Precision Tig 225 and 1/4" Steel

admin

Ok, I was reading another thread the other day and someone stated a Precision TIG 185 was good enough for 1/4" steel.From my understand it would take approximately 250A to weld 1/4".  So I decided to take the challenge and butt welded some 1/4" mild steel channel with beveling the edges about 1/16" on each side.  I was using 3/32 tungsten and 3/32 filler and the machine maxed at 230A.I had no problem forming the puddle and adding the filler.  All looked pretty good when done, nice and hot and nice wet puddle without having the pedal mashed out.  I took a look at the back side and there was heat there, but no real blistering like on thinner materials.  Do you think I should bevel around a 1/4" the way in and load up on the filler a bit more to get better penetration?I am looking to build a tube bender and I was thinking about TIG welding it.  The project consists of 1/4" mild steel.  And will I be able to get a good fillet weld with beveling?Thanks in advance!Build a Barstool Racer at BarFlyRacers.com!
Reply:You could bevel it slightly more and just do a weave or switch to 1/8" filler to make up for the extra beveled are, or bevel both sides and run a bead on each. I've dome both and gotten damn strong welds on 1/4 plate with a 180 amp machine. It can get messy, but I've also been able to weld really thick material by keeping the pedal down and holding the torch there for a second before adding filler to really get some heat into the metal.
Reply:It should do it no problem.  1/4" Aluminum sucks up more heat than steel.I welded 3 X 3 X 1/4" aluminum with my TA-185.  It just barely had enough nuts.  This was before I got a water cooled torch.  I got some hot hands, but it did it.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:Ok, I am game!I am going to try some test welds this week and as soon ay NEW camera battery arrives I will posts pics.Thanks!Build a Barstool Racer at BarFlyRacers.com!
Reply:While it may be possible to get a reasonably strong weld by your technique, I wouldn't recommend it.  A regular procedure for tigging 1/4" butts would be to bevel both edges 30 degrees to a point or small land and leave a 3/32" gap, then root fill and cap in three passes.  This is the standard procedure to ensure complete fusion and penetration.  This would be done at around 110 to 130 amps.  In your case, as you don't have open root experience, and seeing you have access to the backside, I would suggest you bevel but leave only a minimal gap and fill in two passes at the higher heat.  Then weld a single pass on the other side.  This would take longer then your one 230 amp pass but would make for good practice.
Reply:Ok, I did some test fillet welds on the 1/4" flat pieces and I beveled approximately 50% of the metal on the vertical part and ran a pretty nice bead for mild steel.Only problem I could see is I did not get the penetration on the back side as I thought because I ground down the metal and I have some undercut on the vertical part.Is the under cut from too much heat, angle or not enough filler?  I know I could have used a little more filler, it is just hard to see what is going on through the helmet.Sorry no photos yet.  I had to order a new battery for my camera and no it is on backorder...  Thanks in advance!Build a Barstool Racer at BarFlyRacers.com!