Welding Tips and Tricks

Hello everyone and thanks for putting up with a newbie and his dumb questions.

I'm trying to weld 1/4" rod perpendicular to a 3/8" plate (mild steel) using my diversion 165. I have drilled a shallow hole into the plate to help maintain 90 degrees between the plate and the rod, and did a light grind on both materials to make sure everything is squeaky clean.

The main problem I seem to be having is to get the rod to form a puddle; it glows red hot but won't melt down to the plate. It just swells and deforms. I've tried with and without filler.

Any suggestions?

Thanks,

Chuck

couple of Q's:

what amperage are you using?
what's the bar made of? (im assuming 1010 steel or the like)
what size electrode?
how long were you on the bar with the arc?
is the plate puddling at all?


It will take quite a bit of heat to get that bar to melt, particularly if you've got a nice snug fit in the plate, as the plate will draw some of the heat out. 3/32" electrode, 135A is where I'd start. I don't do a ton of thick plate, so I'm not sure that's enough heat, but it's where I'd start. steel gets hotter the longer you heat it, so even if that is a little low, if you leave the arc on the rod, it should melt.

if the plate is puddling but the bar isn't (I'm assuming it's not puddling, but I'm not quite sure what you meant by 'deforming')
it would lead me to believe that the rod is not made from the same material as the plate. the rod SHOULD take less heat to puddle. in that case, I'd be looking at using a filler more suited for dissimilar metals. also, if there is any chance there is a zinc coating on the rod (like from the hardware store) then make sure your quick grind has taken it off. if it were zinc coated, it'd smell bad when you heated it and there'd be a yellowish white powder where it got hot. this is bad for you and if you are welding zinc plated stuff (galvanized) then you should wear a respirator.

if you're sure you've got uncoated mild steel and you're using over 100A w/ DCEN and 100% argon @12-15cfh, you should be getting at least a spot to melt if you keep the arc on for a few seconds. if you're not, something is wrong.

I'm sure someone can chime in if I'm full of shit, as plates aren't my main digs, but hopefully you can figure out whats wrong from this.

also, for a good checklist of problems, check out my reply in the "Need help bad..major problems" thread in the tig forum.

1/8" plate not 3/8", sorry.

The electrode is orange band, 2%, 3/32", my cup size is 6 and the filler is 1/16"

When I say the rod "deforms" I mean that if I put the arc to the rod first it glows red quickly and swells. This prevents me from running a puddle down onto the plate. The rod seems to get too much heat too quickly. So I've been initiating the arc on the plate then moving up to the joint while the filler rod is at the joint, and sometimes I'll get a bead that sticks to both, but it ain't pretty and it seems that, while the bead is welded to both, the plate and rod are not welding together.

I don't think there's a zinc coating on the rod, no smell or powder, and I am grinding off the surface pretty well. I am wondering from your post if they are in fact somewhat disimilar metals. Can two mild steels have a different enough composition to make a good weld difficult? If not, then one of the other factors is in play: electrode size, cup size, filler size or argon rate (I've tried a lot of different amperages).

Thanks for your thougts on this.

Chuck

well, it sounds like your rod is being confined by the hole you drilled and swelling out above it. when the metal gets hot, it expands and needs to go somewhere. that shouldn't prevent you from sticking the two together, though.
if you've got no discoloration or dust, it's probably not plated and you're getting adequate shielding coverage.

if you've got some spare stock, mock up another joint like what you've got and just give it hell, try to melt that rod into the plate and see if they'll fuse. not being able to see what you're doing with the arc, I'm inclined to believe that you're just not putting enough heat on that rod to actually melt it. you're just getting it really hot and it's swelling from heat expansion. I just read your reply again, you said you have trouble running a puddle down to the plate from the rod because of the swelling, does that mean you got a liquid puddle on the rod? if that's the case, i think you need to start your arc closer to the joint but still on the rod. just barely on the rod, though. like 1/16" of an inch. it won't want to undercut terribly because of the hole you've got the rod set in. once it starts to puddle (don't move until it puddles) point the tip down

also, on that bead you've got going, see if you can get the arc nice and tight on that bead and get it to puddle again. then walk it up a bit to the rod then back down to the plate and move forward, add some filler. make sure you wire-brush the scale off before you do that, though. steel tends to pick that crap back up when you re-melt a weld. it will make the weld porous if there is enough there. i mean, it doesn't have to be perfectly clean, but if there is too much crap, the puddle can't get rid of all the gasses before it cools and then... porosity.

if they are dissimilar metals (like one being a fairly high alloy), see if you can get a couple of rods of hastalloy-w from your welding supplier. unless you're going to be doing 20 of these, shelling out the $80 odd bucks a pound for that stuff is not a viable option. if you've got a decent supplier, they should spot you a few filler rods to try out, though. I'd probably stick with 1/16" filler.


hope that helps

"i think you need to start your arc closer to the joint but still on the rod"

That was absolutely the problem. The rod was swelling up with heat but not melting because I didn't have the electrode close enough. I was heating everything up but not melting anything! Typical beginner's dilemma, I suppose, that happens when you've dipped the electrode into a puddle quite a few times and get tired of running to the grinder. Best to give it hell, as you say, and trust experience to keep the tip out of the puddle most of the time.

Thanks so much, that solved everything and I'm off and running.

Chuck

glad you got that worked out something that helped me when i was starting out was to just keep going if you dip in the puddle. it welds like shit and you should DEFINITELY not do that for a structural or critical weld, but for practicing, it gets you a lot more arc time getting that arc length consistent and a lot less grinding. after a while, you don't dip the tip in the puddle as often.

just keep practicing, it only gets easier from here!