clean 1x1in square steel tubing/fix porosity

admin

So I am working with 1x1 square steel tubing. I made a few tig beads (want it to look NICE, need a good first impression), and ended up with a lot of porosity. So if you could please let me know:     -How to clean pre welding, esp. the INSIDE (3/4x3/4), I have been grinding down to shiny metal on the outside and using acetone. I have access to strong industrial chemicals if need be.     -How to fix the porosity that has been made (just on a few spots/corners)     -Also, avoid getting so much undercut???Thank you!
Reply:Picts would help. So would knowing what process you are using as well as settings, rod/wire size etc.Acetone is a good choice for removing oily residue on material. Inside I've used a rag on a stick to help wipe down the inside.Porosity comes from any number of causes. It might be due to poorly cleaned material, or it might be due to loss of shielding gas with mig/tig. Undercut could be from moving too fast, not waiting for the puddle to fill, bad rod/torch angle, long arcing or several other possibilities. Knowing more would help, as would picts.As far as how to "fix" porosity that has already occurred, you grind it out and redo it..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:Okay thank you I will try to experiment with those. May be travel speed to long arc. Could it be not adding enough filler? I will take some pics tomorrow. I'm using dc tig, ER70s2 3/32 i believe, running 80 amps my guess. 3/32 Tungsten, 11 cfh 100 argon, 3/32 arc (for the most part, still a noob). About a 70 degree torch angle best I can.
Reply:1/8" wall tube?  80 amps may be a little low depending on the joint. 3/32" filler can be done but with that size steel 1/16" may work better for you, it will let you feed wire into the puddle without freezing the puddle with each dip. What size cup are you using and how much stickout from the cup? For me 11CFH is low unless I'm using a #4 cup, so maybe try a little more flow. The undercut could be because you are welding slow (heating the steel too much) because of the low amperage. Porosity could be from long arcing with the low CFH.Airco Ac/Dc 300 HeliwelderMillerMatic 200 (stolen)Miller Maxstar 150STLMiller AEAD200LE (welding and generating power) Hobart MIG
Reply:Pics, as promised. How bad is the undercut here? I'm not asking how bad my welds are, thank you trolls. I will be weld more this afternoon. Will try all suggestions, but would love to have more opinions. Attached Images
Reply:The undercut doesn't look too bad, but you need to try to fill it in. Looks like one problem you are having is trying to fill too much at a time. When you have a deep groove to fill it may take more than one pass for a full weld. I can't tell for sure but it looks like you are beveling some edges of the tube, it isn't really needed because of the radius of the tube you are welding it to. That just means you have more to fill in. Try a few more amps, a couple of the welds look cold at the start then when the steel got hot it flowed better for you.Airco Ac/Dc 300 HeliwelderMillerMatic 200 (stolen)Miller Maxstar 150STLMiller AEAD200LE (welding and generating power) Hobart MIG
Reply:Alright thanks, so I should go over the previous welds? Do I want a convex look?
Reply:You might try to go over the weld with a stainless tig rod and usually "sucks" the porosity out.  If there is not a massive amount of porosity.  As stated above, the best/proper way to do it is to cut/grind or arc gouge the porosity out.  If you feel like you have enough weld reinforcement for structural integrity already on the joint and you are just trying to make the one weld cosmetically appealing, give the stainless a whirl.  This will also fill in the undercut usising the stainless as another pass.  DISCLAIMER:  of course if your flow rate is not correct or the wind blows your gas away, or your tig wire is "dirty" or your tig cup is to far away (any number of things) you will continue to get porosity.I'd give it a try using 309 wire, which is used to bond stainless to carbon steel.
Reply:Yes you want a slightly (ever so slight) convex bead as opposed to concave, and don't make it a camel hump!
Reply:Originally Posted by T_MoneyPics, as promised. How bad is the undercut here? I'm not asking how bad my welds are, thank you trolls. I will be weld more this afternoon. Will try all suggestions, but would love to have more opinions.
Reply:In looking at the pictures again, it looks like you have access to the weld with porosity for a grinder.  Try the stainless idea on scrap someday and be amazed.  To get rid of the under cut (which as stated above doesn't look that bad, but is considered a weld defect) let your filler wire go/travel edge to edge of joint.  When you are at the edge point your tungsten at the filler wire and edge simitaneouly pause every so slightly allowing the filler wire to deposit it's stuff then move across the middle of the joint in a speed that will allow the correct amount of build up you want.  This will give you more filler metal where you want it.  In other words don't just lay your filler wire in the middle of the weld joint.  This is not to say the above info is incorrect, it was right on.  Sometimes there are more than one thing we need to do to get a proper weld.  If it was a no brainier they wouldn't need us/welder's.  Easy to get rid of that undercut.  As stated above, sometimes you need to make several passes to achieve what you want/desire.  This is best dedetermined before you begin the weld and knowing that will come with experience.By the way you are a thinking man, your asking the right questions!
Reply:Good eye turk, the Turk has a great point on your amps being low, you are running cold T Money.  The best indication of it to me is in picture 3 at 18 1/2" where it looks like you started at the bottom of the picture (18 1/2") .  You see the " y" looking bead, it is like you didn't even have enough heat to melt the filler wire.  Not to mention Turks insight - never met the man, but he knows what he is talking about.
Reply:Originally Posted by T_MoneySo I am working with 1x1 square steel tubing. I made a few tig beads (want it to look NICE, need a good first impression), and ended up with a lot of porosity. So if you could please let me know:     -How to clean pre welding, esp. the INSIDE (3/4x3/4), I have been grinding down to shiny metal on the outside and using acetone. I have access to strong industrial chemicals if need be.     -How to fix the porosity that has been made (just on a few spots/corners)     -Also, avoid getting so much undercut???Thank you!
Reply:The size of the heat discoloration is a clear indicator you're running too cold and slow. I've been there is how I know.Everlast PA160-STH... and that's about it!
Reply:Wild stab in the dark... Harbor freight 80 amp inverter, scratch start?Only reason I could see for not running hotter is a lack of amps.You didn't build that.'85 Miller AEAD-200LE