Portable oxy-acetylene tote outfits? Worth having?

[IslandTractor]

Well I am actually glad we couldnt use it here, we ended up with a blueshield industrial torch kit, and a b acct tank, and 44ish cf o2 tank. A lot more useful. We have cut rr track with it. It is still light enough to carry up stairs with 2 people, and it mounted on a cart for normal transport. I would recomend something with those size tanks, before I would a porta torch.

I have the same setup. Even the B tank however is really not capable of safely doing much cutting. It is about 40cuft as I recall and that means 5.5cuft/hr (or if you look at more recent 1/10 capacity standards only 4/hr). If you look up the acetylene requirements for even a #1 cutting tip you will see that they are in the 6-7 cuft/hr range (I haven't double checked my memory but looked this up a month ago). That means that even the B tanks are marginal for cutting. Ask someone at a local welding shop. They will clearlly steer you away from B tanks if you are doing a lot of cutting. In theory you can create a manifold to link several B tanks together but that is almost never worth doing considering the hassle.

For cutting (not welding) it makes more sense to use oxygen and propane if you cannot use 80cuft and larger acetylene tanks. Propane is cheaper, safer, easier to get. You can use the same regulator as on the acetylene tank but need T standard hoses rather than the more typical hoses that come with acetylene.

Again, just to clarify, the issue with small acetylene tanks is not the total amount of acetylene in them but rather the rate that the acetylene which is contained in an acetone solution can vaporize out of the acetone. If you draw off gas and exceed the rate that it vaporizes out of the acetone, the tank pressure will force the acetone itself into the regulator which will damage the regulator and then you have risk of fires etc when the acetylene does vaporize. Acetylene is not an intuitive gas like oxygen, argon, CO2 etc. It is useful but you really must understand how to use it safely.

 

[HCJtractor]

Thanks for the clarification. I was under the impression that the main limitation was in the small capacity of the tanks. I could live with that as I would not have used it much. But the issue with safety based on the rate of flow was not something I considered. Thanks for "learning" me! I guess I just saved $400. It is odd that the manufacturers clearly state that these "tote" rigs are capable of cutting 1/2, when in fact, it appears that they are not able to do this safely. Oh well. I will just have to haul my bigger tanks or use the generator. The 18V may also be an option for little stuff, but I was hoping to be able to cut 1/2". Thanks again for educating me. There is a wealth of info here.

 

[IslandTractor]

Thanks for the clarification. I was under the impression that the main limitation was in the small capacity of the tanks. I could live with that as I would not have used it much. But the issue with safety based on the rate of flow was not something I considered. Thanks for "learning" me! I guess I just saved $400. It is odd that the manufacturers clearly state that these "tote" rigs are capable of cutting 1/2, when in fact, it appears that they are not able to do this safely. Oh well. I will just have to haul my bigger tanks or use the generator. The 18V may also be an option for little stuff, but I was hoping to be able to cut 1/2". Thanks again for educating me. There is a wealth of info here.

Although the 20cuft oxygen tank will be another limitation, you could explore using a 20lb propane tank along with oxygen to cut. It is done pretty commonly these days due to the relative costs and availability of propane vs acetylene. You don't really need to reach welding temperatures with cutting so the acetylene is traditionally used just because it is already present as part of the welding set up. Propane is a good and economical substitute. Remember that once you get the metal hot enough to cut with oxygen you can actually shut off the fuel gas and just continue the cut with oxygen alone. No one does that for practical purposes but it works. Cutting is really just very rapid rusting or oxidation at high temperature.

 

[slowzuki]

The smallest we used was b-size. Neighbour has a set with his torches but the O2 cylinder is perpetually empty. Cutting uses all the O2 in no time.

 

[Yooper75]

Not to hi-jack the OP's thread but I have been shopping for a cutting torch for my shop and I have been looking at the propane kit's. Here is my thought, I have propane plumbed into my shop for a forced air furnace and I am temepted to get a propane torch kit, lease an o2 cylinder, and tap into my propane line coming in off my bulk tank to run the torch. Is this doable or is there not enough pressure to run a cutting torch?

 

[RPW]

Minor correction to the history of the bottles, mc=motor car, b=bus. A friend of mine quizzed me on that one. He's been welding since the dawn of ages

 

[HCJtractor]

Although the 20cuft oxygen tank will be another limitation, you could explore using a 20lb propane tank along with oxygen to cut. It is done pretty commonly these days due to the relative costs and availability of propane vs acetylene. You don't really need to reach welding temperatures with cutting so the acetylene is traditionally used just because it is already present as part of the welding set up. Propane is a good and economical substitute. Remember that once you get the metal hot enough to cut with oxygen you can actually shut off the fuel gas and just continue the cut with oxygen alone. No one does that for practical purposes but it works. Cutting is really just very rapid rusting or oxidation at high temperature.

OK, let's forget the acetylene tote. How practical would it be to make up relatively portable set up with propane. I assume the 20 lb. propane tank is what you see on gas grills. Could you mate a similar size oxygen tank (what is next size up from a 20cuft---a #4??) and make a tote that would contain these and be light enough for one person to load (say under 100 lbs.) I would need regulators and a propane torch. Do they sell all this at local welding supply houses such as Airgas? Are the propane tanks just like my gas grills or are they something different? Has anyone done this?? Would it be practical for cutting 1/2" steel on a occasional basis?

 

[Verticaltrx]

For what you are doing I think the little porta torch setups would be fine. I have had a small Harris one for about the past 15yrs and it has worked great. I have regularly used it to cut plate up to 1/2" and round up to 1". If you are skilled with a torch and thrifty with how you use it you can get quite a bit of cutting done with those little bottles.

As for the safety aspect, I think it is being blown a little out of proportion here. In theory, you can have trouble if you draw too much acetylene out too quickly. In practice, however, if you have some common sense you can cut a lot with those little setups. The main thing to keep in mind is use a reasonable size tip and keep the acetylene pressure below 5psi. I would never use a rosebud on one of these, but welding tips and reasonably sized cutting tips are just fine.

 

[deereman75]

I have the same setup. Even the B tank however is really not capable of safely doing much cutting. It is about 40cuft as I recall and that means 5.5cuft/hr (or if you look at more recent 1/10 capacity standards only 4/hr). If you look up the acetylene requirements for even a #1 cutting tip you will see that they are in the 6-7 cuft/hr range (I haven't double checked my memory but looked this up a month ago). That means that even the B tanks are marginal for cutting. Ask someone at a local welding shop. They will clearlly steer you away from B tanks if you are doing a lot of cutting. In theory you can create a manifold to link several B tanks together but that is almost never worth doing considering the hassle.

For cutting (not welding) it makes more sense to use oxygen and propane if you cannot use 80cuft and larger acetylene tanks. Propane is cheaper, safer, easier to get. You can use the same regulator as on the acetylene tank but need T standard hoses rather than the more typical hoses that come with acetylene.

Again, just to clarify, the issue with small acetylene tanks is not the total amount of acetylene in them but rather the rate that the acetylene which is contained in an acetone solution can vaporize out of the acetone. If you draw off gas and exceed the rate that it vaporizes out of the acetone, the tank pressure will force the acetone itself into the regulator which will damage the regulator and then you have risk of fires etc when the acetylene does vaporize. Acetylene is not an intuitive gas like oxygen, argon, CO2 etc. It is useful but you really must understand how to use it safely.

Actually the biggest cutting tip I have is a 0 size, and I hardly ever use it for cutting. When we cut the rr track, we used a 0 tip, and a lot of time. I normaly use it with a smiths aw1 aircraft torch handle. Great for brazing, and sheet metal. I do basicaly all my cutting with a 7 inch angle grinder and a porta-band. And I know all about the issue with small acct tanks, if I ever need to do a lot of torch cutting, or have the need of a rosebud, I will switch to propane.

 

[grsthegreat]

OK, now im way confused. Ive cut LOTs of steel and brackets, rebar over the tears with my little setup. I use a rosebud tip also for over 10 years without any issues.

except for length the bottles will last, whats the big issue??