[AT] OT: Welding with LP ?

[Henry Miller]

On Saturday 10 December 2005 10:15 pm, Stuart Harner wrote:
> I know this has been discussed in the past, but the archives are not
> letting me do a search, so I will ask.
>
> I have an Oxy/Acet. set up, but my Acet. tank went dry (with the valve
> tightly closed) and I am tired of the hassle of getting it filled.  I
> remember some members use LP instead.
>
> What is needed to convert to LP?  I know the Acet. regulator will screw
> into the LP tank, I tried it.  However, I could not get much of a flame and
> when I cranked up the pressure it just blew the fire out from the tip.  I
> tried a small tip and a cutting tip, same thing.
>
> Any advice would be appreciated.

I'm still using acetylene, but I'm not sure why...   

You need to use more pressure with propane.  About twice the pressure you 
would use with acetylene.  Ideally you would get different tips.   In fact 
I'm not sure if any of your current tips will work at all.   The required 
mixtures are different.

>From what I hear cutting with propane is easier, but welding is harder.   Some 
claim that you can't weld with propane at all, but I have seen people do it, 
so I know it can be done - if you get everything right.

Propane burns a little colder than acetylene, in fact it is really close to 
the temperature that iron melts, so if you don't keep your stuff in good 
shape, and adjusted right, you won't have much luck.    Fortunately propane 
burns cleaner than acetylene, so this is rarely a problem once you learn how 
to do it.

Propane will attack some rubber that acetylene will not, so you need to make 
sure your hoses and regulator are propane safe.   (Note that not all propane 
stuff is safe for acetylene either)

Propane tends to burn more on the outside of the flame, rather than the 
center.   This is one reason (other then temperature) that propane doesn't 
weld as well.  

If you are going to weld a lot than either stick with acetylene, or get a 
stick/mig welder.   The latter is preferred by most people, but your milage 
(and budget) may vary.