Re: Hydrogen Generator
Posted: Wed Dec 09, 2015 11:33 pm
Yeah, but the lawn furniture was just sitting there...pyronaught wrote:round up a bunch of scrap aluminum
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Yeah, but the lawn furniture was just sitting there...pyronaught wrote:round up a bunch of scrap aluminum
Actually, the hydrogen was not the cause of the disaster. The hydrogen contributed to the fire, but was not the major player. The paint that they used on the Hindenburg was a reflective paint that contained powered aluminum.Jules wrote:
I know, but....remember the Hindenberg and all that..........
Hindenburg was 7 million cubic feet of gas, and a big volume of it was pre-mixed with oxygen at the tail due to a ripped gas cell. Even on that massive scale a lot of people still walked away from that disaster. An equivalent volume of propane or acetylene would have done a lot more damage.
But thanks to that damn video footage, Hindenburg spawn hydrogen phobia is a big mind virus that plagues hydrogen acceptance. If there was a video of a big propane production plant exploding, would anyone be more reluctant to turn on their grill?
Seven million cubic feet of hydrogen pre-mixed with oxygen was unquestionably the major player there. If the fabric dope was that explosive, the whole outer cover would have rapidly blown off first before the rest of it ignited, yet in the video you can see the cover just slowly burning away like the inert fabric that it was. Mythbusters also debunked the "thermite" fabric dope theory. Powdered aluminum is used in all sorts of auto paint, yet you don't see cars exploding from it. The Germans who designed and built zeppelins were some top notch engineers, they would have burn tested the fabric and rejected it if it were that explosive. If you are making rocket motors then you know you need an oxidizer in addition to metal fuel for it to burn-- a very high percentage of oxidizer for explosive burn rates.lem wrote: Actually, the hydrogen was not the cause of the disaster. The hydrogen contributed to the fire, but was not the major player. The paint that they used on the Hindenburg was a reflective paint that contained powered aluminum.
For those that don't know, the solid rocket motors on the space shuttle were powered by, yep, powdered aluminum.
We use it in the model rocket motors that we build and test.
My plan was actually to go to a machinist forum like cnczone.com and offer to beat whatever the scrap dealers are paying for lathe turnings and chips. Lathe turnings would have worked very well due to all the surface area exposed to the hydroxide solution. You'd really be able to generate a bunch of hydrogen fast with a rats nest of lathe turnings submerged in sodium hydroxide solution.ednisley wrote:Yeah, but the lawn furniture was just sitting there...pyronaught wrote:round up a bunch of scrap aluminum
I generally keep mine set to 6000mm/min but I was able to double that without too much loss of quality. But that's with a Smoothieboard controller, which generally can get the same quality as the RAMBo with the speed about 50% higher (and that should be taken for the purely anecdotal evidence it is. . .). Also, I didn't shove a torture test at it for the 200mm/s run, just something fairly simple.pyronaught wrote:Since these are flat and mostly long straight lines during the print, I've been getting away with print speeds of 6000mm/min and 80% of full speed on the first layer. What is the fastest speed you guys have ever tried?
Yep, looked it up again. Old information, sorry. While clearing up points, the powdered aluminum dope is not an explosive. Even many explosives will not explode if burned in open air. Depends on density and constraint. Water is not considered to be an explosive, but plug up a water heater and have the thermostat fail, no more house.. Mythbusters also debunked the "thermite" fabric dope theory.
I always figured max speed was a mechanical limitation, such as mechanical ringing or the filament getting slung around at high speeds. How would one controller board allow higher speeds than another, are there some motion control algorithms at work there?Tim wrote:I generally keep mine set to 6000mm/min but I was able to double that without too much loss of quality. But that's with a Smoothieboard controller, which generally can get the same quality as the RAMBo with the speed about 50% higher (and that should be taken for the purely anecdotal evidence it is. . .). Also, I didn't shove a torture test at it for the 200mm/s run, just something fairly simple.pyronaught wrote:Since these are flat and mostly long straight lines during the print, I've been getting away with print speeds of 6000mm/min and 80% of full speed on the first layer. What is the fastest speed you guys have ever tried?