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Old 08-02-2020, 04:04 PM
Moving Molecules . Moving Molecules . is offline
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Default Gas welding Gas Type,s.

Hi Team , when Gas welding Aluminium There seems to be 3 gases used.

1. Oxygen hydrogen
2. Oxygen Propane
3. Oxygen acetylene

Are there any preferences for a high-quality weld joint and what gas set up is the safest too use.

I have only used the third, but I am interested in Oxy/ hydrogen

Cheers Matt.
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Old 08-02-2020, 07:33 PM
Mike Rouse Mike Rouse is offline
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You may not want a bottle of hydrogen in your shop. It is a very small molecule capable of penetrating everything. Stay with oxy acet.
Mike.
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Old 08-03-2020, 03:48 AM
skintkarter skintkarter is offline
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Kent is the oxy/hydrogen man (oft used in aircraft work I gather). Quite a few of the whizzy tig guys use an argon/hydrogen mix for greater penetration.

Oxy/propane is mainly used for gas cutting (cheaper than acetelyne and not as hot) in my experience. Come to think of it, I've never seen a propane welding tip, just the cutting tips.
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Old 08-03-2020, 04:18 AM
steve.murphy steve.murphy is offline
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I thought I read someplace that Hydrogen was a cleaner burning gas, which was beneficial for gas welding .aluminum?
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Old 08-03-2020, 08:22 AM
billfunk29 billfunk29 is offline
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Default oxy hydrogen

You don't need to have a bottle of Hydrogen to weld. I have a hydrogen generator torch, uses water and electricity to make the hydrogen. It works very well but not a strong flame. Made for jewelry. Great for thin sheet. Bigger units are available.
https://www.gesswein.com/p-1447-hydr...ter-torch.aspx
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Old 08-03-2020, 10:45 AM
crystallographic crystallographic is offline
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Hi Matt,
Oxy-fuel welding is comprised of several fuel gas choices:

acetylene, being a triple-bonded hydrocarbon, is hottest at 6000F or so
propane (double-bonded, so less heat) - and its derivatives, propylene, Mapp, HGX etc.etc...
Natgas
Hydrogen- cleanest because the only combustion byproduct is water, H2O.

Acetylene is produced from calcium carbide and water, a dirty skanky process that produces 100% pure acet - unless the carbide is produced overseas in a funky plant, making a dirty product, which makes a dirty gas, leaving greasy remnants on your welds.(AIRGAS - GUILTY for over 10 years!!!) We make and sell a gas filter to clean this up.
O/A welds steel, stainless, inconel, bronze, copper, cast iron, mag, aluminum alloys, and in Russia, titanium.

Propane and derivatives, sold as SAFER (insurance companies pushing this), solders and brazes okay. With special torch and tips, it can cut steel. My company sells tips for propane welding/brazing/soldering - but you can use standard single-orifice tips that produce less heat. I have used oxy-propane when I lived in India or was visiting Italy regularly, to weld steel (not good) and aluminum (okay) and for brazing - but I greatly prefer O/A ...!! (staring at watch ---> says to self: "look at the time!")


Natgas - piped directly into buildings, no bottles needed. Insurance companies happy! Low temps - double-bonded hydrocarbon - fairly clean for soldering and brazing (low temp - Not 1800F or ++). Quality fairly uniform - (some folks that have a natgas well on property say their temps are hotter and gas is cleaner...)


Hydrogen - used exclusively in the US during WW2 for welding aluminum in all the aircraft factories, by order of the President FDR, wartime rationing sent O/A to shipyards and etc. steel production facilities.

(Books written later, post-WW2 say "because it was cleaner" - BUT - I happened to speak to the one man responsible, who got the call from FDR, "need-to-know - wartime rules/secrecy, never told anyone else" - and he went out and made the conversions across the US. We happened to have lunch together and then a long chat about aluminum history and welding...)
Hydrogen welds aluminum - 1250F nicely, and solders and brazes at "low" temps. I use O/hydrogen on some WW2 aviation jobs, as per original, for the sharp eyes in the crowd.
WARNING - you should NEVER take acet hoses/torch and then run Hydrogen through them - BOOM! acet. residues Explode on contact with H2. (Danger, Will Robinson!! Danger!!)

--- making this brief --- I've taught this stuff for waaay too long.
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Last edited by crystallographic; 08-03-2020 at 10:53 AM.
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Old 08-29-2020, 11:39 PM
Onicam1962 Onicam1962 is offline
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Quote:
Originally Posted by billfunk29 View Post
You don't need to have a bottle of Hydrogen to weld. I have a hydrogen generator torch, uses water and electricity to make the hydrogen. It works very well but not a strong flame. Made for jewelry. Great for thin sheet. Bigger units are available.
https://www.gesswein.com/p-1447-hydr...ter-torch.aspx
So for me, wanting to get into gas welding aluminum sheet (063 and thinner) would a hydro-welder like this actually work? I have limited space in my garage, and my TiG, MiG, and Plasma are already filling up space. I'd like to avoid having even more gas bottles taking up space.

I bought the flux from Tinman a while back...It's just been sitting, waiting for me to invest in a gas welding setup. The manufacturer of that unit in your link sells directly...in fact, they sell factory refurbs for around a grand.

Would a unit like this be a smart idea, in lieu of a traditional O/A setup? Do the little nozzles on the torch produce enough "umph" to do the job? It appears at though there's a flux that is produced in the chemical process of converting to hydrogen....would I still use the flux I got from Kent? Now that summer is winding down, I'll have more time to spend in my garage with my metal shaping activities.

Mike
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Last edited by Onicam1962; 08-30-2020 at 01:22 AM.
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Old 08-31-2020, 01:40 AM
lots2learn lots2learn is offline
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Quote:
Originally Posted by skintkarter View Post
Kent is the oxy/hydrogen man (oft used in aircraft work I gather). Quite a few of the whizzy tig guys use an argon/hydrogen mix for greater penetration.
Did you mean the TIG guys use Argon/Helium mix for greater penetration?
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Old 09-07-2020, 01:02 PM
crystallographic crystallographic is offline
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Quote:
Originally Posted by lots2learn View Post
Did you mean the TIG guys use Argon/Helium mix for greater penetration?

Not mixing Hydrogen for tig ...NO.


Yes, Helium adds an agitating component to the arc, helping the arc to clean the joint and also to push deeper into the molten pool for deeper penetration. Newer machines have an electric setting to do that now, without chemistry.

I have a 1980 model "Semit mixer" on the side of my 1981 Miller 250 DialArc, enabling me to mix any two gases at any ratio, at any time. Helium is one, CO2 another, O2 a third .... darn machine never gives me good reason to replace it ... going on - dang - 40 years -???? sheeeesh.

But not so "whizzy" - just simply good tig welding practice.

(Or maybe the Lear Aviation welder I learnt from had good advice...?

And I attended a few Aluminum Association national conferences .... chatted with the guys who write the aluminum welding books ....)


I try to get out and around a little ....
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