TIGing .250" 304SS

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Im thinking of welding a stand for my aquarium out of 304 stainless.  I was wanting to use 2.5" square tube, .250" thick.  The aquarium will be 280 gallons, so roughly 2500lbs when its all said and done.  I only have a Miller 180SD Syncrowave, and I know that material thickness usually calls for 250 amps.  Will mine suffice with such thick material?  I was also wanting to put leveling feed on it and was curious what a good way to do so was to handle the load?TIALast edited by turbodls1ta; 11-08-2011 at 11:47 PM.
Reply:Here is what it would look like....
Reply:Anyone??
Reply:I would think if you beveled the joints and did multiple passes you should be able to make this work. I've seen the kids at the tech school run some monster beads on the 1/4" 304 SS with the XMT's set at about 150. ( they usually can't seem to grasp that they are only supposed to be running small beads, not filling the whole corner. Don't ask me why the school buys 1/4" SS rather than say 3/16" or 1/8". I have no clue other than probably to avoid having to back gas)Keep in mind that you get more strength from taller tube than you do from heavier wall material. IE you'd most likely be better off using say 3" tall tube 1 1/2" wide, 3/16" thick vs the 1/4" square you are thinking about using for the main rails.  Taller tube resists bending better even if the material is thinner. Legs could be fairly thin wall say 1/8" or less at 2 1/2" sq. here you might want to choose square since it will resist bending in both directions. Wall thickness can be fairly thin simply because you are using such a large dia tube.  Are you going with SS for corrosion resistance on a salt water tank, or are you going for an "industrial" look where the frame is exposed? I ask because if you are going for a "look", then sizes might be dictated by the looks rather than strength. If this will all be hidden, then go with the thinner cheaper material thats taller.As far as the legs, I'd go with a thick piece of plate I'd thread or tack a big nut to and run large dia bolts with washers attached as feet if I couldn't find some nice levelers. keep in mind all the weight will be concentrated on those 4 points. You'll end up with 600-700+ lbs on the floor at each foot. The more surface area you give it the better the floor will be able to take the load. Most plywood floors won't like 800 pounds on a 1 inch square area, but spread that over 3 or 4 inches and you won't have any problems. ( most floors are designed to take 40-60 pounds per square foot uniformly loaded, keep this in mind if you plan to put this on a 2nd floor. The weight might cause some serious sag or "bounce" in your floor as you start to max out the joists).No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:why stainless?  or are you leaving the carcass exposed and are only doing it in stainless for looks?   I don't see any benefit from using stainless in this application.i would use 2x2 square tubing,  3/16" wall.   your drawing looks ok,  but you may want to consider a center support.depending on how you skin the outside, you may be best using the same tubing at the bottom,  that would mostly eliminate any racking forces in that direction,   and you could get rid of the cross pieces on the ends.XMT 350 MPa, w/D52-DTA 185 TSWHarris of
Reply:This is for a salt water tank.  Alot of plumbing around it, with the tank on top, the filters, pumps, etc underneath, and pipes running everywhere..
Reply:I second DSW's recommendation of taller, thinner tubing. I would also raise your bottom braces up to at least 6" above the ground, I think that would make the frame more resistant to buckling.If you are going with thicker material, you may also consider stick welding. Stainless stick welds can look quite nice if done carefully.JohnA few weldersA lot of hammersA whole lot of C-clamps
Reply:I would tig it using DSW's recommendation for materials.  Also, I would make the bottom surfaces flush all around just like the top.  That way you can shim the bottom if necessary to distribute the weight evenly across the floor.  Hopefully that wouldn't be needed, but is usually rare.  If it sat so the length was perpendicular to the floor joists that would also lessen the load on the floor."The man of great wealth owes a peculiar obligation to the State, because he derives special advantages from the mere existence of government."  Teddy RooseveltAmerican by birth, Union by choice!  Boilermakers # 60America is a Union.
Reply:A sync 180 could weld 1/4" with ease, put a slight bevel and go to town.
Reply:Originally Posted by turbodls1taThis is for a salt water tank.  Alot of plumbing around it, with the tank on top, the filters, pumps, etc underneath, and pipes running everywhere..
Reply:I've never had luck with powdercoating.  One scratch and its useless.  Even if it doesnt get scratched, a defect anywhere on the stand will spread.  I would just like to avoid that all together.  I think the SS will last far longer than any coated steel.
Reply:ok depending on what type of stainless you decide to use and wall thickness ur looking at anywhere from 600 to about 1500$ in stainless..when complete this will be a very nice frame...i personally would add another cross piece between the top 6'1" tubes...possibly make 2 and measuring from the outside make then 2' to center-line...other then that...I 100% agree with DSW's recommendation....Just keep in mind when you weld this together...when trying to keep things square always welding in a way that pulls the frame in your favor...also work on a surface as flat as possible...check for square after every weld...each drop of heat u put into that thing will pull it in or out of square all the way till it cools...
Reply:I like the stand, but perhaps building one out of steel first could $ave a few in the long run.The last line of TIGer305Code:each drop of heat u put into that thing will pull it in or out of square all the way till it cools...I built a frame for a grill out of stainless 1.5 x 1.5 x 1.8" stainless 304 angle.  It pulled out of square so bad I had to cut it apart and start over.  The frame was 24 x 48".  Each corner was coped and tacked twice.  It still pulled out of square enough that it was not usable.When every thing is good, stainless flows like butter.DavidReal world weldin.  When I grow up I want to be a tig weldor.