Welding mild steel for bench / machine legs - tips please.

bpbuilder · Nov 6, 2016

I'm perhaps not in the ideal scenario. I'm having a go at welding - first project for about 10 or so years which is welding up a machine stand. The design is 75x5mm SHS post welded to 8mm flat. The flat has a hole in the front for attaching a M12 bolt/leveling foot to each leg and is welded all around. Each leveling foot needs to take no more than 1kN and is relying on the weld.

The real question is how much can you assess from photos? I've got my welder cranked right up which is only a gasless 135 Amp MIG, and I've picked some of my worst welds to get a hammering from everyone!

Based on the photos am I best to scrap what I've done and start again, get some better gear (and technique!)? Or will it 'do the job'? I'm paranoid with it not being good enough... And close to scrapping it... Does anyone have any useful tips?

Thanks.

Links to photos:
Example 1_zpsiqps3l5s.jpg Photo by morphs_21 | Photobucket
Example 2_zpsads2gxfb.jpg Photo by morphs_21 | Photobucket

Milland · Nov 6, 2016

I've seen (much) worse. Are you using a flux-core wire, or is it solid? You could try welding a short section of the post and plate material as a test coupon, then beat the hell out of it with a sledge hammer and see if it cracks at the welds. You could also saw through the test part to get an idea of penetration.

hobbyman · Nov 6, 2016

The beads are irregular but more important there is no signs of lack of fusion at the edges and no signs of porosity or slag inclusions on the surface. Like Milland said there are much worse welds. Since this piece is on the bottom of the leg the weld simply locates. The forces are pretty mild.

TheOldCar · Nov 6, 2016

Those welds will work fine.

johnoder · Nov 6, 2016

Its a bench/stand - looks just right and will still be stuck together long after we are all gone

If you want it to LOOK better, buy a great TIG outfit and spend six months becoming good at it (which will include no welding on anything not cleaned to bright metal)

After all that, it will still be a stuck together bench/stand

bridgedog · Nov 6, 2016

As already stated these are in compression so welds are locating only. Use it. One thing that might help in the future with your little welder is some preheating before welding. I have seen uglier welds then that by so called "welders". Keep practicing it gets better as it goes.

rbdjr59 · Nov 6, 2016

I too have seen (and welded) much worse. Those will work fine even if in a stressed location. If you want pretty you can grind it smooth and even fill with bondo if you want to paint it and make it a work of art. Or just go to work n the next project!

Blazemaster · Nov 6, 2016

1 kilonewton is only 224lbs, I think you will be ok.

bryan_machine · Nov 6, 2016

If you look up "welding tips and tricks" on youtube, some of the videos talk about how to make a test weld, cut it apart, and evaluate it for penetration using chemicals you can get at the hardware store (at least in the US)

Also, the "beat on it with a hammer and see how it bends" test is actually a crude form of a real live industrial welding coupon test - it has real merit.

bpbuilder · Nov 6, 2016

Thanks very much for the comments guys, that gives me some confidence.

Milland said:
Are you using a flux-core wire, or is it solid?

Flux cored wire (the wire I have causes an annoying amount of splatter at times).

hobbyman said:
Since this piece is on the bottom of the leg the weld simply locates.

I imagine the front weld would be in compression, and sides and back would be in tension. I probably wasn’t clear in my description of how the leveling feet were working i.e. it’s going to be held up with the M12 bolt and nuts. Here’s the link to the detail if you’re interested: Leg Detail_zpscjglt2gz.jpg Photo by morphs_2 | Photobucket

rbdjr59 said:
If you want pretty you can grind it smooth and even fill with bondo if you want to paint it and make it a work of art.

Hmm... I might also use hammertone paint to hide even further

Thanks again for all of your comments.

doobin · Nov 7, 2016

If they're your worst, and done with a 135a gasless mig, you got no worries mate. A couple of good tacks would hold it in your application anyway, as others have said.

If you get yourself a proper mig, you will be producing great welds in no time. With gas shielding you can produce much more even welds, and you look to have the basics down.

Newman109 · Nov 7, 2016

Those welds will work fine. Although somewhat irregular, the penetration looks good and I don't see any porosity or cracks. You did OK.

rons · Dec 7, 2016

bpbuilder said:
Does anyone have any useful tips?
]

Mig welds are can get pretty sloppy. Just go to your local Gold's Gym and look at the equipment welds. Most of the machines I have seen look like they are put together by junior welders.

If you have never done Tig before, get a demo at a welding store.

(I don't know how anybody can say that penetration looks good. JFC)

DDoug · Dec 7, 2016

Instead of investing in a TIG (and the supporting gas bottle)
Why not just an old cracker box stick machine and some 1/8" 7014 ?

You see them all over the place around here for $50-75.

DrHook · Dec 7, 2016

As has already been stated, there doesn't appear to be any severe undercut or cold lap, those welds will do the job!

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Welding mild steel for bench / machine legs - tips please.

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