welding holes shut on fender - help!

[steverino66]

Thought about posting in body area, but I'll try you guys:
I'm preparing to plug front fender holes where emblem was removed (2 - maybe 1/8" holes); using Lincoln hd3200 welder with 75 argon/25 CO2 gas, .023 wire - new gas nozzle and tip.
I watched the Lincoln video, read the manual, re-checked all settings per chart on welder. This is my first gas welding attempt, I've successfully welded a couple of heavier pieces with fluxcore.
I practiced all weekend on a piece of 20-gauge scrap, drilling and plugging holes with a piece of copper held in back of opening - mixed results, a couple of lucky accidents but nothing consistent after about 25-30 holes of practice. Mostly ugly little molten piles, got blow-thru on higher voltage settings.
Any suggestions very much welcome and appreciated.
I'm not welding fenders until I figure this out. Rocker panels project is in my near future also.

[Indian113]

I'm not a expert but how is your wire speed ? did you speed it up as you increased heat?

[steverino66]

Originally Posted by Indian113

I'm not a expert but how is your wire speed ? did you speed it up as you increased heat?

The chart inside welder door gives only the lowest voltage setting (A) and speed from 2-3 for that gas mixture/metal gauge; I tried everything in that range, even tried the B voltage once, no better luck, just blew holes.

[protrash64]

If you're blowing holes in the sheetmetal it's too much juice. Lower setting and hit it quickly. If your adjustments are correct it should be about a 1 second blast of frying bacon, no more. I'm self taught, but have done mostly lite gauge stuff as I wanted to fix body pieces.

Good luck and keep trying.

[Captainfab]

It sounds like you're going about it the right way. I like to use .023 wire on sheet metal for the most part. However sometimes when trying to fill a hole, a larger size wire works a little better. The larger wire does take more amps and volts,but it also deposits more filler, which fills the hole a little quicker. You might try practicing using a colder setting, with a couple smaller tacks. also, if you aren't already, start your tack on the sheet metal next to the hole and let it flow over into the hole. HTH

[bosephus]

You mentioned that you were using flux-core before.Did you change the polarity of the welder when you switched to gas?My machine(hobart 210) requires that you switch the polarity(lead wires should be behind the lid where you place your welding wire) when making the switch from flux-core to gas.Hope this helps!

[Born Lucky]

I would use some type of copper backing on the holes(if you can get it in there) and raise my setting a little bit. When you are spot welding you need to run a little hotter. Most welder today give you a chart to set up your machine with the guage of the material, so start there. If your holes are big you can purchase a kit of pre-cut circles, I beleive Ron Corvell sells this kit. It is a nice kit with different size plugs.
The last thing is practice,practice,practice. Remember you can always grind!
You should practice enough , then you can tackle the replacement planels, there you need a little more talent.
Good luck and go for it Mig welding is not that difficult to learn.

[Malibob]

Born Lucky- About always being able to grind- not always true. I posted on here a while ago about having a similar problem. THe asmins were kind enough to delete my thread after someone offered me a part trough there. Back to the point. My roof section was ruined because I did not know what I was doing. Luckily I did get another section though. My problem was exactly the same and when I hit it with the grinder, the metal lifted and it got REAL ugly. I do agree with practice practice practice though. Get an older body part and cut it up, then put it back together (make sure it is scrap though because it wont go back together with the same dimensions)

[erock805]

Yeah did you reverse your polarity? That will give you issues. just practice some more 1 sec blips on the top edge till it flows over to the other side of the whole. I have filled hundreds of holes and still suck but i can get it done.

Btw heat is not your friend...take your time have a wet rag on hand to cool after welding. I tend to weld them up with out warpage but then grind and put to much heat into the metal.

[steverino66]

Originally Posted by erock805

Yeah did you reverse your polarity? That will give you issues. just practice some more 1 sec blips on the top edge till it flows over to the other side of the whole. I have filled hundreds of holes and still suck but i can get it done.

Btw heat is not your friend...take your time have a wet rag on hand to cool after welding. I tend to weld them up with out warpage but then grind and put to much heat into the metal.

A lot of very good overall input - thanks, everyone.
Yes, I remembered to switch polarity. I will definitely try shorter bursts and I may experiment with the .030 solid wire as captainfab suggests. With the .023 I kept piling up crap weld because I kept seeing copper through the hole!
I'm practicing on holes slightly larger than what I have to fill but it sounds like I shouldn't expect to be good at it after a couple of sessions, which I already guessed.

[chevy_mike]

From experience, I would start practicing with getting some good welds on the gauge sheet metal you are trying to fill holes. Just practice getting the feel for what a good bead should look/sound like. Also gives you a feel for how much heat you can put into the metal before it starts to warp. Once you get that down, switch to doing butt welds of two pieces. Again, get the feel for placing spot welds along the joint and working back and forth to fill all the joint without warping the metal.

Once you get the feel for both of these, holes will be cake. Gotta learn to walk before you run. I have learned how to do large holes and can fill a 3/4" hole without any backing piece or an insert but typically limit the hole to 1/2" or smaller without using a plug to weld in.

Good luck and practice.

[steverino66]

Originally Posted by chevy_mike

From experience, I would start praticing with getting some good welds on the gauge sheet metal you are trying to fill holes.

That's a good suggestion, Mike, since my next fender project will be stitching 2 good halves together after holes are filled.
I'd practiced running straight beads when I attempted the holes - and I believe 20 ga. is the same as the 64 fender I'll be working - you guys correct me if not?
Thanks - lots more practice in my near future.

[chevy_mike]

Curious, is your heat and speed settings variable or fixed steps? Both of my MIG machines are variable and I find that makes a big difference as I can do very small adjustments to get the setting right. I find the models that have fixed steps (i.e. 1,2,3,etc) don't give you the fine control and you can end up needing a half setting between two steps and then you are SOL. At that point, you just have to work with what you have and practice.

Also, are you using a 110 or 220 volt unit? I have found it harder to get the right heat setting for sheet metal on the 220 rig versus the 110 rig. That is why I kept the 110 unit around, basically for sheet metal and up to 1/8". Anything more, I switch over to the 220 unit.

[steverino66]

Originally Posted by chevy_mike

Curious, is your heat and speed settings variable or fixed steps? Both of my MIG machines are variable and I find that makes a big difference as I can do very small adjustments to get the setting right. I find the models that have fixed steps (i.e. 1,2,3,etc) don't give you the fine control and you can end up needing a half setting between two steps and then you are SOL. At that point, you just have to work with what you have and practice.

Also, are you using a 110 or 220 volt unit? I have found it harder to get the right heat setting for sheet metal on the 220 rig versus the 110 rig. That is why I kept the 110 unit around, basically for sheet metal and up to 1/8". Anything more, I switch over to the 220 unit.

110 - voltage steps are fixed A, B, C… but speed adjustable between steps

[chevy_mike]

Yeah, you basically need to practice and do the best you can with voltage steps. This is a big reason when asked about welders, I always recommend one with a variable voltage/speed settings. Just more flexiblity to adjust but when starting out, it can be overwhelming too. I had a master welder help me set mine up originally and then learned with practice. Now I can guess fairly close and fine tune after I start the first weld.

Another tip I had heard about doing, if you have access to reach the backside of the hole, put a nail in from the back side with the point sticking thru. Then hold it with some pliers and weld the hole close, This give a little more metal around the edge of the hole (like a lap weld) and you are less likely to burn thru. Then cut off the nail, finish up the weld and grind it smooth. Just make sure you can paint the backside so it won't create a spot to allow moisture to collect.

[lakeroadster]

Originally Posted by chevy_mike

Another tip I had heard about doing, if you have access to reach the backside of the hole, put a nail in from the back side with the point sticking thru. Then hold it with some pliers and weld the hole close, This give a little more metal around the edge of the hole (like a lap weld) and you are less likely to burn thru. Then cut off the nail, finish up the weld and grind it smooth. Just make sure you can paint the backside so it won't create a spot to allow moisture to collect.

Now there is an idea I will be trying! Thanks for the post.