Noob question alert

[urban]

Hello everyone, I've registered here to ask the some experienced welders a question...

I used to work as a mechanic and we had a MIG welder that I used quite a bit and was ok at, by no means to a high professional standard though.

When I gave up mechanicing I bought a cheap arc welding kit from BnQ for odd bits of welding I needed to do.

I've never been able to get to grips with it properly, I know the welder is no doubt of poor quality being from BnQ and only cheap but I can't get a good looking weld from it, I can run a line of weld and it looks good until I chip off the slag, the slag chips off after a lot of battering but the weld has the slag included in the weld metal (excuse my lack of using the correct terms).

Although the metal is joined I doubt it's as strong as a complete weld line and it also looks terrible, pitted and like a birds splatted on it.

Is there something I'm doing drastically wrong, like the wrong amperage, going too fast etc. I'm using machine mart rods (I'm guessing not the best) 2.5mm usually and around 80amps, I also struggle to get the arc started, it usually just sticks to the base metal again is this due to bad equipment or a wrong set up or just me that's useless at it

 

[ChrisJohnsSculpture]

The most tricky thing with learning arc welding is to learn to distinguish the actual weld puddle from the molten slag and it take sa bit of practice to get a feel for what is actually going on under all the smoke and slag . Probably the most common fault, especially if you;re used to MIG welding is too high a travel speed as you see this huge wedge of hot bead going down and the temptation is to move faster.

Also when you first start a run you usually need a very definite pause, without starting to move the rod to get the puddle properly established and keep a short arc length, almost to the point of pushing the end of the rod into the weld.

I would try a bit more current and just practice lots on (clean) bits of scrap.

 

[urban]

Thanks for the pointers, I've just seen the guide to arc welding on this site too, found that useful, I'll keep trying following the advice.

I take it I should still be able to get a presentable weld from the less than pro gear I'm using?

 

[shenion]

Get some decent rods. Cheap ones are more difficult to learn on.

 

[pedrobedro]

Start with the power low and try to strike an arc. If the rod sticks turn the power up and repeat till the arc strikes and keeps going. Now rest the tip of the rod on the metal and it will feel like it is sinking in under it's own weight and just draw it towards you slowly using the angle of the rod. Use thicker metal and just keep trying till it comes together a bit then experiment with lifting the rod and listen to the arc change from a crackle to a fuzzz as it gets longer. Slag should scrape of with the tip of the hammer or the end of a file not by striking it.

 

[urban]

Thanks for all the tips and pointers, I'll try again taking on board what's been said.

Been having a look round the site, quality forum, full of useful stuff.

 

[the snooper]

also if you are using really thin rods its harder to learn, thicker steel bigger rods until you get the hang if it

 

[Drains]

As all the above, but also, 90A is far more appropriate for starters, and get rid of the machine mart rods. Buy some white box rods (as in basic low end from a proper manufacturer) from your local welding supplier. Never buy from Machine Mart or Screwfix or B&Q etc. They're all good for some stuff, but welding consumables...? No.

 

[mike os]

its been said already... but it is probably the most important bit of advice for arc...

RODS, RODS, RODS...... get some decent ones & keep them dry

then it is just practice...flat, butt joint is the easiest to learn the technique imo

 

[urban]

Thanks again for all the tips.

Just one more question, if I buy some decent rods do they have a shelf life or if I store them in dry conditions will they last for a long time? I only do occasional welding now.

 

[ChrisJohnsSculpture]

General purpose rods will probably be E6013, which should last pretty well without any special storage, just keep them in a warm dry place. They can also be dried out in a normal oven if they do start to go off a bit.

 

[mike os]

should not be that expensive either....iirc the last white box of 6013 x 2.4mm i bought was about £15 with the vat..( about a year ago)

 

[drum]

I'm a noob too and I strongly agree with the bigger rod size advice. Get some 3.2 mm rods, crank the welder up to 120amps and practice butt welding clean 3mm steel. Chamfer the edge of the steel and keep practising until you can't break the weld.

I cut my practice steel in to 3 or 4 inch squares and tested my welds with the vice and lump hammer. Then move onto fillet welds, vertical welds etc.

The more welds you do the better they get and the better they get, the more you want to do.

 

[urban]

I went to my local welding specialists today and picked up some best budget rods, £15 for 5KG so will give them a go later this week and see how i get on.

Thanks once again for all the help.

 

[urban]

Tried the new rods, far better than what i'd been using, still some pretty pants welding but an improvement

 

[urban]

Does cut away edges and undercut mean that the amps are cranked too high or am i going too slow or is there another reason for it.

The welds I'm getting are what i'd describe as presentable (sure they could be a lot better), even ripples, no slag infusion, slag comes off easily but the edges always look too melted or under cut. it's more noticeable when doing a horizontal weld joining a vertical piece to a horizontal piece, think you call it a t joint.

 

[ChrisJohnsSculpture]

Does cut away edges and undercut mean that the amps are cranked too high or am i going too slow or is there another reason for it.

The welds I'm getting are what i'd describe as presentable (sure they could be a lot better), even ripples, no slag infusion, slag comes off easily but the edges always look too melted or under cut. it's more noticeable when doing a horizontal weld joining a vertical piece to a horizontal piece, think you call it a t joint.

Undercuts can be caused for various reasons, too much current or too slow travel speed can certainly contribute. One of the biggest factors is the angle of the electrode to the work. Generally when you're doing a T joint or fillet weld one piece will be bigger than the other, the smaller part will tend to heat up faster and so needs a bit less heat. You can control the relative amount of heat by adjusting the angle of the electrode, basically the heat goes where you point it so angle it slightly towards the bigger bit ie away from the undercut.

The other thing is that on a horizontal weld gravity will tend to cause the puddle to slump downwards slightly and fall away from the vertical surface which can also cause undercutting. The ideal is to get a combination of current, travel speed and electrode angel which causes the correct shaped fillet to form.

at the end of the day, with stick welding in particular it comes down to just getting a feel for the right technique and settings since it's much harder to see the shape of the bead as it forms.

 

[urban]

Thanks for the advice. More practise required me thinks.