Byuing a welder

[layback40]

Originally Posted by Wooders

Think you'd find that a little incorrect.
What you are probably thinking is a neat looking mig weld doesn't always equal a quality weld.
Whereas often an ugly stick weld will be far stronger than it appears.

Hey Dave,
This is one of these arguments that will go around in circles.
It depends on the application.
Structural welding is normally stick for strength reasons ~ portal frames, gas pipelines, pressure vessels etc.
For home use when welding 2 bits of steel together, mig weld bead is much stronger than most general purpose rod material.
For our friend with his new welder, mig will be the go.
Much easier & less slag inclusions.
Most attempts at home stick welding look like chicken sh!t & about as strong.
I am sure you have had to repair blotched home welding jobs for people in the past.
There are very good reasons why DIY welding should not be done on suspension & steering. I hope we all agree on that.

[warod]

Originally Posted by Wooders

Think you'd find that a little incorrect.
What you are probably thinking is a neat looking mig weld doesn't always equal a quality weld.
Whereas often an ugly stick weld will be far stronger than it appears.

Fair comment Wooders.
MIG/MAG welds are very susceptible to lack-of-fusion defects (cold lap) than stick or FCAW welds. Look nice sitting there but not really welded/fused ?
Pulsed power supplies have made MIG welding a little easier for the untrained welder.
Lack-of-fusion defects are less frequently encountered with flux-cored or metal-cored wires (FCAW).......

[murray]

i was being sacastic
gtaw will alays be the stronest weld in correct conditions as with pre heat arc and post time ramp off you dont get cold start lap or end craters

[Wooders]

Honestly in the realm of things the punter should be welding on this forum, the type welder shouldn't really make much difference.
The weakness are more likely to be:
Poor design, Poor preparation, Poor technique, and the metal next to the weld is probably the weakest part

[skwake]

I have stick welded a little and found that if a pro set it all up for me then my welds werent too bad. But I welded up a diff spreader for my TJ by myself with a mates welder and chook shit would have been flattering! Haha. Oxy welding is not a problem for me as that is a major part of my trade being a fridgie but everything else is a whole new deal.

It is worth me learning though as it used to be taught as part of my trade. (incoming refrigeration lesson...)
Ammonia refrigeration plants are all steel pipe not copper, because Ammonia attacks copper. Ammonia systems are making a big comeback since the carbon tax was introduced, raising the price of refrigerants significanty, but ammonia is a natural refrigerant and has no GWP (global warming potential) therefore it is carbon tax free making it a enviromentally and financially cheaper option for appropriate uses.


Anyway as I was saying, fridgies that can weld can install Ammonia pipework as it is welded together rather than silver brazed like copper pipe.

[warod]

Originally Posted by skwake

I have stick welded a little and found that if a pro set it all up for me then my welds werent too bad. But I welded up a diff spreader for my TJ by myself with a mates welder and chook shit would have been flattering! Haha. Oxy welding is not a problem for me as that is a major part of my trade being a fridgie but everything else is a whole new deal.

It is worth me learning though as it used to be taught as part of my trade. (incoming refrigeration lesson...)
Ammonia refrigeration plants are all steel pipe not copper, because Ammonia attacks copper. Ammonia systems are making a big comeback since the carbon tax was introduced, raising the price of refrigerants significanty, but ammonia is a natural refrigerant and has no GWP (global warming potential) therefore it is carbon tax free making it a enviromentally and financially cheaper option for appropriate uses.


Anyway as I was saying, fridgies that can weld can install Ammonia pipework as it is welded together rather than silver brazed like copper pipe.

Ammonia piping will be ASTM A106 Grade B piping and welding specification will be to ANSI B31.1./ ASME IX.
Will generally require GTAW root with SMAW fill & Cap.
NDT usually 100% gamma radiography or X-Ray.....
Good luck fridgie !

[The Beard]

Originally Posted by skwake

So my welder turned up, I went and bought some gas and some MIG wire and had at some metal! I have to say the thing purrs along. I have never MIG welded before and just going by the quick startup settings on the inside panel of the welder I managed a few half decent welds Straight out of the box! Now just time for lots of practice! This is one the first welds - it looks a hell of a lot nicer than my stick welding efforts!

Being pretty cack-handed at using a stick, I was amazed with my first MIG too. For those who are interested in picking up a welder, Fisher Discounts in Fyshwick, ACT have a massive sale (nearly 50% off) twice a year -June and November. I picked up my Unimig 165, stand, mask, gloves and wire for under $1000 a few years back.



Almost worth a trip to Canberra.