The friendly team at ComposiMold recently sent me a sample of their product for review. Like many experimenters I’m mostly unacquainted with mold-making and casting but I’m willing to get messy and give it a go. Let’s dive right in and see how this stuff works.
TL;DR Summary: ComposiMold is easy to use, reuse, and reuse again, even for a casting n00b. It’d make a great gift for a Maker kid. Highly recommended.
Composimold: The Unboxening
Opening the 10-ounce container releases the faintest waft of lemon. It’s not unpleasant or pronounced; only bloodhounds and those accustomed to huffing day-old mimeographs will have the chemoreceptors to detect the scent.
It’s firmer than I expected. I was thinking I’d have something a little gooier, but when ComposiMold is cool it’s got the consistency of a flexed bicep. At 10 ounces the sample container feels satisfyingly dense in the hand. I feel like I could make stuff with this.
Virgin ComposiMold looks surprisingly like honey. So much so that the lovely and talented Mrs. Zheng3, slightly less talented than usual at 5:30am, nearly dropped a heaping spoonful of ComposiMold into her oatmeal. I probably shouldn’t have left the container on top of the microwave last night.
In theory, the mold making process is simple and straightforward: heat ComposiMold, pour it over the object you want to reproduce, allow to cool, and then extract your object.
Naturally I screwed it up.
Jumping into this project like an enthusiastic idiot I naturally made a a rookie mistake right off the bat. I forgot to coat my mold container with a release agent. So I restarted the project. What you’re seeing here is actually take two on my quest to replicate a Seej bloxen.
So! Into the microwave with you, ComposiMold.
Another brief installment of Zheng’s household hints: before photographing the inside of a microwave you’ll want to clean it so the Internet doesn’t think you’re a gavone. Put a cup full of vinegar in the microwave and nuke the bejeezus out of it. The steam will soften the Hot Pockets splatter off the inside of your microwave so that you can wipe it clean with a rag. The healing brush in Photoshop will take care of any pastacules you might have missed.
Thirty seconds in my microwave and I’ve got a golfball-sized nugget of ComposiMold suspended in honey-like goo. Stir with a craft stick (always, always, always have craft sticks around any maker project), give it another 20 seconds of non-ionizing radiation and we’re good to go. During the melt the lemony scent is a little more pronounced but doesn’t stink up the kitchen.
I’ve decided to try and cast a Seej Bloxen for my first project. I’ve made sidewalk chalk bloxen using a 3d printed mold, but I’m interested to see how ComposiMold picks up the detail in the 3D modeled grout and stones of something I’ve already printed. This particular bloxen was produced during my review of Filabot’s recycled ABS filament.
Composimold: Making A Mold
I give the bloxen a rub with some vegetable oil and put it into an old laundry scoop. Here’s where I run into my first unknown unknown in the mold-making process.
The plastic object I’m trying to copy is less dense than ComposiMold, so it wants to float. I try holding it down with a craft stick, but I’m unwilling to wait half an hour for the ComposiMold to solidify at room temperature. I throw the whole thing in the freezer to cool and abort the first try at mold-making.
It’s 9AM on a Sunday morning so I take a break and have some cheese danish before the kids get up and eat it all. After twenty minutes and a cuppa joe I cut open the mold to see how well it captured the details. Click to embiggen.
The detail’s quite fine here. ComposiMold even picked up the layer artifacts left by the 3d printing process. Each of those parallel lines is about 100 microns wide. I can’t use this failed mold for casting, but it provides an excellent chance to test ComposiMold’s reusability.
Forty-five seconds in the microwave and I’m back to pouring a new mold. Easy peasy George and Weezy. So far ComposiMold is living up to its promises.
This time I’ll try suspending the bloxen from a stiff piece of hookup wire before I pour. I drill a small hole in the side of the bloxen, superglue in a wire scrap, and wrap it around a craft stick. (See previous admonition about having craft sticks around.) I’ll use a plastic cup for my mold container this time, because I can just cut it away without having to worry about pre-treating it with mold release. The vegetable oil gets everywhere and I don’t want it schmeered all over my camera and light box.
The bloxen remains submerged this time, if a little off-kilter as the unsecured bottom of the plastic tries to float upwards. The newly-poured mold goes back to the freezer for fifteen minutes or so before I cut away the plastic cup.
The mold resists my hobby knife with the strength of an overcooked ham, but splits easily and the bloxen pops right out. A little vegetable oil on the inside of the mold and it’s ready to be filled with Plaster of Paris.
ComposiMold’s produced a perfectly usable mold. The process has been simple even for a mold-making novice, but today I’m wishing I paid more attention on casting day in sculpture class.
In all fairness, I was trying to get the lovely and talented not-yet-Mrs. Zheng3 to notice me at the time.
Notice that almost all the bubble artifacts on this plaster bloxen faces inwards; this isn’t ComposiMold’s fault, it’s mine. Either I didn’t get the plaster/water ratio correct or I didn’t agitate the mold enough after pouring, or my plaster’s old, or something else. I’d love to see what ComposiMold can do in the hands of someone with more casting experience. ComposiMold also sells a bubble buster that will assist in the casting process that wasn’t included in my review sample.
A couple hours of playing with this product has given me all kinds of great ideas for where to go next with this. Traditional casting and 3D-printing are a powerful combination, so #staytuned for another casting attempt, this time with cement. The younger Zhengspawn and I have a project in mind that’s perfect for ComposiMold. We’ll see how an 8-year old does with this stuff under lax supervision.
If you’d like me to put your Maker-related gizmo, material, tool, or software through its paces at Zheng3.com, email me
and I’ll give it a shot.