Fixing Welding Holes

Unless I am welding some extremely thick metal, it seems I am always burning at least one hole in the metal. I'm no expert welder, just a farmer who has to do repairs. My welds do hold, although they are not always pretty. But it seems that anything I weld ends up with at least one burn hole. To fix them, I have always stuck a nail, screw or bolt in the hole and welding over it. In fact I save all bent or stripped bolts just for this purpose. Last night I was welding some 1/8 inch metal and had to do the same sort of patch, used a bolt and welded the head right into the piece. I'm just curious what the professional welders do when they burn holes.
Yea, I am sure they dont burn as many as I do, but "shit happens", or should I say Holes Happen. I only have an AC stick welder and while I do my best to set the heat range, holes happen.
All tips appreciated.

snipped-for-privacy@invalid.com wrote:
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I have switched to TIG, but still sometimes have the same problem when I get in a hurry. A good welding mask is a great help. With steel, you can sense the temperature of the weld pool by the color. You want to keep the puddle of molten steel small and not too hot. Very generally, the puddle, ie. the part that is yellow to white hot should not be more than something like 2-3 times the metal thickness. The larger the amount of fully molten metal, the easier it is for some of it to just fall on the floor. If the weld puddle gets too big, you can back the electrode away, or speed up the progress across the seam.
With stick, I was not able to fill holes easily. With TIG and a pedal control, I find it a lot easier to build metal up on the edge of the hole and fill it in pretty quickly. I'm still learning, myself.
Jon

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Did you say "extremely thick" on purpose? Or was it a typo?
Anyway, I always just weld these holes shut by welding starting around perimeter.
i

Ignoramus13560 wrote:
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WHAT A TRICK! You do not start in the center of the hole? How long did it take for you to find this out?
Nick

Nick Mueller wrote:
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With a firebrick tight against the underside of the metal, I've welded up a hole starting in the middle. Perhaps not smart, but I wasn't very experienced at the time and it worked.
But ultimately, it's much less trouble if you can manage to avoid burning holes in the first place.
Best wishes,
Chris

"Christopher Tidy" wrote: (clip) With a firebrick tight against the underside of the metal, I've welded
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^^^^^^^^^^^^^^^^^ Kinda hard to strike an arc on the brick, ain't it?

It's 'firebrick', dummy. It is already hot.
j/b
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IFYTP
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Sounds like you get your firebrick a whole lot hotter than I do...

On Fri, 18 Jan 2008 03:06:42 GMT, with neither quill nor qualm, "Leo
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Nah, I use gold.
--- Chaos, panic, and disorder--my work here is done.

Leo Lichtman wrote:
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Guess you're right there!
Chris

On Fri, 18 Jan 2008 04:40:14 +0000, Christopher Tidy
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Chris,
You were suppose to answer that little oops that you were using an Oxy-acetylene torch ;-)

"Nick Mueller" wrote: WHAT A TRICK! You do not start in the center of the hole? How long did it
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^^^^^^^^^^^^^^^^^^^^^ I get what he means. You spiral your way inward, rather than trying to build across. It also helps to stop and restart, so the metal doesn't get hot enough to make another hole.

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Without stopping, the end result wouldbe a bigger hole. Weld a little, wait a little, grind slag, weld some more. In the ideal world, there would be no burnt through holes in the first place, but that happens to me, unfortunately.
i

Ignoramus13560 wrote:
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With a firebrick underneath I never used to stop. Just filled it up.
Chris

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The holes I made, often were not accessible from the other end (for example, welding tubing). Not sure if firebrick would also help with vertical pieces.
i

Ignoramus13560 wrote:
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I never tried it in the vertical position.
Chris

On Thu, 17 Jan 2008 23:27:56 -0600, Ignoramus13560
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That's the problem I most often deal with. For example I was welding a crack in my tractor loader side rails. They are a large tubular metal piece, something like 2.5x5 inches. I got most of the crack welded on the 2.5 inch side when I burned thru. The hole was about 3/8". I just dropped a 3/8" bolt in the hole, with the head on top, and welded the head into the item. When done, the head was not visible, just a bit of a hump. The rest of the bolt is not noticed inside the tube. My guess is that the spot where the bolt is welded is actually a strong spot with the added steel, but thats just a guess.

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I doubt that the spot adds much to overall strength, but it seems like it works well for you.
i

Ignoramus29897 wrote:
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Burning a hole in a highly stressed piece and then welding in a bolt of unknown composition to fill the hole most likely severely weakens the part, first from the excessive HAZ that created the hole, then from the unknown metallurgy filling the hole area and then from probable stress concentration points in that area.
My best recommendation to the OP:
1) Invest in a decent auto-dark welding helmet, they really help infrequent welders.
2) Take a welding class at a local tech school and note your typical welding needs to the instructor.
3) Be willing to invest a bit more in the equipment recommended by your instructor, likely a 240V MIG, or an AC/DC stick machine.
4) Visit a metal supplier and get some pieces (cutoffs) of 1/4" plate so you have suitable material to reinforce areas where you have welded up cracks.

snipped-for-privacy@invalid.com wrote:
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I consider 1/8" (10 gauge) to be as thin as it's possible to weld with a stick welder. If you routinely weld this stuff, it's no wonder you get the occasional blowout. Welding over a plug is a fine technique.
I suggest you look into a small MIG welder. I recently bought a Hobart Handler 135 and it welds just great on materials up to 3/16" thick. All I've ever used in it is .030" fluxcore wire. It's super-easy to weld with, just point and pull the trigger.
Anyway, I don't consider myself a pro welder although I'm increasingly headed that way. I don't ever use stick on anything thinner than 3/16" so I very rarely get a blowout. When I do, I just turn down the amps and gently walk from thicker material onto thinner, working my way around until I've welded over the hole.
Grant