Randomfox Posted January 1, 2013 Posted January 1, 2013 So a friend of mine got me into doing a short fantasy-themed movie thing with him, and part of the plot involves a, as the title suggests, a flaming sword. So my question is, are there any transparent / translucent oils (or other treatments) which would be flammable which could be applied to 1060 steel and produce blue/blue-white flames? And then secondly, with that oil/treatment what form of remote ignition would be best? Oh, and before we really need to get anything as far as safety, the scene it is flaming in is while it's in a stone slab ~20 feet away from the actor in the scene as it is currently planned out.
dagabu Posted January 1, 2013 Posted January 1, 2013 (edited) We have Arms and Armor here in the Twin Cities and they have made oodles of arms for movie props including a flaming sword that had to only burn on the edge. There were two blades made, each 1/3 the regular thickness of a normal blade, one full width and length, the other 1/2" narrower and shorter. A 1/8" thick piece of nomex cloth was sandwiched between the two blades, riveted in and polished so you couldn't see them anymore. They made four swords for the movie, three with the Nomex cloth and one just steel for close ups. The sword was dipped into a mix of alcohol and lamp oil, soaked in and wiped clean. Only the edge burned and it stayed lit for a couple minutes each soak. I was working next door at the ceramic shop in the 1980's when they were at their haydays and got to see them playing with all sorts of fun stuff when on break. You will see a whole crap load of their work if you go to the PGI site a week earlier at the Pennsic Wars in Butler PA. -dag Edited January 1, 2013 by dagabu
Arthur Posted January 2, 2013 Posted January 2, 2013 Do you have alcohol hand sanitiser? It's ready gelled and being mixed alcohols it burns well. Alternatively a gelled diesel (napalm!) will burn longer and hotter. Do NOT heat the real sword as you will kill the steel's temper and it may never look right again. SFX would be to use a dummy sword and have a supply of gel to hand. light with a propane flame (Rothenberger plumbers burner) Edit the "film" to cut the lighting procedure out of the finished final cut. Alcohol gel used as flame paste must be lit before it evaporates which is seconds. Gelled diesel petrol or kerosene lasts longer while waiting
dagabu Posted January 2, 2013 Posted January 2, 2013 Do you have alcohol hand sanitiser? It's ready gelled and being mixed alcohols it burns well. Alternatively a gelled diesel (napalm!) will burn longer and hotter. Do NOT heat the real sword as you will kill the steel's temper and it may never look right again. SFX would be to use a dummy sword and have a supply of gel to hand. light with a propane flame (Rothenberger plumbers burner) Edit the "film" to cut the lighting procedure out of the finished final cut. Alcohol gel used as flame paste must be lit before it evaporates which is seconds. Gelled diesel petrol or kerosene lasts longer while waiting It won't stay on the steel, it becomes a liquid from the heat. Been there... There are no teat treated swords out there commercially, it is just to damn expensive to do so. Heat away! -dag
NightHawkInLight Posted January 3, 2013 Posted January 3, 2013 It won't stay on the steel, it becomes a liquid from the heat. Been there... There are no teat treated swords out there commercially, it is just to damn expensive to do so. Heat away! -dagThere are many heat treated and hand forged swords on the market, though perhaps none that are mass produced. Heat treated or not heating the blade is likely to at minimum change the color, whether by tempering the steel if it were to get very hot, but more likely just by whatever chemical is used tarnishing the metal with carbon as it burns away. Napalm would be a bad idea, as it will not burn away entirely and leave black hardened plastic on the blade that will never come off without sanding. Sterno might be a good choice, though the flame burns rather clear without a coloring additive. If it's too hot and melts away, cool the blade before hand.
dagabu Posted January 3, 2013 Posted January 3, 2013 There are many heat treated and hand forged swords on the market, though perhaps none that are mass produced. Heat treated or not heating the blade is likely to at minimum change the color, whether by tempering the steel if it were to get very hot, but more likely just by whatever chemical is used tarnishing the metal with carbon as it burns away. Napalm would be a bad idea, as it will not burn away entirely and leave black hardened plastic on the blade that will never come off without sanding. Sterno might be a good choice, though the flame burns rather clear without a coloring additive. If it's too hot and melts away, cool the blade before hand. Again, commercially. The fuel will not stay on the blade when in motion, been there done that. But please try it and see. -dag
NightHawkInLight Posted January 3, 2013 Posted January 3, 2013 Again, commercially. The fuel will not stay on the blade when in motion, been there done that. But please try it and see. -dagThe sword is going to be stationary according to the original post.
AzoMittle Posted January 16, 2013 Posted January 16, 2013 Didn't personally build it but worked in a team once where we needed one of these. The basic setup was essentially a sword Ruben's tube. The sword was about half an inch thick, yes it was heavy, with a hollow core and holes running along the edges. The handle of the sword had a flashback regulator, though I doubt it was necessary, and was then hooked up to a propane tank. Keeping the camera a decent distance and not moving too fast did the job; it did have a certain 'staggered' look to the flame due to the distance between the holes but this was smoothed out in post production. I didn't personally work on it so I'm afraid I don't know the exact details but a google search for Ruben's tube should give you a starting point.
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