Welding tips welcome

[Vinnie]

Hey folks,

I couldn't find a suitable place for this in the tech forums so I'll discuss this here.

This weekend I'm going to weld together the 8 poles that I'm going to build a floor with. I've never welded for real before so I'm looking for a few helpful hints and tips from experienced welders. I'll be using a stick (electrode) welder.

So I'm using square tubes (picture in my thread "Vinnie's garage") and I'm welding flat plates on the ends. The tube measures 8x8cm, 3mm thick (3x3", 1/8" thick) and the plates are 8x20cm, 8mm thick (3x8", 1/3" thick). So a plate has the same width as the tube does and it sticks out on the sides.

I'm thinking of first welding the 4 corners to get the plate stuck. But then.... Should I do the even sides first or the sides that stick out? I'm afraid that the plate will curve when I do the latter first. Then again, I could get some U-profile and screw that against the plate to keep it straight while welding?

Or should I just weld the even sides first?

Ideas anybody?

Thanks,

VIncent.

 

[Don C]

Make sure the plates and tubes are clean, bare metal where you will be welding. Where the sides of the plate are even with the tube I would chamfer the edge of the plate where it is in contact with the tube and chamfer all the edges of the tubes.

I would begin by tacking the plate to the tube in the center of the tube, then run 15 to 25mm long beads at various places around the tube, until complete. Make nice fillets on the sides of the tube and long sides of the plate, about 6mm wide. Welding different sizes together can be a little tricky, so you get enough penetration on the plates, but not burn through the tube. If you have any scrap pieces of metal I would practice on them first, so you can get the heat settings correct.

 

[Bentworker]

Stick welding is pretty skilled work. I’d suggest a nice scrap selection to practice on, and some instructor lead training at a junior college or equivalent.

What kind of machine do you have (AC only or AC/DC) What kind of rod are you going to use?

That material is thin enough that you would probably have better results at your skill level with a wire feed (MIG / GMAW machine)

 

[Don C]

I agree with using a wire feed, that's what I would use, but I already have one.

 

[Vinnie]

I have already practiced on scrap with the same dimensions. My biggest issue is going too fast. So I’m not too worried about the actual welding, more about where to start and in which order to weld.

I’ll chamfer the edges, that’s probably a good idea. My neighbour said to first tag the corners, now Don says tag the middle first. I’m sligtly confused now though I think the middle might be better against heat deforming.

 

[Bentworker]

Post some pics of your practice welds if you want some critiques.

Hopefully your machine is DC, that is easier to use than AC

 

[Vinnie]

I don’t have any but at first I went too fast with too little power. I went up to 105 amps which worked a lot better. The machine is DC I believe.

 

[Fabrice]

As Don said MIG welding would be better. Not kuz its fancy hightech, aside the gaz that prevent oxidation into the bath, its just easier to apply the right amount of heat to melt the wire with the metal so it becomes one.

Another +1 on Don's "chamfer the edge of the plate" and bare/clean metal.

With stick welding its easier to think you melted while you just layered the stick material on top of the surface as the sticks usually have a lower melting point than the metal you weld.

I'd say if you want make sure, make a few spot tests where you stay less time and increase for next try . Grind/ chisel/hammer and see if the test weld points are part of the metal or just sticking on it.

Looking at other thread, the beams are like 2.5 mm thick, so don't worry, if you you stay a bit too long, better few well melted points than good looking weld not really thru.