Harris Snyder Posted March 22, 2013 Share Posted March 22, 2013 Hello guys. As a moderately junior blacksmith (and a welder of only 3 days), I have a lot of experience with rebar and scrap steel, and not a lot of experience with stainless sheet metal. I need to bend stainless sheet into a cylinder about 10 inches diameter and about 22 inches high. I'd like to use the thickest stuff that I can (I'm making a furnace shell / refractory casting formers). Any tricks of the trade? Is it possible I could bend something between 1/16 and 1/8 in thickness? I have nothing in the way of hydraulic tools, etc, so I think it's unlikely (maybe 1/16 is doable). My current thinking is to roll it around a set of wooden disks which have been cut to the right size - lay them on the inside at regular intervals and roll away with some help and brute force... But that doesn't sound all the promising. It needs to support some weight - I suppose that I could use thinner steel and then weld bars around it's exterior for strength. Any ideas? Thanks a lot guys. EDIT: forgot to mention i'll be using 304 stainless. Quote Link to comment Share on other sites More sharing options...
bigfootnampa Posted March 22, 2013 Share Posted March 22, 2013 You really need a slip roll former for that. 1/8" would be easy with a good slip roller... maybe you can find a shop that has one? Quote Link to comment Share on other sites More sharing options...
Harris Snyder Posted March 22, 2013 Author Share Posted March 22, 2013 Ah! Exactly what I needed to know. Okay so i'm correct in thinking that doing it by hand is kind of insane. I'll look around. Thanks. Quote Link to comment Share on other sites More sharing options...
bigfootnampa Posted March 22, 2013 Share Posted March 22, 2013 Cheap light duty slip rollers are available for thinner metals but for thin plate, such as you are wanting rolled, a fairly industrial model is required. Unless you have MANY to do it would be much cheaper to locate a shop that already has one. Several members here have made their own slip rollers but that is also a fair sized project for one that will do what you wish. Another option would be to source tubing or pipe of the needed dimensions. This could be feasible to do from scrap or really simple if sourced from new stock. I do think bending this by hand forming methods would be a poor use of your time! Quote Link to comment Share on other sites More sharing options...
ironwolfforgeca Posted March 22, 2013 Share Posted March 22, 2013 rember you will lose 3 to 4 " @ each end when rolling will have to be cut of after rolled Quote Link to comment Share on other sites More sharing options...
HWHII Posted March 22, 2013 Share Posted March 22, 2013 The problem with stainless is that is has a good memory and take more force to get it to beyond its yield point. A slip roll is definitly the way to go. I have built with alot of tanks and pressure vessels. So I have rolled alot of material in my day. Generally a roll that is rated for say 1/4" carbon steel is only rated for 1/8" stainless. Same goes for power shears. As the process would go you first would make yourself a radius template, and then preform the end of your sheets. Either by back rolling in a slip roll or with preform dies in a press brake. This eliminates the flat spots you would have on both ends. After the preform you would slide your sheet in and roll it back and forth increasing the roll pressure after going through forward and back. Now if you are up for a challange and want to try by hand which is possiable up to 10 ga. Here is what you do. Figure out your stretch out for your piece and then cut it in half to make 2 pieces. Mark your pieces in 1/2" increments on both side of your sheet in the direction you want to bend. Make a radius template. Next clamp your part to a heavy steel table sandwiched between a heavy piece of angles iron and take a mallet and beat the sheet down over the edge of the table. Then move your part out a mark then repeat and keep checking with your template. Remember it is better to be a little tight than loose because it is easier to open your part then close it. If you need to open the radius you would hit on the outside of your part not the inside. When your done weld both halves together. It will not be perfect by any means but it will get your job done. Good luck if you try it! Quote Link to comment Share on other sites More sharing options...
Jim Coke Posted March 22, 2013 Share Posted March 22, 2013 Greetings HS, Like Harold said it's possable between 2 2in angles to bend 1/16 stainless.... What I've done is weld a 1/2 in round on the top of the leg of one angle ... space the angles about 1/2 apart and proceed like Harold says.. Slow but it works.... Another thought is to make a 11 inch box and weld a 10 in round flange to it... lots of grunt work Good luck Jim Quote Link to comment Share on other sites More sharing options...
781 Posted March 22, 2013 Share Posted March 22, 2013 Why use stainless tin will outlast the refactory. Quote Link to comment Share on other sites More sharing options...
Harris Snyder Posted March 23, 2013 Author Share Posted March 23, 2013 Wow. I've been signed up here for just a couple days and I've been helped greatly on several questions already. Thank you all, it's an honor to be a part of this community. Okay so there are a few ways I can go it looks like. Sounds as though for stuff 1/8th thick I should really find someone local who has the proper equipment. The angle iron idea and curving it in small intervals is definitely a good one, though I'm considering using thinner sheet, and then just welding some bars to the outside of it to strengthen it up - that may be easier, and i have some 3/8ths mild steel rods lying around that I could use for that purpose. I'm not sure that regular steel will outlast the refractory actually. I dunno if any of you have heard of it, but I'm building the artful bodger's waste oil furnace, and he noted that the mild steel former he had used was flaking away much faster than the lining. I'm sure I COULD get away with mild, but I'd rather be safe than sorry. Now that I think of it, Maybe I'll just make a sort of cage like structure out of thicker bars - that would take most of the weight - and then just weld a thin stainless cylinder on the inside... That way I could go with 20 gauge or so. I mean sheet stainless IS tough stuff... It should be able to support the refractory while it dries. My concern was more the lid. The refractory I'm using is absurdly dense. My lid is going to be 250 lbs or something stupid like that. I just wanted some solid support for that - the "bar cage" approach is sounding like the way to go to be honest. Quote Link to comment Share on other sites More sharing options...
Alan Evans Posted April 5, 2013 Share Posted April 5, 2013 rember you will lose 3 to 4 " @ each end when rolling will have to be cut of after rolled I am intrigued, why would you lose metal at each end? Quote Link to comment Share on other sites More sharing options...
Awalker Posted May 4, 2013 Share Posted May 4, 2013 The portion of the sheet that spans from the center roller to the outfeed roller just does not get bent, exact opposite at the other end. if the distance between your two bottom rollers is 6", then that is ow much metal will not get rolled, half at each end, it is just never put into a pinch by the center roller. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted May 4, 2013 Share Posted May 4, 2013 I bought a number of different diameter stainless ductwork pieces from the local ReStore to replace the bottom of my forge chimney when needed. FAR easier to find something pre-made and scrapped than doing it yourself. Quote Link to comment Share on other sites More sharing options...
Matty mc Posted May 7, 2013 Share Posted May 7, 2013 Hi everyone. I hope I'm in the right place. I'm completely new to forums and metalworking. I'm a plumber by trade and am always wanting to be a jack of all. Thanks for taking time to read my post. I have a huge problem that I have wanted to solve hence have spent numerous hours on the www to figure out. Lingo etc has made it hard as I am not in the know. I want to make two metal hemispheres, to eventuallyake into a ball. I want tools it out of iron about 1/4" thick and about 30" diameter. I am stumped!!!!!! Many hours of looking and researching and I have not much. Can anyone PLEASE help me with information? It would be very much appreciated. Quote Link to comment Share on other sites More sharing options...
bigfootnampa Posted May 7, 2013 Share Posted May 7, 2013 Such a project is well beyond what most smiths would attempt! Sinking and raising plate that thick and so large would be extremely difficult! IMO the best way to approach it would be to consider it a very small version of a water tank and form it in sections and weld it up. Neither easy nor inexpensive! Companies that do this have HUGE presses and expensive tooling for them, to form the sections. They employ teams of highly skilled welders to join them! They have budgets ranging from hundreds of thousands to millions of dollars to get the work done! Your scale is smaller but awesomely ambitious for a guy with little experience in the field! This will be expensive! It will be HARD! Are you SURE you want to do it!?!? Quote Link to comment Share on other sites More sharing options...
Frosty Posted May 7, 2013 Share Posted May 7, 2013 Okay, I addressed this in your other post but knowing it's 30" in dia. helps a lot. Forget using 1/4" and just buy a steel buoy from a commercial fishing supply. Unless you're a skilled metal worker already this is a good way to set yourself for failure. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Jack Evers Posted May 7, 2013 Share Posted May 7, 2013 Years ago on a research project, we put out bids for a 30 inch I.D. pressure vessel to contain 3000 psi. The low bid was about half the next bid. When we checked, that bidder knew where to get a closure to fit the vessel, other bidders were planning to fabricate. Don't try to build from scratch if you can find something already built. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.