Welding Tips and Tricks

Hello I use a Miller syncrowave 350 dx. I’m having an issue with my shielding gas. When I press the pedal the argon flow starts out really strong as in 30-40 cfh and then settles down to my desired flow rate. This seems to be giving me bad starts on ac aluminum. I’m getting a dirty tack. I have the machine setup with a .8 second preflow and am running a #5 cup with a standard collet body at about 12 cfh. Does anyone have any thoughts on why I’m building up this pressure? I recently replaced my tank hose due to a leaking fitting and the new one seems a bit long. Thanks


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Sounds more like your regulator is damaged to me. Got a spare you can test with?

Most regulators with a flow meter are set up on the reg to run 50 psi. This allows pressure to build up down stream from the regulator when not welding. You can try to shorten your down stream hose as much as possible but the only sure way is to adjust/ or get an adjustable regulator and lower the pressure to 10 or 15 psi.

Your flow meter is indicative of how much gas is going into your hose, not how much is coming out. When you're not calling for gas, the pressure should build slightly in that hose and then your welder would vent that when you strike an Arc and Flo should rise up to your desired flow rate.

Like CJ says, almost sounds like something wrong in the regulator. Like it's sticking when it first turns on.

Aadecktor wrote:Hello I use a Miller syncrowave 350 dx. I’m having an issue with my shielding gas. When I press the pedal the argon flow starts out really strong as in 30-40 cfh and then settles down to my desired flow rate. This seems to be giving me bad starts on ac aluminum. I’m getting a dirty tack. I have the machine setup with a .8 second preflow and am running a #5 cup with a standard collet body at about 12 cfh. Does anyone have any thoughts on why I’m building up this pressure? I recently replaced my tank hose due to a leaking fitting and the new one seems a bit long. Thanks


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Question #1: Did it always do this? As in, before you replaced the tank hose?

Question #2: How much longer is the new hose compared to the original?

Question #3: Is your new hose of a larger ID than the original?

Question #3: What does your new hose look like compared to the original? AKA: can you post a pic?

Thanks for all the suggestions. As soon as I get back into the shop I’ll go through everything. I started thinking about the reg. After I posted. I’ll let you know.


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Yup.. LIke mentioned above, normal regulators/flowmeter combo's allow the outlet to pressurise to something like 50psi when the gas-solenoid in the machine is shut off. This basically 'inflates' the hose from the tank/regulator.

When you hit the pedal, the gas solenoid opens and this initial volume under pressure in the hose will rush out in a big burst until the pressure drops enough and the regulator and gas flow meter starts to 'meter out' the gas from then on.

Sounds a lot like your new gas hose from the tank to the macihne is not rigid enough or simply getting a bit too long and it inflates more than your old hose so you get a bigger 'exhale' from the line when the gas solenoid opens.

There are specific 'gas saver' regulators out there that combat this, but they are often quite expensive.

With a bit of hacking you could (in theory) make a 'remote solenoid' (remove or bypass the one in the machine) and fit one right on the outlet of the flow meter, so any pressurised volume when it's closed is reduced to a minimum and that would pretty much remove any initial rush of gas as you hit the pedal.

Depending on the machine this may be driven by line AC voltage, so any such mod is 'at your own risk'..

Bye, Arno.

So I think I figured it out. As I said, I installed a new hose, but I also added a y valve which also had a long hose. Both of these hoses together were accumulating too much agron giving me a blast when I pushed the pedal. Removed the second hose and back to normal. Thanks for all the input.


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Aa,,,I don't mean to be nosey, but, was there a specific reason for the Y valve in the second section of the supply hose? If you want to supply a second machine, you'd probably be better off with a dual regulator. OR if you wanted to allow yourself to mix in some helium for your tig torch, OSCAR designed a frankenmixer and I'm sure he can help you out with the build.
Also, IF you are still having to deal with a puff of gas, you could adjust a higher rate for pre flow before the arc starts and that would allow the higher amount of shielding gas to disipate.

It is for helium. I just need to shorten the hose.


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