Vertical MIG welding: uphill v. downhill

I did these welds on a 69 Bronco frame. The rectangle piece is 10 gauge or about 1/8" thick and the orientation is as-seen in the pictures. Therefore the welds running top to bottom in the picture were done vertically. One method -- uphill -- promises better penetration than downhill, but doesn't look as good. The other method -- downhill -- looks good, is easier, but has the potential for cold lap. I did both with the gun pointed upwards although at slightly different angles. For the uphill I held the gun at about 45 degrees and for the downhill I held it about 30 degrees from normal/perpendicular to get the arc more directly into the metal to get better penetration.

My question for you guys is which technique is better for an automotive application? Obviously looks are important so the downhill might be favored. Strength is important too so maybe the uphill should be used. But with the steels we're working with -- typically less than 1/4" -- is penetration even an issue? I hate when my uphill welds turn out like boogers and I have to grind them out. I almost never mess up my downhill welds.

I was using a basic Lincoln 220V 170A welder on the hottest setting with .030 wire and C25 gas.

 

God created grinders to make fugly welds look less fugly. Uphill is ALWAYS better. Either practice more or learn to grind without destroying.

 

Its all in how you control the puddle, uphill is a side to side sweeping motion with a gradual uphill climb. Keep praticing and they'll start to look better

 

A guy at work who is a MUCH better welder than I am MIG's downhill and swears by it. Who am I to argue with him?

 

for thin metal like that down hill will work just fine...just a little wip up as you go down will make it look like your welding it flat...goodluck eric

 

I used to weld for fa actory that was OEM for CAT, if they caught you welding uphill you were fired on the spot! They told me they did tests that proved to them that a good downhill was better than a good uphill.

 

Downhill usually works better for me, the puddle kinda rolls down into the area you're currently welding instead of out and down onto the area you just welded.

 

What you described is what I usually see happen to my uphill welds. It's like when wax pours down the side of a candle and builds up on itself. I have also experimented with the uphill technique where you go side-to-side (or inverted V's) and pause on each side. Actually that's how I did the one in the picture. It's pretty hard to do on a thin lap joint. I can see where it would work well on an inside corner on some thick material.

 

Christmas tree pattern on the downhill.

 

I always thought uphill would be better, so I try it once in a while and always go back to downhill. 100% sucess downhill. dosen't matter lap, seam, or 90*vee, downhill works better.

 

What do you mean by a Christmas tree pattern? (Of course I'm not a MIG welder - never used one, just TIG). Same 'pattern' or approach apply to TIG?

Any input on TIG versus MIG? I have a rotisserie for my frame work - so I do very little of either one . . . so I'm always looking for input. I've probably done most of mine downhill, but have found that as long as I'm watching the puddle and how close to the material I am with the electrode, that I can go either direction with good results.

 

Looks to me like you need to turn heat down a little and your wire speed down also and slow down some and down hill works better for me hope it helps!

 

A verticle up weld(when done properly) is stronger than a verticle down weld. That being siad, a verticle down weld is much easier to do with good results. Verticle up welds are a major pain in the ass. I would trust my verticle down welds before ever trying a verticle up!

 

I weld MIG down hill, but can go up. TIG I weld up hill but can go downword. To cert you have to TIG up and MIG down if that helps. I find its best to do what the puddle tells you to do and get penitration.

 

Just to throw my .02 cents in there, I was trained to always always always MIG uphill, at least for structural applications(1/4 and up). You get better penetration, that's a fact. But I can see where in certain cases(on metal that isn't too thick) you could get away with downhill.

 

Bored and stroked: I don't think this debate applies to TIG!

Problem with MIG is you pull the trigger and wire comes out. Heat and filler input are directly related to each other. With TIG you control each one independently so I think either uphill or downhill will produce strong, pretty welds.

 

I can see in structual or thick welding up being better as the weld beads are larger. Im only.150 certed mig tig.

 

MR FART, Are you watching the puddle when you weld and if so what is it doing when you welded that?

 

Me too...

Most people weld downhill because it's easy. Gravity helps pull the weld puddle down and it usually ends up looking better. On thicker metal, you should weld uphill. It helps to use an upside down V pattern when welding uphill. That's one of many techniques to get good looking uphill welds.

 

I've always been a fan of mig welding downhill. I can usually turn the heat up a notch when going downhill and the metal just flows together for me using tiny circles as my technique.

Here's a couple examples

 

Structural steel(3/16"-I believe & up) is ALWAYS welded uphill, light gauge can be welded downhill without any problems-providing good penetration & sufficient weld deposit.

 

[Hi!], I'm assuming that you're referring to my uphill weld. The puddle is sagging a lot. That is actually one of my better looking uphill welds which means it didn't sag too much. This is with using the inverted V motion and pausing on the sides. Usually the puddle sags so much that it hits the nozzle. I then try to correct it with faster travel speed. This pic shows an abortion that I ended up grinding out and redoing with a downhill bead.

Part of the problem on this weld was visibility.

It doesn't look like it would be difficult to access in the pictures, but this is a part of the frame just ahead of the rear tire and I had to manipulate the gun around a few suspension components and turn my head+mask at weird angles to get it over the tire and under the wheel arch (Bronco has a 2" body lift). Getting my face in close helped, as opposed to welding at arms length.

 

well as a guy that welds lots for wrk.......and private stuff..................

prctise practise.....................

and what size wire you using??

I always weld hot.....up or downhill............position welding is always best....if you can

I always weld uphill on big stuff.........

to get good welds up hill ... turn down the wire speed and voltage,,,,

and always practise on a spare scap......

also looking at your welding... you have to watch for under cut.... that is were your weld cuts into the peices you are welding.....

good luck and most inportant make sure your welding area is clean of contamination...do not use brake clean

 

the rule of thumb is 1/8 and thinner is welded downhand, uphand is used on thicker plates to help preheat and give better penatration. walk the weld down using a side to side motion, across the top weld from the left to the right doing a counter clockwise circle, pause on the top and over lap 1/2 of the circle,on the tube use the side to side downhand motion, work on it and youll get good at it ..

 

Downhill on the 10 ga. will be just fine!!!!!!!!!!--------Don

 

I get frustrated reading welding threads on here so I'll just throw this out there.

I've worked in factories where they do downhill for heavy welds (1/4"-1/2"), as well as one that requires uphill.

My personal preference for anything on a car, including frame work, is if it is done properly a downhill can provide a strong enough weld.

That being said, I read as far someone saying they like downhill because the weld "falls" into it, that is exactly what you don't want.

IF YOU ARE CHASING YOUR BEAD DOWN, YOUR DOWNHILL WELD IS NOT GETTING PENETRATION

If you got your settings right you should be able to aim your wire up into the joint and go down slowly without it ever running.

 

Weld up hill for greater penitration!!!

 

I know when I mig weld uphill I concentrate on spending more time on the sides of the weld than in the middle, that helps me avoid the ropey look.

 

I usually down weld since it is easier for me and looks better. As long as you move slow enough to get penetration and have the current up, it should be fine, short of building a battleship.

Bob

 

Agreed!