Bad Porosity

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Hey guys i was doing some welding on the bottom of my car and experienced some porosity issues. What is a leading factor for porosity i thought i cleaned it well enough and i was outside so i turned up my regulator this is a mig process? If you look in the pic its the edge that runs along the muffler.
Reply:you might have your pressure to high set it on about 30 to 35 cfh. if that doesnt work then you need to clean the material better.....arc lenghth is a big one to keep your nozle about a quarter to a half inch away from the stell
Reply:Oils and oxygen cause porosity.  Was there any cutting oil on the plate that you welded on?  What about oil on the bottom of the car?  Is there any leaks in your gas connection at the lead to the feeder?  Worn out O-rings on the pin can cause oxygen to be sucked in with the shielding gas.  Make sure your nozzle is cleaned out and not full of spatter and nozzle gel.  Some cheaper nozzle gels can actually gum up inside your diffuser and reduce the ability to flow.  There are simple flow meter gauges that you can place over the end of the nozzle to ensure that you are getting 30 to 35 cfh out of the nozzle.  They are a tube with a ball that is pushed up by the gas.  Usually less than 10 bucks.  I will usually run anywhere from 1/2" to 3/4" contact tip to work distance and be fine.
Reply:You know what i clean the surface by using a 3inch rol loc disc i never thought to use a solvent could that be it?
Reply:Originally Posted by sixxgeeeeyou might have your pressure to high set it on about 30 to 35 cfh. if that doesnt work then you need to clean the material better.....arc lenghth is a big one to keep your nozle about a quarter to a half inch away from the stell
Reply:http://www.hobartbrothers.com/pdf/datasheets/HB_25.pdf
Reply:You probably need something more than the roloc disks to prep that. I'd go with a sanding disk or grinding wheel as well as some sort of cleaner/degreaser both before and after grinding..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:i want yo to try 12 to 15 with a cheap maching with some crap gauge
Reply:I think you all are missing the point.  He mig welded it outside.  There's your problem, no matter how high you turn up the flow, if there's the slightest breeze you may not even me able to feel, it'll blow your shielding gas away. You'll have to grind the weld back down and weld it in you garage if possible, or use some tarps or cardboard to help shield the weldIn the field: '06 Ram 3500/Miller PP350    '14 F-350/Lincoln Classic 300DIn the shop: MM252, Hypertherm PM-85, White face MM200