Welding Tips and Tricks

Hi;
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Enjoy site and the videos, and like the tig finger!

I have to mig weld fill a 1 inch hole in 1/4 inch steel plate. Can this be done without creating any warping problems?
How do I do it?

Thanks, Ron

I think the nature of the plate effects this a little - whether it is hot rolled or cold drawn - is there stress left from other welding or folds / forming - but in principle it should be OK - don't use more heat than you have to - I would start trying to lay a bead half the thickness of the plate & just weld round in spirals from the edge of the hole till the middle is reached - then turn the plate over & do the same from the other side - most of the shrinkage forces should then cancel each other out. - I have to admit I tend to put put a heavy copper backing strip on then blast it in from one side - if it moves too much that sort of thickness can be easily wailed on with the big hammer ! - but then I'm usually welding earth moving stuff - not space shuttles !

Noddybrian's right.

If you have access to both sides, a backup is a great way to go. Carbon blocks work great, but if you're worried about distortion, use copper (as brian suggested), or a thick chunk of aluminum as big as will fit, clamped tight, to sink the heat of the weld. Weld in circles as suggested, aiming the arc to the edge of the steel closest to the backer, pausing to cool every circle or two, and be prepared to grind and fill the backside, as it won't be uniform or smooth. Also, as Brian suggested, the weld can be planished to relieve shrinkage, with a heavy dolly/anvil and medium-weight hammer.

Steve S

My 2 cents:
1. What's the point wasting a whole lot of electricity, gas and wire?
2. I'd put a patch and weld it in. 1/4" is a convenient thickness. Bevel it on both sides if possible and weld from both sides.

I use a rotor-broach a fair bit & try to keep the plugs they cut out to hand - these can be recycled into heavy washers or I have used them to fill holes or cap tube ends - forgot to mention it before as the question was more related to feasibility of welding rather than various methods - welding a plug into the hole will be quicker and use less heat so create less distortion - but is not as strong - a complete weld of the hole should leave the part as strong as the parent metal was originally.

If the patch is the same material as the plate, and assuming the plate isn't heat treated, and you use the proper filler metal the patched plate will be just as strong as the original plate.

RonaldP wrote:Hi;
Forgot my login info so had to create all new.
Enjoy site and the videos, and like the tig finger!

I have to mig weld fill a 1 inch hole in 1/4 inch steel plate. Can this be done without creating any warping problems?
How do I do it?

Thanks, Ron

i'd love to help but you're kinda vague on some essential details like do you have access to both sides? the overall size of what has the hole in it will determine how much heat it'll take without warping. if you use a steel backer plate can it stay in after welding? this may act as a stiffener. in my long career as a maint welder I have used many different shaped copper blocks on steel rod handles that I use to build up and fill holes. using the 411 available I would say plug weld it with a copper back up bar.

Hello;

I thought I would let the people who were good enough to answer my question know what I ended up doing.
The hole was in a large gun safe made of 1/4 inch steel that I side drilled to get at the backside of the lock to figure out the combo.
Put a new combo in.
Made a 1 inch X 1/4"thick "plug", chamfered on both sides, that I welded in incrementally while letting it cool down between welds. Welded on each side. I don't know if that was overkill in this instance but finished it off without any problems.
Thanks to all.