How do you regulate 1psi in Oxy/Acet welding?

I'd like to tap the knowledge of the expereinced OA welders if I can.
Published information for OA welding with small tips - say a 0 are to use
very low pressures such as 1psi (O) + 1psi (A). The problem is that the
generally obtained Victor kits supply regulators that have an operating
range of 5-125psi (O) and 2-15psi (A). It seems then that it's about
impossible to obtain a well regulated 1+1 from these setups. I'm not
referring to the guages - which admittedly are inaccurate at these pressures
and in the case of the O guage only start at 5 or 6 psi, because you can
*ignore* the guages and bring the gases up from zero well enough - but the
actual regulation of the gas. How is it possible to use 1+1 when the
regulators won't reliably regulate to those low pressures?
I've had it suggested to use 5+5 instead, but I can't obtain a nice quiet
(ish) neutral flame at 5 and 5 with a 0 tip.
The flame is too fierce for 18 or 20 guage steel.
What do I do to obtain the right flame? Or what do *you* do?
Ken
Reply to
Ken C
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Gas torches have Torch VALVES for adjusting flame. Torch Valves seem to work for even bigginers. Torch valves are at hand so you can adjust flame at work location whithout returning to tank to adjust regulators. 5 psi supplied to torch or even 10 psi should work ok.
Reply to
R. Duncan
What he said. :-)
What you're actually trying to accomplish is to get the proper *volumes* of oxygen and acetylene to the mixing chamber of the torch. Having gas supplies with constant pressures allows the needle valves in the torch to regulate CFM flow. It doesn't really matter much what those constant pressures are as long as they are constant and adequate to support the required flows.
Now obviously, too low a pressure won't allow you to reach the desired flow, even with the torch valves wide open. And too high a pressure will make the needle valve adjustments very touchy, almost closed, which makes it hard to adjust. But there is a fairly wide latitude between those two extremes.
Gary
Reply to
Gary Coffman
Gary Coffman wrote: (clip) Now obviously, too low a pressure won't allow you to reach the desired flow, even with the torch valves wide open. And too high a pressure will make the needle valve adjustments very touchy, almost closed, which makes it hard to adjust. But there is a fairly wide latitude between those two extremes. ^^^^^^^^^^^^^ When I was just learning, I was taught the following technique by a really good welder, and it works. First, open both torch valves about a turn. Then bring the acetylene pressure up with the regulator, and light the torch. Ignore the gauge--make the flame look right. Then add oxygen, again using the regulator for control, to balance the flame. Again, ignore the gauge. Then, while welding, use the torch valves to fine-tune the flame.
When you shut the torch off and relight it, do so with the torch valves. Since they are pretty wide open, the flame balance will not be "touchy."
Reply to
Leo Lichtman
Thats exactly how they tell you to light the Henrob torch. It uses lower pressures than a regular torch. I've taken to lighting my Victor the same way and it does make getting a neutral flame a lot easier.
J
Reply to
James Arnold
Use a welding torch shank that's in good condition and that isn't shared by gorilla welders wearing gloves. If you don't abuse the needle valves by closing them with a hammer, then a stable supply of a few psi to the torch can easily be regulated down to the tip by a fixed valve on the torch.
-- Die Gotterspammerung - Junkmail of the Gods
Reply to
Andy Dingley
Ken, Victor's pocket chart lists 3-5 psi fopr O2 and Acet. on 000-2 tips. This allows you to set the flame with the torch valves as already explained. Too many variables: hose diameter, length, etc., for an exact setting. If you are welding thin material adjust to a soft sounding neutral. When you go with larger tips and heavier gauge metal the neutral may sound louder. Ask your local dealer for one of the Victor tip charts. Its pocket size and usually free for the asking.
Reply to
cope
Cope, Thanks, I have that chart but it's in disagreement with all the other published info I've read (e.g. Modern Welding). That's not to say it's wrong - just different. Although even 3psi is below the min regulation presure for the as issued Victor Oxy regulator Maybe I expressed my question badly although I appreciate all of the replies (except the first one - telling me that there were knobs on the torch - duh, really?) If we agree that the regulator pressure settings (whatever they may end up being) are lower for a #1 than a #2 and lower for a #0 than a 1 etc etc. And if we assume that the final neatral flame pressures for a #0 (or go even further a 00 or 000) are below 2 for acet and 5 for oxygen then it seems we have a problem because the "D" Oxy regulators supplied by Victor in *all* of their OA kits are 5-125psi regulators. That implies to me that they do a poor job of maintaining a steady pressure *below* 5psi. I find that my flame wanders with the 0 tip when I obtain the correct neautral flame. So I am assuming that the correct pressure is below 5spi and that the regulator is doing a crappy job. No?
Ken
----- Original Message ----- From: "cope" Newsgroups: sci.engr.joining.welding Sent: Sunday, October 05, 2003 5:43 AM Subject: Re: How do you regulate 1psi in Oxy/Acet welding?
Reply to
Ken C
Another torch problem is valves with loose packing nut. When torch valves change setting with feather touch tighten up packing nut a little makes life easier.
Reply to
R. Duncan
So you don't like results with regulators set at 5psi. Have you tried setting pressure at 10psi then use torch valves to adjust flame? Did that work better.
Did Leo Lichtman's adjustment system work better?
If not maybe your trying for too small flame for torch tip.
A regulator made to supply both cutting torch and very small welding torch might not maintain real stable PSI at 1psi, 2 psi or even 5 psi the pressure your trying to set because of size of orifice needed to supply welding torch and regulator's hysteresis which is lag effect due to friction .... At higher pressures the lag is smaller percent of set pressure so less of a problem. Well used old regulators have eroded orifice making it worse.
Smith's Little torch is tiny for welding, braising and soldering thin metal.
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Tin Man Tech sells small Meco Midget torch for thin metal.
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Even with the small torches at above links torch needle valves set the flow rate and the regulator just maintains pressure. For the valves to work properly they need enough driving force (pressure). Common globe valves have flat seat that is pushed against orifice to adjust flow or stop flow. Needle valves push needle taper into orifice to meter gas flow with greater precision. Needle valve also meter shielding gas flow from flow meters. That shows how precision & stable they can adjust flow rate when supplied by higher stable pressure.
A regulator made to supply both cutting torch and very small welding torch might not maintain real stable PSI at 1psi, 2 psi or even 5 psi the pressure your trying to set because of size of orifice needed to supply welding torch and regulator's hysteresis which is lag effect due to friction .... At higher pressures the lag is smaller percent of set pressure so less of a problem. Well used old regulators have eroded orifice making it worse.
If you don't like this answer then go ahead and try another discussion board again but that will not get you better answers.
Reply to
R. Duncan

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