Plug Welding question

[74ChargerRallye]

I have heard that a person can use a magnet holding a piece of copper as a backing to a hole in a panel or door that is being plug welded to resist burn-through and to assist in creating a better weld.  I was wondering if anyone has tried this, or if there is a special tool that can be used to aid in welding a large hole (when not using a path)?  Does any manufacture make a magnet that has is copper lining/skin, and if so where can I get one?

I am a beginner mig welder, and any help would be appreciated.

Thanks

[Todd Wilson]

I dont know about a magnet  but you can use a copper piece to weld up holes. It works real good. The copper is a good backing that the weld wont stick to but the arc will still burn and it also takes away heat from the sheet metal.  Have someone hold the copper piece or you hold it as you weld. It will get hot so have a glove or hold it with plyers. Get creative here if you have too. Use a penny or a piece of copper pipe. I thnk eatwood sells copper pieces for welding. Wedge a piece of wood behing to hold the copper. What ever works.


Todd

[mopar_madman]

I believe the eastwood co. sells the tool your talking about. Its a copper paddle with a handle on it.

[runningman]

I used some really strong magnets to hold copper pieces to do some areas on my floor that I couldn't reach, worked great!!

[74ChargerRallye]

Thanks for the replies.  I went to the eastwood web site and found the following.

Here is the tool....
http://www.eastwoodco.com/shopping/product/detailmain.jsp?itemID=1181&itemType=PRODUCT&iProductID=1181

Here is the link to the copper plates. http://www.eastwoodco.com/shopping/product/detailmain.jsp?itemID=1241&itemType=PRODUCT&iMainCat=1412&iSubCat=1417&iProductID=1241

I may just get a strong magnet like runningman suggested to hold the copper plates in place while welding.

[runningman]

I got about five of them to place around the edges.  I got those copper plates from eastwood

[daytonalo]

THIS IS EVEN EASIER, I MADE MY OWN OUT OF 1/8 THICK 1 1/2 WIDE 10 INCH LONG BRASS SCRAP . EVERY ONE WHO WALKS IN MY SHOP TAKES HOME A PIECE !

[69fourspd]

First thing, I wouldn't use a strong magnet directly behind the weld.  The stronger ceramic magnets will actually break up the molten steel as soon as it is layed down with a mig.  if anything, just use a magnet to hold the copper up to the metal on the outsides of the area.  As far as the copper goes, you can even buy a 1 or 2 inch copper pipe at a local hardware store and split it down the middle to flatten, or even hammer it flat.  Works great as a backer and is cheap.  If you have an extra hand, it may help to keep a cold wet rag on the back of the section you are trying to fill to prevent warpage.  Good luck!

[Todd Wilson]

First thing, I wouldn't use a strong magnet directly behind the weld.  The stronger ceramic magnets will actually break up the molten steel as soon as it is layed down with a mig.  if anything, just use a magnet to hold the copper up to the metal on the outsides of the area.  As far as the copper goes, you can even buy a 1 or 2 inch copper pipe at a local hardware store and split it down the middle to flatten, or even hammer it flat.  Works great as a backer and is cheap.  If you have an extra hand, it may help to keep a cold wet rag on the back of the section you are trying to fill to prevent warpage.  Good luck!

Thats a good point. I also wonder what a strong magnet would do to the arc. If it would cause it to move around some.


Todd

[runningman]

Yeah, I use the magnets to hold the copper at the outside edges.  The magnets are pretty small in dia 1/8" or so, and the copper is pretty thick as well so they are just barely strong enough to hold it.