Thread: Total NOOB begs nicely for help.

Those old machines were made in a time where no one welded box section that was 1.6mm thick.
If you were welding on 3mm wall thickness IT WAS CONSIDERED THIN.

Today when all designers can think about is cutting down on weight and cost (thicker walled metal costs) thin wall sections can be joined in various ways.None of them include use of a transformer based arc welding machine.

Unfortunately your transformer based machine won't do this particular job adequately for you.While it was, and is, a great machine in many other ways,I don't believe it can be set low enough.

For comparison,I have recently welded 1.6wall 50 x 25 RHS but this was with a an inverter machine using 2.6mm rods at 58 amps.

The short answer is that your machine is unlikely to run an electrode at the amps required not to burn through your.
it does not mean you welder is useless.It will be ok for thicker sections.

Grahame

The way most get aroung welding thin stuff with the Stick is crank it up and go like stink.
If your welding small sections on butt joints you can place a good tack on the red spots and then run a full weld straight ontop of the tacks. If you are fast enough you wont burn through when you get to the end of the section. As Grahame said though, stick welders usually arent good for thin stuff unless you have an inverter machine. They almost make welding easy.

Originally Posted by fatboycrash

Better, but I'm still blowing holes where the end of one length butts up against the side of another length. At the end mainly. I can run a bead no worries on a scrap piece if it's in the middle of the piece but if I get to the end it just seems to blow away.

Hi Shannon and welcome. I'm just a mug but I've had the same issue and found a work-around. The problem is the radius on the corner leaves a gap so the end of the upright (if it's a T shape) is hanging in space. You can aim your arc at the solid piece (top of the T) and run a quick bead. You're not aiming to join the two, just build up one side and close the gap a bit. This also gives a bit more metal to absorb the heat. Let it cool, de-slag and try again, using short runs. With practice you'll hear when it's about to blow through.

Thanks everyone for your help!

Bryan, that's exactly it!! It's going to make building this thing a little longer. I'm playing with the idea of making 'plates' and welding those to the 'meat' of the shs.....

Hopefully Julia will come through for me with a nice big fat tax return and I can get a nice inverter... !!! Any suggestions? Go the 300 buck or suck it in and go the 1000 plus??

Originally Posted by Bryan

Hi Shannon and welcome. I'm just a mug but I've had the same issue and found a work-around. The problem is the radius on the corner leaves a gap so the end of the upright (if it's a T shape) is hanging in space. You can aim your arc at the solid piece (top of the T) and run a quick bead. You're not aiming to join the two, just build up one side and close the gap a bit. This also gives a bit more metal to absorb the heat. Let it cool, de-slag and try again, using short runs. With practice you'll hear when it's about to blow through.

Bryan nailed the problem, and his solutuion is a novel one

Clearly the problem is that the open end of the RHS needs much less heat to melt than the closed side of it. Thus if you apply heat evenly to both, either you won't get penetration on the side, or you'll burn through the open end. One solution is to weave the rod, spending a bit more time on the side of the RHS to achieve penetration, then bringing it over briefly to the open end *just* long enough to melt it and extend the weld pool between the two before moving the rod back to the other side.

As for an alternative welder, as mentioned in a few other threads, the BOC Smootharch 130 is a brilliant little inverter machine, 10A plug, weighs nothing, welds very nicely. Costs about $350 or so.

I,ve welded heaps of 1.6 box with a transformer stuck permanently on the high 3.2 rod 135 amp setting of 10 years .Very rarely blow holes.Just be welding 3 or 4 spots at once and do reeeeealy short runs, just a zit then the other spots further along then back.or just tip a little water on the weld between short runs .And striking the ark on the uncut box section and just flicking across to the cut section before ending the arc . Definitely can be done and will u get it down

. But if u have more time than money and old buzz box , especially as u can turn yours down, should be fine .The ceramic thing that slid in and out of the windings was broken on mine and thrown away a decade ago so it was on max all the time .1.6 wall box , 2.6 rods 140max amps definitely can be done .The rods would turn bright red half way through and I would just dip them in water .Do what ever it takes to get it to work.Good luck mate
-- mat --

[Did just got an inverter one lately and it is a lot easier being able to adjust the amps and just weld continuously though]

Originally Posted by RustyArc

One solution is to weave the rod, spending a bit more time on the side of the RHS to achieve penetration, then bringing it over briefly to the open end *just* long enough......

It doesn't sound like there's enough time to do anything but weld flat out in a straight line. Wouldn't it be better just angling the rod at the closed side and going straight?

Anyway what sort of amps can you get a selfwelder 140 down to?

I gave it a go with some 1.6mm thick galv SHS with my inverter using 1.6mm 6012 rods - 1st run at 90amps just for the hell of it - tricky, but with some practice I reckon it'd be possible. Second one at 45amps - which was about right - see photo.

Regarding paint removal, my vote goes to the flapper disc. Good luck with it.

Cheers - Mick

Originally Posted by fatboycrash

I need a welding bench and had a plan in mind for a 1m x 2m bench on castors with a 5mm top. Good for working on motors too...

I just put a small bench together a while ago and did a bit of searching around for ideas: "http://www.offroadfabnet.com/forums/showthread.php?t=5651" had a collection. Cheers - Mick

A couple of things you could try.
1. make sure you have 0 gap at the joint, gaps are good for penetration, not something you need.
2. If that doesn't work notch the tube so you have a lap joint one side, the other 3 sides will be internal butt joints. If the steel has been cut this will make your table 10mm lower.

One last thing you can try that "may" help. Start your weld as normal and then lay the rod down flat along the weld line and the welding "may" just look after itself.

Just one more thing about how your bench is designed, where possible have welds holding the bench together, not holding the load.

Thanks again everyone! That's given me a few extra things to try. Notching the SHS to minimize gap is good and I will try going flat out with a 3.5mm electrode... 'though I can see that possibly ending in tears!

I have no idea what amps the old Lincoln selfweld 140 can go down to, it's not really graduated like that. It's more 2.0/2.5/3.2 electrode graduations. I just SO like old stuff. The PCB was layed out sensibly, labelled so that it could be repaired, a circuit diagram was placed on the inside of the cover and the transformer had real copper.... I think I may have been born in the wrong era??

Thanks for the tips on the benches Mick. Wow!!! Check some of the gear in those blokes sheds!!!

Thanks again, I'll let you know how I get on.