Welding blow through on gaps

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Today I was welding some 16 gauge 1.5 inch square tubing at 90 degree angles and had a lot of issues with blow through. I cut the corners to be joined at 45 degree angles with a grinder and when I put them next to each other to weld there was a small gap (1 mm) on a lot of them. As I was trying to weld and I passed over the small gap with my puddle it was blowing through and making a big hole. Any tips or tricks to solve this?I was running pure co2 with a HH 140 using recommended settings.
Reply:Turn the welder down for those sides of the miter, Burn through is common there. You can also weld a little an stop to let it freeze then weld some more.
Reply:Originally Posted by walkerTurn the welder down for those sides of the miter, Burn through is common there. You can also weld a little an stop to let it freeze then weld some more.
Reply:What type of metal is this? What process?
Reply:Originally Posted by JMcL213What type of metal is this? What process?
Reply:I figured carbon or stainless, but idk what he meant by HH140, figured that was a machine...
Reply:In situations like that, I find it helpful to do a cold or stop-start pass to fill the gap, then once the gap is bridged, put down another pass to clean it up and make sure it's got good fusion and penetration. When there is a gap, the heat is concentrated at the edges of the metal and they melt off quickly, but once the gap is bridged, the heat can move away from the arc and you will have a lot less problems with blow-through even if the "bridge" that you put down is relatively thin compared to the base metal.I'm just a hobby weldor, but that's what I do.Everlast PA160-STH... and that's about it!
Reply:that's pretty thin metal, 80/20 mix is going to give you less blow through. 75/25 would even be better than straight CO2. HH140 = Hobart Handler 140.If I have a gap I tend to widen my puddle out. Moving it down the sides of the gap not accross the middle of it.allowing the weld to build up and not concentrating the heat so much in one spot. Moving faster will help as well. You should be moving pretty quickly with that thin of metal anyway. I'm surprised you're not blowing through all the time using straight CO2.There are no problems. There are only solutions. It's your duty to determine the right one.Hobart Handler 210Airco 225 Amp MSM Stinger
Reply:turn it lower move a little faster
Reply:I'd use the 12/6 weave like we sorta call it at school, manipulating the puddle back and forth from base metal piece to base metal piece, either dipping the wire at both the 12 oclock and 6 olock positions or walking the wire (assuming we're working with carbon or stainless...)
Reply:Can you improve the fit with an angle grinder a bit?  keep a grinding wheel on one and a cut off wheel in another?miller syncrowave 250hobart handler 140home made 400 amp engine driven in progress...