Adventures in Polyurethane Mold Building Part 1.

I say adventure because I'm not sure this will turn out. Here is the bamboo tiki light I am attempting to turn into a concrete tiki light holder. I need to build a mold for the rubber (the easy part) and make the lamp water tight (the hard part).

Here we go, two part polyurethane used to make durable and reusable concrete stamps and molds. It's not cheap but if the mold turns out, I will be able to make a bunch of these to help defray the cost.
On the left the mold for the mold. On the right, the sealed tikiman. I backed the face area with masking tape and filled in the light bulb access and cord holes with molding clay.

Then I sprayed everything with a liberal shot of silicone mold release and glued them down. Per manufacturers suggestion there is 1/2inch between the mold and the tikiman. Once the polyurethane is set I will split it in two halves to remove the bamboo.

The silicone glue will have to set up at least a day before I can make a mess, I mean pour the mold.

Fiber Optic Concrete Progress

The mold construction for the fiber optic bar/buffet top is coming along. I taped off the bottom, drew an abstract shape, cut out the shape, and glued in crushed glass. I almost cried while making the crushed glass out of a broken Murano glass lamp from Italy. It even had the master's signature but was unsalvagable as a lamp. The bigger pieces were glued in with a drop of epoxy and the little pieces sprinkled on after spray adhesive. What is the weird frame you ask, hold tight.

Here is the fiber optic setup. The bottom piece is the led light generator and the black encases all the fiber optics.
I bought a multi-strand setup that had small, medium, and large fibers. I cut enough to run into the cabinet and split the case open.

The bigger fibers got attached to the larger glass pieces to make them glow. I just attached them with hot glue. I will have to be careful placing the concrete, but they seem secure.

The strap is there to keep the fibers out of the way. I drilled very small holes into the white part of the mold and have been inserting the smaller fibers. This is a very time consuming process. It will be cool when finished and I can't rush otherwise the fibers will come loose.

Concrete Fireplace Surround

The next concrete at home project is replacing this beige tile fireplace surround with a concrete one. The surround will be flat black concrete and be a little thicker and taller than the current version. Afterward the gas log will be removed and replaced with a low profile burner and crushed glass. The tile was held on with a combination of mortar and construction adhesive. Either way the underlying material is very rough and will create a great bond with the new concrete.
Pretty standard melamine construction. This mold used (2) 24"x48" pieces which cost about $20.
The new concrete will be about 1 1/2" out from the original. Because of the small clearance the concrete will have a maximum aggregate size of 3/8" to allow placement.
Since the floor is concrete and I did not want to drill into the slab, the mold has feet out from the front and back. Silicone adhesive was used to seal the mold to the concrete and glue it into place. It will be fine as long as the concrete is not vibrated too much during placement. In order to accomplish this, the concrete for this placement will be self consolidating.
Due to the upcoming volume of pieces that will be created this summer I have started modifying a prebagged quikcrete mixture for various applications. By adding additional supplementary cementitious materials, admixtures, and fibers I have created mixtures both for inside use and outside. Once the testing matrix is complete I will post the results of my research.