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shorty
04-22-2003, 12:48 PM
Just a quick question......If you fill an exhaust pipe sith sand, plug both ends, heat and bend the pipe (controlling the colapse through the width) will kinking be eliminated??????
Thanx,
Shorty

Joel
04-22-2003, 03:31 PM
Yes.
But if there is ANY water in the sand, it will turn to steam and create serious pressure.
Be careful, Joel

SJorgensen
04-22-2003, 04:00 PM
Also I think if you put a wire in the pipe you'll have a much easier time removing the sand. Of course if the sand is properly dry and has no binders like casting sand, it will just pour out.
Spence

shorty
04-22-2003, 04:04 PM
Thanx guys....
I was thinking of using silica sand like the kind for sand blasting......I don't know if there are any binders in that type of sand but I'd assume not.....

gamachinist
04-22-2003, 06:21 PM
Hey Shorty,if you heat that silica enough do you think you'll get glass packs(vroom vroom)?Robert.

shorty
04-22-2003, 06:54 PM
LOL!!!

wierdscience
04-22-2003, 09:43 PM
I saw a guy do it by sliding a garage door spring into tube heated and bent to the shape he wanted and pulled the spring after it cooled, worked good.

shorty
04-23-2003, 02:04 AM
that's pretty cool......I'll have to check the i.d. of the exhaust pipe I've got and start scopin' out the neighbours garages....Hope they don't get too suspicious when I start measuring up their springs!!!

wierdscience
04-23-2003, 09:52 PM
Ya it does work leaves a few little wrinkles but hey theres always a few,guy that thought it up is a geuine wild man,he was kicked out of the Army in Vietnam for selling Heliocopters,I never asked which army!He tends to fixate on some ideas like the spring thing so far I count about ten uses for them and more evryday.Rascal even used them to counter balance the tailgate on his utility trailer.Picked up on the punkin chunkin idea too,this should be interesting http://bbs.homeshopmachinist.net//biggrin.gif

shorty
04-23-2003, 10:19 PM
What the heck is punkin chunkin.....?????

docsteve66
04-23-2003, 11:10 PM
Shorty: Do a search on "punkin chunkin" or go back to posts made on 02-15-03. You would not believe it if any one just gave you the basic facts. And anvil shooting is a good read also.

wierdscience
04-23-2003, 11:20 PM
Watched an anvil shoot at a tractor pull not too long ago got the crowd kinda pissed kept setting off everybodys car alarms http://bbs.homeshopmachinist.net//biggrin.gif

CCWKen
04-23-2003, 11:21 PM
Down here in Texas, we have "Chip" tosses. I remember back in the old days, we made tennis ball canons. (Much cleaner).

docsteve66
04-24-2003, 01:43 PM
What did you shoot the tennis balls with? I tried propane/air, singed the fuzz right off.
If you like booms- someone suggested setting up Oxy/Act torch for best burn, blow up a balloon and it explodes. Never tried a balloon,but (as result of the suggestion) I did it with a condom. Condoms work nice too http://bbs.homeshopmachinist.net//smile.gif.

When Gson gets a little older, I intend to try use some battery acid, water and battery to decompose water, but catch the gasses in a single container and detonate it. The enegry produced should be near what it took to de-compse? right/wrong? Law of conservation of enrgy unless the solution becomes warm. Volt amp meter to compute power in, (watts to calories/btu) and give some idea of what that many calories does when expended in a hurry. No sweat, I will use a remote to trigger things.
Steve

BTW, if you have the power availalbe, I think exhaust pipe packed with sand and capped can be bent cold. Any sort of vent should get rid of the steam problems. Tube will surely swell before rupturing.

shorty
04-24-2003, 04:03 PM
We use oxy/acet in a 3" pipe with a wee iddy bitty hole in the end then we stuff a shop rag in the tube and shoot the rags at the grapples goin by on the highway........BIG BANGS FOR THE BUCKS!!!!!!!!! Probably 40 -60 feet.....now if a guy was to WET the rag.....hhmmmmmmm

wierdscience
04-24-2003, 09:26 PM
Did the car battery and bang thang what a riot!30gallon plastic trash bag duck taped to the top and a lit match tosed from a distance and pop!!!!!!neat thing about it water breaks down in the right mix.Also did the ox/hy in a milk jug trick,in the city it attracts cops though! http://bbs.homeshopmachinist.net//biggrin.gif http://bbs.homeshopmachinist.net//biggrin.gifHmmmmm.... must have been a car backfiring officer http://bbs.homeshopmachinist.net//wink.gif

Weston Bye
04-24-2003, 09:28 PM
A fellow I knew was visiting his dad on the 4th of July. Dad says to him and brothers: "come watch this". Into the garage where the oxy/acetylene torches were. Proceeds to fill a garbage bag with gas. Before he could finish filling "something" (static electricity?) sets the thing off. Ruptured eardrums and singed hair of all present, blew out the windows and puffed out the back wall of the garage. Was heard in town, several miles away. The cops showed up. The story made the newspapers. Didn't quite qualify for the Darwin award. Could have wiped out a whole family before they reproduced.

Wes

Weston Bye
04-24-2003, 09:31 PM
A fellow I knew was visiting his dad on the 4th of July. Dad says to him and brothers: "come watch this". Into the garage where the oxy/acetylene torches were. Proceeds to fill a garbage bag with gas. Before he could finish filling, "something" (static electricity?) sets the thing off. Ruptured eardrums and singed hair of all present, blew out the windows and puffed out the back wall of the garage. Was heard in town, several miles away. The cops showed up. The story made the newspapers. Didn't quite qualify for the Darwin award. Could have wiped out a whole family before they reproduced.

Wes

wierdscience
04-24-2003, 09:59 PM
Ouch!I don't ever play with acytlene cause it don't play, that stuff accelerates faster than TNT and tends to go off by its self over a certain pressure.I did do something stupid with it though,a coworker and I were getting some 30'sticks of drill pipe out of outside storage and one of them was full of wasps(the kind that get pissed easy and like to sting anything in reach)so I got the bright idea to give'm a little gas and light'm up,only thing is I also gave them a healthy dose of ox and bang!rust flakes and drill mud went evrywhere,our ears rang for two hours!

ttok
04-26-2003, 01:39 PM
Acetylene is dangerous. When it is confined in welding cylinders, I recall that it is dissolved in acetone. It CANNOT take any pressure. It is HIGHLY unstable.

Many years ago (mid 1960's) I inspected a chemical plant which used acetylene as a feedstock. The acetylene was made in a production unit which was located about 500' away from the rest of the plant. The acetylene was transported in a special pipe(never did know what it had inside - baffles or something) with a flame arrestor every 100' or so. Special pumps (compressors??) were also used, and nowhere in the pipe or the compressor was the pressure allowed to exceed 20 psig (34.7 psia).

Acetylene decomposes (detonates) at 20 psig and 100*F. In addition, it detonates (without any oxygen) when it is kept in a container above a certain SIZE (20 feet in any dimension or greater) even well below 20 psig. This is what the nut in the garage did wrong!!! Technically, when the mean free path of an acetylene molecule exceeds 20 feet at pressures below 20 psig and 100*F, it decomposes causing a detonation. The pipeline between units in the chemical plant had some kind of internal baffle system which kept the acetylene molecules from seeing a mean free path greater than 20 feet. The oil pipe above could easily have detonated without oxygen, but it probably had crud in it which kept the mean free path below 20 feet (lucky!!) Again, inside the welding cylinder, you can exceed the 20 psig pressure because it is packed with acetone and possibly some inert material, and the welding hoses are small in diameter.

shorty
04-26-2003, 05:05 PM
Perosnally, I'd never 10 psi of acet line pressure from the tank....In welding school we were taught 15 psi is the MAX. safe operating pressure.....still makes a great cannon though....We tacked a 2' piece of 1" square tube to an I beam on an incline and then slide a 3'4 " piece of tubing into it, about 6' from the low end and put a little oxy/act to it...struck an arc at the end on the I-beam....unfortunately the tube was aimed at the electrical box....put a golf ball sized hole in the box and busted some fuses pretty bad...what is it they say....young and stupid!!!!!

abn
04-27-2003, 05:59 AM
If using an internal spring to support the bend it has to be a close fit and will be very hard to "pull" out especially with small radius high angle bends. Fabricate a puller with a T handle and twist the spring in the direction it is wound and it will decrease in diameter giving clearance to remove it.

-Pipe an Tube Bending and Jointing, Stanley P. Marks

Cass
04-27-2003, 02:30 PM
If you want a real smooth job buy "U" bends at a hot rod shop. They are so called "mandrel bent" in which a solid mandrel is pulled through the tube as it is deformed in the bending machine. Very round and no wrinkles. The U bends give you a 180 degree turn so you can cut what you need to make the turn you want. Lay things out hacksaw the U bend, tape the pieces together in the right orientation with 3-4 pieces of masking tape running the length of the tubing. Use a 1/16" arc welding rod and tack the tube pieces together. When you acetylene weld the complete joint the heat makes the tape easy to remove, you can essentially blow it off. Be sure to put out the flaming pieces. This worked very well in building "bundle of snakes" exhaust headers for race car engines. Sand and springs inside are very slow and do not produce as nice a finished job.

shorty
04-27-2003, 06:10 PM
Years ago you could buy a box of elbows (mandrel drawn) from hooker and fab up your own headers....haven't seen them in quite some time though.....