How do I start welding?

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BenH:

--- Quote from: mattinker on November 06, 2013, 03:57:54 AM ---
--- Quote from: DavidA on November 05, 2013, 07:03:40 PM ---AdeV,

... the more oxygen needs to be in the shield gas.,,

I never knew that. I always assumed that the idea of shield gas was to keep out oxygen.

And I've been welding for fifty or more years. Just shows how one can bumble along.

Dave :doh:

--- End quote ---

Well spotted, somebody got it the wrong way round! Free oxygen (not attached like the O in CO2) it to be kept out by the shield.

Regards, Matthew

--- End quote ---

No that's correct it's really only MIG (metal inert gas) welding with pure Argon (as used for Aluminium) CO2 or Argo shield is MAG (metal active gas) welding, with Co2 some of it breaks downs and the free oxygen burns the steel to create more heat, you get less of that with Argo shield light but then Argo shield heavy has added oxygen to burn off more steel and add more heat to the weld. It is the nitrogen your trying to keep out of the weld more than other things as it makes the weld brittle.

PekkaNF:

--- Quote from: raynerd on November 05, 2013, 03:47:21 PM ---....
I think maybe my mentioning of "thin plate" was misleading in my original message I'm talking 3-10mm plate and bar. Basically, making racking frames, welding box section...that sort of thing.
....

--- End quote ---

I lived my teen years on the farm and we used stick welder (MMA) to fix just about anything that had to fixed. Then I rented/boroved MIG to fix cars, my first car had a deer visit indoors.

Now I have invertter MMA and I say that for what kind of welding you are planning to do probably MMA would be most economical and educational choice. I had (and still have one) buzzbox cheap and nasty AC MMA. I don't recommend them unless you have a good teacher and are with really small budget. It's hard to use and very limitting. Bigger ex-industrial transformer welding machines can be had if you are willing to cart them out (least here some time ago) but tehy might need 3-phase supply, then again you 650A supply for hig % vs. 50A 50% of the nasty ones.

Compared to MIG/MAG
+ no gas
+ you can buy and use very different sticks, MIG/MAG you need to chance reel and possibly burner liner, nozzle etc.
+ Good versatility
+ inverter machines are pretty good, even the cheap ones
+ Some inverter MMA welders go down to 5A and offer remote control and TIG controls for added flexibility

- if you need production efficiency MIG is better, but megabucks with the cylcle you would need.
- thin plate is much harder and modern car body work not really feasible.

For car body work and other thin plates that needs some capacity MIG/MAG would be my first choice, but really hard to get any half decent machine under 600€ and almost decent is a bit over 1000€ + gas bottle + gas + old reels of wire you throw out + consumables.

Compare that for MMA, where you can buy half decent inverter 200€ range and very nice at 500€. And specially when there is very little extra expences and consumables to spend. Maybe longer and better cables that comes with cheapest ones (really cheap ones have something that looks like jumper cables and toys-r-us type stick holder and earth clamps).

I bought one ex-industrial inverter that i could use for TIG for about 200€ single phase from 10-160A (althought it needs over rated mains outlet at 20A) and only once thermal switch tripped when I was welding non-stop storage racks outside on good sun.

And one thing: Buy good helmet, gloves and cover yourself fully. Don't skimp on this one.

Happy huntting,
Pekka

mattinker:

--- Quote from: BenH on November 06, 2013, 04:44:00 AM ---
--- Quote from: mattinker on November 06, 2013, 03:57:54 AM ---
--- Quote from: DavidA on November 05, 2013, 07:03:40 PM ---AdeV,

... the more oxygen needs to be in the shield gas.,,

I never knew that. I always assumed that the idea of shield gas was to keep out oxygen.

And I've been welding for fifty or more years. Just shows how one can bumble along.

Dave :doh:

--- End quote ---

Well spotted, somebody got it the wrong way round! Free oxygen (not attached like the O in CO2) it to be kept out by the shield.

Regards, Matthew

--- End quote ---

No that's correct it's really only MIG (metal inert gas) welding with pure Argon (as used for Aluminium) CO2 or Argo shield is MAG (metal active gas) welding, with Co2 some of it breaks downs and the free oxygen burns the steel to create more heat, you get less of that with Argo shield light but then Argo shield heavy has added oxygen to burn off more steel and add more heat to the weld. It is the nitrogen your trying to keep out of the weld more than other things as it makes the weld brittle.

--- End quote ---

This interesting and new to me, I was always told that one had to avoid oxidisation, I started stick welding forty years ago, I got into MIG and TIG within the last ten years. I am so used to stick that I use it whenever I can. I did a TIG Al welding course a few years ago, the oxidisation problem with Al was ever present. I haven't done any TIG on steel so I can see that I am probably off course about the shield gases!

Regards, Matthew

Dawai:
Knowledge + experience is the most important thing I read and agree with. Each mode of welding requires lots of practice.

One thing I didn't learn for years, not being a real welder?? don't look at the arc-flame, listen and see to move it where you want it, look at the puddle it creates. I've seen some much better welders than I flick the gas torch away to see the puddle-heat, then right back. This also reduces the heat.

I learned to tig weld with a buzz box (scratch start), learned from a oil pipeline welder I was working around, I learned to go fast, add rod to cool the puddle. AND bad habits are hard to break, even with the "heat" pedal on my tig I wanna go fast and dump the rod in the puddle to cool it. I SUCK at thin metal with the tig. (with thin metal the heat comes quicker, the puddle is on your shoes instead of the metal seam) I can however weld thick metal great, malleable, almost as good as the gas torch. For thick metal I normally grab the stick welder thou.

Blacksmiths welded things like weather vanes in a forge, I think that is a lost art. I'd not have a clue how.

Fergus OMore:
Ah, this weld pool thing!

The old blacksmiths used to 'get rid of the dottle' in the weld pool. Dottle is the old word for the unsmoked residue at the bottom of a clay smokers' pipe. What is contained is all sorts of impurities and the result is porosity. In other words, if you have a boiler, you have leaks. If you are doing a garden gate, so what, if you are facing a boiler inspector, you have trouble. So the torch is used to lift the impurities to the top of the pool.
I can or could do it, My father was one of the old fashioned blacksmiths and I spent many a childhood moment at the side of his anvil.

A little note about forge welding? Of course, you have to have your steels white hot and able to be kneaded like bread although you needed a hammer to mix it. Somehow, I agree about the forgotten arts. My father rejoined broken leaf springs and then got the right temper back with a stick. A little further back in the history book, the old German sword makers in his village kneaded wrought iron into steel folding it and adding carbon on each fold.

Looking back- and a bit forward, we are still doing much the same with case hardening and also spinning items until they become white hot and a join occurs.

I still temper my carbon steel tools with a potato. Those who use their own urine- are a law unto themselves.
It's called 'nitriding' or night riding :scratch:

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