I need tips on welding holes in my frame rails and sheetmetal with my mig

I got a bunch of holes to weld up on my rear frames rails on my 68 mustang are thin gauge soda can style. I also want to fix some small holes in my door but I am so afraid to make a mess or blow through the hole. I have welded holes using a copper s**** backer but these holes I am unable to use a copper backer. This will be my first attempts doing such

I was told by a friend to just heat the metal with a map torch really good and just start at the end of the hole and use a circular pattern to build it in the middle he did say it might take quite a few times so I don't blow through.

What sorta tips can some of you guys give me

 

if its a big hole, use a plug

 

That's a smart idea for the frame rails, but on the sheet metal not sure. The holes range in size from a small pea to about 3/8 diameter

This car I'm wrenching on is a tin can the metal is so flimsy and ****, which is why I'm worried to screw up, it looks like 20-22 gauge

 

Hey,

Weld washers into the smaller holes, then weld up the center holes once you've ground/sanded off the zinc/cad plating.

 

I don't understand. Are you just trying to do a cosmetic job on your frame? If it is soda can thin, wouldn't you want to cut out the bad and weld in some new plate?

 

hi the holes in my doors are just bodywork from rush and after I blasted them , the frame rails aren't rusty they just were drilled with so many holes I guess for fuel lines or who knows what. I just want to weld everything up and s***ch weld all the other unibody seams for rigidity, I'm not using plastic to fill these. I just want to try so,e technique with my mig but aren't sure on how to approach it

 

Don't weld up the unibody unless it's damaged. Sub frame connectors will do wonders.

I'm not sure what "body work rush" in your door is. or "try so,e technique" so your gonna have to explain.

 

I think what your friend told you should do the trick. Just watch your heat and maybe practice on some test pieces first. Good luck.....

 

Use bright nails from the back side. I learned it from a post on here a while bsck.

 

on the unibody frame extra holes.... I sometimes cut a small piece of thick sheetmetal. A piece that is narrow enough to fit through the hole, but is a bit longer.

Now lay that patch on the ground lead, and just a quick zap to stick the wire to the center.


Then unhook the ground, and trigger out 2 inches or so, of wire, and cut it.

Now you have a patch with a bendable wire handle that you can sneak through the hole, and then pull it flat against the back of the hole.

 

Keep the heat down, weld a bunch of spot welds so it cools before you hit the next weld.

 

Now thats a smart technique, i think i might need to oversize the holes if i go this route, def more time but should work

 

that's brilliant! do you get the plugs off a punch machine?

 

or for sheet metal if its not to big of a hole put a peice of aluminum behind the hole and weld it, if its too thin then replace it, works good for me. and for holes in the frame I use filler rods on a mig welder if its too big.

 

Now this would save the day, where can i get a kit like this?

 

On the smaller holes hold a block of br*** or copper behind what your closing up. It not only provides a backer but ****s the heat away.

 

i would open up a couple of these holes with tin snips, looking at the backside for rust. keep cutting till you find solid metal on the backside. you will also have a problem "chasing" the holes do to it being thin. welding up holes and leaving rust on the backside will result in the rust coming back through. cut out the rust and make a patch.

 

Above all watch your heat, work on several holes at a time...jump around and have patience.

 

I've used .025 wire on the sheet metal. Practice practice practice. Otherwise what's already been said.

 

get an ***ortment of nails - find a nail size that fits into the hole, hold the nail by the sharp end & weld it into the hole - use a cutoff wheel to knock the nail post off

 

On small emblem and trim holes, you shouldn't need back up .
Take your (.023 wire ) mig and set it for a good hot tack.
Have a wet towel handy. Aim your wire up at the top of the hole. Give it a good arcing tack, another tack below it while still hot, again and again as you drop down.
If you don't close it in 5-6 tacks,...Stop...cool the entire area...Finish up ....Cool again.
Grind the excess weld down with the edge of a cut off wheel...finish with a small 90 deg. grinder and roloc discs.
Always keep work area small and cool !
Sounds easy , doesn't it?
Practice on some old tin first!

 

the sheetmetal plugs from my earlier post in the yellow box came from Ron Covell, but I don't think he sells them any more. the others in the red box came from the s**** bin at a local fab shop.

 

When I didn't have any s**** to fill holes I have a flat piece of copper to out behind the hole your welding, fill it in. Weld won't stick to copper. This works of course if you can get anything behind the metal your welding and unless you can lay nice beads, you will have to do more grinding and hole filling this way than filling it a large hole with metal plugs or washers. I wouldn't suggest doing this method for holes larger than your thumb. Good for trim holes
Happy welding!