Filling holes

My sheet metal has had a wide assortment of tops and doors and has lots of little holes. How have you filled similar holes? I'm thinking bondo. I have been trying MIG welding some holes in light material and that seems pretty unsuccesful. Looking for feedback.

 

have you tried backing the hole up with a sheet of copper or brass when you weld it?

 

No I'll try that!!

 

Randy you took the words right out of my mouth!
I did it with a MIG. Had to lower the heat and slow the wire feed but a copper block behind the hole it worked great.

 

When welding it, have the heat low and just do a whole bunch of little tack welds until the hole is filled. It will be on the verge of burning through the whole time, if it starts to just slow down a bit. But I haven't tried the copper trick.

 

I use a thick pc of aluminum just because I have it laying around. Same result as the brass.

 

I just used a bunch of little tacks on my grill where I had some holes. Worked really well, some burnthrough at first because the material was way thinner then I thought( probably a good thing I burned through then) but it worked. I even went slow and I had very little to have to grind off.

 

If it is some real small holes and you have a bunch, try some JB Weld. or one of those epoxey sticks at the parts store. Sure is a quick fix. I cover the holes on the outside with tape and fill in from the bottom of the hole. So far so good.

 

I've done the same as Cliff, JB Weld or POR15 Patch. I leave the tape a little loose so it forms a flange on one side. Of course, start with clean, roughed, metal.

 

Anybody use an oxy/acetylene torch with a small welding tip and steel rod? That's what I'm planning on using, but I'm not to that point yet so I haven't tried it. Been a lotta years since I've gas welded, but don't have one of them fancy eee-lectric welders. Of course, I'm talking about small holes here, for bigger holes I'll cut a sheet metal filler plate first.

 

I've never tried the copper or brass trick. So far I just lower the current and increase wire speed or hand speed.

So how's the copper work? It it just to create a heat sink and provide support or does it actually melt into the weld?

Do you clamp it behind the hole or just hold it? (hand warmer issues aside)

Oh how thick, copper sheet or a nice healthy block?

I plan to give it a try this weekend. Thanks

 

I Use magnets to hold it too the panel, really strong ones (from inside a computer hard drive) it acts as a heat sink, keeps the blob of molten metal roughly flush with the panel and sometimes it will stick a bit but does not become part of the weld..

I suppose if the backing piece is thick enough it will keep the temp down to where it won't stick at all, but I just use some old 18 guage sheet I have a pile of..

hope it helps

 

I used to use a torch to work on body work, but you have to be very precise with the flame. too long and the panel warps.

wire welder makes it much easier.

 

I used a wire feed and a piece of aluminum strap 1in x 4in x 1/8in thick (just laying around shop) as the back up to fill about 250 holes in my tub. The strap could be easily bent to fit and if I could use welding clamps (big hoop shaped vise-grip things) I did, but many just were too awkward so I just duct taped it into place. I learned the proper technique as I went along, by the time I was on the 20th one I had it down. Go slow, kind of criscross till filled and a grinder to make look pretty. The weld didn't stick to the aluminum, just sort of blackend it, I used the same strap to do all the holes (it looked pretty beat up but did the trick!).
Joe

 

Yes, used a #00 or #000 tip IIRC and welders paste round the area I was welding. Oh yeah kept my hammer and dolly close by. Wire welder makes things little quicker now.

 

I've used aluminum blocks. Whatever's laying around but usually about 3/4 thick. Because it is a different material it doesn't melt into the weld, that's why you use aluminum or copper. It helps to provide support so as not to burn through and make the hole bigger. Sometimes it's hard to turn down current enough to not burn through sheet metal, depending on the machine. I either clamp it or just hold it with gloves, it doesn't heat up that much if the holes are small. If I'm filling in a big hole with a filler sheet I'll definitely clamp it all together, the blocks then help keep it straight and flush while still helping with burn through. Tack it into place and weld it in small sections on opposing sides so the metal doesn't warp. Grind smooth when finished.