06-17-2012, 05:17 PM
Heres a useful tip for spacing - If you happen to find somewhere where the rail road is installing new ties, see if you can obtain a couple pieces of the heavy banding strap material they use to band the new ties with, and make spacing shims out of them. Cut the banding to make several different lengths from 1 to 2 feet and also take a 12" piece and a 14" piece and weld them together to make a "T" these are really good for spacing tube and pipe, especially when it comes to making a full penetration welds.
On the distortion topic, as mentioned previously, weld a test piece to determine the amount of "draw" for the specified joint, then you can easily correct for it. I used to make I-beam trusses for pre-engineered metal buildings mostly out of 1/4" material and would always tack up the components out of square due to the drawing effect from the continously submerged arc welded fillets along the intersection of the flange and web. Once welded everything was square after it cooled off.
On the distortion topic, as mentioned previously, weld a test piece to determine the amount of "draw" for the specified joint, then you can easily correct for it. I used to make I-beam trusses for pre-engineered metal buildings mostly out of 1/4" material and would always tack up the components out of square due to the drawing effect from the continously submerged arc welded fillets along the intersection of the flange and web. Once welded everything was square after it cooled off.