Small oxyfuel torch for use aboard

[Jammer]

I have had an oxyacetylene torch in my home shop for long enough that I've had to send the regulators and the torch handset out for rebuilding. It's a huge setup with a size K oxygen bottle, a 145 cf acetylene bottle, 50 feet of hoses, and high-flow industrial regulators and handset. The outfit as a whole weighs 200 pounds. When I got it, I was working on agricultural machinery, and that sort of capacity is what you need if you're going to heat up, say, a 1"x3" bar of steel so you can bend it back from whatever you hit.

It has always been my presumption that I would never have a torch aboard while cruising. I am questioning that after concluding that I could not complete an alternator repair without a torch as the pulley nut was seized to the shaft threads sufficiently that an impact wrench and JB-80 would not break it loose.

Wondering if anyone else has been down this road.

There are four practical alternatives for fuel:

• Size MC acetylene cylinders. This is what HVAC contractors use for silver-soldering while on a ladder or rooftop. They are also used by jewelers. The cylinder weighs 11# empty and holds 10 cf of acetylene. The maximum recommended withdrawal rate is 1.5 scfh or around 2000 BTU/h which is only enough to run a Victor #000 welding tip and none of the cutting tips. Ordinarily these are paired with a 20cf oxygen cylinder which will outlast the MC in non-cutting applications.
• Size B acetylene cylinders. 26# empty, holds 40 cf of acetylene. Maximum withdrawal rate is 6scfh or 9000 BTU/h. These will officially support a welding tip up to Victor #1, which will weld 3/32" thick steel, and a cutting tip up to Victor #00, which will cut 1/4" thick steel. Usually paired with a 40 cf oxygen cylinder. The oxygen cylinder will have to be replaced more often than the acetylene cylinder with this pairing, especially if any cutting is done.
• 7# propylene cylinders. Propylene has largely replaced MAPP because it is easier to manufacture. It has similar properties, and is sometimes sold as "MAP Pro" in disposable torch cylinders. The 7# cylinders are aluminum and are identical in construction and size to 6# propane cylinders. Propylene, like propane, is a stored as a liquid. 7# of propylene is 58 cf. Withdrawal rates are temperature dependent but at least 15 scfh which is 35,000 BTH/h -- unlimited for our purposes. Usually these are paired with a 40 cf oxygen cylinder which will have to be replaced at least twice per propylene cylinder.
• Disposable torch cylinders. You get 14 oz (around 8 cf) of propylene ("MAP Pro"). These can be paired with a 20 cf oxygen cylinder, or a disposable oxygen cylinder that holds 1.4 oz or about 1 cf of oxygen.

Acetylene can be used for any purpose (welding, cutting, brazing, soldering, heating, etc). Propylene can be used for any purpose except welding and is somewhat more difficult to use, because the flame will tend to blow out when lighting and adjusting the torch. It is more difficult to find tips, and they are more expensive. Propylene will tend to melt tips intended for acetylene because of aspects of the burn characteristics that I don't fully understand.

Propane can be substituted for propylene and can be somewhat cheaper and easier to find, though propylene in 7# cylinders is inexpensive enough that the difference doesn't matter much.


Fuel would have to be stored in a propane locker or on deck.


Torch wise for acetylene the Miller-Smith AW1A or the Victor J-2 are obvious choices.

I think probably the size B acetylene outfit would probably be the most sensible choice for supporting mechanical repairs while cruising. It's still an awful lot of space, and the complete outfits are around $800 including tanks and gas.


On the other hand, the rig can easily pay for itself by facilitating one repair.

[kayakerChuck]

Almost anywhere there are people, somebody has a gas rig. A good story, real need, $20, and a six pack has bought/rented me all sorts of dumb repairs in dumb places.

For the expense, headache, and maintenance of keeping a rig aboard, I'd vote for not taking it unless you have a specific, known need.

[rslifkin]

Personally, if I felt the need for a torch aboard, I'd likely just grab the handheld Bernzomatic torch out of my garage at home that takes one of the disposable propane or map-pro cylinders. I can't think of many situations where I've needed more than that working on cars, and none where I've even needed that torch on the boat. Most importantly, a torch like that isn't fussy to use, it's very low maintenance and will do fine sitting for a while and then just work when you need it.

[Jammer]

Originally Posted by rslifkin

I can't think of many situations where I've needed more than that working on cars, and none where I've even needed that torch on the boat.

Either your cars and boat are newer than mine or you have a much, much better impact wrench.


I have the right angle drive from a family member's commercial lawn mower on my bench right now. Seal failure, loss of oil, leading to a bearing overheating and seizing up. No way it's coming apart without a careful and precise application of fire.

[rslifkin]

Originally Posted by Jammer

Either your cars and boat are newer than mine or you have a much, much better impact wrench.


I have the right angle drive from a family member's commercial lawn mower on my bench right now. Seal failure, loss of oil, leading to a bearing overheating and seizing up. No way it's coming apart without a careful and precise application of fire.

I've used the torch plenty of times, but with the appropriate tricks (such as heating and then holding a candle against the threads so wax gets pulled in as it cools) stuff usually comes apart. If it doesn't, it's likely far enough gone that it's a matter of "get it apart by any means necessary and replace the damaged parts".

[Spot]

O2 and propane would be lots of heat and able to cut steel and the O2 might be a first aid item for diving. If you have plain air SCUBA tanks, would a Prestolite (?) style (air and fuel) be useful? For welding I'd think about the small 110/220v inverter setups. Then there is plasma and trying to be ready for alt metals like stainless, aluminum, cast iron, bronze...

The stuff my fabrication daydreams are made of

[MicHughV]

I've been happy with mini-propane cans, obtainable at any hardware store and fitted with a small burner. For most little jobs it works just fine.

Here's a Amazon link with all sorts stuff.

https://www.amazon.com/s?k=mini+prop...l_6thgpovb0m_e

[Shrew]

For that one time you MIGHT have a seized bolt. That wouldn't be good enough for me to store for long periods of time. There's always someone willing to take 15 min to make $20.

It's not lack of skill, it's simply a matter of when I've moved that @#$$%$ thing for the 1,000th time, if someone were to say "$20 and this thing is never a problem again". Yep, $20 sounds pretty good.

My storage and access to it are worth more to me.

Now, if you're planning on doing true expedition cruising (e.g. arctic circle, Antarctica) then yes, absolutely makes sense. However if you're talking about US, Bahamas, Caribbean, I'd leave it and the other large shop tools behind.

I recall a few years ago a guy insisting he needed a lathe, and justified all the things he expected to do with that lathe. If I recall, he drew from a single experience in needing a lathe to fabricate something and was convinced he needed it on the boat, just in case.

[deblen]

https://www.amazon.com/s?k=mini+oxy+...f=nb_sb_noss_2

[wholybee]

I would not want to carry any extra gas with me for a torch. Whether that is a large bottle, or the disposable canisters. So if I carried anything it would run from my existing lpg tank for cooking.

You have to be very far off the beaten track to not have access to a torch. Most remote places that don't have ready access to supplies depend on fabrication skills.

[RaymondR]

Have a look at the H2O oxyhydrogen torches which are available. I have no experience with them but look like they might provide high heat without the need to carry storage bottles.