Edge weld on sheet metal box
Edge weld on sheet metal box
(OP)
I am creating a water tight sheet metal box, and would like to specify on the drawing where and how to weld the edges closed. WHat would I put on the notes and would I use a fillet weld on the outside edge then grind flush for a neet and clean look? or do I weld on the inside edge (probably harder)?





RE: Edge weld on sheet metal box
RE: Edge weld on sheet metal box
Does your joint look like that?
RE: Edge weld on sheet metal box
RE: Edge weld on sheet metal box
RE: Edge weld on sheet metal box
B.E.
You are judged not by what you know, but by what you can do.
RE: Edge weld on sheet metal box
RE: Edge weld on sheet metal box
http://en.wikipedia.org/wiki/Fillet_weld
We can't tell from your sketch what the joint configuration is or what type of edge prep could be possible.
We can't tell from your posts what strength is required.
We can't tell from your posts how nasty looking an inside appearance you are willing to accept.
"Water tight" means nothing by itself. Are you trying to keep water in, or to keep water out? How much? What is the pressure differential? Spray? Submerged? Hot? Cold?
Designing a weld joint is more than sticking a random weld symbol on a drawing. It starts with quantified requirements.
RE: Edge weld on sheet metal box
RE: Edge weld on sheet metal box
RE: Edge weld on sheet metal box
Usually drawn as a corner weld. But to assure leak proof welds, I use a Zyglo dye penetrant with aid of an ultraviolet (black) light to test weldment for thru wall leaks.
Robert
RE: Edge weld on sheet metal box
Fold the corners up so there is a backing piece behind the two plates. Clamp the folded corner into a jog or fixture tightly to hold the corner square and pretty, then try to tack first weld from the inside at at least two locations. Then finsih the joint from the inside so your GTAW tip can cross from one side to the other. You'll have better access from the outside, but a much more difficiult weld.
Alternative: Use a folded joint with a "flap" or lapping side behind the corner, then braze the joint. The braze will "suck into" the very small gap between the two sides instead of melting the two walls.
Alternative: It will take four more "parts" but fold up the walls into position, but clamp them into an angle iron going up the corner from bottom to top. Then braze or weld up the corner joint. Use the angle iron as reinforcement after assembly, and as a built-in jig to hold the corner square and perpendicular during assembly.
RE: Edge weld on sheet metal box
RE: Edge weld on sheet metal box
imagineers (Mechanical) (OP)
I was not paying attention to the thickness of sheet you were specifying .9 of a mm is equivalent to 20gauge sheet metal. In normal industrial practice it is more common to put a spot welded tab flange with a sealant, rather than a weld.
If you insist on torch welding this part (TIG) heliarc is recommended. Then I would suggest you up the gauge to 18 gauge ( 1.25MM ) This will give your welder a far easier time with less chance of burn through and distortion.
B.E.
You are judged not by what you know, but by what you can do.
RE: Edge weld on sheet metal box
RE: Edge weld on sheet metal box
RE: Edge weld on sheet metal box
Bring donuts.
Mike Halloran
Pembroke Pines, FL, USA
RE: Edge weld on sheet metal box
Best regards - Al
RE: Edge weld on sheet metal box