nzjetboating Web Board.

nzjetboating.com Forums => Tech Library => Topic started by: Paul on July 13, 2012, 17:32:33 PM

Title: Welding: Shielding gas options
Post by: Paul on July 13, 2012, 17:32:33 PM
I'm Looking for info re welding shielding gases.

Found the following so far:

http://www.mig-welding.co.uk/welding-gas.htm (http://www.mig-welding.co.uk/welding-gas.htm)
http://www.mig-welding.co.uk/gas-composition.htm (http://www.mig-welding.co.uk/gas-composition.htm)
http://shdesigns.org/Welding/gasmix.shtml (http://shdesigns.org/Welding/gasmix.shtml)
http://en.wikipedia.org/wiki/Gmaw (http://en.wikipedia.org/wiki/Gmaw)

Does anyone have any other references, or local data?
Title: Re: Welding: Shielding gas options
Post by: lachlan on July 13, 2012, 18:13:39 PM
what info do you want exactly ?

your question is a bit like someone asking for info on cars ...
Title: Re: Welding: Shielding gas options
Post by: Paul on July 13, 2012, 18:21:56 PM
what info do you want exactly ?

Say for steel, ali and stainless, what's options are out there for welding gasses and which have what benefits/drawbacks/costs?

What would you use, given the choice and why?

What places can you get cylinders from (BOC/Supagas/etc)?  Would you go rental/customer-owned?  What sort of prices are people getting?
Title: Re: Welding: Shielding gas options
Post by: PM on July 13, 2012, 21:17:40 PM
Alloy - Argon
Stainless - Argon
Steel - Usually 12% CO2 / Ar mix, or 100% CO2

Grab your ankles at BOC, unless you use a significant volume (read 20+ 'G' size cylinders per year). Supagas and Air Liquide both sell industrial gasses.
Title: Re: Welding: Shielding gas options
Post by: tim k on July 13, 2012, 22:27:08 PM
depends what you want to weld, ali and stainless usually straight argon,
steel argon mix but can use co2, can work well with flux core but better if matched.
if you tell us what you have in mind then much easier to answer you question.
Title: Re: Welding: Shielding gas options
Post by: Jeff B on July 14, 2012, 05:15:22 AM
Ali- pure argon
Stainless- we use argon/co2 or sometimes argon/hydrogen
mild steel- argon/co2(argoshield)
Plastic-????? ??? ;D
Thats for MIG welding, for tig welding we use pure argon for everything.
Title: Re: Welding: Shielding gas options
Post by: Paul on July 14, 2012, 16:03:51 PM
Cheers guys.

If you were to MIG steel with pure argon, what are the problems created, or why is this combo not good?

Is there much difference in results/strength/looks, with argomix vs CO2, when MIG'ing steel?  Apart from argon being 3 times the price of CO2.
Title: Re: Welding: Shielding gas options
Post by: MRM on July 16, 2012, 17:46:51 PM

Stainless- we use argon/co2 or sometimes argon/hydrogen

Would you use hydrogen? BOOM! fl.

Title: Re: Welding: Shielding gas options
Post by: MRM on July 16, 2012, 17:53:21 PM
How much welding are you looking to do Paul?

Tradezone or one of those out east had little disposable cylinders for dabblers, 1 or 2 kg I think.
Apparently you can't buy cylinders any more, and renting them is the same cost per year whether you use 1kg or the whole cylinder.
The tradezone guy said they used to fill cylinders, but now they send them to BOC to fill, and on occasion they have just confiscated the customers cylinder for whatever reason. He has had to ring customers up and say "sorry, your cylinder is gone!"
Title: Re: Welding: Shielding gas options
Post by: Paul on July 16, 2012, 20:00:51 PM
Would you use hydrogen? BOOM! fl.

I believe the argon/hydrogen and also the CO2, is classed as MAG welding (Metal Active Gas, vs Metal Inert Gas) - exactly the same gear, just different gas.  You can also get an Argon/Oxygen mix!  I think the active gasses are something to do with breaking up scale/rust/corrosion, or something, so the spark can get trough to the base metal.
Title: Re: Welding: Shielding gas options
Post by: Paul on July 16, 2012, 20:19:42 PM
How much welding are you looking to do Paul?

Tradezone or one of those out east had little disposable cylinders for dabblers, 1 or 2 kg I think.
Apparently you can't buy cylinders any more, and renting them is the same cost per year whether you use 1kg or the whole cylinder.
The tradezone guy said they used to fill cylinders, but now they send them to BOC to fill, and on occasion they have just confiscated the customers cylinder for whatever reason. He has had to ring customers up and say "sorry, your cylinder is gone!"

Probably not a lot.

Don't really want to want to be paying monthly rental on big cylinder.  I believe all of the 'old cylinders' that BOC handed out all those moons ago, were/are, still BOC owned, this was when BOC used to hand out cylinders and you paid for the gas only.  Due to tanks coming back many years/decades later, BOC's business model changed so there was also a monthly rental. So when people take these old cylinders back, they may well also be out of test date.  For some gas cylinders, it is the Law that if you present an out of date cylinder for fill, then it either has to be sent away for test (at your cost); crushed flat; or have all the thread reamed out of the neck (making it useless).  I guess there were some big safety issues with old cylinders, coming back with damaged tanks/valves and they want to sort this out.

Coming back to 'customer owned' cylinders, you CAN still get them - indeed there are multiple companies on trademe that sell them:
http://www.trademe.co.nz/Members/Listings.aspx?member=884430 (http://www.trademe.co.nz/Members/Listings.aspx?member=884430)
http://www.trademe.co.nz/Members/Listings.aspx?member=1179440 (http://www.trademe.co.nz/Members/Listings.aspx?member=1179440)

They have a '10 year test' and I believe the 'breakeven' on the cylinder purchase, is about 2 years, vs renting one.  With some cylinders you can also get them retested after the 10 years is up, or dispose of them.  One of the downsides to 'customer owned' appears that getting them filled is not an instant thing - some need to be sent away and they are 'batch filled', so you may be without a cylinder for 2/3/4 weeks.  Wheras with rentals, it's almost like swap-a-bottle.  The LPG tank in my car is now on it's 7th year and I'll need to retest/replace that tank at/before 10 years is up (assuming I've still got the car!!).  :)  Re-test is relatively simple process and is like a dive cylinder test.
Title: Re: Welding: Shielding gas options
Post by: JR on July 16, 2012, 20:36:35 PM
How much welding are you looking to do Paul?

Tradezone or one of those out east had little disposable cylinders for dabblers, 1 or 2 kg I think.
Apparently you can't buy cylinders any more, and renting them is the same cost per year whether you use 1kg or the whole cylinder.
The tradezone guy said they used to fill cylinders, but now they send them to BOC to fill, and on occasion they have just confiscated the customers cylinder for whatever reason. He has had to ring customers up and say "sorry, your cylinder is gone!"
I have even seen Co2 Sodastream gas bottles used on welders.... Bloody funny to see such a small bottle on a welder... Cheers JR
Title: Re: Welding: Shielding gas options
Post by: Paul on July 16, 2012, 20:41:31 PM
I have even seen Co2 Sodastream gas bottles used on welders.... Bloody funny to see such a small bottle on a welder... Cheers JR

I believe people have also used CO2 fire-extinguishers with an adaptor, on their welder (unscrew the 'spray nozzle', screw on adaptor, activate and clamp trigger!!).  :)  And it's allegedly rather cheaper than welding suppliers and a bit easier to get refills..
Title: Re: Welding: Shielding gas options
Post by: 88V8UTE on July 16, 2012, 22:26:20 PM
I have even seen Co2 Sodastream gas bottles used on welders.... Bloody funny to see such a small bottle on a welder... Cheers JR

 aAe a very easy way of doing it!! when i was 18 i built up my Falcon speedway saloon using a cheap Mig and sodastream bottles, when i ran out i just shot down to the supermarket and swapped for some full ones, an added bonus is you dont need to worry about testing, i bought half a dozen REALLY old sodastream bottles off trademe, took them in to swap no worries *-), does work out a bit dearer than a big bottle, but if your not doing much welding its really convenient!!
Title: Re: Welding: Shielding gas options
Post by: H2OSkier on July 17, 2012, 10:26:59 AM
Here is the low down on Gases.

BOC trade names used are in New Zealand.

Mig (Mag) Steel - CO2 gives deep narrow penetration with a pronounced bead profile, produces alot of spatter, is slower, won't support spray transfer, but is relatively cheap.
Argoshield (Ar/CO2/O2) gives shallower, wider penetration with flatter bead profile, is low or almost spatter free, will support spray transfer, is faster, but more expensive.

100% Ar is not recommended for Mig of Steel or Stainless due to porosity, poor fusion, and large uncontrollable droplet size.

Mig of Stainless - Stainshield (He/Ar/CO2) gives clean fast weld with good penetration, flat bead, low spatter, no porosity. Can use Ar/CO2 which is cheaper.
DO NOT use any Argon/Oxygen mix with stainless.

Mig of Aluminium - 100% Argon, or Alushield (Ar/He) which gives much faster weld due to better energy transfer.

Tig - DO NOT use anything with Oxygen in the mix.
        Any CO2 can break down and release oxygen.       
for Steel use 100%Ar, or Ar/He mix
for Stainless, use 100% argon, or Ar/He mix, or for BEST results use Stainshield Tig (5%H2 in Ar) The hydrogen scavenges any oxygen that may be present, gives around 15% faster weld resulting in much reduced heat affected area and much less discolouration.

for Aluminium, use 100% Ar, or for BEST results use Ar/He mix - around 15% faster, less distortion, better(quicker) pool formation at start of weld. Downside is price and you use more.
DO NOT use anything with Hydrogen,Oxygen or CO2 for Aluminium.

These are all BOC trade names, but the other gas suppliers all do similar mixes.

Cylinders - Rental or owning is down to your situation and preference.
Rental rates vary considerably with BOC being the most expensive by far, and usuallly not prepared to negotiate.
If you don't have a choice in you location you will be stuck with renting their cylinder - they won't fill yours.
If you buy a cylinder, check that your gas supplier will fill them well into the future.
Owning is a good option if you have a static requirement with low, infrequent, consumption. check on the "Gas Price" for filling your cylinder compared with "Gas Price" for a rental - some suppliers charge more for filling your cylinder.

Does that help you Paul
Title: Re: Welding: Shielding gas options
Post by: Paul on July 17, 2012, 10:44:58 AM
Does that help you Paul

That's excellent.  Cheers Ross.  :)
Title: Re: Welding: Shielding gas options
Post by: Paul on August 16, 2013, 10:12:59 AM
4043 is designed for welding 6xxx series aluminum alloys. It may also be used to weld 3xxx series alloys or 2xxx alloys. 4043 has a lower melting point and more fluidity than the 5xxx series filler alloys, and is preferred by most welders because it "wets and flows better" and it's less sensitive to weld cracking with the 6xxx series base alloys. 4043 can also be used for welding castings. 4043 also makes brighter looking MIG welds with less smut because it doesn't contain magnesium. 4043 gives more weld penetration than 5356, but produces welds with less ductility than those made using 5356. However, 4043 is not well suited for welding Al-Mg alloys and should not be used with high Mg content alloys such as 5083, 5086 or 5456 because excessive magnesium-silicide (Mg2Si) can develop in the weld structure to decrease ductility and increase crack sensitivity. (One exception to this rule is 5052, which has a low magnesium content.)

5356 wire has become the most commonly used of all aluminum filler alloys because of its good strength and its good feed-ability when used as a MIG electrode wire. It is designed to weld 5xxx series structural alloys and 6xxx series extrusions, basically anything other than castings, because castings are high in silicon. Its one limitation is that 5356 is not suitable for service temperatures exceeding 65 degrees Celsius. The formation of Al2Mg at elevated temperatures at the grain boundaries makes the alloys prone to stress corrosion. For components that will be anodized after welding, 5356 is recommended over 4043, which turns jet black when anodized.
Title: Re: Welding: Shielding gas options
Post by: Paul on December 04, 2016, 22:43:44 PM
Re-spooling welding wire!   O))))

https://www.youtube.com/watch?v=7DLvggf2NPE&feature=youtu.be&t=11m25s