One Bad Pixel
Better than The Nullset. =D

Casting with epoxy putty

Recently, I have been getting back into art and sculpture stuff, as it was part of my younger days which I never explored. I have been having a lot of fun, and looking forward to lots more fun, expirementing with different mediums and products.

The most recent product I have had the chance to use is Smooth-On Free Form Epoxy Putty which is a 2 part, 1:1 by volume epoxy putty. I wanted to take a minute to review the product, since it is quite new and has very little reviews.

I have to admit, I was a little skeptical and curious about it, expecting it to be like play-dough that hardens. I was unsure how well this would work with a mold that has a lot of detail in it. Turns out, the stuff is extremely light and not dense at all. More like Moon dough, if you have ever seen that.

As far as measuring, you could probably get more precise than I did, but it has been curing fine for me, so I am guessing close is good enough. You dig out an equal sized ball of each part, then knead them together until they reach a consistent grey color (1 part is white, the other is dark gray) then press them into your mold and wait the recommended curing times. The curing times and pot life is mass specific, so thicker masses will cure faster and have less working time. If you are making a large item, it is probably best to roll it out while working, to give yourself more working time.

Because of its extremely low density, it is extremely good at picking up details in your mold. In fact, I picked up details that I didnt even realize were in my mold from when I was tooling the original clay to make the mold.

On the topic of strength, this is where I was most surprised. Based on the weight of this stuff, I almost expected it to cure into something akin to styrofoam, but a sample piece I made about 3/8in thick, 1in wide, 6in long was so strong I have been unable to break it by hand. I imagine that using a tool on it would probably break it.

The stuff can be sanded, drilled, tapped, and what not after it cures, so it is nice for making things that need attachments added later.

The odor is not extreme, albeit not incredibly pleasant either. It smells like those biodegradable packing peanuts. Yuck.

Anyways, I have been having a lot of fun working with the stuff, and I encourage anyone to give it a try as an alternative to liquid casting materials. It seems to work best for hollow objects or thin shell objects (in my case, wearable costume armor)


3 Responses for “Casting with epoxy putty”

  1. Stu Miles Says:

    Hi Jim
    Thanks for the info – I am going to get some of this free form air to experiment with.
    I was looking for a sort of casting material to use without a mold – large 2×2 foot area
    on metal welded armature. Am thinking about filling the hole with foam or chicken wire and then
    coating with free form – saves me the trouble of fiber glass, paper mache, liquids –
    well I’m hoping any way.
    Might you offer any advice on these processes ?
    If I can get it to work I’m then needing to figure out a gesso under coat so I can use oil
    paints on it.
    Well if you might have the time to respond.
    Thanks, Stu

  2. Jim Says:

    I think that you will like the stuff, other than the price. It would be easiest to lay it down over rigid foam, but would probably work if you used small batches and waited a couple of minutes for it to start firming up.

    Good luck! If you want more suggestions, maybe send a pic of what your working with to

  3. wisata bromo Says:

    yes i like
    good luck if you want more

Leave a comment!