Fixing burn through

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I was welding a bracket to the frame of my truck and have I have made a 1/8'' burn through hole near the seam weld of the frame (seam weld on bottom of frame rail). Can I just weld the burn through or leave it. It is right where the frame steps up under the firewall on a 1999 dodge dakota. I don't think it will crack or anything.BTW the bracket that was welded to the frame has been removed.Opinions?? BTW I removed the bracket that  is how I saw it.
Reply:Holes in frame flanges are bad. Frequently the manufactures recommend you never drill the flange, only the web, because the flange is where most of the strength comes from. Holes there will almost assuredly lead to cracks at some point most likely. Unfortunately welding on frames is also a bad idea usually for the same reason. Newer trucks often use High tensile alloys and are sometimes heat treated. Special care must be taken when welding on frames, Preheat, post heat, special HT alloy filler and so on may be required. Often the mfg will recommend replacing a frame rather than welding on one.Not seeing it, I wouldn't recommend either leaving it alone or welding it up. This is probably something to have someone who knows what they are doing look at it to determine if the frames F'd or is repairable. My guess is if you blew a hole in the frame to start with, you really don't have the skill to do this sort of repair properly, or the frame is so rusted that it should probably be replaced anyways..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:The frame is not at all rusty. I will try ro post a pic when it is light out enough to take a pic.Can you explain flange and web please?? I am not familiar with the terms.
Reply:The flange is the top and bottom part of the frame. in a [ shape it's the two horizontal parts. The web is the vertical part that seperates the two flanges.  Some frame shapes are more complicated for stiffness, but the same general rule applies.The flange takes the loads (usually compression on one and tension on the other) and the web helps to stiffen the thin flanges from buckling and keeps them apart. The reason they usually let you put holes in the web is the same principal as a truss. You really don't need all the material in the web, just like a truss has holes thru the middle..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:If you must make a hole in the web, keep it within 1/3 the distance up or down from the center of the web.
Reply:Cool that clears things up a bit. I forgot to get the req'd pic today. I was too busy cleaning the old lady's car. Tommorrow for sure. Then you can help me determine how to fix it.
Reply:A lot of times, you can fix a burn through hole by grinding the back smooth, clamping a piece of copper tightly to the back and using that as support to fill in the hole with weld metal.  When you are done filling the hole with weld metal, unclamp the copper, fill in any little voids back there for cosmetic reasons, then grind both sides nice and smooth.  Finish with rust-oleum.
Reply:Wire welders excell at fixing burnthrough.Do a swirly on itBuild the hole in by building a bead in a circle around the edge of the hole and continuing towards the inside of the hole.  Very simple.  Keep going until the hole is filled.  If you have to play with it to keep the puddle from dropping thru, do it.  On a long thin hole the principle is almost the same, but just build it back in shorter lengths.Won't be perfect, but it's better than what you have now.  Defects in the swirly can be repaired with a second pass.  In many respects it's the same principle as whipping, and like I say.......defects can be fixed on the second pass after grinding1/8 is nothing, wait until ya gotta fix a BIG HOLE"Any day above ground is a good day"http://www.farmersamm.com/