First time build - Steel Frame CNC Router

[Davek0974]

if i can suggest popping over to here...

http://www.mig-welding.co.uk

You can pick up a lot of good help, *some* of those welds look ok, some look dodgy but all will most likely do the job.

You should not need to re-run a weld, what sort of gap are you bridging? Any more that a mm or so and you will struggle.

[cropwell]

Have you got an auto-darkening mask. If it is set too dark you will not be able to see properly what you are doing. Also reflections from the back of the glass can make it difficult to see where the weld is going, I have a leather shroud on the back of mine to cut out reflections from the workshop lights.

cheers,

Rob

[examorph]

Dave - Thanks for the link, it was very helpful in clearing up some of my confusion. Gaps I would say so far have been ~1-2mm, although the rads make them look much bigger.

Rob - Thanks, think a good starting point for tomorrow would be to pick up a decent mask as so far I have been using the hand held mask that came with the welder.

[Clive S]

A decent angle grinder will work wonders to the look of the weld

[Davek0974]

Dave - Thanks for the link, it was very helpful in clearing up some of my confusion. Gaps I would say so far have been ~1-2mm, although the rads make them look much bigger.

Rob - Thanks, think a good starting point for tomorrow would be to pick up a decent mask as so far I have been using the hand held mask that came with the welder.

The mask will be 99% of your troubles - bin that hand-held POS, nobody uses them anymore. Get a reasonable auto-darkening helmet, around £45-50 but will be a life-changing purchase, set to about 10 or 11 on the scale to start with, fast reaction and MIG setting.

Then make sure you have some decent welding gloves at least one on your left hand anyway (assuming right-handed), hold gun with right hand and steady the end with part of the left hand. This will improve appearance and quality no-end.

Watch more videos - MIG is pretty easy to get right, but you need to follow examples, take a few examples too as there are some crap videos out there that will steer you wrong.

2mm is a big gap, get it smaller if possible, if not then use a gentle weaving motion on the run to get the two parts to fuse fully, only do one run but make it a good or at least usable one. Don't forget, you are not just applying weld, you need to get the three parts - two components and the mig wire to become one solid item.

Grinder work will make you a decent grinder not a decent welder - again, get it right from the start, only going where you need a fit. Do a test on two similar parts then cut down the middle, you want that weld to be going most of the way through if not all.

Practice, practice, practice.

What gas are using ????

One other thing - cover up ALL bare skin - MIG will give you a sunburn like no other and very fast, i can get a burn in as little as 6" of welding at 160A and it stings like hell, main target is the left arm and chest if shirt is open collar.

[cropwell]

I don't know how much you intend to weld after your build, but I found using disposable bottles expensive, especially when the regulator leaks.
CO2 is not the best shield gas, Argon, Carbon Dioxide with a trace (2%) of Oxygen seems to give better results. I bought a Hobbyweld 15 cylinder with a decent regulator and I don't regret the money spent.

Weld spatter does not hurt - at first - so I echo the cover up. If you smell bacon when you are welding, you have spattered yersel. I don't wear socks and it ain't fun when it goes down the side of your shoe

Cheers,

Rob

[Davek0974]

Yes, CO2 will give a bit more spatter but a hotter, deeper weld, Hobbyweld 5 or 15 will be better but standard pub CO2 is sometimes easy to get ;)

Set you flow to about 8-10lpm no more.

Disposables suck very quickly, don't go there if at all possible.

[examorph]

Thanks for the advice guys, will check this out. Little more progress made today:

Ground down all the welds slightly and fully at any mating faces (does this weaken the welds?):

Attachment 17865Attachment 17866

Welds seemed to start getting a little bit neater:

Attachment 17864Attachment 17867

I am running on a small tank of CO2 which as per your comments isn't the best as its already ran out I noticed it a long time after my welds started getting worse and thought it was just me welding horribly (although that would have been part of the reason )

Attachment 17869

The empty tank meant I was only able to get both sides done this week:

Attachment 17868

Will be back on it next weekend and hopefully have the full frame/gantry welded

[Davek0974]

No, grinding flush will not affect a good weld, but it needs to be a good weld ;)

Pictures 2 & 3 look much better, a steadier hand will improve it even more.

Ask the local friendly pub landlord, plain Co2 is what you need and they use lots of it, I started out on that and gave him £20 a go, needed to buy the right regulator but it was great for learning on.

[JAZZCNC]

Nah Co2 is too spattery buy 5% mix and you'll get much cleaner weld.
Also 90% of the time where people go wrong with Mig is the wire speed is too slow and they travel too slow dumping more heat than needed into steel and giving raised welds.

Preparation is key so nice ground fillets on edges and with well setup machine then you'll run perfectly flat welds in no time. No grinding Required.