Mill build welding

[bandmiller2]

Its an unfortunate fact steel moves when you weld it, your perfectly aligned your square joints are not so. Take a square cut piece of angle iron and set it on another with a perfect 90 angle, weld or tack one side. The DanG thing will have moved and if you try to hammer it square it will break the weld. Now do the same thing with a slight gap between the pieces (1/16-1/8") now you can square it up and not break the weld. With experience you can know how much a piece will move and compensate for it. A slight gap also allows better penetration for the welded bead. You old spark welders have any other suggestions. ?? Frank C.

[Dakota]

I tack weld as many pieces as I can before I ever do the final welding.  This will hold things nice and square.

[Kbeitz]

Clamp it good. Light tack all around. Try tacking on both side of the joint.
Use your welds to help pull it the way you want.

[drobertson]

Use of heat too,,

[DannyLand]

Jig things up whenever possible on a sheet of old plywood.   Layout your frame on the plywood using basic nails or blocks of plywood with screws on either side of the steel to hold it in place and then small weld tacks all over.  Leaving an 1/8" gap works but can leave room for things to move more in the wrong direction so I dont recommend it.   If your cuts arent square, be sure to recognize them for their long points and tack there first.  Soon as you apply heat, things are going to move no matter what, but all those little tacks will solidify the frame a lot and reduce chances of movement when you burn things solid.   Also, move around the frame with the welds, dont go blasting through three sides of a joint all at once.  I know Im not an "old timer" but Ive been welding for over 20 years now and have learned the hard way how not to do something.   Like Kbeitz said, you can use the heat to your advantage sometimes to pull things back into square.  What kind of welder are you running, stick or mig?   Gas or flux?

[paul case]

Yeah,

I have had those problems. I found that if I am welding a 90deg on say 6'' channel that instead of tacking on the top or bottom tack it in the middle first then the top and the bottom may move out a little it wont be so out of whack as to be a problem. usually it doesn't move apart at all. Then you can tack the top and bottom without the heat causing them to move away. Clamps work sometimes but much of the time there is nowhere to put them.

Happy welding!

PC

[Kbeitz]

Remember that welds pull... Not push...

[scully]

Tacking correctly is everything . Understanding pull and how to counter tack for it is very important . I.E. Dry fit and check square , if it needs to go one way or anothere tack it to pull that way . Then tweek for opposing tacks . Stick and mig will act a little diffrant as with stick you weld slower and concentrate heat and filler metal longer . This can result in more pull . Always counter weld oppasit as much as you can . I try not to let a weld cool much before I jump to the other side and run it quik ! Clamping is your friend . clamp the snot out of it when you can . I suggest having a good heavy plate fab table . Many times I will tack my peices right to the table and weld them out ,then grind off the tacks .  If you are using the stick weld prosses I sugest you use ER7018  60 series rods wont be as clean or run as well in position .

[Ox]

Clamp well if possible.  If not, I make my tacks just strong enough to hold.  As in I just strike an arc for no more than a second.  This minimizes any heat.  Then I'll go to the other side and tack for a second and a half.  It just feels like twice the time.  The additional heat will pull the piece back straight.

[Kbeitz]

I think I found one a little better than the  ER7018 ...



 

[ozarkgem]

I think I found one a little better than the  ER7018 ...



 

Have you tried these yet?  I personally like 7014. You will need a rod oven to keep 70 series rod dry.

[Kbeitz]

I think I found one a little better than the  ER7018 ...



 

Have you tried these yet?  I personally like 7014. You will need a rod oven to keep 70 series rod dry.

Its all I've used for the last 2 years... Every so often one gets hard to start but other than that
I'm real happy with them... This last week my life depended on my welds with these rods.



 

[YellowHammer]

Welds pull when the filler metal shrinks, so the smaller and cooler the tack, the less filler metal applied, and so the less the shrinkage and the less the pull in the joint.  It's also always helpful to put light tacks at a neutral point or neutral axis in a joint, where the weld pull doesn't really cause problems, such as the ends of the legs, not in the mid body of the fillet.  I like to do small tacks in three corners, like a triangle, to fully constrain the motion of the joint. 

[Ljohnsaw]

I think I found one a little better than the  ER7018 ...



 

Have you tried these yet?  I personally like 7014. You will need a rod oven to keep 70 series rod dry.

Its all I've used for the last 2 years... Every so often one gets hard to start but other than that
I'm real happy with them... This last week my life depended on my welds with these rods.



 

KB, which are you using - 7018, 7014 or 80T-AC Plus?  I picked up an almost full box (50#) of 7018 for $40 last year.  Got about 15# left - I like it.

[sandsawmill14]

i dont see the advantage to the high strength rods when welding mild steel as it is only 55-65k psi anyway ???  some of the china stuff aint that good : but i do use 7018 for most stuff if its fairly clean but i use alot of 6011 and dont clean before i weld  :-[ ;D  you can burn off a 1/4"of rust and it will weld fine but not always so pretty ;D i know im gonna catch it over admitting that but it works smiley_curtain_peek  :D :D :D  when im welding something that matters such as truck axles, shafts and such i use a 120 something or other i cant remember the rest of the #s and i am out of them right now they are pretty expensive so i dont keep many the last ones were about 26 bucks a pound it is a high tensile ss rod and when i get some more i will try to remember the #

[Kbeitz]

I think I found one a little better than the  ER7018 ...



 

Have you tried these yet?  I personally like 7014. You will need a rod oven to keep 70 series rod dry.

Its all I've used for the last 2 years... Every so often one gets hard to start but other than that
I'm real happy with them... This last week my life depended on my welds with these rods.



 

KB, which are you using - 7018, 7014 or 80T-AC Plus?  I picked up an almost full box (50#) of 7018 for $40 last year.  Got about 15# left - I like it.

80T-AC Plus

[bandmiller2]

I have a bunch of 10018 gov. surplus in sealed cans but as stated its kinda wasted on mild steel. 6013 is my go to rod, DC reverse polarity. If you have good position 7014 is sure a pretty weld. I have an old Hobart motor generator DC welder that is pure joy to use. Frank C.

[sandsawmill14]

surest way to tell if you need a better rod is if it breaks in the weld or beside the weld (assuming you are welding properly) if it breaks a 2nd time you can patch a cotton rope with a piece of steel cable but the rope is not any stronger

[drobertson]

surest way to tell if you need a better rod is if it breaks in the weld or beside the weld (assuming you are welding properly) if it breaks a 2nd time you can patch a cotton rope with a piece of steel cable but the rope is not any stronger

I would be close to saying changing rods and techniques if cracking is happening, good chance there is a high carbon present. A pre-heat, and post heat maybe required.

[DMcCoy]

Anymore I use backing plates and lots of clamps.  Angle iron for 90 corners, flat bar for straight work as backing plates and clamp heavily.  I also clamp 45 degree bracing for longer pieces.
After clamping I check again, and will hammer adjust things into position if needed then tack it down.  Because it is so well clamped I tack pretty heavy, pull off the clamps and weld it up.
It takes a little time but the time spent on rework is close to zero for me.  Tacking with-in range of my angle grinder makes life easier as well.

I learned to weld with 6011, which once you can consistently make a nice weld with it the other stuff is amazing.  I use ER7018 almost exclusively anymore, flows like butter.

[Kbeitz]

I have a bunch of 10018 gov. surplus in sealed cans but as stated its kinda wasted on mild steel. 6013 is my go to rod, DC reverse polarity. If you have good position 7014 is sure a pretty weld. I have an old Hobart motor generator DC welder that is pure joy to use. Frank C.

I try to stay away from rods stored in sealed cans. Never had luck with them.
Gotta be in a cardboard box for me.

[Satamax]

Guys, i don't know the rods you were mentioning.

But one, which is like magic for me, either 312-16 or 312-17. Ok, it's costly. Might not have perfect qualities in some cases. But boy, how well does it flow. And on cast iron, it's the best thing i ever tried.

[drobertson]

Those satamax almost sound like an Nicole alloy rod, if so this explains how nice it works with cast iron.

[mburrow]

312-16 and 312-17 are stainless steel rods

[drobertson]

312-16 and 312-17 are stainless steel rods

Ahh yea! Got mixed up, both work well for cast, thanks for the correction!