A Tale of Two Stumps

This started out as a project to put something a little more organic on tables than the blocks of foam and plastic we're used to seeing. Tree stumps for what ever reason is what I latched onto.

It was a mix of known and suspect for me. I know we can produce a descent tree stump. I suspect it can be done in such a way to make it reproducible for a low cost.

It was a bit of unknown territory so I opted to proceed as cheaply as possible.

Let's start with the materials list for the proofs.

Biggest/cheapest block of air dry hobby clay my local Micheal's had available. From a sculpting standpoint this stuff is garbage. Once you know that, it's easy to work around it's limitations. The two biggest are it shrinks as it dries, and it takes forever to dry it properly.

Next is a cheap mold.

Liquid latex and Plaster of Paris

Cost of mats, about $20 (It's Micheal's, coupons!)

For starters some of the NOVA build crew sat around a table for a couple hours and knocked out some stumps. Such as the one pictured here.

Once it'd spent a week drying out I got down to getting a basic Latex mold.

The Latex mold is an inexpensive option for duping larger size objects. Latex does good job holding detail as long as it isn't too fine. Think of it as your Xerox option. Fuzzy but gets the message across.

The liquid Latex needs to be painted on in thin layers and allowed to dry between each application. This is a major time sink. I used a heat lamp to shave a bit of time off drying each layer, but it still ended up being 20 or more applications to produce a thick enough “skin”.

Once the Latex mold was done it needs a scaffolding to hold it in place while it's in use, i.e., full of goop and curing. Enter the Plaster of Paris. I created a basic box form around the Latex master and dumped plaster in it. We could get into two part molding and keys for this part but it's overkill. I made a solid cube of plaster and used the cutting wheel on my Dremel to split it. Function over form.

Kit it together with a little help from duct tape and add a little plaster, somewhere in the 12 to 16oz range, to the master mold. Boom, we've got a reproducible object.

 

Proof of concept done. Now it's onto the next stage...