MMA welding scaffolding tubes

[SirDick Diodenob esquire]

Need advice please . Last time I arc welded was about 30 years ago using an oil cooled welder , was hopeless then and still am . Using a Lincoln 140 amp invertor which gives a very smooth arc , easy to strike and keep going much easier to use than a buzzbox or oil cooled welder . The poles are being welded at right angles with one being ground out to be a good fit against the cross peice . The poles were originally galvanised but heavily corroded , used a grinder to take both peices down to clean mild steel and a welders clamp to get an accurate 90 degree angle. Using 2.5mm MWA E6013 sticks , tried currents between 65 and 90 amps and so far used 10 sticks for one joint which if I think should have used maybe 2 or 3 sticks at the most and its still not finished after three hours work so I will never make it as a welder but somehow I need to finish this job as its for someones birthday this friday and it still needs painting . First problem is unable to see a thing through the cheap Halfords mask and difficult to even keep the run on course on the joint but will try a Murex glass shade tommorow , may as well just close my eyes with the mask I am using today . I think I should be using bigger rods and a higher current maybe 4mm and 120 amps ? The joint is butted with no groove , is this a bad idea and would it help if I grind a channel in it ? Have read the posts on welding pipes but seems to be mainly about using TIG rather than MMA and for welders who already have a high skill level .

 

[backpurge]

What sort of stress is going to be put on this

 

[Arsonista]

Those magnetic clamps tend to 'pull' the weld towards them. Better to get some good tacks on, and then adjust it manually. (With a BFO hammer). 3.2 sticks might be a better bet at about 100+ amps. Also a joint like this is not the easiest one to be starting on, if you've got time, practice on some straight runs. Anyway, good luck.

 

[SirDick Diodenob esquire]

Thanks for the advice , I will get some 3.2mm rods , the stress is more on me to get them up before Friday than on the poles , they are for washing lines and before anyone says it I know would probably have made more sense to have bought a ready made set of galvanised poles because so far its taken the best part of a day to grind off the corrosion and burn 10 rods on one joint which still looks very dodgy to me which is partly due to being completely unable to see what I am doing and I cant blame the machine as its a good one . The poles cost £5 but the tins of primer and top coat plus grinding wheel and rods came to nearly £20 so its not turned out the way I planned but anyway at least when they are finished I will have some satisfaction and hopefully my next job will be completed quicker than the three days for this one , the proffessional welders on here can now breath easily as I will definitely not be taking this up to make a living .

 

[madkayaker]

put a V on the end of the pipe next time this give you a gap to fill this will give you a stronger weld

 

[backpurge]

As said above, bigger rods, more power. Wouldn't advise putting a prep on what is basically a fillet weld unless you grind it back that far that you can bottom the rod out in the root of the prep

 

[pedrobedro]

Ours is made from scaffold pole with a cap welded on it and for the cross bars I drilled 10mm holes and put some bar through then welded it in. It's lasted 20 years so it is better than the one next door bough which rotted through at the bottom after 5 or 6 years even though it was galvanised.

 

[Lewis Medlock]

Is the welding return ('earth clamp') on clean shiny metal?

Are the electrodes in good condition, ie not damp etc...

All the best, Jim

 

[Delgado]

As said, and IMHO those are one of the hardest welds to do with MMA as you have to keep the rod angle correct whilst rolling your wrist and moving your arm to get around the joint. If it's only for a washing line you could probably get away with just doing it downhand (tut, tut) in the position shown in the foto. Turn your amps up to at least 95 (drag the tip of the electrode along the metal, you want as short an arc length as pos.), weld across the top and down to the middle of one side, start again from the top and weld across and down to the middle of the other side, then flip the whole thing over and do the same again (make sure you clean the slag out from the ends of the welds or you'll get a hole). It's easier to keep the rod pointed at the correct angle and burried right in the join if you hold the electrode with your non welding hand, but make sure you wear thick gloves. Nothing wrong with using 3.25 electrodes, although if you do it downhand you'll have to go really, really fast or the slag will overtake the weld bead.

Hope this helps and Good luck!

 

[Andy from Workshopshed]

I'm wondering if you need to clean up those poles a bit more before welding, I find a flap disk is pretty good at that job.

Test them with a large hammer before installing, washing lines have a surprisingly large load when the washing is wet and the wind is strong.

 

[SirDick Diodenob esquire]

Thanks for all the further advice which I have tried to take on board . Have decided after using a grand total of 20 sticks on one joint thats enough . The earth is good and the sticks have been stored inside the house in a dry place . The welding machine is as good as I could expect for , whats missing is the skill to use it properly . I have ground back the welds as far as possible but clearly didnt do it properly on previous passes as you can see the worm like slag inclusions but I will still be welding this at Christmas so have decided its time to put the paint on . It seems strong enough but I will warn the other half to wear a hard hat initially when pegging out the washing just as a precaution , I am just hoping that I can weld the second pole better . One lesson learnt is not to use corroded steel poles again , would have been better using brand new tube as even after hours of grinding its still heavily pitted and thats probably where the rust will come through again .

 

[syborg]

hi mate.

did u grind off the galv before u tried welding it?
a nice 4mm 45 degree chamfer on the extra pipe would of given you a nice deep weld to build onto.

peace

syborg

 

[asmeix6g]

IMO DONT grind a prep onto the fishmouthed tube as its only going to make it more prone to blasting the arc through it!
also stick with 2.5mm rods 70 amps or so make sure its clean first, because your effectivly welding a 'circle' make sure all your welding is done on the flat or vertical up if your try to weld vertical down (stove) it will go horribly wrong.

Why is everyone recommending grinding a prep into the pipe? its not a high pressure transfer line! its a couple of bits of old scaff tube! im not having a dig at anyone, im just saying try to make the guys life easier....

 

[gordon stephenson]

Definitely no prep required.

 

[SirDick Diodenob esquire]

I did grind off the galv before starting , the poles were well corroded to start with . Five months on and I am still working on this birthday present , not to worry the poles should be ready for her next one . With the benefit of hindsight corroded scaffolding poles are just fit for the scrapyard , more hassle than they are worth trying to grind the corrosion out but you live and learn .

Having now burned at least 60 sticks on this job using an invertor also tried it with a mig machine I am finding the invertor much easier although this may have nothing to do with the arc or mig being better than the other . I tried putting a V into the joint on one of the fish mouth ends and your right it makes blowing holes more likely which then become an absolute pain trying to fill them in . I have added steel balls plus decorative scrolls to hold the lines and by the time I have finished I reckon the real cost just in materials will have been about £60 which is quite a bit more than buying a ready made set .

 

[squazy84]

hi.if your anywhere near the west of ireland eg galway/mayo, i can give you a hand or point ya in the right direction

 

[SirDick Diodenob esquire]

Thanks for the offer , I am in Donegal so basically isolated , went to Dublin last week and it took four and a half hours to do 140 miles , dont think I got over 30mph for the first 60 miles , you just have to like tractors in this part of the world .

 

[squazy84]

im in mayo fully qualified tractor mechanic