[TheForge] Oxy/Propane reprise

[Peter Fels & Phoebe Palmer]

Paul N wrote:
> I guess I'll have to take a closer look at those adjustments. I was 
> primarily playing with the lower "butt end" pair, and didn't fuss with 
> the valve for the jet that much once I got it cutting.
> 
> Actually, once I established heat, and hit the O2 jet, things got 
> quieter, and it cut pretty nicely until I'd get ahead of the heat and 
> have to wait.
> 
> Also given what Andy has added, the fact that this plate was plenty 
> rusty on both sides probably contributed to the difficulty I was having 
> getting initial heat. But once I got a cut established, getting it 
> re-established in the same kerf was a relative piece of cake.
A quick pass with a small air hammer preps the surface well enough.
> 
> But my thinking was that I figured the guys in the junk yards probably 
> don't prep anything and just burn through. And the #2 tip should have 
> been overkill.
Makes a rude cut...more preheat gas.
> 
> That leaves just my gas control and technique to look at. I had better 
> luck getting my primary cone close to the work for the pre-heat, and 
> then once I started cutting, moving the torch off the work, and cutting 
> with maybe 1/2" to 3/4" distance between the tip and the surface.
Too far...preheat cone should just touch .
  Again,
> it was 3/8" plate, so while not hugely thick, it did require a bit of 
> oomph (but thicker than anything I had cut with even acetylene in the 
> past. I'm only a hobbyist, and my cutting experience was maybe 2 hrs in 
> a Community College welding class last semester)
> 
> I really appreciate the help guys,
> **Paul
> 
> Peter Fels & Phoebe Palmer wrote:
>> Paul:
>> Check all the O rings and make sure they are perfect.
>> Make sure the seats of the cutting attachment tip are clean and smooth.
>> It sorta sounds like you might not be opening up the oxy valve on the 
>> torch butt wide enough before you adjust the oxy valve on the cutting 
>> attachment.
>> Check that the tip oxy jet is clear.
>>   As soon as you can see a red surface, you should be able to start your 
>> cuts. pf
>>
>> Paul N wrote:
>>> Well, I spent a couple hours messing around with oxy propane cutting 
>>> today, probably ran through 40-60 cu ft of O2.
>>>
>>> It took me awhile to get the flame balance to where I could cut (Notice 
>>> I didn't say "correct", as I'm not sure that term would be accurate).
>>> I have a "clone" of a Victor r100 torch, and was using a #2 oxy/propane 
>>> cutting tip. I was working outside, so there was some wind to contend 
>>> with. I had the propane at about 6psi, O2 at about 25psi.
>>>
>>> I had to "ratchet" up to working settings on the torch. If I just turned 
>>> up the propane at the torch, the flame moved away from the tip, and if I 
>>> added O2 at that point until I got a nice clean cone, it wasn't hot 
>>> enough, nor was there enough O2 flow to cut. So I had to alternate: add 
>>> more propane, add some O2, etc. until I got a decent flame.
>>>
>>> I was cutting 3/8" plate (cutting a 30" circle to use for a base of a 
>>> legvise mount I hope to build). It took several tries to get things 
>>> acceptable, along with the tip to work distance. Even then, I got some 
>>> occasional popping in the torch. I thought that would be an indication 
>>> of excessive heat, but adding more O2 made it worse, and adding more 
>>> propane made the flame "noisier", and had me thinking it was too high.
>>>
>>> It's obvious I need some more practice, and perhaps play around with the 
>>> gas settings some more, as I had to move pretty slowly to maintain a 
>>> steady cut.
>>>
>>> Still, every once in awhile, I'd move the torch in a way that would 
>>> result in losing the cone, but not the flame, and I'd have to back off 
>>> the pressure to re-establish the cone. So maybe I had it turned up too 
>>> high. I'll have to spend a little more time with it to get more familiar 
>>> with using propane. It's obviously different from acetylene.
>>>
>>> Next step will be "plunging" cut (not starting at an edge) I'm going to 
>>> assume that there's some difference there too, as with acetylene, I had 
>>> actually started to form a puddle before hitting the cutting O2.
>>>
>>> Comments and further advice is welcome.
>>>
>>> Thanks again everyone.
>>> **Paul N.
>>>
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