Dumb newbie welding question help needed soonest

[an0nymous]

Have a Lincoln mig 140 I bought from lowes. My experiments with sheet metal (18 ga. automotive) using flux core wire resulted in bad blowthrough.
Read a bit studied technique (go slow almost tacking). Bought gas, ouch. Hooked up gas, reversed polarity. I am ready to go right now. but I am confused. Cylinder is connected to regulator, cylinder is open gauge showing 140lbs. and then
http://www.lincolnelectric.com/assets/servicenavigator-public/lincoln3/im890.pdf
"Set gas flow rate for 30 to 40 cubic feet per hour (14 to 18 I/min.) under normal conditions, increase to as high as 40 to 50 CFH (18 to 23.5 I/min.) under drafty (slightly windy) conditions." HOW?

I sparked the tip no sound of gas. The faces of the gauge shows 0 on one side 140 on the other.Theres nothing on the front of the machine that hints at metering. I thought maybe the face of the gauge twisted but no...
anybody? I am prepared to feel dumb but grateful. Trying to do this before the kids come home...

 

[MillerMav]

It sounds as though you simply need to open your regulator. The gauge from the bottle to the regulator is the 140psi. The gauge that shows pressure during use is the one to the left. Open the regulator a full turn and then pull the trigger (with the machine on). Watch that gauge. It should quickly spike to a pressure.

That pressure is the one Lincoln is talking about. A good rule of thumb is 20-30 for most projects.

Your "blow through" is simply because your amperage is to high for the thickness of the metal. Try backing it down slowly, each time striking an arc onto a test piece. While you should work your way around sheet metal by tacking in different areas to prevent warp you should not be blowing through unless you throw to much power at it.

 

[an0nymous]

Thanks for the quick response heading out to the garage now.
edit hrmm.. pulled trigger, wire feeds fine, no sign of life on the zeroed gauge. (face reads ar/co2). other gauge sits constant at 120lbs.
Bottle is fully open.
I blew the dust out before connecting the regulator so I am certain the bottle is unobstructed.
the tip on the gun is the correct copper one (as opposed to the plastic flux core one) and there are no signs of obstruction anywhere. Heck, this will be the hoses first use.

I am going to disconnect the hose from the regulator and open the bottle briefly.
ok with the bottle connected to the regulator and the hose off there is still no flow as I slowly open the bottle. The issue is definitely at the regulator.


looking back at the comment above you said "open the regulator" thats probably the issuie. but how to open it? I don't see any sort of valve on the regulator itself...

Looking at pictures of regulators online it seems like most have a knob on the front. this one does not. hmmm

There is threading on the identation in front. I'M MISSING THE KNOB.
To lowes!

Final Edit: A bit of 5/16 threaded rod and a hilman threaded t-handle and the gas now flows! Thanks so much.

FINAL FINAL EDIT: OMG SHIELDING GAS IS AWESOME, THIS LOOKS A TRILLION TIMES BETTER THAN THE FLUXCORE.

 

[WhoWhatNow]

Post a pick of your regulator set up. It sounds like you do not have the regulator open. You should have a reading on the gauge since the gas solenoid is in the machine. In other words gas should be flowing to the machine at all times. Remember that regulators are opened by tightening the knob.

 

[shawnspeed]

If it is a freshly filled bottle it should have way more than 120lbs pressure....12-1500 psi, at a minumum on a fresh bottle....we used to get fresh bottles that tested ++ and they would be at 2200 psi...Is your flow meter the type that has 2 gauges, or a gauge for tank pressure and then a glass/plastic tube with a floating ball for flow??? If it is a dual gauge type there should be a knob that screws in to adjust the flow..the tube type usually has knob on top of the tube to ajust flowrate...hope that helps...Shawn

 

[Zeke]

Some regs have only an acorn nut and are supposed to be preset. But if you're seeing bare threads on a post in the center of the diaphragm, take it back.

 

[mirrorimg]

Does your regulator look like this? There is a T that you turn to adjust the flow out of the regulator. Also, did you swap your wire or are you using gas on the flux core wire?

 

[an0nymous]

I updated post 3 above pretty much as stream of consciousness thing. Thanks for all the replies.
The short answer: I was missing the knob and post for the regulator, No idea where it might have gotten to or if it was ever shipped.
I fabbed a new handle out of 5/16 threaded rod and one of them fancy lowes "specialty fasteners" and everything works great now.
This was definitely a good idea. all of sudden I can draw a puddle without spatter and it looks "right".
I'm stripping a fresh piece of trunklid now to shape and put into my fender hole and am anticipating much less cursing.
You guys are great.

 

[BD1]

Glad you got it working. Here's a couple welding sites that will help if you don't know about them.

http://weldingweb.com/forum.php

http://www.millerwelds.com/resources/communities/mboard/forumdisplay.php?3-Welding-Discussions

 

[theknurl]

an0nymous;
this is the most common flow meter/regulator;
http://www.google.com/imgres?client...tbnh=182&tbnw=122&start=0&ndsp=16&tx=54&ty=88

the round gauge shows tank pressure, the glass tube flow, adjusted by the knob on the left (reg set at 25 PSI)

this is the 2nd type;
http://www.google.com/imgres?client...bnh=184&tbnw=190&start=31&ndsp=15&tx=88&ty=78

flow is adjusted by the knob, flow is read on the 2nd dial

this is the 3rd type I use one for back flowing Ti;
http://www.google.com/imgres?client...h=185&tbnw=232&start=76&ndsp=16&tx=123&ty=105

an0nymous;
glad you got it going

mirrorimg;
that's an acetylene regulator, red band starting at 15PSI and left hand threads