Overhead welding. whats involved ?

[zardoz]

I have a chance at a job, which includes doing a weld test. I am fine with three of the four test jobs but the fourth is overhead butt joint. I do remember having problems with overhead MIG welding in the past.

I am only a level two C & G and have never done overhead welds at college (apprently this is done at level three, which I could not get on this year due to "cut backs" )

Can anyone give me any help, tips, or welding voodoo ?

 

[chunkolini]

Make sure your trousers cover your boot tops.
I can remember upside welding being impossible, then one day it clicked.
But I could not see what I was doing differently.
Good luck, I would go and practice a bit first.

 

[zardoz]

Thats just it, I have no idea of what gauge of metal i will be asked to weld on. Come to think of it, I have no idea of the machine that they will be using for the test either. Im sure it must make a difference if you can alter it for spray transfer, or short circuit, or whatever. Which would be best for 1/4 inch mild steel ?

 

[justin]

get a welding cap, burning your scalp is no fun.

 

[awemawson]

I've velcro'd some leather cut from a welding apron to the back of my helmet to stop the zarps burning my neck. It also helps reduce reflections inside the helmet and lets me see better

 

[Mad Mick]

Hi Zardoz,whatever you do you will need dip transfer with a very short arc.If you have thick plate with 60-70 degree inclusive angle with root face and gap you will probably find that you need to keep your torch angle well away from the vertical or you will blow thro' too easily on the root run.It used to work for me,but I only work one day a week now since I retired last year and most of it is tig work.Hope this helps you friend.

 

[zardoz]

Thanks for all the tips guys.

 

[chunkolini]

watch out for spatter building up in the shroud, can get messy very quickly.

 

[Lewis Medlock]

Mad Mick gives good advice. Positional mig is a ****** if it's going to be tested- it's the easiest process to look good but fail a bend test.

Overhead butt you want to be going for lower range dip transfer (19 ish volts and wire feed to suit). 2mm root face and gap but slope and tilt angles are crucial to avoid poor interpass and sidewall fusion.

Can you get to Hereford? You're welcome to have a go at my place

Good luck, Jim

 

[Lewis Medlock]

Can you get to Hereford? You're welcome to have a go at my place

I'm there Saturdays and Sundays too!

 

[zardoz]

You are a gentleman sir. I might be able to get down on Sunday. Will message you Saturday if thats ok ?

 

[Tino]

Over head its more difficult to get good penetration, using less inductance than you would down hand or vertical helps a little. Good luck.

 

[Lewis Medlock]

You are a gentleman sir. I might be able to get down on Sunday. Will message you Saturday if thats ok ?

I'll be there Sunday so no drama if you do or don't make it, PM'd my number


All the best, Jim

 

[Spot the welders dog]

You are a gentleman sir.

Count yourself into that select group as well -

Lewis Medlock: Outstanding, +1 also.

Good luck

 

[Electric Glue]

Mad Mick gives good advice. Positional mig is a ****** if it's going to be tested- it's the easiest process to look good but fail a bend test.

Overhead butt you want to be going for lower range dip transfer (19 ish volts and wire feed to suit). 2mm root face and gap but slope and tilt angles are crucial to avoid poor interpass and sidewall fusion.

Can you get to Hereford? You're welcome to have a go at my place

Good luck, Jim

I'm wondering why this lad is being advised to only use dip transfer with overhead? If you're welding anything of any thickness you need to be spraying. Dip just doesn't penetrate enough. Please don't leave people thinking you can't spray overhead.
Oh and this is my first post so, hello everyone

 

[Lewis Medlock]

If you're welding anything of any thickness you need to be spraying. Dip just doesn't penetrate enough.

Don't be silly

 

[outofthefire]

I used to weld galv overhead on wagons and like chunko found one day it just clicked. I used to wear a full hood and always used ear plugs you dont want a blob of weld in your ear.

 

[Electric Glue]

Don't be silly

How am I being silly? Please elaborate. Are you saying you can't spray overhead, or that spray doesn't give better penetration than dip?

 

[Mad Mick]

Spray transfer is used in downhand normally.I've only ever used it vertically or overhead momentarily when filling a small hole in order to overcome the heat sink effect of the existing metal,a sort of momentary 'hot start' if you like.That is my experience anyway.

 

[Electric Glue]

Spray transfer is used in downhand normally.I've only ever used it vertically or overhead momentarily when filling a small hole in order to overcome the heat sink effect of the existing metal,a sort of momentary 'hot start' if you like.That is my experience anyway.

Using spray is called for in the weld spec. I'd have a job on doing it downhand as turning a 450 ton boat is a bit of a mess about I've noticed that a lot of the stuff on here is aimed at 3mm and thinner. The tutorials on here call 4mm "thick"!
Maybe that's where "normally" comes from. I'm talking 25/30mm plate and dip just won't cut the mustard, even with pre-heat.