I wanted to fill the trim holes with lead but I've had too much trouble finding someone willing to do it. What is the next best way to deal with this kind of body work?
Two ways. 1) Use a wire feed welder and slowly fill the holes with one tack at a time. Then grind smooth. Use this method some of smaller holes. 2) On the larger holes use a small pieces of sheet metal cut to fit the hole size. Weld with small tacks going really slow. One at a time. Then grind smooth. you can back it with a piece of copper to help you hold it in place. On either one of these be sure to keep the metal cool. You don't want to warp anything and cause yourself a major headache later.
There's a lot of threads on this but mynameisnotpete basically gave you the rundown. Just make sure you go very slow and allow the metal time to cool to prevent warping. Also, try doing one hole on one end and then another hole on the other to keep the heat and whatnot balanced throughout the panel.
When doing this method, try keeping a damp cloth nearby to dab the welds after each tack. It helps to soak the heat out of the area.
This will also make the panel shrink and be even more brittle than before. If you're gonna MIG it the weld will already be hard enough, don't go making it worse. I am now a firm beleiver in TIG welding and the ease with which you can work the weld afterwards.
Hmmm... Didn;t think of that. I got that tip from an old paint and body guy. Maybe he wasnt as good as I thought...
There is a "soft" mig wire that a guy showed me...I did a story with him about the right way to put on a quarter panel, and one of the keys is using this soft wire...we did a demonstration where he ****-welded to pieces of sheetmetal together, and then bent it every which way to intersect the weld, and it not only didn't crack, it bent uniformly with the parent metal. I've been looking through my notes to try and find the kind of wire...easy grind or something like that. I haven't bothered calling a welding shop yet to see what they recommend. But anyway, that will solve the hard/brittle problem. Eastwood sells a copper paddle with a handle that works VERY well for backing up a panel to fill a trim hole. Get that paddle, go slow with the welder to keep heat to a minimum (Spot welds/little blips at a time) and you'll be able to fill trim holes. -Brad
If you can get behind the holes you need to weld them closed, TIG preferred, gas weld next, mig last, then once you have the hole closed you need to smack it a couple of times with a hammer and dolly to counter the natural shrinking that the welding will cause and then do not cool with water as this will only make it shrink more and make a bigger dent. Rex
I normally go thru my junk drawer for the proper size head on a steel screw then weld that in SLOWLY then grind.. for the smaller ones, like they said, tack slowly...
You might be thinking of ESAB "easy grind" wire. I've been using that stuff a lot for the past few years on sheet metal and I like it. It is easier to grind and not as hard to work and bend as the usual stuff. It welds a little differently than the usual stuff, but doesn't take much time to get used to. I think the bead is a little narrower and hotter. You have to go down just a hair in heat from what you're used to to keep from blowing through. Use .023" wire for sheet metal.
posted this some time ago about filling trim holes http://www.jalopyjournal.com/forum/showthread.php?t=199760
grab a piece of 1/2 or 3/4 soft copper tube about 1 foot long flatten the last inch and bend the flat to a 90 this will give you a flat surface to hold over the back side of the hole while you weld it up. This works great because the copper dissipates the heat, You can put anti splatter on the copper to keep it clean and no grinding needed on the inside it leaves a nice flat surface.
the water doesnt make it shrink more it just speeds the shrinking process. so you may see it rise ( or sink ) but it will do it just the same at my shop our practice is to use compressed air, to cool the weld. the shrinking is still going to happen at the weld its self, but it keeps it from warping the surrounding metal. I usually tig weld them, and will fill holes without a patch no larger then 1/4 in some are just the right size that you can use a hole punch slug, punch a hole in s**** and use the slug to fill the hole. remember dont hammer and dolly just because you think its part of the process. sometimes the hight of the weld before its ground will be the only contact with the hammer and it will actually push the weld down leaving a low spot. try to use soft wire if you mig but tig if at all possible, and dont be shy.. jump to it you only learn by doing.
I bought a box full of 18 gauge circles in several different sizes. mine came from Covell but I don't think they sell them any more. anything like 1/4 or bigger give or take a 16th I use a plug. use a step drill to re-size the hole to fit your plug. tig prolly would be better but I think most of us have a mig if anything. don't use .035 wire, get the small stuff.. I've used the easygrind wire and really noticed no difference. grinding... this is where a lot of people mess it up. I watched a guy put a patch in, weld it fully without stopping, and grind the whole thing down again without stopping with a 4" flapper wheel. warped the **** out of the panel. I like to grind my mig welds with the edge of a 3" cut off wheel using my air powered die grinder. I use the thicker wheels. you grind just the weld, not the surrounding metal. this, along with alternating where you grind keeps the heat down. it also keeps you from thinning the surrounding metal like you would with some other methods I wish the HAMB was around back when I started doing this stuff... where else is someone going to get all this good advice for free??
Isn't the faster cooling what makes it more brittle? Same thing as quenching a machined part to make it stronger, but also makes it brittle. The speed of the MIG weld may put less heat into the metal surrounding the weld, but the quickness of the weld makes it hard and brittle right at the weld. A slower TIG or Oxy/Acet doesn't do this. Or so I have read. I'd rather have a little wave or distortion that I can hammer on than slightly less distortion that I can't hammer much at all. At least I can work the TIG to almost perfect.
Use a 16 penney nail inserted from the back side of the panel hold the nail with a set of vise grips and mig around it nail will absorb heat instead of panel cut it off and grind the weld very little filler needed.
yeah it can make it more brittle, i use the air because its a slower cool then water, but think of it this way post flow on a tig welder is cooling the weld. With sheetmetal (16 g and thinner) the brittleness will never really be noticed, i cool with air all day every day and still hammer strech and shrink the weld area and haven't had anything fail me. this includes chops and sections. and welding a small portion at a time ( 1/2" - 1") and cooling while moving around the patch panel will give you a straight weld that can be hammered then ground leaving pretty much not trace behind. BUT! do not cool a weld on any plate metal (frames, suspensions cages, etc) this is where high stress can be and when your welding a bigger gap ( adding more fill rod) and a hotter weld you can create an area likely to fracture or break under stress.
When I filled the holes in my firewall, 38 if I remember correctly. I used a 1/4 x 2 inch piece of copper buss. I drilled and tapped it for a 3/8 piece of rod. Ground it flat and that was the handle. My son held it on the outside so I could weld it from the inside. The mig wire or filler wire wont stick to the copper and very little bondo was needed to finish the work. The buss definitely draws the heat away from the work area.
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