100A stick OK for 1/4"?

[e9999]

disclaimer: newbie welder here (but keen to learn)

objective: need welding some 1/4" receiver tubing for one of my trailers. That would be two 1/4" thick square tubes with rounded edges on top of one another so kinda beveled already, so to speak.

problem: I don't have 240V readily available at home. Seems like with MIG the 120V tops off at about 140A and that 140A is not enough for 1/4". I'm getting the impression that I need about 200A on a MIG to do 1/4" in one pass. (That true?)

possible easy and quick solution: I can get ahold of a 120V 100A stick welder of non-major manufacturer. Frankly, it looks like a cheap little toy and I am sure not the greatest quality (that may mean AC only?), but I can use it and I have lots of rods available. Main thing, it's 120V. And to my surprise the specs say that it can do 1/4" steel (I assume that means in one pass).

Question 1 : is it true that a small 100A stick could do 1/4" mild steel in the real world? That's like 1/2 of what I'm told a MIG will need. Or is just marketing BS?

Question 2: I am no serious welder. I played a bit with TIG and can do an OK if unrepeatable bead, and a sorta OK bead with flux core. Stick, it's been 30 years since it touched it a couple of times, so call that zero experience. So, assuming the machine can do it, is it worth it for me to learn to stick weld just to do 1/4" with only 120V? Just need that one job for now but conceivably armor later. Weld cosmetics will not be an issue for this app, but strength will be.

Question 3: Should I forget about that altogether, and learn how to do multiple passes with a 120V 140A MIG until I can get 240V installed which may not be right away?

 

[Pin_Head]

My first choice would be to use a 240V welder even if it means running two extention cords from two different circuits from the two different buss bar sides in my breaker box to get it. Pick 20A circuits if possible.

Second choice would be to use the 120V wire feed with flux core and multiple passes. You don't mention what type of joints, but if they are butt or fillet welds, use a 60 degree bevel with a 1/16 land and root gap. Then run 3-4 passes chipping the slag in between passes.

I have never been able to weld reliably with 120V stick welders and I don't want to learn. The open circuit voltage is too low to maintain the arc easily. If you try it, get 1/16 inch rods and do multiple passes. What you would really want is 1/8 7018 at about 125 A.

 

[e9999]

My first choice would be to use a 240V welder even if it means running two extention cords from two different circuits from the two different buss bar sides in my breaker box to get it. Pick 20A circuits if possible.

Second choice would be to use the 120V wire feed with flux core and multiple passes. You don't mention what type of joints, but if they are butt or fillet welds, use a 60 degree bevel with a 1/16 land and root gap. Then run 3-4 passes chipping the slag in between passes.

I have never been able to weld reliably with 120V stick welders and I don't want to learn. The open circuit voltage is too low to maintain the arc easily. If you try it, get 1/16 inch rods and do multiple passes. What you would really want is 1/8 7018 at about 125 A.

OK, thanks, need to digest that a bit to understand it all.

240 still better way to go eh? shoot...

I don't know the joint nomenclature but picture a rounded corners typical square receiver tube sitting on a larger one, kinda like a number eight. I'd want to weld the joints where the bottom edges of the smaller upper tube sit on the horizontal flat top surface of the bottom tube. It'd have an inward bevel that would be filled.

 

[Pin_Head]

Kind of like this but where the flat piece is another piece of tube? It is not an easy single pass weld even with a 240V welder because you need a wide weave and you have to hold a long time at the sides to tie in the toes. I did two passes, which was more ugly but effective. I used 3/32 7018 because I have a lot of it to burn.

 

[e9999]

Kind of like this but where the flat piece is another piece of tube? It is not an easy single pass weld even with a 240V welder because you need a wide weave and you have to hold a long time at the sides to tie in the toes. I did two passes, which was more ugly but effective. I used 3/32 7018 because I have a lot of it to burn.

right, like that, but upside down, the smaller tube over the big tube/flat plate. That might help perhaps. Or conceivably I could put the trailer on its side so it's a vertical "flat plate" and a square tube on the side if that's much better for the weld.

well, realistically, though, if that would be a challenging weld even for a pro, I should probably forget about it all and have a pro do it since those welds (there could be plenty over 5' or so however) would hold the tongue of the trailer. If I do, what should I tell the welder to use for technique and wire/rod if he has all the serious equipment?

 

[Pin_Head]

I wouldn't do any welds on the tongue of a trailer even though I took a welding class many years ago at Sac City College. I would pay a pro. The rule for me is if anything I weld might conceivably hurt someone, then a pro needs to do it.

 

[e9999]

yes, I'll likely end up doing that if I'm not 100% sure I can do a good job on it and that would require a lot of learning and testing, which I am ready to do but may not have the time now if that is indeed a challenging weld situation. It's not like one weld is holding the tongue, though, it's actually a reinforcement that I plan to put on the existing tongue and I could do 10' (not 10") of beads on it would I want to, but that seems rather brute force rather than skill. And I'm always very conservative with these things too.

I may still play with the 120V stick on something, though... And my neighbor has a 240V one I think

anybody else cares to chime in as far as the stick vs 140V / weld etc for an experienced welder to do?