First time build - Steel Frame CNC Router

[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.

[Davek0974]

Yes, spattery a bit more but if you can get it, its far cheaper than any pro mix and great for practising on. A little spatter on a job like this is not really that crucial i feel, I never had that much that it was a pain - its not like chalk and cheese.

+1 on the wire feed, this must be set right first off, as you said, too low will give a weld but damn, things will get hot and can lead to a large heat affected zone and distortion etc which can easily be avoided.

Current is pretty easy, if this is like 4mm box then any hobby welder in the 150-180A range will likely be on full-tilt, but getting the wire feed and motion speed right takes a little practice.

[Boyan Silyavski]

I started using CO2 only and it seemed cheaper, but its not. Once you swallow the pill and rent big Argon mix bottle you will wonder why you have not done it on first place. Not to speak of that i need not clean additionally the job. And believe me, it took me all day only cleaning spatter, when i welded my machine.

But to make things easier:
-brush parts around with oil prior to welding. As i said i use olive oil. So the spatter will not stick to the oiled part.
-dip the clean Mig gun every 10 min into the oil while welding. That will help keep it clean all day.