haven't made it to the body yet!
Meanwhile Oliver's two production molds are about half-dry. I am dying to test them.
at 2:28 PM
Sunday, August 22, 2010
All the Flying Hearts tiles sold from the Auction Barn in a flash, so many folks didn't get to see them. If you'd like to see all the finished ones to date, I set up a page on the website.
Those are all gone, but I will be doing a few more in the future. They were a fun break from playing in the plaster, and all the money went to help Melissa and Herman. Good all around!
at 3:29 PM
Thursday, August 19, 2010
Around here, most ponies wear hats. That's because ears create an undercut; the area between them is hidden. So unless the mane is thick enough to cover the space between, there is a mold piece that goes there.
When horses have turned heads, there is sometimes a second piece that fits over the head or the head and neck. Both Finn and Vixen have these. I had assumed that Elsie would need a hat and most likely a second piece since her head and neck turn quite a bit. But after looking at her a bit, I'm rethinking that part.
One of the first things I did, back when I first started learning to make molds, was draw hypothetical mold lines on many of the Hagen-Renaker minis. I figured they were good examples since they were made with the same process (earthenware slip from plaster molds) and they were mass produced and sold relatively inexpensively. If anyone knew how to make workable molds, it would have to be them!
What I noticed was that many of the horses had heads that turned just right. That is, the turn shifted the ears and even the nostrils to one side of the mold. The rough outline of their mule above shows how this works. See how both the ears are visible? Nothing is hidden, so the mold can pull freely without the 'hat'.
What I've found intriguing about Elsie is that her ears are the same way. I'm not sure I can design the mold to eliminate the hat altogether, but I have been surprised by just how much of her face is on the same plane.
But before I can think much about her face, I have her tail to worry about. As the picture shows, I was was able to cut it free with a jeweler's saw. I am finding its abstract shape an absolute bear to mark for mold lines. Unlike a four-legged animal it isn't an obviously two-sided object. I've decided to have a go at claying it up with only one set of lines drawn (the one side I can see clearly), and then seeing where I am.
at 4:47 PM
Wednesday, August 18, 2010
I'm in the process of getting pictures of all the finished tiles, and should have them up on the website in the next day. Watch on the "New!" page for teasers, but they will eventually have their own page there. There are enough of them (almost 20) that it will be easier to show them there than here on the blog.
And this is my elaborate system for taking pictures of relief work: a piece of cardstock set on the back porch. It works surprisingly well!
at 11:06 AM
Tuesday, August 17, 2010
While I wait for Oliver mold pieces to dry, I've been decorating the tiles I glazed for the Flying Hearts Fundraiser. I like Sarah's term for this better, though. Festoonery. I have been festooning my tiles, which has been great fun. I promised myself that I had enough beads, baubles, ribbons and wire to festoon all three hundred tiles, nevermind my twenty, and that I wouldn't go out and get more. (I did, but only a few...)
As I mentioned in an earlier post, terra cotta clay has intimidated me for some time now. When I began testing my own tiles in preparation for the project, it didn't look like I was going to have any better luck this time. By the time the box from Sarah arrived, I had decided that I would just throw caution to the wind. Carefully selecting my glazes and applying them just-so was obviously not working. I decided instead to just grab whatever glaze was handy and see what happened. (It seemed a fitting tribute to the sculpting artist, at least!)
Oddly enough, that did work a lot better. It was also fascinating, because the terra cotta altered the glazes in unexpected ways. My favorite was this one.
The tile to the left is Lynn Fraley's "In The Ribbons". It was cast in white earthenware and glazed with my favorite sea-green glaze. The Flying Heart tile to the right has the exact same glaze. The only difference is that it was cast in terra cotta. The oxide in the clay turned the colors to blues and purples.
What isn't visible in that photo - indeed I haven't been able to capture it in any photo - is that the high areas where the terra cotta coloring shows through don't actually look red-brown. They look like copper, including a slight glittery effect. I found that some of my translucent glazes sometimes gave an even more pronounced metal-flake glitter look. Others had pigment that clustered most densely in small dots. What's more, if I fired the tiles a second time the colors changed again.
It was a lot of fun, but it certainly gave me a new appreciation for just how reliable the underglaze colors really are.
at 2:50 PM
Tuesday, August 10, 2010
The master mold for Oliver is done. The rubber original had not yet been poured when this picture was taken, but it is now curing in the mold. It will take a day before I know if the casting is good, but since he is at a stopping point I decided it was time to tackle his mother.
The first step for Elsie was going to be removing her tail. I am still on the fence about whether or not I'll need to lop off her head (more on that in a future post), but there is no way that tail can stay where it is. If an undercut is an area on the original that overhangs and obscures another area, then her tail is the mother of all undercuts! As can be seen in the picture above, the entire tail loops back around and sits in front of the rest of the tail.
And to make her even more interesting, there is another undercut area behind the fringed edge near the dock on this side. She has lovely tailbone detailing under there, so it needs to be preserved. The logical thing to do is cut the tail off where it meets the body. I have already drawn the cut line in the top picture.
I hate cutting, and hate cutting resin most of all. It's really hard to get a clean cut, even with a jeweler's saw (which will be necessary to avoid cutting the other part of her tail along with the rest). In this case, however, cutting the resin is the lesser of two evils because cutting the rubber master would mean I'd have to find a way to get the tail to fill properly with rubber. If there is something I dislike more than sawing on resin, it's fiddling around with complicated rubber pours!
So tonight I'll do a little tail docking. Once that's done, I have to start making some decisions about how I think the rest of her will work.
at 3:38 PM
Monday, August 9, 2010
No, not the weather kind - though Charlotte has had a bit of that recently. Flooding is the process of filling undercuts on an original so a simpler mold can be made. I mentioned flooding in my previous post about preparing the Meows and Minis cat medallion. It has been on my mind as I've worked with Oliver and Elsie.
The biggest lesson I learned from molding Vixen was that I needed to reevaluate my use of flooding. I had fallen into the trap of thinking that flooding was an "easy out" not well suited for highly detailed sculptures. It seemed like a cheat. I also hated the idea of altering an artist's vision for their piece. Flooded areas have to recreated in each casting, so that leaves the door open for mistakes.
What I found with Vixen was that flooding sometimes ensures that the finished casting is actually closer to the original. That's because it's easier to take flashing off from a piece of greenware than it is to build back an area that has been scraped away. On pieces that have minor undercuts, intentionally adding flashing so the mold pulls freely is sometimes the smartest answer. Otherwise the mold will skim off the undercut (if you are lucky), or the entire casting will tear apart. It only took reconstructing a dozen or so Vixen withers to bring that lesson home for me!
Most of the flooding I did on Oliver involved minor flashing on the mane and ears. The one area with a more drastic treatment was his tail. The overall tail shape was pretty simple to mold, but the individual strands formed long "fingers" that lined up one behind the other. By filling them I could ensure that the mold pulled freely without breaking the tail. This would also protect the "points" of his tail while I cleaned the rest of the casting. (The flooding in between the strands will be removed last.)
I used the hardest type of green Chavant clay for my flooding because I wanted something sturdy enough that I could leave it on the original as a reference. The picture here was taken after the original was removed from the completed master mold, so obviously the filled areas are pretty bombproof. Although it isn't visible in the picture, I also added a distinctive texture to the flooded spots to give me a visual cue about what needed to be removed. My hope is that this will result in a less "fiddly" mold - and ultimately more shiny Olivers!
at 6:43 PM
Tuesday, August 3, 2010
I still have photos and a BreyerFest report to make, but I thought I'd pass along this picture showing the start of the Oliver master mold. Oliver and his mother Elsie, both sculpted by Sarah Minkiewicz-Breunig, are new releases for 2010. Oliver's master mold is part of the reason I am behind on my posting. Work on it was interrupted for back-to-back trips, first to Kentucky and then to Alabama, so I've been eager to finish the project before I hit the road to Ohio in a few weeks.
In this picture he's being prepared for the pouring of the first large side. The claying up isn't completely finished; the edge along his topline has to be brought up tight to the original. This is important since it determines how tightly the mold will fit, and therefor how much (or how little) flashing will be present on the castings. Extra time spent getting this part right means less time spent later. The rest of the mold keys (the indentions around the outside) have yet to be cut and the outer edges still need to be made square and true. Unless there is trouble getting a rubber casting, this is usually the most time-consuming step.
Fortunately this is a very straight-forward mold to make, so I don't anticipate any trouble. I was pleased to see that he even fits within my favorite set of mold boards, which are smaller and easier to handle. Elsie is a tight fit even for my largest set, so I suspect I'm going to need to get my husband to make a bigger set before I start working on her mold. I should probably break down and have him make them from plexiglass like this set Joan has, because being able to see through the sides is really useful, and the clamps don't gouge them.
If only everything could be molded with Legos! They don't have the strength for larger molds, but for smaller projects they are faster. That was how I could make ten new molds for the cabochons used in the previous few posts. With just one functioning mold and really humid weather, I could only cast two beads in a day. That wasn't going to work, since they are the sort of thing that only makes sense in large batches. I made the new molds just before I left for Kentucky, so they are now dry and ready to use.
My plan is to experiment with glazes on the cabochons and the Flying Hearts Fundraiser tiles during the rubber cure times. I swear the hardest part of moldmaking for me is leaving the rubber long enough for it to properly cure. I'm always dying to see if it really worked! So a distraction is a good thing. If it all works out, I'll have Oliver and Elsie plaster molds drying and a fully stocked Etsy store by fall.
at 11:36 AM