I am welding a piece of 2" square tube that is 1/8" thick. I am makeing a bend in the tube by cutting a slot on three sides and bending it and welding it up.

The problem that I am having is that I don't have a good way to make the cut a V shape so that the edges all line up with no gap. When it comes to welding it up it will blow a hole in the edges of the gap. I am using a 3/32 6013 rod with the arc welder set to 60A. I tried the 40A setting, but could not get an consistant arc.

My thought is to use a 2" square thin plate ground to the shape of the gap and weld it up. That would make the gaps smaller.

Would a mig welder be able to fill the gap? I don't have any experience using a mig welder.

Any other thoughts? Different rod?

Thanks

I am probably the furthest thing from a quality, experienced welder, but maybe that's exactly what you want. MIG is by FAR easier, but unless you are using a 220V unit, you won't get the penetration and strength with a margin of error for something major (rock sliders come to mind). For 1/8" however, a 110V MIG would be insanely easier and would fill the gaps nicely. Try a friend's. For that matter, come on up to Littleton and give mine a go.

<small>[ 29 July 2002, 03:43 PM: Message edited by: Bill_Morgan ]</small>

</font><blockquote><font size="1" face="Verdana, Tahoma, Arial, Helv, Helvetica, Sans">quote:</font><hr /><font size="2" face="Verdana, Tahoma, Arial, Helv, Helvetica, Sans">Originally posted by Kendall:
<strong>I am welding a piece of 2" square tube that is 1/8" thick. I am makeing a bend in the tube by cutting a slot on three sides and bending it and welding it up.

The problem that I am having is that I don't have a good way to make the cut a V shape so that the edges all line up with no gap. When it comes to welding it up it will blow a hole in the edges of the gap. I am using a 3/32 6013 rod with the arc welder set to 60A. I tried the 40A setting, but could not get an consistant arc.

My thought is to use a 2" square thin plate ground to the shape of the gap and weld it up. That would make the gaps smaller.

Would a mig welder be able to fill the gap? I don't have any experience using a mig welder.

Any other thoughts? Different rod?</strong></font><hr /></blockquote><font size="2" face="Verdana, Tahoma, Arial, Helv, Helvetica, Sans">6013 is decent for this application, no too deep penetration. Try running either AC or switching DC polarity to put less heat in the metal, also keep the arc very short. Then try just putting small tack welds across the gap every inch, then tack in the middle of the gaps a few times then fill in the bad. You can fill some pretty large gaps this way.

if you're using arc- keep it clean and short tacks, tap and wire brush ALL the slag off before restarting, and keep the arc short.
Or go with a mig, it's so forgiving and you can plug the holes, I do it all the time.
Dave

</font><blockquote><font size="1" face="Verdana, Tahoma, Arial, Helv, Helvetica, Sans">quote:</font><hr /><font size="2" face="Verdana, Tahoma, Arial, Helv, Helvetica, Sans">Originally posted by 4Crawler:
<strong>...try just putting small tack welds across the gap every inch, then tack in the middle of the gaps a few times then fill in the bad. You can fill some pretty large gaps this way.</strong></font><hr /></blockquote><font size="2" face="Verdana, Tahoma, Arial, Helv, Helvetica, Sans">This has worked very well for me also... using the short tack welds to eventually bridge completely across gap.. Then you can go back over it using a wide weave pattern to layer up more metal..

Putting the first tack weld on the far side of the bend and letting it cool before doing any further welds will also help stop the joint from closing further as you bridge the gap.. This may be important if it already bent to the angle you want it to be and don't want the welding to further close the joint and change the angle.. Molten metal across a gap develops tremendous pull as it shrinks while cooling down, and will tend to close in the gap and change the angle of your bend. The first tack the furthest away helps block any further change as you progress..

Mudplugga's point is very important... you don't want to leave slag in there and make the next pass over it.. An air driven needle scaler is worth the money, saves a lot of time and works very nicely to clean the slag off before the next weld.

<small>[ 29 July 2002, 05:49 PM: Message edited by: Dandeman ]</small>

Kendall, try this...sometimes when filling a gap its easier to use a bigger rod , it has more metal in it, but try to use it at the same heat setting your using now..just go up one rod size. like the other guys said, use short tacks and let em cool inbetween, the go over it again. the main thing to do is keep the arc as close and short as possible. Once its welded , grind it down smooth, cut a shallow V into it then reweld with the smaller rod at the same setting to be sure of good penetration. Im not sure if you can understand what Im saying, its often easier to show someone. <img border="0" title="" alt="[Big Grin]" src="images/icons/grin.gif" />
Heres another way to try it..take another rod while welding and put it in the arc , it will melt and help fill, sort of like you would do when braising, cept your using an arc instead of a torch...Always to remember to regrind with a shallow V and to reweld a nice bead with good penetration...I hope you understand all this,Dave

BTW if all else fails, put a doubler plate inside it to cover the gap and weld away...

maybe it's just me, or i didn't read this while skimming over posts, but why not cut the bend out, and fold it in, that way the tube hits the tube. there will be no gaps, and you can just wed it together. this would be easier then trying to fill the gaps.

</font><blockquote><font size="1" face="Verdana, Tahoma, Arial, Helv, Helvetica, Sans">quote:</font><hr /><font size="2" face="Verdana, Tahoma, Arial, Helv, Helvetica, Sans">Originally posted by Cobb:
<strong>maybe it's just me, or i didn't read this while skimming over posts, but why not cut the bend out, and fold it in, that way the tube hits the tube. there will be no gaps, and you can just wed it together. this would be easier then trying to fill the gaps.</strong></font><hr /></blockquote><font size="2" face="Verdana, Tahoma, Arial, Helv, Helvetica, Sans">Yes, I missed that the first time as well. Cut out a pie wedge piece if possible, or just make a miter cut at a small angle and turn the end piece 180 degrees and weld it back together. You need to weld 4 sides this way, vs. 3 sides with the wedge cut.

Thanks for the replys.

I have already cut the three sides and we cut a little too much, so we have a gap on all three sides. I bent it so that the outside of the bed will be on the outside of the truck. It was purely for astetic reasons.

I will try the short welds letting it cool in between.

</font><blockquote><font size="1" face="Verdana, Tahoma, Arial, Helv, Helvetica, Sans">quote:</font><hr /><font size="2" face="Verdana, Tahoma, Arial, Helv, Helvetica, Sans">Originally posted by Kendall:
<strong>I will try the short welds letting it cool in between.</strong></font><hr /></blockquote><font size="2" face="Verdana, Tahoma, Arial, Helv, Helvetica, Sans">Also try the different polarity and/or AC settings to change the heat going into the metal (if your welder supports this). Reversing the polarity (make the electrode negative) will greatly reduce the heat into the metal, and running AC is about 1/2 way between the two. This is the main advantage of having an AC/DC welder, gives you added flexibility.