Welding Help

racerx1699 · Post by **racerx1699** » April 24, 2011, 10:21 am

I've started patching holes in my cab and I'm having problems with the welding. I’m no welder but I did a lot of practicing on flat medal. Now that I'm trying to weld in panels I'm getting holes ever where I start. I have a Lincoln pro mig 175, set on B for heat and 4 for speed, and .025 solid steel wire. I'm using 75/80% mix argon/co2, set at 15psi. The bottom picture is the clutch rod hole in the firewall welded from the inside, you can see the holes, and I didn't get good penetration in some areas.

charliemccraney · Post by **charliemccraney** » April 24, 2011, 10:51 am

It doesn't look like you spend much time cleaning the metal before you weld. You need to use an abrasive disc of some sort to get it nice and shiny before you weld. Wiping it down with degreaser and even sanding wheels don't do the job well enough.
Cleaning the metal is the hardest thing to learn to do. It's not that it's difficult. It is that you just want to get in there and weld. After you do that several times and have to grind the welds off and start over, you learn to clean it.

kstones63 · Post by **kstones63** » April 24, 2011, 12:28 pm

Try turning the heat down a little bit more and slow down the wire speed more. I had a similar problem when I did mine and I figured out that the heat was too high and the wire speed too fast. The problem was that when the metal would get hot, the wire speed being too fast wouldn't melt and it would push the wire right on through the weld and blow out a hole.

Kevin

66fordtrucknut · Post by **66fordtrucknut** » April 24, 2011, 4:39 pm

Hey Donnie, turn your gas up too to like 25 CFH, Are you doing it outside? Wind doesn't like mig or tig. That looks like gas coverage to me, Also make sure all your gas connections are tight, If you keep having prob. maybe I can come down one night and see whats going on.
Charlie

MadMaxetc · Post by **MadMaxetc** » April 24, 2011, 5:54 pm

I actualy think it is a combo of all 3.

Heat to high and speed to fast.
Gas flow to low.
Better cleaning.

I had the same problem on my 67. I didn't remove enough of the rusty metal and was trying to go to fast. The settings was just a learning thing.

Keep trying, you will get there.

Trav_450R · Post by **Trav_450R** » April 24, 2011, 6:16 pm

The metal that your welding doesnt have to be spotless but it does need to be fairly clean, unless your TIG welding then is better be like a polished finish! Id play with the heat and WFS on a scrap piece of steel, turning it down until you get it just right to where it will get great penetration but not burn holes in anything. If you have a fairly good sized hole just pretty much make tacks back and forth between sides and meet in the middle. Only holding the trigger down for second. Kinda like building a bridge i guess

supersmitty · Post by **supersmitty** » April 24, 2011, 6:21 pm

I heard too that changing to a 0.30 wire works better than the 0.25.

flareside64 · Post by **flareside64** » April 24, 2011, 7:05 pm

Yes try a .030 wire, you'll need to change out the contact tip also, the gun liner should be the same. First lower your heat to the first setting. and change the gas pressure to 25 psi. Lower your wire speed one more notch if the welds look to cold and not penetrating good enough. When welding sheet metal, dont try to weld long beads.. skip weld with 1/2" weld length max. Bounce around on your patch and let the metal cool. It will take awhile, but take your time and just remember not to get the metal too hot.

flareside64 · Post by **flareside64** » April 24, 2011, 7:09 pm

also, best solvent to use for cleaning the metal is acetone

racerx1699 · Post by **racerx1699** » April 24, 2011, 7:25 pm

Thanks guy's, I knew I'd get some good ideas. I'm almost to the end of a wire roll so I'll try .030 wire, up my gas pressure and do a better job of cleaning. It's easy to get in a hurry. Charlie, I have to weld outside, the sparks would tear up my floor.

f100matt · Post by **f100matt** » April 24, 2011, 7:53 pm

Just throwing it out there.... Be careful when using chemicals to clean the metal before welding. NEVER use brake cleaner!!

Brake cleaner (tetrachloroethylene)+welding= phosgene = very dangerous

read this article:
http://www.brewracingframes.com/id75.htm

dmsmith6 · Post by **dmsmith6** » April 24, 2011, 7:55 pm

All of the responses above have this pretty well covered, but you can also try clamping (if possible) a flat piece of copper or aluminum behind the weld area. This will absorb some heat and will not allow the weld to push through.

kstones63 · Post by **kstones63** » April 24, 2011, 8:10 pm

racerx1699 wrote:Thanks guy's, I knew I'd get some good ideas. I'm almost to the end of a wire roll so I'll try .030 wire, up my gas pressure and do a better job of cleaning. It's easy to get in a hurry. Charlie, I have to weld outside, the sparks would tear up my floor.

I think that you will be going the wrong way by using .030 wire. It is bigger, needs more heat to melt it and in turn it pushes through the thin metal when it gets hot. I was having that problem and realized that I had forgotten to change my wire back to the .023 wire. That helped my problem quite a bit.

Kevin

charliemccraney · Post by **charliemccraney** » April 24, 2011, 9:00 pm

Another thing, that's probably not your problem, but results in better welds for me is to cut the "ball" off that forms on the end of the wire when you finish a weld. It makes it easier for me to start the weld.

cooter · Post by **cooter** » April 24, 2011, 9:27 pm

when welding, everytime you hit the trigger make sure you are on top of your last weld instead of starting the weld on the unwelded metal.

64crew4x4 · Post by **64crew4x4** » April 24, 2011, 11:46 pm

If you have alot of Welding to do in the sheet metal, I would suggest getting some scap steel of the same thickness....practice the Stitch welding as others have suggested....

Learning curve on Thin steel can be frustrating....also your welder has set heat ranges which make it a bit tougher as well.....

If you have scrap fenders or some other part of your truck sheet metal you can learn on that is best....

I run the Next welder up from yours....I do nasty, rusty, painted sheetmetal all the time with it....I run .030 wire on a Mix, and around 25-30 on pressure..I am outside alot too...

One trick I have learned is to do the 1/2 inch stitch like others have said, and if you are quick about it, you can keep the steel just hot enough that it will burn the paint as you weld...

Another trick....if your Fresh Patch steel is slightly thicker than The original steel, keep your weld pointed more on it....thicker material will handle the heat better....and let the weld puddle flow/blend over to the original sheetmetal...
I also use a Harbor Freight 80.00 Auto Dimming shield when doing these welds, so I can stay Shield Down through the whole weld process...
Alot of the time, you will need to just spot weld, cause the original steel is so Thinned out...

Practice...Practice...Practice....

ICEMAN6166 · Post by **ICEMAN6166** » April 25, 2011, 1:33 pm

like a game of connect the dots, start out with a bunch of spot welds then connect them. if you put them too far away you will build up too much heat and melt thru. an inch length on one pass is pushing it unless you have infinite voltage and wire speed settings.

i had no wire feed experience when i bought my lincoln 135.
first thing i attempted was a full corner spot on a cab (from the tank hole down the door opening and then down the vertical ridge on the back of the cab) using .035 flux core.
compared to what i can do now years later with a gas bottle and .023
the 1st attempt really looks like a bunch of small metal turds on 2 joined pieces of tin.

theres lots of welding pics in my uni build thread
http://fordtruk.com/forums/viewtopic.php?t=11692