Learning to weld

[Gary_in_Indiana]

I've decided I ought to try to acquire at least one useful, marketable skill before I die and I'm hoping to make it welding. /w3tcompact/icons/smile.gif A few weeks ago I bailed out a customer who was having a cash flow problem by purchasing his new-in-the-box Hobart MIG welder and I think it's time for me to take it out of the box and learn how to use it.

While I've been wanting to do this in the fall anyhow, in today's mail I got a flyer from the local Vocational Technical College and they offer welding courses there. I'm seriously considering enrolling in one. I'm guessing since I have a MIG welder that the MIG Welding class would be the one for me. /w3tcompact/icons/clever.gif/w3tcompact/icons/smile.gif

I was surprised to see listings for Shielded Metal Arc, Oxy-Acetyline, Fabrication, Pipe Welding and TIG Welding among others. I'm thinking since the name of the class (MIG) matches the name on the box... /w3tcompact/icons/smile.gif

My thoughts are they'll probably be pretty strong on emphasizing safety, proper equipment and techniques there. Frankly, since I have zero knowledge or experience with this those are things I'd like to learn and learn right. Any thoughts on other things I ought to consider on this?

 

[RoyJackson]

MIG is Metallic Inert Gas which uses argon, helium, carbon dioxide or combinations thereof. The intent of the shielding gas is to prevent contamination or the weld (while the metal is molten...the "puddle"). MIG welders use the filler wire running through the gun as the electrode.

TIG is Tungsten Inert Gas (commonly called Heliarc welding because helium was originally used as the inert gas). Basically the same as MIG, but the electrode is tungsten and the filler rod is seperate (like oxy-acetylene gas welding).

If I recall correctly, Shielded Metal Arc uses granular pellets (can't remember the compound) as the shielding media. I haven't seen this used much. It's more of an automated welding (vs. manual welding) set up. The last time I saw it used was for welding tank hulls and turrets (you know...tanks..like tracked military vehicles).

Welding flat isn't any big deal. Learning to weld vertically and overhead can be challenging. I was always OK on flat welding, but never got the hang of vertical or overhead.

Other then the usual precautions (eye protection), welding emits UV light. You can get a pretty nasty "sunburn" if your wearing short sleeved shirts. Nice thing about MIG and TIG is that you get no slag to chip off...and splatter is minimal (I'll tell ya the tale of a piece of hot slag going down my trousers sometime). Another thing to consider is that, although inert gases aren't poisonous, you still want to ensure adequate ventilation. Inert gases contain no oxygen.

Oh..another...after you weld aluminum, there is no appearance of heat as you see with steels. You learn just to touch it lightly to check for temperature...this is after you pick a few hot weldments up. Nice thing is, the learning curve is quite quick.

 

[Robert_in_NY]

I have heard of welders suffocating while welding inside of tanks. The argon built up and eventually there was no oxygen left in the tank. But I doubt too many homeowners will be welding inside of tanks or doing too much welding for it to be a problem but it is something to remember.

 

[EdKing]

<font color=blue>If I recall correctly, Shielded Metal Arc uses granular pellets (can't remember the compound) as the shielding media.</font color=blue>

Shielded Metal Arc is actually the technical term for regular arc or "stick" welding. When I got my MIG welder, I picked up a basic welding manual which explained the different welding processes and terminology.

<font color=red>Actually I am not a weldor, but I did stay at a Holiday in last night.</font color=red>/w3tcompact/icons/laugh.gif

 

[DocHeb]

<font color=blue>If I recall correctly, Shielded Metal Arc uses granular pellets (can't remember the compound) as the shielding media.</font color=blue>

You're right - the granules are affixed to the welding rod and are consumed (with the rod donor metal) in the welding process. This method is also known as stick welding. There are different welding rods (and therefore different granules) with varying flux/shielding properties that are used for different welding situations. Lots of good information for beginners at <A target="_blank" HREF=http://www.lincolnelectric.com/knowledge/articles/list.asp>Lincoln Electric</A>.

 

[patrickg]

Yet another $0.02... Don't forget MIG using "InnerShield" wire. Wire feed guns that use inert gas to exclude oxygen from contact with molten metal can sometimes also use wire with its flux on the inside, like solder with the flux on the inside. This is a compromise in between stick welding and MIG with inert gas. Advantage is you don't need inert gas bottles, regulators, etc. You get a pretty good weld on mild steel. The down side is that it isn't quite as clean, has some splatter and slag but can be pretty darned good and not require chipping/grinding.

There are about three main facets to welding: 1. The mechanical part with the hand-eye skills/technique/art, 2. the metalurgical part where you need to know what alloys are and do in the welding process (filler material selection must be appropriate for the alloy(s) being welded), and 3. Welding engineering stuff like design of weldments where you consider lap vs butt welding, skip welding, stitching, how things warp and move with heating and cooling and how to prevent associated problems or use the "warp" effects to advantage. Being able to weld things together doesn't automatically train you in how they should be welded together/designed etc.

Kinda goes back to the verification and validation dichotomy.
1. Am I building the right thing. 2. Am I building the thing right.
Welding skill and technique is only part of the equation.

Even if you are a whiz with MIG it is good to learn Oxy-Acetylene for cutting unless you have the big bucks for a plasma/air cutter or ...

Patrick

 

[Gary_in_Indiana]

Doc, thanks for the link. That's just the kind of help I was hoping to get.

 

[RoyJackson]

"Shielded Metal Arc is actually the technical term for regular arc or "stick" welding. "

I'll buy that...

Thanks for the correction...now I got to figure out what welding process I was describing.

 

[Hoosier_Daddy]

Gary, I have been thinking about doing the same thing. I assume you are talking about IVY Tech. I just hate driving to their school location. I haven't seen their flyer yet. When does the class start? Tom

 

[MossRoad]

Do it!

I went to IVY Tech in the late 70's and early 80's and got an associates in TV/Radio repair and another one in industrial electronics. I took some welding courses after that and they were alot of fun. It is amazing what you can learn from a good instructor. I also have a "set myself on fire" story, which I will share now.

I was ARC welding a practice pad in a booth. I had on a flannel shirt and it was tucked into my pants(no no). I was welding along and got to the end of the pad and stopped. Funny thing was, after I stopped, there was still an orange glow of light. I lifted my visor to see my shirt and pants on fire. I instantly slapped off the power to the welder, set the electrode on the hook, grabbed my fire extinguisher and put myself out. Looked around and no one had noticed, so I bunched up my burnt shirt and doubled my self over, limped out to the instructor and told him I had a stomach ache and went home. I had no hair left on my belly and a slight burn, but no real damage. Guess if I would have taken a test on safety, I would have flunked. /w3tcompact/icons/laugh.gif