[TheForge] Oxy/Propane reprise

[Paul N]

Well, I managed to gather my stuff together for a brief trial tonight, 
following the advice of the group. While I'm still not completely 
satisfied with my technique, I was much happier with the result.

Once I got going, I was probably moving at perhaps as much as 15"-20" 
per minute (far cry from my earlier attempt) and my cut was a LOT cleaner.

I still need to get a little more familiar with the flame/cone pattern.

I was trying to get a set of sharply defined preheat cones, but at that 
mixture, the tip was popping fairly frequently, so I richened the 
mixture a bit. I think I may have been hitting the gas valve while I was 
cutting, because that re-occurred a few times, and I had to repeat the 
process. As it was, while the flame was completely blue, the cones 
weren't what I'd refer to as "crisp", and were a little fuzzy. Still 
quite a bit shorter than what I think I recall from using acetylene.

I was on a time crunch (only had about 1/2 hr for setup, cut and 
cleanup), and didn't have time to make more than a couple cuts, so I 
still have some more practicing to do, and I still didn't do anything 
about the rust. While it seemed to slow the initial preheat, I found 
that I could start cutting before I got what I'd consider a good red 
heat all the way through the piece.

Thanks for the hand-holding.

**Paul

Peter Fels & Phoebe Palmer wrote:
> 
> Paul N wrote:
>> probably based in the assumption that I knew what I was doing :-)
> That helps me make my mistakes.
>> I looked back in the earlier messages, and yes you did raise that issue. 
>>   But I don't think I quite understood the mechanics, and probably still 
>> don't. I hadn't had an opportunity to drag my stuff out again yet, and 
>> my wife has this thing about my lighting fires in the house.
> \What's-a matter her?
>> I'm still a little unclear on the 2 O2 valves. I had assumed that the 
>> bottom valve controlled the mixture of the preheat, which left the other 
>> for the cutting jet. Obviously, that's not the way it works.
>>
>> I'd been looking for a schematic of the torch "plumbing" to help me 
>> understand it better. While I only spent a few minutes web searching, I 
>> haven't found anything yet.
> Paul; when you plug in the cutting attachment, O2 control is shifted 
> from the torch butt to the cutting attachment. The torch butt valve is 
> opened up wide and left that way.
> Mixture adjustment for the preheats is done at the cutting attachment 
> for O2, with the oxy lever depressed.
> I suspect you'll find you don't need quite as much O2 regulator pressure 
> for that thickness steel, either.
>
...
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