R2D2 - Dark Roast Edition

Step 6: Shoulders and legs

The shoulders and of course the legs are really too oversized for the R2 unit.  They were built perhaps a little overkill but it’s the materials that I had ultimately at the time.  At first I was going to make the shoulders and legs all one piece but decided I wanted to have a little segregation of levels where the shoulders meet the legs.  As I looked around my shop for inspiration I remembered I had some stainless steel cantruss that I was going to use to make a tie-down rack on the perimeter of my truck bed. 

(Cantruss or Uni-strut is a type of U-Channel used in industrial settings for building structures and supporting things like gas lines or heavy duty cables.)

I cut two sections of cantruss and welded them together open point to open point.  This created a nice thick bar.  The legs were left extra long as they could be trimmed later.  Looking at pictures on the net I drew up some plans using a combination of GIMP open source software and the free version of Inkscape to convert it to a vector image.  From this I printed up the size I wanted and traced the perimeter of the shoulder.  I then cut 4 of these out of my plate and welded one to the face of the leg and one to the back from inside.  Always clamp items together when welding otherwise things tend to move around when charged with electricity. 
Next I cut a long piece of steel to span the gap going all around the shoulder.  I tack welded the starting point and chucked it in my clamp.  Allowing a long span of steel allows easy bends.  As I bent it around the shoulder I would tack weld it in place, often with the use of clamps for positioning.  The Strip was deliberately cut wider then needed.  This way when you weld, the edge melts in to the weld give a stronger joint.  The excess is just ground off in the finishing process.
Oh-yeah, grind it off till smooth = finishing process