Asma Posted February 1, 2017 Share Posted February 1, 2017 Hey, I need the least complicated way to build a stainless steel hollow ball with a large radius. Like the one in the image. Can I get some ideas? Quote Link to comment Share on other sites More sharing options...
jeremy k Posted February 1, 2017 Share Posted February 1, 2017 Asma - I am not trying to detour you from this, but there are some considerations that would have to be dealt with. You will have your work cut out for you with that project, Easy / Least complicated? No easy way, the larger the project the more complicated, let alone very expensive, both in time and materials. If you try to use thin mat'ls for sake of weight - you have major handling issues with large floppy pieces and forming ( large hydraulic press with dedicated top and bottom dies for achieving the correct radius), or heavier - you have issues with forming ( large hydraulic press with dedicated top and bottom dies for achieving the correct radius) and handling large heavy pieces. For a sphere that size, the forming has to be spot on so when it's all welded together it is a constant radius. Then comes the polishing - lots of costs in different grits of abrasives and time involved to get a mirror finish - With a mirror finish, any imperfections on fit-up during welding will show up like a sore thumb. Fit-up of the welded joints will have to be less than a 1/8 of the thickness of mat'l so you have thickness to grind smooth and still have plenty of base metal for the joint. Those types of sculptures look fabulous when all done, but require a vast amount of cost, equipment, and expertise to make them look so simply done. I would like to hear more about the project you have, involving such a sphere. There is a page in the shinydecor site that gives you a rough idea on the process of how these spheres are made. It appears that they "inflate" the welded shape to get the sphere shape. https://www.shinydecor.com/news.php?id=167 Quote Link to comment Share on other sites More sharing options...
RobbieG Posted February 1, 2017 Share Posted February 1, 2017 I love that they form it up using hydraulic pressure - must be a massively beefed up version of a blow mould for drinks bottles. Quote Link to comment Share on other sites More sharing options...
jeremy k Posted February 1, 2017 Share Posted February 1, 2017 It would not take a whole lot of pressure to expand but the explosion hazard would be Huge. Quote Link to comment Share on other sites More sharing options...
Jim Coke Posted February 1, 2017 Share Posted February 1, 2017 Greetings Asma, Research floats that are used in the food processing industry and boilers. I have a few that are stainless but not all shined up. Forge on and make beautiful things Jim Quote Link to comment Share on other sites More sharing options...
JHCC Posted February 1, 2017 Share Posted February 1, 2017 This is definitely not "least complicated", but here is an interesting article about the construction of Anish Kapoor's "Cloud Gate" sculpture in Chicago (AKA "the Bean"). Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted February 1, 2017 Share Posted February 1, 2017 I agree with Jim; there is probably an industrial supplier of these things already, then the electropolishing---again a farm out process, (Hazardous waste generated!!!!!), leaving you the final polishing Quote Link to comment Share on other sites More sharing options...
jeremy k Posted February 1, 2017 Share Posted February 1, 2017 JHCC - The Cloud Gate link is a good article, this is a good example of what something large costs - The original cost estimate was $9 million, but project complications led to a final cost of $23 million. http://www.billslater.com/cloudgate/ I realize this is a bit larger than Asma is referring to but it helps to put size vs. cost into prospective. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted February 1, 2017 Share Posted February 1, 2017 should have been cheaper due to material sourcing: From that website: shiny stainless steal plates Quote Link to comment Share on other sites More sharing options...
JHCC Posted February 1, 2017 Share Posted February 1, 2017 17 minutes ago, ThomasPowers said: should have been cheaper due to material sourcing: From that website: shiny stainless steal plates Next time: WOOTZ! Quote Link to comment Share on other sites More sharing options...
BIGGUNDOCTOR Posted February 1, 2017 Share Posted February 1, 2017 There is no easy, inexpensive route for this project unless you can find one surplus somewhere. Have it done on a large spinning lathe. But that will require a big spinning lathe, forms, and big sheets of stainless. Getting the weld seam smooth will be the biggest hurdle. Find something already round (float,etc) that you can have chrome plated. Some propane tanks have spherical ends welded onto them. Cut them off and weld them together. Then plate. HAHAHAHA! The last picture in the above link states that they do custom suffocating for free..... I wonder if they are just pumping water into them to inflate the ball. Quote Link to comment Share on other sites More sharing options...
Kozzy Posted February 1, 2017 Share Posted February 1, 2017 You might also check into a web image search on "Lapidary sphere machine" of an alternative idea about polishing spheres. The method shown in the earlier link/video shows just how out of spherical those large balls actually are and a polishing system similar to what is done for stone will result in a much more spherical product (if the walls are thick enough to take it). Might be over-kill for your needed product, though. Stainless is a pain to mirror polish and will haze over time also so you might consider a path of pre-polishing and then plating or some method of electro polishing rather than fully mechanically polishing. Again, depends on the result you are seeking. Quote Link to comment Share on other sites More sharing options...
Frosty Posted February 1, 2017 Share Posted February 1, 2017 9 hours ago, jeremy k said: It would not take a whole lot of pressure to expand but the explosion hazard would be Huge. Oh contrare Jer. (Sorry I couldn't resist, I used to hear that all the time) Anyway, there is zero "explosion" hazard inflating hollow forms hydraulically and if you do it submerged i a tank of water you don't have to worry about a pinhole slicing you like a razor does a banana. You could use a pressure washer if you have time. Asma: I doubt strongly there is an easy or inexpensive way to produce polished hollow stainless steel spheres this size. We could've in Father's metal spinning shop but would have to sub contract for welding and polishing. Just our part would've been REALLY expensive, especially for a one off or limited number. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
jeremy k Posted February 1, 2017 Share Posted February 1, 2017 Frosty - Sorry - You are correct, I was thinking inflating with air out in the open. Quote Link to comment Share on other sites More sharing options...
Frosty Posted February 1, 2017 Share Posted February 1, 2017 6 minutes ago, jeremy k said: Frosty - Sorry - You are correct, I was thinking inflating with air out in the open. Don't be sorry, a lot of artists inflate hollow ware with air in the open it just wouldn't work on this scale, not safely at any rate. In the '60s Popular Science carried articles about inflating asteroids by drilling to the center, packing in ice, welding a thick plug and heating it with concentrated sunlight. The bright red hot asteroid would soften, the ice would boil and inflate the asteroid. Funny how a couple decades in space brings out some of the difficulties involved in doing anything is space. There's a good John Ringo series that does a lot of asteroid inflating, first book is, "Live Free or Die." Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted February 1, 2017 Share Posted February 1, 2017 And I just finished re-reading "The Hot Gate" last night at 10pm... Quote Link to comment Share on other sites More sharing options...
arftist Posted February 5, 2017 Share Posted February 5, 2017 You can actually buy hemisperes. Careful fit up, some good TIG welding Electro polishing will not give a mirror shine though so expect to spend a lot of time polishing. Quote Link to comment Share on other sites More sharing options...
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