a couple of mig questions

[Vinny]

Ok, so I finally got a round tuit and switched my HF 150T/2 mig/flux welder to mig and gas. Got the wire switched out and polarity changed, but have some questions...

1) A couple of years ago (or so it seems) I saw something on Welding Web about making the switch and nozzles. Just spent a couple of hours looking for it and no go, so I'll ask here. There are two types of nozzles for this gun, one is straight and the other is tapered toward the tip. I thought the post on welding web said to use the tapered nozzle for gas and the straight for gasless, but when I replaced the nozzle back then I put the tapered one on (that post was stiff fresh in my mind at the time. Which nozzle should I be using or does it really even matter? For the time I'll be using CO2, when that runs out I'll switch to AR/CO2 mix.

2) Since I'm using CO2 my flow meter won't go on the tank so I'm using a regulator. What is a good starting point for pressure?

3) Two spools came with the welder. 0.030" flux was loaded when I bought it used. The guy I got it from said he never tried mig so the original spool of mig wire that came with it was in the welder's wire compartment. It's 0.090". Is that a bit thick or will it be ok since it's a different type of wire?


I have some welding to do on some 1/8" plate tonite. or tomorrow, or ... we all know how well I procrastinate!

[Highpower]

It kind of depends on what kind of 'tapered' nozzle you are talking about Vinn. If you have two nozzles like this, then you could use either one if you wanted to. Note that the "tapered" nozzle here has a smaller ID than the straight nozzle. The larger straight nozzles are for providing more gas coverage on higher amperage welders with a hotter arc. The smaller tapered nozzles are more common on smaller welders. One thing to look for is to make sure that when the nozzle is on the gun, that the end of the nozzle is even with the end of the contact tip that the wire comes out of. If the end of the contact tip sticks out slightly from the nozzle that is OK. You just don't want it recessed inside the end of the nozzle.

Now if you are talking about a plastic or bakelite "tapered" nozzle like this, that is for flux-core ONLY. That type of nozzle only keeps spatter off of your contact tip and gas adapter. It isn't made to have shielding gas flowing through it.

You don't adjust the pressure on a MIG machine, only the flow rate. Shielding gas normally runs at a non-adjustable static pressure through the regulator portion, and the FLOW rate is what is being adjusted on the gage dial. The actual pressure stays the same. I've never tried using a plain CO2 regulator for a Mig gun, and can't say if it would work or not. There are no normal pressure settings - only flow rates. 20cfh (cubic feet per hour) would be a good starting point for that.

.090 wire is WAY too big for that welder. .030 - .035 would do you just fine.

[Vinny]

I thought that wire was a bit thick but it's what came with the welder (note: this is one of HF's first ones, built in Italy by Hobart). Guess I'll be stopping at either home depot or HF on Monday (no time tomorrow aka Sunday).

Your first pic is what I'm talking about. The tip is about 0.092 from the tip of the nozzle (checked with my caliper).

I have a flow rate chart for the flow regulator I have matches what you say about flow rates. It's based on nozzle ID. Unfortunately I can't put it on this tank. I had borrowed a buddy's welder some time back and his had a regular regulator on it. Don't remember what it was set to.

[Highpower]

They do make cylinder adapters that will change the fitting sizes for you. I don't know what kind of tank you have or flow meter so I can't say which one you need to get the right combination. Generally CO2 tanks have a CGA 320 fitting vs. an Argon/CO2 tank that uses a CGA 580 fitting. Small tanks use something else.....

One example: https://www.arc-zone.com/index.php?main_...5ig28otfg2

[Vinny]

In the pic on that link, the end closest to the camera is what my flow meter has. So I'd need the opposite. As close as I can tell, I need to go FROM 580 to whatever the CO2 tank has. Since it's only temporary, I'm inclined to not go with the cost of an adapter. Oh, note: I don't know for certain the regulator/flow control is 580. It just looks like the photo your link has.

Ok, I just looked at the ebay listing for the "Flow Meter Regulator" and it is CGA-580 RH. When I get the AR/CO2 tank am I going to have to specify this?

Thanks Willie!!!

[Vinny]

I just thought of something... that 0.090" wire would prolly be perfect for that clamp tool that's been posted here and other places that I've been meaning to make!

[ironmonger]

If you check the regulator of the flow meter that 'works' with the welder, on the face of the gauge you should see in small print "based on a .030" orifice" or some thing like that. If that is what yours says, then you can just use the pressure gage that you have. If that is the case the orifice is built into your welder, and you should not use a 'flowmeter' with an external orifice. That would be any kind of flowmeter that has an glass or plastic cylinder on it with a 'floating ball' to indicate flow rate.

All flow meters are based on the principle that a known pressure flowing through a known orifice will deliver a known flow.

While I can't tell you what pressure you should set yours at, an educated guess would be about 25 psi. I would expect to use about 25 CFH as a flow rate. The following is a guess, but it would make sense that the .030" orifice is sized to have the incoming pressure equal the flow rate in CFM. It would make sense to pick a size that would use the markings on a gage... just sayin'

The fancy flow meters that have a non adjustable pressure and a tube with a floating ball have a variable orifice to adjust the flow. The glass cylinder is calibrated to show the out put but the regulating principle is the same. As you get used to using your new configuration, look at the welds and compare them to online samples and watch for signs of low gas flow in your test welds.

paul

ARS WB9HCO

[arvidj]

(12-27-2015, 02:50 AM)Vinny Wrote: I just thought of something...  that 0.090" wire would prolly be perfect for that clamp tool that's been posted here and other places that I've been meaning to make!

Some food for thought if you are thinking of using the 0.090" wire.

The wire should match the feed rollers, liner and the contact tip. A quick search suggests that for 1/16 ... .0625 ... was the biggest tip I could find. Try looking at the spool again and see if you may have misread the label. Something like 0.9mm, which is .035", would be a much more reasonable size for any kind of machine that did not require a forklift to move.

If what you have is really 0.9mm\.035 wire then check you welder to ensure the rollers, liner and contact tip are correct. At least on my welder there is a set of rollers for .025", a set for .030-.035", and a set for .045". 

Note also that we're talking steel wire, not aluminum, which appear to come in .052" and 1/16", but I don't think you need to worry about that as aluminum will not go well with CO2, steel liners and a push gun anyway.

Arvid

[Highpower]

(12-27-2015, 02:46 AM)Vinny Wrote: Ok, I just looked at the ebay listing for the "Flow Meter Regulator" and it is CGA-580 RH.  When I get the AR/CO2 tank am I going to have to specify this?

Thanks Willie!!!

No you won't have to specify the fitting. The CGA (Compressed Gas Association) designations are standards for each of the gasses being used.


Think of them in terms of electrical plugs and outlets. There are different types and sizes for a reason. You can't plug a 20 amp drill press into a 15 amp wall outlet. It won't fit. They are designed that way so you can't 'accidently' overload the circuit. Yet, you can put a 15 amp plug into a 20 amp outlet and it will work because the circuit can handle the lesser amperage.

The CGA fittings are designed to do the same thing. They keep people from putting the wrong type of regulator on a cylinder that contains an incompatible gas for that regulator. That is also why fuel gases fittings have LH threads and inert gases have RH threads. Things can go boom when you accidentally mix two different gases that shouldn't be mixed. The standardized fittings help to prevent that.

[Vinny]

You are correct Arvid, that is 0.090 mm. I also put a mic on it and it's 0.035", so that saves me a trip to HF. The rollers that are in it are the only ones that came with it.

Just checked the manual, it does recommend the use of a flow meter, but not to use an AR/CO2 flow meter with straight CO2. Funny thing is, HF doesn't sell a flow meter, they just have a straight regulator for their welders. I got mine from USA Weld. While the manual does say 10-30 CFH, it doesn't mention pressure, so I'll start at 25 PSI as Paul suggests.