propane or acetylene ?

[Renze]

Careful cutting galvanized the fumes are toxic! Only in well ventilated and don't breathe it.

Problem is that all fuses blow as soon as i turn on the light in this pig barn that has been abandoned since 2 years: let alone turn on the fans !

I do drink lots of milk when working in there. Its known for decades that milk takes away the poisons of zinc and paint primer fumes. Still think i gotta find that gas mask though...

I do need 3 bar to cut this dirty scrap.. The oxygen consumption in relatively thin steel disappoints me a bit, but its still better than using an angle grinder...

 

[MJPetersen]

Renze,

I found what I used to make myself a laminated card for next to my torch. I will attach it as a PDF. It states that it is for Acetylene/Fuel Gas, so it should be appropriate for Propane also. It has both psi and metric. If you adjust the flame to a slight oxydizing state (without cutting oxy), then it will cut without having 3 bar. Maybe you need more heat to burn through the junk--your cut will not be as pretty (but then cutting galv is not going to be pretty). Turn up the heat (more gas volume and lower the pressure), but turn down the oxy pressure. According to the chart you will not need 3 bar until you are cutting material thicker than 25 mm and for most material .345 to .5 bar on the fuel should be sufficient. I gleaned this material from Victor's site a while ago--I did not just now make it up.

Good luck!!

Mike

 

[Transit]

Reading through all the replies, not one word of safety. Not that it is a deal killer, but be aware there are safety issues with any compressed gas that should be taken into account. Some localities will not allow flammable compressed gas to be stored at home; read, cannot use it. There are posts on TBN about compressed gas safety, read before you buy.

 

[smfcpacfp]

Reading through all the replies, not one word of safety. Not that it is a deal killer, but be aware there are safety issues with any compressed gas that should be taken into account. Some localities will not allow flammable compressed gas to be stored at home; read, cannot use it. There are posts on TBN about compressed gas safety, read before you buy.

Probably a good reason why nobody mentioned safety - the original poster didn't ask about safety.

 

[Prodirt6000]

acetylene all the way!

burns much hotter. so many more uses

 

[Renze]

Probably a good reason why nobody mentioned safety - the original poster didn't ask about safety.

I already knew that propane is much safer, because it is more stabile: Propane turns to liquid when compressed to 200 bar, where acetylene explodes above a certain pressure. Thats why the acetylene bottles are filled with a sort of aceton mud. When decompressed, the aceton releases acetylene. As i mentioned in another thread, when you bounce a bottle of acetylene, you can cause a chemical reaction inside the bottle which will generate heat, and unless the bottle is thrown into cold water, will explode the bottle.
Also with acetylene you need a flame extinguisher valve, to prevent the flame to bite back into the bottle. Propane doesnt backfire because it doesnt burn unless it is mixed with oxygen.

I am allowed to store the BBQ propane bottle at home, and the same bottle is used for the torch. No regulations here.


By the way, i just burnt my first 100 liter bottle of oxygen yesterday. I butchered old farm machinery, a silage feeder bucket, of which i salvaged the hydraulic cylinders for my grader project, and the slatted floor elevator for my bale processor. Oh, and we scrapped a hydraulic tail lift off an old truck we scrapped, which will become my brothers tractor drawn midi excavator (7.5t) hauler, tilt bed, aluminium foldable sides, with a Hiab crane up front.

Scrap prices are rising slowly, even though the past two months the prices have dropped 2 cents again. In the news was that in Holland, the recession is officially over because the economy is growing again, so i think the scrap prices will be back to 15 cents when in January, new production orders for the new fiscal year, are handed out to manufacturing and construction companies. I have lots of it, so i hope to take the scrap out at last years peaks (35 cts per kg !)

 

[MEhorseFarm]

In a past life I sold welding equipment and gases. The Acetylene vs Propane debate for cutting was always being knocked around amongst my customers. A lot of it came down to personal preference and cost. But be aware, there is a hidden cost that is often overlooked, and has not been mentioned in the forum. That is the amount of oxygen needed to achieve oxidization. Acetylene requires a 1.5:1 ratio (1.5 cubic meters oxygen to 1 cubic meter Acetylene) whereas Propane requires 4.5:1 ratio. The cost of the tank of propane is cheaper, but depending on what you are paying for Oxygen, that savings may not be as great as you think. Both will work for cutting just fine and propane will actually cut thicker steel (up to about 8") than Acetylene (up to 2") but for most of us, cutting less than 2 is more than adequate.

 

[MJPetersen]

Ah. That explains Renze's statement that he used significantly more oxy than I thought normal--thnaks for that bit of info.

Mike

 

[Renze]

But be aware, there is a hidden cost that is often overlooked, and has not been mentioned in the forum. That is the amount of oxygen needed to achieve oxidization. Acetylene requires a 1.5:1 ratio (1.5 cubic meters oxygen to 1 cubic meter Acetylene) whereas Propane requires 4.5:1 ratio. The cost of the tank of propane is cheaper, but depending on what you are paying for Oxygen, that savings may not be as great as you think.

Yes the oxygen consumption is a bit of a disappointment. I pay 40 euro for a refill of 200 bar in a 50 liter bottle. Propane is 28 to 30 euro, dont know the exact size.
The acetylene bottle i'd have to hire for 20 euro per month and 70 euro per fill or so. the Oxygen bottle rent is 70 euro per year.
I'm not that much cheaper as i thought but it works for me, and i dont pay rent for an acetylene bottle when not in use.

 

[helenxu96]

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