Welding thin metal with stick welder?

[gavuk]

not just invertors, use a Dc tig set for stick welding and it's far better, easier to start and less sticking!

Agreed ,should read,invertors,dc or oil cooled......in fact just about anything is better than a buzzbox

 

[sardine]

a method

If i have to do thin sheet with stick, i put a copper bar behind it, and put tacks every half inch, pausing a second to get full penetration, then clean off and put another set of tacks overlapping, until the job is done. I keep the electrode dead vertical, that kind of works, but it's not pretty, and you need an inverter, to get the low amps.

And i came by 2 free boxes of Oerlicon 2mm's they are much better than 1.6's.

 

[shenion]

And i came by 2 free boxes of Oerlicon 2mm's they are much better than 1.6's.

In general, I found the same. The 1.6mm rods have a lot of flux so you need to run them hot to prevent slag inclusions.

The 2mm rods seem happy to run a low current.

 

[martinez]

I've attempted to weld 3mm plate on my boat with arc, saves dragging the mig down there and the Murex Inverter I got off fleabay for £25 welds great. Had a few problems though so may return to mig after all. I cut out some of the hull to weld patches in and have managed to match everything up fine, I bevelled the edges for welding but after trying 2.5 and 3mm rods didn't get good results and was blowing through a lot.
I don't want to have to weld from both sides hence the bevelling. any advice ?

 

[Lewis Medlock]

I've attempted to weld 3mm plate on my boat with arc.
I cut out some of the hull to weld patches in and have managed to match everything up fine, I bevelled the edges for welding but after trying 2.5 and 3mm rods didn't get good results and was blowing through a lot.

I don't want to have to weld from both sides hence the bevelling. any advice ?

Practice!

I take it you're not rolling your boat over to weld on the flat and the hole isn't in the bilges so you'll be working somewhere near vertical?

You're more likely to blow through 3mm sheet if you put a prep on it so don't bother with the bevel- you'll penetrate with a tight ish fit up and a decent 3mm rutile electrode.

Conversely a good rutile 3.2 rod will do thin stuff with correct arc length, polarity and technique, a couple of weeks ago I bodged a snapped Transit exhaust with 3.2 Superblues. It wasn't pretty but done on site in 15 mins and (in my humble opinion) as good as most 'MOT' welding.


All the best, Jim

 

[martinez]

right yes, vertical and I'm not well practiced either just a weekend welder. I'm also not that clued up with rods types. I'll have a look what I've got and have another go.
I bought all these recently any advice on which are best ?
http://www.ebay.co.uk/itm/261088474539?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

 

[PTvor]

A lot of those rods are 450mm which you might find a bit awkward.

If you can't do the equivalent welds on 3mm sheet easily and to the standard you want in the comfort of your back yard, I'd say you were asking for trouble trying to do them on the boat.

 

[rich r]

A lot of those rods are 450mm which you might find a bit awkward.

Nothing a hacksaw or boltcutters won't sort out. As a bonus, you could end up with twice as many rods

 

[martinez]

A lot of those rods are 450mm which you might find a bit awkward.

If you can't do the equivalent welds on 3mm sheet easily and to the standard you want in the comfort of your back yard, I'd say you were asking for trouble trying to do them on the boat.

I don't think I'd have much problem back at home. I learned to weld on cars using an old transformer from a milkfloat, then upgraded to a buzzbox, first time I used the inverter and DC I couldn't believe how easy it was to get a good result !
I'd only use mig these days for cars, but the murex has drawn me back to stick. I'll have a practice tomorrow down the boatyard and see if I can improve things. but which rods do you recon will be best for job? I found the 3.2s better than the 2.5s but vertical welding is a swine.
By the way chap next to me asked me to weld small repair on his boat and it looked fine after a couple of practice runs. that was horizontal and up on the keel, but his boat was 4mm not 3mm

 

[PTvor]

Of the rods I've got, the one I'd reach for for anything important/difficult/fiddly like the boat is a 2.5mm Elga P45S. On my inverter I'd set the current to 75amps and drop it a bit for the verticals. That's on my inverter, they all vary a bit.

I'd find a 3.2mm a bit much for 3mm sheet. The Fleetwelds are celluosics and your inverter may not run them anyway, not all of them will.

If you're limited to the rods from that lot you bought, I'd say the 2.5mm FEREX 7018LT.

But, whichever you decide to use you have to try it first on 3mm sheet that doesn't matter and be sure you can do it, rather than jump in and test it on the boat and find you are blowing holes.

 

[martinez]

thanks for that. had another go today and found the 3.2 6013s easiest at 80 amps and keeping the arc short.
It's been some time as I said since I'd used a stick, but found after a while that I started to recognise the sound and use it as reference for the weld (it's like riding a bike).
I tried the 2.5s but had to move like a whippet and it blew holes too easily. with the 3.2s I could lay a fastish bead then wire brush and weld over.
still not perfect but seem to be getting there. still having to do too much grinding but the penetration is good and I can fill in the bad bits.
I really need more practice

 

[PTvor]

The other thing you can do is try using the rod negative. The arc is a bit gentler and less penetrative and you might find you get on better. Worth a try.

 

[martinez]

Reversing the polarity did occur to me, never had that facility before only having had AC so will give it a try. cheers for all the advice
I may even cut some sheet up and spend a few hours in the garage practicing

 

[jonnyBMX]

Thats sensible, as no amount of fume is 'safe' I wish I had that kind of ventilation, instead I wear paper masks which steam up my visor lenses

just an idea, i use a 3m 7500 series mask with filters for welding under my welding mask works very well!

dust/fume masks for welding from 3M its the 7500 seris (7501 -small 7502- medium 7503 large)

tried to upload the pics but cant atm

 

[martinez]

Thats sensible, as no amount of fume is 'safe' I wish I had that kind of ventilation, instead I wear paper masks which steam up my visor lenses

just an idea, i use a 3m 7500 series mask with filters for welding under my welding mask works very well!

dust/fume masks for welding from 3M its the 7500 seris (7501 -small 7502- medium 7503 large)

tried to upload the pics but cant atm

Did I miss something ? where did that come from !!!

 

[jonnyBMX]

they were talking about using ventilation and different masks so i suggested one? which is why i quoted the original bit