Welding Question

[AndyM]

My mig welding is the pits - literally - lots of porosity. I am using a Miller 185 with 25/75 shielding gas set to @ 25 psi. Tank has lots of pressure, but I am beginning to doubt the gas is getting to the tip.

Is there an easy way to check? I don't know, - soap bubbles or something?

Thanks

 

[Repair]

My mig welding is the pits - literally - lots of porosity. I am using a Miller 185 with 25/75 shielding gas set to @ 25 psi. Tank has lots of pressure, but I am beginning to doubt the gas is getting to the tip.

Is there an easy way to check? I don't know, - soap bubbles or something?

Thanks

I use the same welder and it does a good job.

It does sound like a gas problem.

One thing you can do is turn off the tank, pull the trigger and see if the low pressure gauge goes down quickly while having the tip in a container of water.

 

[AndyM]

Great thought. I wondered about the water idea but somehow I had this nag in the back of my head about sticking a electrified tip into water - I guess the answer is leave the power off - duh. Never thought of that.

Thanks

 

[D2Cat]

I'd think 15-18 PSI would be plenty.

 

[AndyM]

Ok, good to know. I will dial it back once I know for sure it's getting there at all.

 

[jkcolo22]

Great thought. I wondered about the water idea but somehow I had this nag in the back of my head about sticking a electrified tip into water - I guess the answer is leave the power off - duh. Never thought of that.



Thanks

I read "turn off the tank." I don't think the solenoid will trip to move the gas through if the machine is off. How about releasing the feed wire tensioner and sticking a balloon over the end (with the machine on).


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[Bulldog]

I can hear the gas come out of mine. Are you welding in wind or have a fan blowing on you?

 

[North Idaho Wolfman]

Make sure it's running 25 PSI while open and flowing, not static pressure.
Check polarity of the leads, there is different polarity for flux core wire than solid wire, and make sure you are running the right wire.

 

[CrashmanS]

Yep you can hear it coming out. Make sure the gas nozzle is clear and you haven't pulled the welding cable out of the machine. There are two orings on the welding cable where the wire enters the cable that can be used seated. Between these two orings is where the gas enters the welding cable on its way to the nozzle.

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[hodge]

Make sure it's running 25 PSI while open and flowing, not static pressure.
Check polarity of the leads, there is different polarity for flux core wire than solid wire, and make sure you are running the right wire.

This^. Watch the gauge when you pull the trigger.
Chances are, though, that you are getting gas, and your problem is elsewhere. It's probably you, not the welder. Any significant wind will blow the shielding gas away. How far away are you keeping the tip?
Pull the tip off and see if the holes are clogged, where the gas comes out. When you pull the trigger, you can hear the gas come out. If it isn't clogged, and you hear the gas, then all is good in regards to the Mig gun.
Do you know someone, friend or family, who knows how to weld? Have them run your machine, and #1 determine that it is working right, and then #2- observe you, and help correct what you are doing.
Welding takes lots of practice, and it is hard to do that practice when something isn't working right. Whether it's the welder or you, there can be enough factors to make it difficult to proceed. Someone with experience can probably spot the hang up immediately, then you are back on your way to learning.

 

[Tooljunkie]

Im thinking a few things,as mentioned cable not in welder correctly.
Gas set too high.
Polarity reversed.
I can hear the gas exiting the nozzle too.
Perhaps you can paint us a picture so to speak, materials you are welding,indoors or out and type of wire you are using.

 

[Daren Todd]

Make sure the material is clean, clean, clean as well. Oil, paint, and even slag from the foundry on the metal can screw you up.

I usually hit it with some brake clean or contact cleaner to get any oil off the metal if Ive had a metal shop do the cuts for me.Then buzz down the areas to be welded with my bench grinding so I have good shiny metal. It makes a huge difference.

 

[Yooper]

Do as Daren advised and post a picture of the results. A visual will help us help you. Also, let us know what wire you are using. You might try switching in a new spool of wire to see if that helps.

 

[D2Cat]

Here's a site that may give you some helpful information.

http://www.millerwelds.com/resource...ng-discussions/25582-recommended-gas-pressure

http://www.netwelding.com/sales_literature.htm

 

[dandeman]

One additional thing I always do when starting out to weld after the MIG has not been in use for some time, is after opening the tank, I release the wire feed roller and pull the trigger to "prime" the hose to ensure the CO2/Argon is at the tip before starting the first weld..

This is also the time I set the gas flow rate to the proper value, since I always back off the regulator setting to zero flow when finishing up after a welding session. Don't remember where I read it, but backing off the gas regulator to zero (where there is no spring pressure on the regulator diaphragm) was a recommended practice.

I started the practice of priming the welding gas/wire feed hose after noticing on the first weld, the sound of the weld and visible porosity at the beginning of the weld was there indicating that the shielding gas had not yet got to the tip..

 

[dandeman]

I usually hit it with some brake clean or contact cleaner to get any oil off the metal if Ive had a metal shop do the cuts for me.Then buzz down the areas to be welded with my bench grinding so I have good shiny metal. It makes a huge difference.

You may know this, but others may not, make sure if using brake clean or contact cleaner is that it is non chlorinated.. otherwise MIG welding temperatures, the CO2 mix shielding gas and chlorinated compound residue on the cleaned part can combine to make phosgene gas i.e. a deadly poison gas used during WWI. I won't use the the above mentioned cleaners on metals to be welded due to the risks of contents not being properly labeled.

Recommend reading this article http://www.thefabricator.com/articl...ore-welding-a-risky-move-that-can-turn-deadly

 

[torch]

Polarity reversed.

I was wondering about that too. Is the machine set up for solid or flux-cored wire? Flux core requires straight polarity, but you want reverse polarity for your solid wire and shielding gas. My Millermatic has a couple of brass buss bars above the drive roller that have to be swapped to switch from forward to reverse.

 

[AndyM]

WOW - lots of great reply's, thanks. I will take some time today to look at each
and see if I can narrow down my problem. It certainly could be any of them - my weld spool is OLD as I don't use the welder a lot, my technique is questionable (see prior point) and so on.

I will post back once I know a little more.

Thanks all.

 

[AndyM]

Well I have good news and bad news. The good is I used the water test to confirm no gas was getting to the tip. The bad news is I found out why - I had installed a spool gun to do some aluminum work which involves installing a diverter valve. It has to be set to the correct gun (and wasn't).

Man it's a b!tch getting old.

Now I can work at the other stuff!

Cheers all.

 

[Lil Foot]

Important safety tip:
When checking to hear gas flow, do not point gun at ear.
Maintenance man at work (who was not a qualified welder) did just that, wire feed was set on high, and he punctured his ear drum.
Can't fix stupid.