Oxy/propane

[aero]

I still think you are on the way to giving yourself a hiding using propane for welding.

I have never seen it used for welding, the reason is (i've done some scratching about as its been bugging me why propane is not used for welding) that the inner flame does not get hot enough. The outter flame does but this makes propane better suited for heating and hence cutting. Its welding performance is somewhat poor as a result of this.

The next issue is the quantity of propane you will use, cheap tho it may be it doesn't stay cheap for long as you have to supply a greater quantity to the torch. Appearantly you can do a bottle very quickly if attempting to weld.

The torch itself will be a big pepper pot affair, basically a cutting torch as you won't get sufficient heat from a single jet.

 

[Lippyp]

As I said, I want it for heating and the odd bit of cutting NOT welding.

 

[aero]

I'm sure someone mentioned welding!

 

[Lippyp]

Not me in relation to propane, I did say I hadn't gas welded since school and I'd stick with mig for the time being, although I did mention wanting to learn lead loading.

 

[MrFluffy]

gas air hearth

LippyP, Ive just brought home a Gas/Air hearth which is designed to run on propane (along with a small blast furnace, like y'do), but has its own little 3 phase compressor on the base, Im not sure if the guy who sold it has another one left, but when I was at his yard before xmas he had a few stacked up for sale and I can ask if your interested. That would give you the torch already set up for propane (mine has two), hoses, gas controls and a handy air supply and also a firebrick platform for heating or brazing on if you wanted, you can still swing the torch round and heat something else although the entire hearth+compressor isnt exactly portable.
I can take a foto of it if you want to see what it looks like and the dealer is not far off the beaten track in kent so its on your way over
The other thing is you can buy propane regs most places in france as you know, but they wont flow enough gas to run a torch as I have a big roofers style propane torch on a cylinder already and the flame is pathetic, theyre designed to run small porta fires etc, so I have to go off on the hunt for a highflow regulator too, weldequip you may have pm

 

[cobminor]

If you want a proper Propane regulator look at the Bullfinch range of stuff.

 

[Lippyp]

I have a proper bottom draught coke forge half finished, I just need to build a hood and stick a flue up through the roof and finish off the fan controller as I intend to do some proper smithing. The other problem is I don't have a 3 phase supply. I've seen proper high pressure Propane regs on ebay like this one

http://cgi.ebay.co.uk/ADJUSTABLE-HI...W0QQitemZ120075599069QQihZ002QQcategoryZ76066

 

[MrFluffy]

Lippyp,
beware if you pick up a french bottogas or similar bottle later, the propane fittings are different on them, instead of the cone and socket, almost all the ones ive seen are flanges with a flat rubber seal between the regulator and the bottle.
With bottogas the blue and silver cylinders are propane, and the straight blue are butane, but theyre the same reg fitting...

 

[Lippyp]

My french house is just a holiday home at the moment so all my work is done in the UK, I just use Butane for cooking on over there (I thinks its an Elf bottle, blue with a yellow top)

 

[lexi]

While we are on subject of heating and cutting with oxy/prop. What settings on the mix for heating metal red hot and also for cutting.

Alex

 

[weldequip]

Fuel gas pressures for cutting (acetylene or propane) rarely move much above 5psi for a lot of common cutting tasks, it's the oxygen pressure that needs to be increased. As a general rule of thumb use about 5psi fuel gas & 35psi oxygen. Obviously these pressures would need to be increased for thick sections but use those pressures for 'general' cutting/heating.
weldequip

 

[18yrswelding]

Propane hoses have a different inner lining to acetylene hoses, Propane gas will eat into the inner lining of an acetylene hose at an accelerated rate, only use equipment for the gas it was designed for!

 

[weldequip]

That's very true. It's not just about colour coding, ie. orange for propane & red for acetylene hose.
weldequip

 

[morph]

Hi, just a couple of things i thought important enough to start posting about! Most stuff about propane has been said- saftey, regulaters etc. I am a farmer and also a retained firefighter so come across propane most of the time. I stopped using Acetalene 5 or so years ago for cost reasons and have never looked back. 1 27kg? cylinder lasts me 2 full size oxogen bottles so the saving is massive. It will heat and cut everything-never tried welding as got petrol welder but will easily solder and braze.

Now my main point. PROPANE IS 1000 TIMES SAFER THAN ACETALENE!
In a fire a lead stopper in a propane cylinder melts and releases the gas. This stops any risk of explosion. Every fire i've been to with propane the cylinders have cooked off safely. Now acetalene is completly different, for a start the cylinders are about 10mm thick and there is NO saftey features on them. I have had numerous training sessions on acetalene and the general rule is RUN!!! This applies even if its taken a heavy knock- they are like bombs. There is a tecknical reason for this, google "Disolved acetalene". I will explain if asked but bit of a essay needed!!

 

[weldequip]

I don't doubt the safety issues & certainly wouldn't argue with somebody in the fire service! but acetylene has a much faster pre-heat than propane which equals a lot faster cutting speeds. I did see a comparison chart once and with the faster cutting rates, acetylene works out much the same cost wise as propane. That said, most volume users (scarp yards etc.) do use porpane.
weldequip

 

[Hitch]

Morph, i think you have your cylinders mixed up. Acetylene has the plug, not Propane.
Propane bottle is about 3mm thick, with no safety plug.

 

[weldequip]

I did wonder that? The plug is on the base of the Acetylene cylinder. I was always lead to believe that propane cylinders go up like a bomb whereas with acetylene the fire can be contained within the cylinder, they just keep dowsing it in water or throw it in the nearest canal/river.
weldequip

 

[morph]

I don't know what the books say but i can cut as quick with propane- probably running at higher pressures using more gas. I cut through 6 foot of 1" plate today in under 5 mins so can't be too bad. The gas is so cheap it doesn't matter about it but just depends on how much extra oxogen i'm using...

 

[morph]

I can catagoricly(?) say that the plug is on the top of a propane bottle. I've seen loads of propane cylinders gassing off. Once had a call to a load of outdoor henpens on fire, each was heated by 2 47kg propane bottles with 15' between pens. As 1 group of bottles cooked off the heat made the next lot ignite. None of the bottles moved a inch. Flames shot out of the top but no explosion(wouldn't want to happen in my workshop though!)
Acetalene is dissolved in porous clay (i think) inside a very thick steel cylinder- that's why they are so heavy empty. Inside the cylinder the gas is trapped in the clay-once the clay starts to degrade eg, fire or heavy knock the acetalene starts expanding and heating up. Then all you can do is apply cooling water for at least 24 hours and a 400m exclusion zone.

 

[Hitch]

I still disagree-
Acetylene has the plug. Not Propane.