Materials:
Alja Safe
water
mixing buckets
measuring buckets
power drill
mixing wand
extra heavy duty incredible duct tape
hot glue (and gun)
milk jugs
Alja Safe is honestly the coolest material I've ever worked with. It's the stuff they use to make molds of teeth at dentists' office. It's incredibly accurate and insane to work with. That being said, it is pretty expensive. Because I was going to make several large life casts, my art department bought a big box of the stuff, which was a godsend.
It comes in a powder, and like plaster, you want to keep it as dry as possible until you're ready to use it. In Florida, it's humid even in our dry winter months so I keep the box in the basement, behind the ceramics classroom where it's nice and dry.
The process is pretty quick, with a bit of set up time that definitely pays to be careful during. This was the first apparatus I built for the alginate casting. In my later ones, I started using milk jugs more than anything else because they're much easier to work with. You want a soft plastic because you'll be pulling it apart at the end. That being said, this boot (or whatever casing you need for the particular body part you're casting) needs to be water tight. The alginate is a bit thicker than water but blow outs are a huge deal because this stuff is so expensive. I got to the point on my final boot where I hot glued every inch of seam after a bad experience with purple goo shooting out the bottom because of poor planning on my second one.
When you're constructing it, you want to make sure that the body part can float in it. If it touches any of the sides, those blemishes will show up in the final product.
The Alja Safe is mixed in a 1:1 ratio to water which means pretty simple math once you figure out what the volume of your apparatus is minus the volume of your body part. It's a bit of guess work but it becomes really easy if you use gallon jugs because you can just count them up. With this first one, we poured water into it and then dumped it into a 5 gallon bucket. This method is incredibly messy and pretty inaccurate because we ended up mixing a whole bunch of extra alginate. Alja Safe and alginate are the same thing by the way, one is just the brand name for the skin safe type of alginate.
We pretty much just eyeballed the right amount of alginate with the measurement of water beside it. You can go all out with weighing it but it's fairly simple to eyeball it in two of the same type of container.
When you mix, you should use a power drill with a mixing wand attached. You have to make a vortex in the water while the other person is pouring the powdered Alja Safe into the water. Mix for a couple of minutes until it's past the point of looking like cake batter. You don't want clumps of powder affecting the wonderful goop that will capture your body part perfectly. Splash a bit of water around your leg/foot to break the surface tension between your skin and the Alja Safe.
When we poured the alginate into the boot, we put a bit in the bottom, then I placed my foot in and my helpers poured the alginate goo into the boot around my calf. Let the goo set up for about 15 minutes (the product will come with exact instructions but that's how long I waited) until it's solid. It's a weird experience but oddly enjoyable. You have to make sure not to wiggle too much and that you're not touching the sides of the boot but other than that it's pretty cool to balance your foot in goo for 15 minutes.
Getting out of it is a whole different story. Sometimes your foot gets stuck. It's a good idea to have an air compressor on hand but I only had to use it one time and that was the time I had the blow out and everything went pretty poorly. When the alginate is set, you can start wiggling your toes and foot to slowly pull it up. This is a good point to have someone stand on the board while you pull up with your leg. Your gluing skills will be tested but trust me, it works. You'll hear a disgusting squelching sound as it comes out and that's good too because it means air is getting around your foot.
The alginate will hold steady for about four hours, but it's best to pour your material right away so you can just get it all done. If there's a bit of water in the heel of the foot, that's okay, just take a paper towel and lightly mop it up before the second pour. I make plaster positives of my feet from the alginate casts but I've seen people use cement and a bunch of other materials. I'll be going through the plaster pouring process in my next post.
