COMMUNITY : FORUMS : SQUARE PEGS

yes i do think this is one of the things you dont want to try at home you could get put in the hospital for crying out loud!

part of the problem is getting the plastic to last long enough to pump up.

if a super soaker had a water pump, this would make it safer-but not by much. get away from the idea that pre-made plastic items are going to be safe. at best, you need an auto store or junkyard for gas-safe plastics. remember-if you can get wet using it, you might as well be dead.

A) The plastic you are looking for is called "HDPE" (plastic gas cans)
B) Super-Soakers are commonly made from "PETE" and "LDPE".
C) Neither are particularly vulnerable to gasoline as they are to acetone.
D) Flame cannot possibly even get sucked into a nozzle that small.
E) Learn your plastics: http://tinyurl.com/2ctgfu
F) Making a watergun shoot flammables is never safe anyway, so don't even try it unless you are going for the Darwin Award!

soz for double post but had to say: if i poured sulphuric acid on you, would you say "oh well at least it isent nitric acit whitch would eat away my skin much faster" or: oh shit i'm gona die if i dont get this of me quick!

I'd much rather nitric acid over sulphuric acid. Concentrated sulphuric acid does nasty things to orgainic material, concentrated nitric gives you time to wash it off before any grave damage is done. L

asuming the same molarity and that you'r not wearing clothes, both are equaly corosive when at the same acidity (sulphuric is diprotic) although it also dehydrates the skin on contact, turning it a browney black and halting its progress.
this is why i would prefer nitric, although nitric mixed with sulphuric would be much beter as it wouldn't get as hot. and would form the same protective layer.

Not sure what you mean by this post, but there is such a thing as "quench-space" for any form of combustion, this is why too high a compression ration in an engine can cause it to be nothing mroe than an air pump. Gasoline is not an acid, it is an alkali....

a flame can get suked into a nozle 60 microns in diamiter ie. thare aint no nozle small enuf 2 stop that flaming sonovabich from exploding. if reacting atoms/molecules can pass through it then sustainable burning can ocur. also you need to think about how presurized soaker chambers work as it is esentialy the same as the combustion chamber in a car (all it need is an exhoust and a spark plug ;) ps. dont do it people its just to dangerous for the hasle. (unless you have a death wish, dont make a bloody explosive flamethrower.)

yes there is, it's called oxygen, your gas can't burn without it. that's why only gas fumes only burn and not the liquid itself. plus, if you put vodka or rubbing alcohol in the gun, it would work beter lol.

wow didn't expect people to still be commenting on this discussion.
petrol can burn as a solid liquid or a gass, tests have been done with octane and decane on the efects of volatility on combustion.
what i think you meant is that it doesn't tend to burn as a liquid.
when you pump up a water gun (not including the rubber blader veraity) you are forcing air into the chamber. this creates a fuel/air mix whitch is known to be eplosive. roughly 5 drops of octane in a vaporised mixture with air, is capable of creating an explosion with the same destructive efect as half a stick of dynamite.

some plastics used in water guns are soluble in ethanol. hence the same problem as octane. if you want to do this and insist on not modifying/rebuilding the gun. at least grab a bottle of argon from some welding suplier and use it for the air input. at that point you'r above statement would be true.

ps: paintball "nitrogen" canisters are actualy compressed air and so contain oxygen, therefore cant be used to make air intake safe.

The fuel mix inside the tank is too high to support a rapid reaction, it simply doesn't have enough oxygen to burn in the tank. On the other hand gunpowder which has its own oxygen or oxidising agent (KNO3) can burn in a container producing explosions.

flame cannot burn through .60 MM holes much less 60 microns...This is why some high-proof alcohol bottles have screens on them. Even faucet screen is more than a 60-micron opening.....you do know what a micron is, don't you?

http://en.wikipedia.org/wiki/Micrometre

Do your math before you post something so absolute please...

the efect of the screen is to avoid a fuel/air formation within the bottle, allowing it to burn, this happens because the volatile liquid is constantly producing vapor so forcing air out of the bottle.
yes i do know how big a micron is. if you still think a flame cant be passed through 60 mesh, grab a glass bottle, fill it a quarter with propane gass, then top it up with oxygen. place 60 mesh over the mouth of the bottle and try and light it. gf you'r face.
i take no responsibility for what you decide to do based on my advice.

Link above is to a PDF document BTW

try again? the edge of the liquid is what vaporizes and burns.

If theres a mist, all the droplets are apart and wont feed back into the tank to explode. If its a steady stream, it will. Its this same concept that doesnt make you get electrocuted if you pee on the third rail of a subway. It's also why fire breathers have to get their blowing into the perfect mist before they actually use fire and flammable liquid.

ok, um, that's two very different things. electricity is conducted by touch-a broken stream of droplets won't conduct (but may be close enough to reduce resistance enough that sparks can bridge, so don't test your theory. accidentaly peeing on an electric fence is one thing, third rail is in a different class). fire needs air (or at least an oxidizer). fire breathers need to have a mist to maximize the surface area so that all the fluid burns quickly. if they don't exhale fast enough, the flame travels back into their mouth (flame propagation rate-basicaly how fast something burns). in this case, IF your supersoaker doesn't explode (gas softens many plastics) or dribble all over your shoes, the last shot is going to be air with a significant amount of gas vapor-an explosive mix that will travel into the tanks and explode. to try to say it a different way, a glass full of gas will burn only at the surface-pritty, smoky, hot, but not to dangerous. a room filled with gas vapor will explode as all the molicules and droplets burst into flame at (nearly) the same time.

Actually, most fire breathers have it much safer than it appears... they use kerosene (paraffin to the brits among us) as their fuel source (if they're smart). By and large, they don't have to worry about the fuel igniting in their mouths because kerosene doesn't burn well as a pool of liquid, and is nowhere near as volatile as gas (petrol) or white gas (meths). The real dangers of fire breathing come in a few different forms... 1. fire breather inhales directly after emptying mouth, or with mouth partially full and gets burning kerosene inside lungs 2. wind changes and either forces flame into face or into mouth 3. burned lips from dripping fuel 4. cancer or poisoning from fuels that are not pure kerosene (naptha is nasty stuff) none of this applies when breathing fire with alcohol, however. The alcohol is much more volatile and can easily fill your mouth and lungs with flammable vapors. BREATHING FIRE WITH ALCOHOL OR GAS IS VERY DANGEROUS. The other issue with alcohol is that any proof that will burn well enough to breath fire with will also be strong enough that a significant amount of alcohol will be absorbed through the tissue of the mouth... you can easily find your mouth numb, or yourself tipsy without ever having swallowed and believe me, you don't want to breath fire with numb lips. the biggest issue with a steady mist is simply getting a good fireball.

yes and no. it is dangerous but if you exercise common sense you should be ok

more like a self immolation device. it might squirt burning gas, it might leak gas all over you, it might fail under pressure covering you with gas while you are holding a flame, it might just have the nearly empty tanks explode near your face. there's what, 4 or more types of plastic in a super soaker that could fail (tanks, seals, valve/trigger group, tubing, nozzle...), the joints could leak, plus things like filling and emptying it (under pressure or not), spills, bad gust of wind, splash effects... you can make a safe flamethrower, but not out of a water toy.

your right there are so many ways to make a safe flamethrower but out of a kids back yard toy now dont we all think thats crossing the line a little bit

oh my god u must be an 8 year old mental patient to think you need an exact amount of air per fuel.... ANY AIR AT ALL WILL BE ENOUGH TO MAKE THIS INTO AN AIR FUEL BOMB (asuming the air you have in your ward has oxygen in it :P) also be aware that alchohol is a solvent and so will disolve the plastic unles you custom make a water pistol from a plastic whitch is not soluble in petrol (very hard) when that thing blows your arm of, and soaks you from the explosion in burning petrol, as you run for your life, a burning beacon on the back lawn of some estate in london... DONT COME RUNING TO HUG ME!

Since when does alcohol dissolve plastic? Hydrocarbons and petroleum distillates dissolve plastics. Not alcohol.

soz just got it wrong way round (i ment petrol when i sed ethanol -alchohol-) but the same combustion ocurs whith vaporised alchohol as whith petrol

YES

i saw one on youtube.

see above

right, im asking whats different between the plastics.

from
http://en.wikipedia.org/wiki/Plastic

Common plastics and their uses

Polyethylene (PE)
- Wide range of inexpensive uses including supermarket bags, plastic bottles.
Polypropylene (PP)
-Food containers, appliances, car fenders (bumpers).
Polystyrene (PS)
- Packaging foam, food containers, disposable cups, plates, cutlery, CD and cassette boxes.
High impact polystyrene (HIPS)
-fridge liners, food packaging, vending cups.
Acrylonitrile butadiene styrene (ABS)
-Electronic equipment cases (e.g., computer monitors, printers, keyboards).
Poly(ethylene terephthalate) (PET)
-carbonated drinks bottles, jars, plastic film, micro-wavable packaging.
Polyester (PES)
-Fibers, textiles.
Polyamides (PA) (Nylons)
-Fibers, toothbrush bristles, fishing line, under-the-hood car engine mouldings.
Poly(vinyl chloride) (PVC)
-Plumbing pipes and guttering, shower curtains, window frames,flooring,erotic clothing.
Polyurethanes (PU)
-cushioning foams, thermal insulation foams, surface coatings, printing rollers. (Currently 6th or 7th most commonly used plastic material, for instance the most commonly used plastic found in cars).
Polycarbonate (PC)
-Compact discs, eyeglasses, riot shields, security windows.
Poly(vinylidene chloride) (PVDC) (Saran)
- Food packaging.
Bayblend (PC/ABS)
-a blend of PC and ABS that creates a stronger plastic. :Car Interior and exterior parts

Special-purpose plastics

Poly(methyl methacrylate) (PMMA)
-contact lenses, glazing (best known in this form by its various trade names around the world, e.g "Perspex", "Oroglas", "Plexiglas"), fluorescent light diffusers, rear light covers for vehicles.
Polytetrafluoroethylene (PTFE) (trade name Teflon)
-Heat-resistant, low-friction coatings, used in things like "non-stick" surfaces for frying pans, plumber's tape and water slides.
Polyetheretherketone (PEEK) (Polyketone)
-Strong, chemical- and heat-resistant thermoplastic, biocompatibility allows for use in medical implant applications, aerospace mouldings. One of the most expensive commercial polymers.
Polyetherimide (PEI) (Ultem)
- A General Electric product, similar to PEEK.
Phenolics (PF) or (phenol formaldehydes)
-high modulus, relatively heat resistant, and excellent fire resistant polymer. Used for insulating parts in electrical fixtures, paper laminated products (e.g. "Formica"), thermally insulation foams. It is a thermosetting plastic, with the familar trade name "Bakelite", that can be moulded by heat and pressure when mixed with a filler-like wood flour or can be cast in its unfilled liquid form or cast as foam, e.g. "Oasis". Problems include the probability of mouldings naturally being dark colurs (red, green, brown), and as thermoset difficult to recycle.
Urea formaldehyde (UF), one of the aminoplasts and used as multi-colorable alternative to Phenolics. Used as a wood adhesive (for plywood, chipboard, hardboard) and electrical switch housings.
Melamine formaldehyde (MF), one of the aminoplasts, and used a multi-colorable alternative to phenolics, for instance in mouldings (e.g. break-resistance alternatives to ceramic cups, plates and bowls for children) and the decorated top surface layer of the paper laminates (e.g. "Formica").
Polylactic acid
-a biodegradable, thermoplastic, found converted into a variety of aliphatic polyesters derived from lactic acid which in turn can be made by fermentation of various agricultural products such as corn starch, once made from diary products.
Plastarch Material
-biodegradable and heat resistant, thermoplastic composed of modified corn starch.

which is why you have to know what you are dealing with.

None of the above. There is not only a flame-screen at the end of the tube, but also the valve itself aslo prevents flame from traveling through it. Remeber that gasoline does not burn. There is no way to make gasoline burn within the reaches of human technology. Gas FUMES burn. Those who know what "quech-threshold" is know why flamethrowers don't explode, and it has absoluteny nothing to do with how fast it comes out, since once you stop, you have stopped the flow but not the combustion...

Even "real" flamethrowers are unpopular with their users, due to the risk of burn-back and blow-back (where the wind brings the flame right back at you).

Flame-throwers don't explode because they pump fuel out faster than the flame burns back along the stream. The fuel tanks need to be pressurised, which is why Supersoakers are so tempting to turn into flamethrowers. Unfortunately, most easily-obtainable fuels will dissolve the plastic of the gun (plastic dissolved in petrol = napalm), and the pressure drops off so quickly when you fire that the flame can easily burn back towards the gun.

Consider this: your supersoaker is slung from your shoulder, tucked under your arm. When it eventually explodes into a ball of fire an napalm, you won't be able to drop it, and it will be burning through major arteries.

Enjoy yourself.

"you won't be able to drop it, and it will be burning through major arteries." Lol I'm not trying this. Maybe if I set it up so the trigger could be pulled remotely, but I definitely wouldn't hold it myself.

Yeah, like if it floods or something and then goes BOOM!

Hence the cynical reply lol