Indicate!


Last year I got my friend, Scott C., who owns a CNC milling machine, to make me a master Fuel Rats plaque – it’s 18″ across.

Making the mold for that thing took some work and about a gallon of silicone. When you’re doing a casting like that, you want to be very careful to dig all the air bubbles off the surfaces so there are no holes in the mold, and to degass your mixed silicone in a vacuum chamber before you start pouring it. My casting was good and bubble-free and clean.

I mixed a half a spoonful of alumilite gold pigment into the resin, then took a paintbrush and gave a fine coating to the silicone. The resin I used was “accu-color” clear polyurethane (much cheaper than the water-clear stuff!) – it sets up fast and runs up to about 200F while it’s curing – you have about 50 seconds to combine the resin and hardener and pour it gently but quickly and smoothly into the mold. Hint: make sure molds this large are on a levelling plate or a large board with wedges under the edges so you can adjust the level quickly and easily.

It takes only about 15 minutes for the resin to be rock solid. Be conservative and let it sit overnight if you’re not making massive fast production runs.

There are some bubbles in the edges where the gold pigment dust appears to have trapped some air. That casting is about a quart – about a liter – of resin, $25 worth. Screw-ups with large castings are not good.

The Fuel Rats asked me to make a plaque and send it to someone who had an amazing achievement (I will get to that) so I couldn’t send a plaque that was not top notch. So I spent 45 minutes cleaning the gold out of the silicone with soapy water and let the mold dry overnight so I could try again. Make sure you don’t get water in contact with urethane resin, it’ll foam up and be crumbly when it cures.

My favorite plaque look is steel and bronze. You can get powdered steel and powdered bronze on Ebay. It’s not cheap but it makes the resin heavy and metallic. It also needs to be polished a lot with steel wool to bring out the metal texture. It’s hard and dirty and tiring of one’s hands, but the results are worth it:

The Fuel Rats: We Believe It Ain’t Dead ‘Till It’s Overkill

Who earned this plaque and why? CMDR Malibu gets the plaque. A group of players drew a Fuel Rats logo on the galaxy by plotting their travel over the course of 1 million light years of in-game flying. A rough rule of thumb in Elite is that 1,000ly takes about an hour to fly. This was not a small effort.

You’re our kind of crazy!
o7, Commander

Comments

  1. kestrel says

    That turned out *great*! Well worth the effort. And congratulations to CMDR Malibu, what a creative and clever thing to do. Love it!

  2. komarov says

    That’s pretty impressive. As a curious layaboutperson I have to ask where that concentric ring pattern comes from. Is it a tool mark from the mold? Because the mold looks smooth (or at least unpatterened) in the picture.

    The flying is impressive, too, not least since I haven’t done much beside fly a stripped-down mining brick whose interstellar capabilities were mostly hypothetical.* But the logo looks a bit sinister when superimposed on the galaxy. Are you sure the fuel rats don’t secretly run the place? Today it’s “We’ve got fuel…”, tomorrow it might be “We’ve got all the fuel.”

    *Ah… grind.

  3. says

    komarov@#4:
    I have to ask where that concentric ring pattern comes from. Is it a tool mark from the mold?

    Those are the marks from the end-mill that cut the master. Silicone molds are amazingly accurate and resin castings are, too – the marks are maybe 1/10000 of an inch but they’re visible. You can’t feel them with you fingertip but you can see them. It’s pretty cool. I’m not sure what one would do to get those marks out; probably another CNC run with some kind of ultra-fine abrasive or burnisher.

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