Quote:
Originally Posted by animenerdjohn
At Hub City we had a pretty fun collision with 16  . You can see the numerous places our frame split. We Covered the whole thing in tin foil and had it rewelded (This time without the faces being ground off). No issues. http://i.imgur.com/h1bglpH.jpg |
Quote:
Originally Posted by Kevin Sevcik
I have to say, I have little sympathy for people who go to all the trouble of welding up a frame, only to grind all the reinforcement off. As you discovered there, unless you've done a proper bevel prep on the edge, a butt joint is quite likely to have low penetration and little fusion of the base metal. And so you can end up with fractures that follow the original seam quite impressively. Any time one of my mentors suggests we weld something up and grind it flush, I give them the evil eye and they usually decide that perhaps we don't actually need to grind it, actually...
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This x 2.
I would prefer an open root weld in this situation over a bevel, less prep effort and virtually no chance of a LOF defect. I say having written WPSs and earned an AWS certification in TIG welding aluminum.
Quote:
Originally Posted by btslaser
A flush weld with the proper relief bevel and penetration would have been fine (it was 1/8" wall 1x2 6061 tubing). Had the welds not been ground flush it also would have been fine (as was the case for the NASA repair welds on one side only that lasted another regional and the championships). We told our sponsor NOT to grind these welds but after they were smooth and sexy the welder assured us that there was plenty of penetration. Lesson learned... we should have sent it back.
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Unless the welder has (or had) a certification in the weld they did, they have no qualification to make such a statement. Welders are not generally structural engineers, "plenty of penetration" might not be strong enough even if the weld did have full penetration.
Also, as mentioned by three_d_dave, welded material is generally weaker and needs the extra material provided by the weld bead even with full penetration.
This is what a single-sided, single-pass aluminum weld should look like:
