How do I start welding?

[BenH]

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

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

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]

....
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.
....

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]

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

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

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.

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

[AdeV]

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

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

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.

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

TIG welding uses pure argon generally as the shield gas. You don't want O2 when TIG welding because it will oxidise the electrode... To get extra deep penetration with TIG welding, you crank up the amps, use a fatter electrode, and just weld a bit slower. In fact, if anything, the problem with TIG welding is it tends to really load the part up with heat - much more so than MIG in my experience.

MIG, because it's laying down new metal, if you want to go deep (oo-er) you need to get more heat into the weld quickly. Best way to do that is to add some O2 to the argon, the O2 reacts with the steel to make extra heat which melts more metal & allows you to make strong welds even in thick metal with minimal warpage. I'd imagine that if you were mig welding aluminium you'd want pure argon rather than argoshield.

[mattinker]

TIG welding uses pure argon generally as the shield gas. You don't want O2 when TIG welding because it will oxidise the electrode... To get extra deep penetration with TIG welding, you crank up the amps, use a fatter electrode, and just weld a bit slower. In fact, if anything, the problem with TIG welding is it tends to really load the part up with heat - much more so than MIG in my experience.

MIG, because it's laying down new metal, if you want to go deep (oo-er) you need to get more heat into the weld quickly. Best way to do that is to add some O2 to the argon, the O2 reacts with the steel to make extra heat which melts more metal & allows you to make strong welds even in thick metal with minimal warpage. I'd imagine that if you were mig welding aluminium you'd want pure argon rather than argoshield.

Thanks,
I thought I had it all clear in my mind! New parametres to ingurgitate!

Regards, Matthew

[DavidA]

You may find this usefull.

http://www.mig-welding.co.uk/gas-composition.htm

I use Air Products Cougar 5 for my MIG and TIG

93% Argon,  5% Co2,  2% Oxygen.

Dave.

[DavidA]

...and going through the zinc coating by stitching with a mig and getting the zinc to flow back evenly was fun...

You could have made your life a lot easier if you had removed the zinc first.  Must be  a sure way of getting inclusions in your welds ?

Dave.

[Fergus OMore]

...and going through the zinc coating by stitching with a mig and getting the zinc to flow back evenly was fun...

You could have made your life a lot easier if you had removed the zinc first.  Must be  a sure way of getting inclusions in your welds ?

Dave.

Err Umm? One word- Thatcham covers it.

Norman

[tom osselton]

I'm using a cheaper 100 amp tig inverter that  have to say works quite well and is good for I think 3/16 with the tig it cost about $500 by the time it was set up not too far a price from a cheaper / used mig set up.

 

[TLGriff]

I used to teach welding in high school and always started the students out with oxy-acetylene welding. It's a great way to learn the theory of welding and it uses the same mechanical movements as other types of welding. The next logical step was stick and MIG, followed by TIG which requires the most skill and knowledge. I would recommend the same approach in the home shop. A gas welder will teach you the welding process and be much for useful than electric welders. When you aren't welding, you can use the gas welder to heat stubborn fasteners for disassembly, flame cut steel parts, heat treat parts and even repair the exhaust system on your car. It can also be use to braze, silver solder and in a pinch, even weld aluminum although that requires considerable skill. It can even be used to impress the neighbors by making a heck of a boom on New Years Eve, not that I've ever done such a thing. 

The first welder I bought for my shop was oxy-acetylene, followed by MIG which I use primarily for automotive sheet metal work, then TIG/stick. I use them all, but the gas welder gets the most use by far.

Tom

[awemawson]

Tom, I agree wholeheartedly that oxy-acetylene is an excellent basis for learning. Sadly though on this side of the pond it is very difficult to get acetylene other than in rented cylinders, and the rental is very silly money. So for Chris starting out it is probably not a contender. There are suppliers who will outright sell an oxygen cylinder, but acetylene in reasonable sizes so far has eluded me. My cylinder rental is currently counted in £100's per annum for a full size acetylene, oxygen and argon which frankly I can't justify.

Andrew

[DavidA]

Andrew,

Yes,  the rental is a real problem.

My half sized acetylene cylinder cost me £135 for a five year contract. Plus the cost of the gas. That was from Air Products. I suspect that the contract has run out, so when the cylinder is empty I will have to do it all again. I am very careful using the gas welding set because of this.  So I can easily make the one acetylene last a year.

I bought a full size oxygen bottle many years ago and manage to get it changed at a local scrap yard.  Mind you,  the last change was  some time ago,  so I don't know if they will still do this.

Dave.

[PekkaNF]

... My cylinder rental is currently counted in £100's per annum for a full size acetylene, oxygen and argon which frankly I can't justify.

Andrew

All three or just one bottle. Honestly if I could rent Argon for 100 (EUR/USD/GPB) a year here I would go for TIG in nanoseconds.

I'd say: Go for stick. If you can get an invertter that you can use later for TIG even better. Stick works well on stated 3 to 6 mm materials and is versatile and more economical when not used full time. If it were much thinner metals I would recommend MIG/MAG, but consumables are a killer and proper use really needs tutoring. I had a vocational school welding teacher to teach migging few evenings and without his input it would have been pretty steep learning curve - even with Morris Marina which was recovering from a minor deer damage.

Pekka

[BenH]

Albee do rent free Acetylene over here, nice thing is the bottles come with regulator and flashbacks built in. When the last on mine is used up my BOC will go back and I'll have one of those instead

http://albeegascylinders.com/

[awemawson]

Interesting Ben as they list a stockist quite near to me. They are very shy of putting prices on their web site - any idea what they are charging ? I am paying BOC £109  each per annum rental for 'portapak' sized cylinders  of oxygen and acetylene - I think that's a 'Y' size and an 'L' size with the chancellors iniquitous VAT on top of that. So that's £261 a year NOT including the gas !!!!

[TLGriff]

I'm surprised acetylene generators haven't made a comeback if the gas is so hard to get. Calcium carbide and water is all it takes.

Tom

[b4dyc]

Try this link to one of the Albee dealers http://www.pg-merlin.co.uk/page/oxygen_and_acetylene_cylinders_in_kent
I have one of their Argon bottles. Seems to last an age for me 

[vtsteam]

I own all my bottles -- half size originally cost about $100 ea. and am lucky enough to be able to fill them locally for something like $30 ea.

Of course I'm reducing that cost further now by using oxy propane for cutting and brazing.

That's about $20 for a 20 lb propane cylinder refill -- but that's about eight times the fuel gas that the acetylene represents -- so the equivalent of $240 worth of acetylene for cutting and brazing. I can also have it refilled just about anywhere, rather than a welding supply outfit. Running out on a weekend isn't a problem -- except that, I've never run out at all!

[awemawson]

OK so £363 plus VAT =  £435.60 to start up - yikes ! So after two years I'd be saving on BOC - long term it looks good - short term it hurts

[BenH]

When I checked last at my local a few months back it was £190 for the bottle and £50 ish for the refill on the Acetylene, but bear in mind with the regs and flashback in if you did not already have the gear it would work out cheaper as such. Acetylene bottles are always going to be more expensive than a regular high pressure gas bottle though.

For the oxygen I'm going with a Adams gas trade size oxy as that work out much cheaper and has a lot more in, but you need a reg already. For me as I use oxy propane for cutting and brazing, the smaller Albee Acetylene will last a long time for the odd welding job.

The Adams trade size is 20ltr @200bar, so a fair bit more volume but the bottle cost is about the same as a Albee to buy. I already use Adams for my Argon and my local supplier is very good, so I'd be happy sticking with them but depends where you are other options might be better.

[awemawson]

I've had Portapak cylinders from BOC for perhaps ten years (groans at the cost) so already have gauges, I've also got a 'proper' set of grown up full size oxy-acetylene cylinders and gauges that I got off a certain auction site many years ago and have had refilled from various sources over the years through various back doors  but I'd not really admit to that  

It's actually handy having two set ups - the big cylinders usually have the cutting gear on, whereas the Portopak has the welding torch.

[Arbalist]

When I was taught to gas weld over 30 years ago they always said not to worry about a flashback - it would take hours to become dangerous and the fire brigade would deal with it if necessary...

http://www.hse.gov.uk/pubns/indg327.pdf

[doubleboost]

Hi
Interesting discussion
I have  MIG TIG &  Stick( MMA) welding at home
The one thing I do not have and never will have is Acetylene
Far to dangerous to have near the home
I rent half size Argon and Argoshield bottles for £6 a month each
Considering the price of diesel and tabs (cigaretts)
Not to bad for a hobby
John