Distortion After Tack Weld

[jonfilipa]

I tack welded up the first fuselage side for a II-S today. Felt pretty about the results given that this is my first homebuilt, but not surprisingly was left with a little bit distortion. Nothing too bad and barely noticeable for the most part, but nonetheless still there.

I tried bringing a couple areas back up to a dull cherry red to relieve any stresses, but even with a sheet of steel under the 4130 tubing it didn't take too long for the plywood table to start smoldering. So, I'm guessing it makes the most sense to save any stress relieving and minor corrections until when I have both fuselage sides upright. I'm just looking for some feedback to either verify or offer other suggestions before I pull the first side out of the table jig.

[chuck59]

Not to worry. Tack up both sides, the top and bottom before you start welding in earnest. This will give you a rigid structure. Now start welding. Start at the tail and do a cluster. Move diagonally, and weld another. Continue. I like to hang a plumb bob from the tail post that points to a centerline that has been chalk lined on the floor. You'll be surprised at how much this moves back and forth as you weld. As you continue, you'll get a feel for how much it moves. The idea is to have it back on center as you finish the last weld. It's not that hard, and honestly not all that important to be perfect. Just do the best you can.. ;D
Hope this helps.