Random thought.

"Rainbow" (rainbeaux) 02/19/2016 at 10:22 • Filed to: None

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I realize it would be difficult to build and maintain, but would it be legal to use lava lamps in your taillights? It would be exactly the right amount of retro-stupid-awesome for a ‘70s van with portholes and shag carpet. I’d think it could be made to work by using red gel in reddish orange liquid, or vice-versa, and having it heated partially by the exhaust in order to keep it flowing during the day as well. (not redirecting flow, but possibly adding an alternate pipe on each side that goes up and out around the light. Still allowing the gases to escape directly backward, but giving an alternate route to just take whatever’s left over.) I can’t see a reason for it to be specifically illegal, but I’m not sure. It would be a fun project if I ever end up owning something like that. (And, of course, it will have a wizard riding a unicorn on the side. That’s a given.)

Grindintosecond > Rainbow 02/19/2016 at 10:42

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Problem #1: the time it takes a Lava Lamp (God bless Edward Craven Walker ) to heat up the blob of wax so it rises and falls within the limits of thermodynamic heating. It rises from heat and falls from cooling up top.

Problem #2: there really isn’t a problem 2.

Good idea,, but for most of us, it wouldn’t work so well unless on long road trips or for long haul truckers.

Urambo Tauro > Rainbow 02/19/2016 at 10:42

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Sounds cool, but trying to get DOT certification for road use would be a nightmare...

TheRealBicycleBuck > Rainbow 02/19/2016 at 11:04

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There are two factors limiting the feasibility of this idea. First, a shaken lava lamp is a mess.

Second, the temperature range at which a lava lamp functions is very narrow. I learned this from the lamp on my desk. The a/c vent blows onto my lamp and cools it just enough to make it stop working. I drop a styrofoam cup on top of it to capture enough heat to make it work again. As it cools down, it makes some pretty crazy formations.

RamblinRover Luxury-Yacht > Rainbow 02/22/2016 at 14:30

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I missed this thread, so I’ll put in the how-I’d-do it now: First off, RealBicycleBuick is right that being shaken would cause trouble, but the coolness comes of being able to have it parked somewhere, not so much while driving. So that’s not a problem - the starry looking splatter of blobs just needs to pass enough light while driving. The second part, that temp that has to be really tightly controlled, can be handled by a 12V water heating element on a thermostat, so the (sealed) bath on the bottom has a lot of thermal mass to make sure it heats up and stays heated up properly. You’d basically need some kind of cup you could seal to the bottom of the lava lamp internal bottle.

The heating element is pretty easy, just ransack a 12V coffee maker. It might even have a good setup for the “cup”. *Or*, you ransack 12V fridge/heater coolers - I got one at Goodwill not long ago for cheap. The only trick is the thermostat wiring and getting the right temperature set. So how do you make the top cool enough to make the lava lamp work? Probably stick it to the chassis metal with a big mounting bracket. If the top isn’t cool enough, you could use a 12V cooler also on a thermostat (same piece as in the 12V fridge/warmer - what’s called a Peltier plate).

Finally, lights. Pretty much you would just need a set of LED lights up in the bodywork behind the lamp so they’d shine through in normal taillight mode. For operation more like a proper lava lamp, you’d either make a sealed block to go in the cup (which wouldn’t be bright enough) or just put diffuse lexan behind the bottle in the bodywork and lights behind that.

The best part about using the whole area behind the bottle is that you could put in really complicated multi-color LED setups to use while the van is parked.

Anyway, no way is any of it street legal, but it would be possible to get a really good result for pretty cheap. For a less spectacular effect, you could do it on a Corvair van with the bottles sideways...

A later 60s ChevyVan or Econoline would probably be a better bet, though.