Logan's Run wall crystal

Sean, RE red lights, no, I haven't been able to find any red LED light sets in my area. No one will have any until Christmas, and I haven't remembered to borrow a piece of red gel from work yet. RE other paints, no, I managed to cover all three of the paper ones with the same can of red spray paint. I don't plan on painting the plastic one.
 
I decided to try a fourth paper crystal that I've been making out of construction paper for strength, so maybe I can try to make a mold. I wanted to put something inside the paper pieces to stiffen them up and keep them from collapsing. I tried that expanding foam you can use to fill gaps in your walls. That stuff just keeps on expanding. For an hour. It got satisfactorily firm, but hardened up before it finished expanding, so now the bigger crystal pieces have either burst or puffed up like little pillows. Oopsie. Back to cutting more.

The thing is, it worked. All I need to do is figure out how much is needed. Or just maybe leave one side off, let the filler expand as much as it needs, and cut it flush once the filler has hardened completely.

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Turns out that the expanding foam hasn't been such a great idea. It's simply too flexible. No matter how much I sand the pieces I can never get the bigger piece facets flat, because the foam bends inward and then back into place. For many I've cut out a side and carved out the foam with an exacto knife, and then refilled them with popsicle stick and toothpick segments white-glued together. It takes a couple of days to dry completely, then I fill in between the wood with Spackle, wait for that to dry, then sand it flat. The result is cleanly flat facets and edges, and facets that are solid to the touch, not flexible. It's just taking a frustratingly long time.
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Before I forget, here's the final shot of the one I just finished. I got frustrated with it for a while because the inner foam was making it hard to sand flat. My solution was to carve into the problematic sides, dig out the foam, and replace it with pieces of wood glued together with white glue, and then sealed inside spackle. These took a good while to dry, but afterwards they let me sand the facets as smooth as I wanted them to be.

Another thing that slowed down the process was that I had built the model incorrectly. Once the error was pointed out, I fixed it by cutting off the incorrect facets. I later corrected the 3D version as well, before starting the 24" version.

On the 24" version, I've bought a gallon can of Bondo. I plan to make the cutouts with a thick card stock, glue them together, and then fill them with the bondo.


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Work continues on the 24" diameter power crystal. I was only able to find a 23 3/4" wood disk, but was able to find some iron-on edge veneer. 7-8 layers of that brought the disk diameter to just above 24", so I have some play in mounting the crystal facets to the surface. (Though it was a bit hard on the non-stick coating of my iron.) The wood surface is WAY more stable than the styrofoam I used for the 12" version. I've given it a couple of coats of white latex primer, and have been sanding it flat in between coats to remove all the wood grain texture. I need to get another can of the latex. I've assembled these paper forms for the surface.

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I am trying an experiment in duplication. Instead of making more paper forms of each crystal segment, I've put them together as molds. I bought a gallon of Bondo, and when I think the forms are complete I will try my hand at creating the crystal segments out of that. I'm hoping it will be more substantial than the paper, and easier to create more uniform shapes. To strengthen the paper molds I have been coating them with layers of wooden craft spreaders on the outside, held together with clamps as they dry to try to keep the flat surfaces flat. When dry I have been painting them with the rustoleum paint I had for the earlier crystals. When they seem rigid enough, after coating them with wax or petroleum jelly or other non-stick agents, I will try mixing up some of the Bondo and pouring it into the molds. I'm hoping this process will save me a lot of the time I have spent on the paper versions in stiffening them up enough to stay rigid so I can sand them flat. I'm hoping I can either try to make them hollow in the center, or fill them up with paper remnants to minimize the amount of Bondo I will need.



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Getting the base prepared. The first shows preparation with latex primer, sanded in between layers to fill in the wood grain and the border between the edge of the original plywood and the heat-application wood veneer. I used multiple layers of the veneer to both smooth out the edges and scale up the disk to go beyond 24". In the second shot I have spray painted the base with white primer, which has smoothed out all the brushstrokes, sanding marks and completely hidden the edge of the veneer. Moving on to the facets.

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I bought a gallon can of Bondo to make the crystal facets, and so far it has overall been a success. As a newbie to Bondo I'm finding some of the pitfalls of it's use, for example being better about running something along the corners and edges after the Bondo has been poured in to take out all the bubbles.

I've also learned not to get textured plastic bowls in which to mix because they can create little sections of non-hardened Bondo. I also didn't realize how much heat the Bondo would put out. This softens the oil-based paint that I used to make the paper watertight, and can tend to make that stick to the hardened Bondo. I have a tub of beeswax furniture polish that is a good release agent, except where the Bondo didn't harden.

The central pyramid has a hole in it because I wanted to cut away a section that had a lot of non-hardened Bondo. I will fill it in tomorrow when I make more batches. I'm hoping the paper molds will last until I get all the copies I want made. I want to have at least one spare of each element. I think if I want to go ahead and keep making these, it would be best if I make "perfect" versions of each element, and then make a Bondo mold of each. I believe such molds will be able to hold up better than these paper ones will be able to.

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Bondo is awesome, except for the smell. My neighbors knocked on my door asking if I had had an accident or something. Since I already had the smell in my place instead of leisurely creating a piece or two at a time I powered through and created all the rest of the pieces today, plus a couple of spares. Instead of fixing the messed up sections it really took less time to just make new ones. Now I have to spend some time sanding them smooth. The amount of heat generated by the curing Bondo proved quite hard on the Rustoleum paint I used to waterproof the molds. It came out stuck to some of the sections, more as the process went along and the paint became more and more damaged.


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Awesome ! but you really shouldn't be doing bondo inside. the fumes and dust are not good for you. safety first. and we would like to keep our prop people around for a long long time...:thumbsup
 
Just got back from a week in Vegas for a work conference. The pieces have had 5 days to harden and, hopefully, outgas more chemicals. I sanded all the pieces with 100 grit sandpaper to flatten all the sides up, and then with 180 grit to get a finer surface where called for. I didn't photograph that process because I didn't want to expose my camera to that dust. I also wore a dust mask and eye protection so I wouldn't inhale it, and did all the sanding outside.

Last night and this morning I used PC.7 epoxy to fill as many bubbles I could find, rebuild hard edges and points where the Bondo didn't fully flow into the molds, and strengthened the insides where the Bondo was too thin. I also built up many of the bottom edges to make a thicker surface for attaching the pieces onto the mounting disk. It takes a lot longer to set up than the Bondo, but that was an advantage because there are so many little issues to fix. A bag of plastic gloves and another of disposable plastic bowls has kept my cleanup to a minimum.


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So now I'm learning about Bondo shrinkage. At first I thought I was sanding the elements too harshly, but then I lined them up on the base with the overhead printout and learned that, no, it's not me, they all shrank at the same rate. When I set the pieces inside the paper cutout versions I made I can really see how much smaller they have become. Good thing they sat for a week: I would hate to see what would have happened if I had started using the PC.7 epoxy on them before they shrank to their final size. As it is, I'm just hoping that there won't be any more substantial shrink problems in the future. I don't like the gaps in between the elements, and I don't want to cluster them around the center of the base and leave a bare circle around the outside. My solution is to build a base for each element out of wood pieces glued onto paper cutouts of the base of each element. I'm relatively confident that wood and paper won't shrink. When I have finished with each base I will glue each element to it's corresponding base, and then fill in all the holes with more of the PC.7. Then it will be sand patch sand patch sand. I will need to be careful when sanding, not to sand inside the paper glued to the bottom of each base.


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Work since Christmas. I sanded all the bondo parts down to correctly fit on the wooden bases. That meant I sanded off all the red paint.

I sealed the pieces with several coats of water-based varnish I had on hand so that when I painted them the wooden parts wouldn't swell. It also fills in the very many small bubbles in the Bondo. I've been having to do a lot of hole patching and bubble filling using the dark-grey PC7 epoxy filler. This filler seems to be harder than the Bondo. Bondo holds in a lot of air pockets, and as I sand these I break through into new air pockets again and again. Sometimes when I'm sanding I start getting swellings in the surface, where I've sanded the surface so thin over the bubble that it starts to balloon out. So annoying: I have to carve away the entire bubble with an Exacto knife so I can fill it in with the PC7 and then sand it flat again.

Finally the bulk of sanding is done and I've painted them red again with water-based Rustolium paint. I'm painting and then sanding them over and over with finer grit sandpaper to try to get the faces as flat as possible, and to fill the pesky air bubbles that seem to keep coming through.

I'm hoping to get all the pieces to a point where I can use spray paint and smooth everything out for a finished piece.


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