Has anyone ever...

[Ian Bee]

... Done this?

Welded some ends, onto say, 50 mm x thin wall round tube. Connect it up to a high pressure water unit, and then heated local areas with oxy.

Theory being, that where it goes red hot, it will swell in that localized area, that's if the water inside doesn't daw all the heat out of the unit.

I've seen dudes do this with expansion chambers, using compressed air, and it works, but I want to actually deform the tube.


Cheers


Ian

[SATAUS]

Hey Ian,

Never tried it before.
My first thoughts are that the water would boil
and turn to stem and maybe even blow up in your
face.
If you’re going to do it I would be very careful, and
maybe put some sort of relief valve in it.

Good luck and be bloody careful.

Scott

[Brian McCollim]

I think that would be very dangerous. When you change a liquid into a gas it expands at an exponential rate. If you have this confined, it will probably expand rather quickly. Also called a B.L.E.V.E. for Boiling Liquid Expansion Vaporization Explosion. I would rather see you try compressed air at a controllable pressure and then add heat judiciously to allow the material to move. This too can be dangerous and should be done with caution.

[zaraki]

hot air also expands..

take a gas-pump to pump the water pass the tube you want to deform and through a radiator back into the pump all closed up to get a car-like water-cooling system. (would need a pump-like part with a "reserve" of water that you pressure the system with when you've heated the place of the tube that needed shape)

ridiculously hard to accomplish and probably not very good end-result either, but a fun idea that i've have been thinking of as well, but scraped it sense it seems to hard do control the shape.

(first post!! i might not have spelled right or got the grammar right, please ask if got anything totally un-understandably :D)

zaraki

[olcarguy]

Sounds way to much like an accident waiting to happen. What exactly are you trying to achieve, might be better to ask how to do this rather in making a steam bomb.

[Brian McCollim]

hot air also expands..

take a gas-pump to pump the water pass the tube you want to deform and through a radiator back into the pump all closed up to get a car-like water-cooling system. (would need a pump-like part with a "reserve" of water that you pressure the system with when you've heated the place of the tube that needed shape)

ridiculously hard to accomplish and probably not very good end-result either, but a fun idea that i've have been thinking of as well, but scraped it sense it seems to hard do control the shape.

(first post!! i might not have spelled right or got the grammar right, please ask if got anything totally un-understandably :D)

zaraki

Yes hot air expands and could be enough to shape the part. Water expands at a rate (if I remember correctly) of 972 times it's volume when converting to steam. That is a lot of pressure in any system. If you set it up like a cooling system on a car, I doubt that you would have enough pressure to do any good.

[kit]

I've said it before many times here, knew a guy who killed himself with steam in a sealed pipe.

Don't try it.

[Ian Bee]

Okay...

My inner thoughts have been verbalised now by many, extremely dangerous.

What I am trying to achieve, is to make bones.

I have managed to roll the round tube, so it flattens, twists, and resembles femurs, ulnas, ribs, etc. I now want to stretch and bulb the ends, to resemble the ends of real bones.

So, if I prepare my rolled, and deformed tube, which is say... a metre long, plug the ends (tig), blow the ends out to resemble knuckles, then cut off the green and ends, seal over.... bone.

I am currently going down the road of wire forming, followed by cold galv. spray, but too expensive. Making sheet knuckles, and feathering them is a long and arduous task as well, which is why I considered pressure forming.

Cheers


Ian

[Dawai]

Two part die, shaped like you want the "expanded pipe" to look like. (a bone) to build a hydrostatic former, take a 2hp electric motor, belt drive a old chevy power steering pump tied into a water hose for fluid, it will make a 1500 psi hydro-former.. Run hose to pump reserve for fluid supply and pressure line to tube to form.

It will "blow" the tube out into the form.. and if your form can not contain it, it will explode, split, and the spray can send you to the morgue or hospital. CHICKEN in a poultry house is cut this way, with a water jet knife.. .. As a demo at the last job I looked at? they cut a glove up with one.. I was running conduit down the line there..

I'd make the form from steel..

I have saw 10 foot diameter end bells for "tanks" made this way from discs they tig weld together, hook the fitting in the middle and let it pump for two days. A way of forming something easily that other people can not figure out. That is free forming no mold hydroforming.

Do a youtube Hydroforming search. There they use a pressure washer to supply fluid..

If it is a onesie-twosie production.. I'd suggest building the ends up and tig welding it all together instead of building molds and doing all this, but if it is your desire to mass produce these..

This is slightly safer than "steam" expansion.. You could always use explosives ya know??

[Ian Bee]

"... Reason: typo// high speed wobble.. on keyboard..."

Awesome!!!

[Ian Bee]

Okay, what about this...

I have my steel bones, all curved, and twisted and stuff, with some green either end, and the ends are open.

What mechanical thing, can I put inside, to force the walls out, under heat?

Sometimes there is not a lot of room inside, maybe 10 mm. on the smaller bones.

Maybe a rod, with a ball on the end, and keep rotating it inside the tube, until I come close to the shape?

Am I re-inventing the wheel here? I am sure that what I am trying to do, has already been done by some folk.

Ian

[olcarguy]

Sounds like you are trying to make these in one piece. Simplify things and make multiple parts. Knee joints are complex, 2 or more pieces would be required and then welded together......why make out of metal, why not cream coloured plastic and injection moulded.

[Ian Bee]

Sounds like you are trying to make these in one piece. Simplify things and make multiple parts. Knee joints are complex, 2 or more pieces would be required and then welded together......why make out of metal, why not cream coloured plastic and injection moulded.

Good point! Got to be steel, as it is street art.

Doing them in halves longitudinally was also considered, but seeing I've got the forming under control, the last piece of the puzzle, is now to blow the ends out.

Still may have to use sheet, tig, and feather off, but that is not my prefferred option.

Hydro forming seemed to be the go, but it appears to be too risky.

Maybe I'll work in reverse, and make knuckle ends with larger tube, heat and knock down (shrink), then tig them onto my middle bone shapes, perhaps...

Cheers


Ian

[captainkirk]

Instead of getting "all fancy" just use a hammer and a round ball ground on the end of a steel rod (or welded if you have a welder)

I don't think it would take much time to form the ends you could even get more creative and make the sort of double ball joints like there real thing.

I know not near as much fun as blowing up the house and yourself:D

post a picture of it when your finished (we all love pictures and shiny objects)

Kirk

[Doug98105]

Here's a way we used to make simulated bamboo for an architectural project. You might adapt this technique to your project.

For this project we bulged seamless brass tube. The picture shows one test bulge. The finished bamboo pieces had two bulges close together.

The picture shows the method. 1" diameter brass tube, two prices of solid stock and a 1/4" thick disk of urethane sandwiched between them. Apply pressure and the urethane bulges the tube.

http://www.metalmeet.com/forum/picture.php?albumid=3&pictureid=5819


Tube bulging works best on seamless tube. The next picture shows a direction arrow bulged on larger diameter 321 stainless tube. This was the first test which didn't come out so well until I perfected my technique.


http://www.metalmeet.com/forum/picture.php?albumid=3&pictureid=2032

Doug

[Ian Bee]

Cool!

So, what if I packed with say... Sand?

I could weld some solid rods on the outside, where I DON'T want deformation, then grind them off after.

What pressures ae you running on your press?

Cheers


Ian

[CARS]

:confused:

No offense to David, but you are picking on someone who will do anything once (possibly more often), who is **** near telling you that you will injure yourself in some form or fashion, and you still want to expand metal with steam, water, or ??? Did I hear sand???

JMO, but you are either thinking so far out of the box (which is great if you don't hurt yourself), or you are just going to hurt yourself.

(Hell, if the King didn't make any lengthy post, I am thinking you are just trying to hurt yourself. We are not GM and we don't have access to hydro forming. Grab a sandbag and a hammer and see what you can form! I would love to see it!)

[Ian Bee]

:confused:
Grab a sandbag and a hammer and see what you can form! I would love to see it!)

Spent thirty years, in my own sheet shop, and I so don't want to do this in sheet.

I am on a home straight with the tubes, just need to flare out the ends, as per previous posts.

I still may wire form, and cold spray with a Metco, but it's not my preferred option.

Exploring options, unorthodox... yes, and I am quite aware of the risks. Just never know, someone here may have a lead on a process, which I could adopt...

Cheers


Ian

[Dawai]

Dapping block. A square block and domed punch set from Harbor Freight..
It makes round parts from sheet metal.. weld them together.. Project completed. All body parts intact. I used it on the first metal roses I made for pretty ladies.

HOW I did "rounded" roses. I cheat. I made the wife a spray of large stainless roses 12 feet long on a stem.
http://www.youtube.com/watch?v=AbjbUPlWXjs

Chris.. turns out you are my age, but not lived as long, or is that as many miles of asphalt.
If you hang on too tightly, you are not enjoying life.

[Ian Bee]

Dapping block. A square block and domed punch set from Harbor Freight..
It makes round parts from sheet metal.. weld them together.. Project completed. All body parts intact. I used it on the first metal roses I made for pretty ladies.



Awesome! I think this may have to be the go. I was messing around with the Atlas Copco planishing hammer, but it was taking too long. I've got a spare press, so I'll turn up some dies, and experiment.

Cheers


Ian