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  #1  
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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  #2  
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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  #3  
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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  #5  
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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  #7  
Old 08-03-2020, 01:06 PM
Moving Molecules . Moving Molecules . is offline
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Hi Kent, thank you for this great piece ... your fingers must be hurting.

I have used Gas welding oxyacetylene on a 1958 mklll Aston Martin in 2017.

But would really like to try oxyhydrogen Welding with New hoses and torch.

It burns a little lower than oxyacetylene doesn’t it.

Would you say Oxy hydrogen welding is safer and produces better welding for high end classic cars?.

Also looking for some new goggles.

Cheers Matt UK.
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Last edited by Moving Molecules .; 08-03-2020 at 01:09 PM.
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  #8  
Old 08-03-2020, 08:43 PM
crystallographic crystallographic is offline
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Hi Matt,
I did a ratty old Aston DB once, with a bent frame.
Aston 4.JPG
A_Aston DB4_aluminum damage repair.jpg
B_Aston DB4_aluminum damage repair.jpg
C_Aston DB4_aluminum body damage repair.jpg

Aston DB4_8_copy.jpg
D_Aston DB4_aluminum body damage repair.jpg
Z_Aston DB4_aluminum body damage repair.jpg
I used O/A, my Meco torch, my sooper dooper flux, and my gaggles.
But no Wonder Butter ....

(I left it ready for a kiss with a Vixen, checked with straightedges and gauges ... Nice ! ... the owner got all excited ....)



I have 5 torch/bottle sets here, for O/A. But only one for O/H.
I flipped a coin ... O/A won.
And it was a Monday.
But not a full moon - like tonight .... (Snoopy Dancing image ---> here)
Makes no diff to me. So I flip a coin.
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Last edited by crystallographic; 08-03-2020 at 08:48 PM.
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  #9  
Old 08-03-2020, 09:08 PM
BTromblay BTromblay is offline
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Hi,

I'm still new to Oxy/hydrogen welding, have been doing it for this past year in aircraft components. My background is in TIG welding and have switched over to gas welding do to the increased crack resistance, easy to develop full penetration, high weld density and authentic looking welds for metal shaping components and restoration work. Most of my knowledge has been learned thru Kent's videos, books and conversation and hours of practice. I have also purchased vintage books, written by ALCOA and other aircraft books of the time period.

Please take this observation with an understanding of my level of experience as written above. I feel that Oxy/hydrogen is easier to weld aluminum than oxy/acetylene due to the flame temp being closer to the melt point of aluminum. An example would be taking a TIG welder and turning up the current. Can you weld with it? Yes. Is it easy? No. This is subjective, Kent has demonstrated welding with a rose bud. Can you do it? Yes. Easy? No. I find that the lower temp allows for more control and a slower speed across the panel then acetylene. The ALCOA manuals spec to up one tip size compared to Acetylene due to the lower temp. Flame set up can be challenging in the beginning due to the clear flame, but definitely doable.

We don't use hydrogen at all for welding steel or stainless due to hydrogen enbrittlement. It is for aluminum/nonferrous use only. It is one thing to consider if it is your only source for welding.

Bill
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  #10  
Old 08-04-2020, 07:48 AM
Moving Molecules . Moving Molecules . is offline
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Quote:
Originally Posted by BTromblay View Post
Hi,

I'm still new to Oxy/hydrogen welding, have been doing it for this past year in aircraft components. My background is in TIG welding and have switched over to gas welding do to the increased crack resistance, easy to develop full penetration, high weld density and authentic looking welds for metal shaping components and restoration work. Most of my knowledge has been learned thru Kent's videos, books and conversation and hours of practice. I have also purchased vintage books, written by ALCOA and other aircraft books of the time period.

Please take this observation with an understanding of my level of experience as written above. I feel that Oxy/hydrogen is easier to weld aluminum than oxy/acetylene due to the flame temp being closer to the melt point of aluminum. An example would be taking a TIG welder and turning up the current. Can you weld with it? Yes. Is it easy? No. This is subjective, Kent has demonstrated welding with a rose bud. Can you do it? Yes. Easy? No. I find that the lower temp allows for more control and a slower speed across the panel then acetylene. The ALCOA manuals spec to up one tip size compared to Acetylene due to the lower temp. Flame set up can be challenging in the beginning due to the clear flame, but definitely doable.

We don't use hydrogen at all for welding steel or stainless due to hydrogen enbrittlement. It is for aluminum/nonferrous use only. It is one thing to consider if it is your only source for welding.

Bill
Fantastic two posts, Kent and Bill, can I personally message both of you if I come across any problems.

Our Email is : Precisionpanelcraft@gmail.com

Also Kent Great job in saving his British Icon.... For my contribution, Look up on YouTube ; the things you find in a House survey, DB2 Aston Martin by Peter Ward.

This is the car l remade.... it has a great story but also a Sad one.

1958 Aston Martin DB2/4 mklll Drophead l think 14 are left from the 71 made.

When you push a human being, a human being will perform...😉

Kind regards Matt
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