Talk to me about oxy LPG.

[soundman]

Oh yes well aware that oxy/LPG does not have the temperature to weld steel and even if it did because it does not have the excess carbon that acetylene has it would promote corrosion at those temperatures.

If I swing across to LPG it will be mostly for heating, and brazing....and may be a little cutting.

cheers

[LordBug]

The real question is, how much do you currently use your acetylene?

I'm sure you enjoy being the life of the party by filling garbage bags with it then chucking it on the fire and all, but that can't be worth the rental

[Karl Robbers]

The real question is, how much do you currently use your acetylene?

I'm sure you enjoy being the life of the party by filling garbage bags with it then chucking it on the fire and all, but that can't be worth the rental

Oh, I don't know about that. A well filled garbage bag has brought joy to many. What price on the children's happiness?

[welder]

Oh, I don't know about that. A well filled garbage bag has brought joy to many. What price on the children's happiness?

not as much fun as an aluminium drink can

[soundman]

Aparantly popper juce containers work very well too.....so I an told.

cheers

[Optimark]

[QUOTE=soundman;

If I swing across to LPG it will be mostly for heating, and brazing....and may be a little cutting.

cheers[/QUOTE]

Just as an aside, I attended the Elmore Field Day, which is a great place to purchase a tractor or other farming implement, as well as a myriad of welding demonstrations. There was one stand with a fella running compressed air and LPG to cut steel, very impressive.

Great speed, super clean cut and not too many downsides that I could see. There some limitations though, specifically the thickness of material that could be cut. In answer to a direct question, I was told that a piece of steel he had cut earlier that day was about as thick as one could go, it looked to be about 15mm thick, as far as I could ascertain. The speed and cleanness of cut was what impressed me the most, plus the ability to have the handle sitting there waiting to be picked up, then with a squeeze of the trigger(?) it was off and he was off cutting merrily away.

I do realise his environment was specifically set up for demonstrations, but with a group of farmers (and myself) surrounding him, there wasn't much room for BS being spread. I wondered about the compressed air side and asked about the pressure required, seems he was running about 5 Bar pressure, but I couldn't get a flow rate out of him in litres per minute. But, looking at the demonstrations and listening to his compressor in the background kicking in, I don't think the compressor requirements would be great.

Mick.

[Karl Robbers]

Would you happen to know the name of the torch that he was flogging?
In theory it shouldn't work because there should be insufficient oxygen in the air to react with the iron in the steel, but if you saw it working then obviously it does.

[soundman]

If ya pushng the air pressure up arround the 70psi, there may be enough oxygen compared to pure oxygen running at 25psi.

It may also be that the mechanism for cutting is different......compressed air may be displacing more metal by pressure rather than burning it by oxidisation.

remember the limitation seems to be 15 ish mm for this oxy air....where the limit for oxy acetylene is inches.

On that basis LPG air, realy has nothing on plasma.........my pissy little 40 amp chinese plasma cutter will do 6mm with little or no effort......it would probably do 15mm at a push...a 50 or 60 amp machine would on 15mm steel.

cheers

[Karl Robbers]

If ya pushng the air pressure up arround the 70psi, there may be enough oxygen compared to pure oxygen running at 25psi.

It may also be that the mechanism for cutting is different......compressed air may be displacing more metal by pressure rather than burning it by oxidisation.

remember the limitation seems to be 15 ish mm for this oxy air....where the limit for oxy acetylene is inches.

On that basis LPG air, realy has nothing on plasma.........my pissy little 40 amp chinese plasma cutter will do 6mm with little or no effort......it would probably do 15mm at a push...a 50 or 60 amp machine would on 15mm steel.

cheers

Hmm, not sure. I would have expected that the balance of Oxygen/Nitrogen would still prevent effective oxidation of the steel despite the more dense column of air that the increased pressure would bring. One observation was also the clean cut produced, something that arcair does not produce when used for cutting. Different heat source, but similar method of metal removal if we are proposing that the Air/LPG torch is cutting by physical displacement of molten material.
Very interesting from a technical perspective if nothing else, but ultimately limited applications I am guessing, given that both gas and electricity are required.
No more portable than a plasma, cuts less than Oxy fuel, but can heat and no cylinder rental or Oxygen gas costs, but electricity cost for compressor.
I definitely would like to know more.

[Optimark]

Would you happen to know the name of the torch that he was flogging?
In theory it shouldn't work because there should be insufficient oxygen in the air to react with the iron in the steel, but if you saw it working then obviously it does.

Unfortunately I didn't even take a picture of it, but it was red coloured with a sort of bend a bit like a boomerang, with the hand part being longer than the nozzle part. He had it hanging on a hook and when he had gotten his pieces of metal lined up, he reached over, I heard something, (which I assume to be a lighter) then the next thing he was cutting. I couldn't, or didn't see any flame, but it was a clear sunny day with very bright sunlight.

Really clean cuts, more interestingly, the very slight slag on the underside, he just used another piece of steel to push it off. Although where he started the cut there appeared to be about 2-3mm of molten metal at that end that didn't, or he couldn't, just push off.

I checked my Elmore Field Day catalogue, but there are literally over a thousand vendors there and without knowing the actual name of the exhibitor, I couldn't find him.

Mick.

[Karl Robbers]

Might have to research this one a bit more.
I like to keep abreast of developments, you never know when you may need to pull a rabbit out of the hat.

[Michael G]

Mick, Below is a link to the site map for Elmore.
http://www.elmorefielddays.com.au/un...Floor_Plan.asp
If you can work out roughly where you saw the torch the exhibitor list should be able to pop up some names that can be investigated further.

Michael

[Optimark]

Mick, Below is a link to the site map for Elmore.
http://www.elmorefielddays.com.au/un...Floor_Plan.asp
If you can work out roughly where you saw the torch the exhibitor list should be able to pop up some names that can be investigated further.

Michael

Hmm, never knew that interactive list existed. I am working on the basis that this map is facing East as presented, not north as is usual for maps. I base this on the orientation of the sun as we walked around.

From memory it was 8th avenue on the west side. We entered via gate 11, then proceeded south along the boundary, which is 10th avenue, we then walked north along 9th avenue, then south along 8th avenue. I'm reasonably sure it was a small (width wise) stand on the west side of 8th avenue and around the area of stands 970 - 970 - 966 - 962. It is possible that this was a stand within a stand, if you know what I mean. Onetrak on stand 970 would seem to fit the bill best, going on memory that is.

Mick.

[Michael G]

Onetrak is earthmoving equipment - does that sound right?
(Yes, north on this map is to the left)

Michael

[LordBug]

If ya pushng the air pressure up arround the 70psi, there may be enough oxygen compared to pure oxygen running at 25psi.

It may also be that the mechanism for cutting is different......compressed air may be displacing more metal by pressure rather than burning it by oxidisation.

remember the limitation seems to be 15 ish mm for this oxy air....where the limit for oxy acetylene is inches.

On that basis LPG air, realy has nothing on plasma.........my pissy little 40 amp chinese plasma cutter will do 6mm with little or no effort......it would probably do 15mm at a push...a 50 or 60 amp machine would on 15mm steel.

cheers

Considering you've got a MIG, you can cut through far, far thicker than that if you want