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Has anybody ever used one of these "magnetic brass backers"? Susposed to cool the weld and reduce the heat distortion on sheet metal. Good news for a beginer or ad hype? Found it surfing the Eastwood site.

http://www.eastwoodco.com/jump.jsp?itemID=23462&itemType=PRODUCT&path=1%2C2%2C1397%2C1412%2C1417&KickerID=438&KICKER

Thanks
Brad

there's lots of talk about that kind of thing in the body shop ... see this thread - home made works as well or better and is much cheaper

Bill

The welding industry calls that a "backing bar". It is definately not ad hype. Some backing bars, for certain welding applications, are made to smother the back of the weld with inert gas to protect the back of the weld. When you are MIG welding you have a shielding gas protecting the weld pool from contamination. If you have 100% penetration, then the back of the weld is exposed to the atmosphere and is contaminated. Anything you can put on the back, can only help, even if just a little.

Richard & Red58
Thanks for the explanation. Another question or 2, does the copper melt and have to be replaced every so often. If not what keeps it from sticking to the weld? and am I right that will reduce the holes from blowing through the thin sheet metal?
Thanks again
Brad

Your copper "spoon" shouldn't adhere to the weld. It should reduce the hole blowing as long as your temps/wire are proper.
Dan

All gasoline handling equipment was brass in the 40's and 50's. I used pieces of brass that my father discarded as a backing to weld long before I knew you could buy anything like that. It helps on thin stuff.

Brad - as Dan sez, the copper doesn't weld or melt - it conducts the heat away too rapidly - it will get 'sooty', which will reduce the heat conduction, so should be cleaned regular, and it helps most if you can clamp it tight to the piece

blowing holes is a particular problem with old metal that's corroded somewhat thin, new 22 ga metal can be welded without melts if you don't have the MIG set too high and take it easy

Bill

One thing to note is magnetic welding "helpers" of any sort give a TIG welder fits. Makes the arc wander and quite difficult to weld very close to a magnet.

Grigg

If anyone is interested I had some fun making my own welding jigs. Check out the link below & you can see how easy they are to make.
"Buttweld clamps" Most of the materials can be found at any hardware store. I already had most of these in the shop. The copper stock came from old discarded electrical house panels bought at a scrap yard for $10.00! I used the copper bussbars found inside. Approximately 1/4"Thick x 1 1/2" wide & about 2ft long. I made 6 pcs 4" long ea. I know these are thicker than they need to be, but who cares they work real good.
I think the fact that we became Bolters makes us want to do our thing. This is the fun stuff.

http://s150.photobucket.com/albums/s107/vickraft/weldingjigs/

I found this today getting some cheap tarps. right at $9

http://www.harborfreightusa.com/usa/itemdisplay/displayItem.do?itemid=97874

Brad

I saw those bits in Eastwood as well, and had seen someone use a copper spoon to fill in trim holes a long time ago. They are a great tool to have around, esp if you do alot of butt welding like I do!
I just went to Ace hardware and bought a 4"x10" sheet for about $4. Beats the Eastwood price all to heck.