Creating a large metal sphere

[Matty mc]

Hi everyone. Can anybody give me any information on where to start when it comes to forming two hemispheres, ultimately to make a sphere out of iron about a quarter inch thick.
I have a project in mind for my house that my little girl wants and I promised to make it for her. I am very new to metalworking.... I am a plumber and I always turn my hand to anything I think is possible, but researching this has made it look a lot more difficult. You guys and girls on this forum seem to have a huge amount of knowledge so I thought what better place to come. Researching on YouTube and google has come up with a lot of different things but I guess you need to know what to type in to get the right answers to start. Any tools/techniques/materials/processes would be muchly appreciated on this topic. Thank you very much.

[swedefiddle]

Good Morning,

 

Anything is possible. Most people can't start grade school at level 4 and expect to appreciate getting to grade 12. What I am trying to say is, start simple, learn how to forge, learn how to move metal, then you will be answering your own question.

 

The problem with the internet is people want instant answers. If you don't put in the time, you won't know what you can or cannot do. Don't be afraid of making a mistake, it is not a mistake, it is a lesson. Learn from your lessons.

 

Where are you on this rock?? Post your location. There will be a Blacksmith group/guild/association near you. Don't be shy, we don't bite, become involved and you will meet the most pleasant and interesting people, regardless of what we look like. :) :)

 

Neil

[John B]

How big a sphere?

 

1/4" plate is bordering on industrial for the amatuer, so does it have to be that thick.? or solid?

 

If it is just to be appearing spherical, then you could make it from segments and weld each together, this would be more manageable than trying to make a hemisphere from one piece.

[Frosty]

Welcome abord, glad to have you. If you'll ut your general location in your header you might be surprised at how many of the gang here live within visiting distance.

You're going to need to be more specific in your questions or you'll only get really vague answers. How big a sphere? Why 1/4" material or did you arbitrarily choose it?

If all you need is a sphere 12" in dia. then it's a whole different kettle of fish than a 5' sphere. If all you need is a sphere, the 1/4" thick is excessive. A 12-24" sphere could easily be made from 16-14 gauge sheet and raised with some basic tools and a couple classes and some experience.

If I was pressed into taking on a commission like this from 1/4" steel I'd be seriously thinking of buying an old car and converting it to a BIG honking spinning lathe but unless you have a pretty solid grounding in metal spinning a person would probably cripple or kill themself trying something this scale. Goes for me too, I haven't touched a spinning lathe in more than 45 years.

Okay, so make it from manageable pieces like a soccer ball, weld and grind smooth. That I could do but whooeeee what a project! Try to raise 1/4" steel plate of any diameter? NOT without a lot of specialized tooling and at least one skilled helper to manhandle the thing.

This June I'd maybe see about casting it during the Valley Arts Council's, Art on Fire, annual public event with an iron pour.

This could be as simple as hitting a commercial fishing supply house and just buying a steel buoy and putting the finish of your choice on it. But we don't know even what size sphere you want.

This may be an easy project or something so far beyond reason as to be fantasy.

Fill us in on the specifics we'll see what we can do for you.

Frosty The Lucky.

[Matty mc]

Hi again all. My location is AUSTRALIA. I'm in Victoria which is the south east coast. Sorry for the vague answers earlier. I'm building a fire pit and that was why I chose to work with such thick steel. 1/4" is roughly what I thought if need for the strength and look I desire.
I'm not sure if yous have seen the up north fire pit that is made in the USA but if you have, that's the idea I'm trying to replicate. I don't wanna steal Thier idea. My daughter wants a family portrait in that kind of styling on the outside of a firepit. I emailed the company and asked them how the sphere was constructed and was told it was 2 hemispheres made by a steel press somewhere in the US. Ps thanks again for your replies

[Frozenforge]

Ive seen a pattern like they use on baseballs enlarged and transfered to sheetmetal shaped and welded as they formed it into a sphere, but in 1/4 plate that would be a whole different undertaking. Are you near the coast? Old mooring bouys for boats were steel spheres if you could find one of those and repurpose, modify and customize

Good luck

[Frosty]

The outdoor fire pits are common here, almost every supermarket sells them. Most are thin steel, 16 gauge or less.

 

If you don't put your general location in your header folk are going to get tired of asking where you live and eventually just stop reading your posts. Click on your "Profile" click "Edit Profile" put your general location in the location and enter. That's it, no worries mate but it'll increase the chance you'll get results.

 

The gang from down under on IFI is pretty large but if they don't know you're close by what difference does it make?

 

Frosty The Lucky.

[HWHII]

Here is a photo of what you are looking for. What you need to do is find a company who makes spun heads for tanks and pressure vessels. This one is 30" dia. and 10 GA thick. You can buy them in all different sizes, But only a few in spheres. I buy mine from a company in Ohio. If you are lucky you can buy seconds. These are heads that come of the machine during set up for a run. They don't meet specs or code and they are just scrap. My supplier sets them aside for people like us who like to make fire bowls out of them or art. It is harder to get seconds any more because when they have them they go fast, first come first serve basis. You can always buy firsts though, but the price is double and the shipping will get you too. For me when I have bought them 200lbs is where you get your first price brake on shipping. Hope this helps!

[Dodge]

Welcome Matty. I see that you are in Victoria, Au. Member Dale Russell is also from Victoria if I remember correctly. He is an experienced smith and again, IIRC, teaches some new smiths. PM him he could be you neighbor :)

[Jacques]

My brother also send me a link to Up North last week and also would like one.

 

Making something like that in 6mm steel is going to be a mission, but I am considering making it from 2mm thick stainless.

 

I'll have to do a CAD drawing to figure out the sections, cut it out with plasma and then use the Trumpf with the doming tool to form each section and then welding it up.

 

All this is absolutely theoretical, I just do not have time at present.

 

Good luck on the project, we would like to see pictures.

[David Gaddis]

Have an experience person remove the ends from a now non-serviceable propane tank from a farm or house. A 200 gallon tank should do fine. If you are inexperienced in this project it is paramount that only "well qualified" persons do the tank end removal.

 

Good luck

 

 

Carry on

[Dale Russell]

G'Day Matty ,

 

Where in Vic are you ? I'm in the Upper Yarra Valley ( near Mt Donna Buang )  

 

What size ball you looking for ?

 

Mite be able ta help or point you in rite direction bloke , drop me a PM & we'll see what can be done

 

Dale

[Mark Emig]

I talked to a guy once (very skilled smith), who said they used to weld plates together with a spacer between them around the edge, fill it with acetylene and oxygen and blow it under water with a spark plug threaded in for ignition. He told me he did it after he found out that bathyspheres were originally made like that. Sounds pretty nuts.

[naturalsteel]

I've made a few fire pits like this from the aforementioned propane tank ends.  I've gotten my 3 foot diameter hemispheres from Propane companies.  When they take them out of service, they have to cut them up so it pays to get to know the guy who does this so he'll save the ends in a usable form.  If you're friendly enough they'll sell it to you for scrap prices.

[jawno]

I saw a bunch of tank ends in a scrap yard in SLC, Utah when i was there last year on vacation. I went in and asked about buying them but didn't have the room to haul them. Hoping to get some next time I visit. They were asking like fifty or seventy five bucks depending on condition and maybe size.

[forgemaster]

How did you go with getting your sphere? Any luck. Did you give us a size you were looking for?

[ThomasPowers]

Propane tank ends!  I was given a 14' long tank just for that purpose.  Do purge them and cut them safely though!!!!

[Matty mc]

Hi all. And thanks again for all of your input. I have been sidetracked from this the last week or so but I really appreciate all replies.
I am in mornington,Vic. I am looking more into the whole idea of buying an old cylinder or maritime buoy, as the whole process of making it from scratch sounds crazy for me at the moment.
The thickness doesn't have to be exactly 1/4" but I want something ultra sturdy and of good size.
Next task is finding the old buoy or cylinder and that's me started.
Cheers.
Matty mc

[Bentiron1946]

I don't know about in AU but here in the US I can buy new tank ends, no danger from propane, a little more expensive but safer, also just a catalog item in most cases. Then there is pipe caps, the big ones, for 24" schedule 40 steel pipe, kind of expensive but perhaps if you went to a scrap yard you could find a section of pipe and cut a cap off. Good stuff that schedule 40 and thick!

[Frosty]

contact the bulk propane supply companies within reasonable distance. The supply the gas and the tanks. they will have tanks they have decommissioned. You can probably get what you're looking for for scrap prices. The ONLY hazard you'll need to worry about is dropping one on your foot.

 

Frosty The Lucky.

[ianinsa]

I talked to a guy once (very skilled smith), who said they used to weld plates together with a spacer between them around the edge, fill it with acetylene and oxygen and blow it under water with a spark plug threaded in for ignition. He told me he did it after he found out that bathyspheres were originally made like that. Sounds pretty nuts.

 

If your pool has become a pain in the proverbial & you want a long holliday at the state's expence at some undisclosed location... Try this at home!

 

P.S. If your wife proposes that you try this method you'll know that she does not want a divorce and maybe you should stop eating those mushrooms she picked for you.

[Bentiron1946]

That's a good one! Vacation at states expense! I have an acquaintance that make expandable sculpture out of steel(thin)plate, welds the seams closed, welds in a valve, then connects it to an air compressor, applies heat to the panels and watches it expand and hopes it doesn't explode. Paints the panels in vivid colors and sells it to unsuspecting collectors, really it kinda nice but I think you want something thicker than what he uses.

[Frosty]

Explosive forming is no doubt fun. Using compressed air and heat is fun but can get exciting sometimes.

 

If you have a good pressure washer you can plumb a quick connect to the project and if a weld breaks all you'll get is a spray of water, nothing flying in the air. If you're concerned about pinhole leaks (they ARE dangerous) put it in a tank of water or pond. The pressure gauge will tell you if it leaks or pops a weld.

Frosty The Lucky.