Thread: One little big job

Hi NewLou, I hope that is not your photo in your avatar!

Only joking, so ... this is my new aquired welder.


http://www.justtools.com.au/prod2406.htm


It has plenty of power to burn a hole in the I beam in question...well may be not with 0.9 wire. That is all I have. May be worth my while buying 1.2 wire?

I have another question to the expert welders. How do you go about welding different kind of steel with a MIG? Do you have a collection of different rolls of wire for different applications like you do with sticks? Expensive...

Originally Posted by fubar

had to do something similiar after a design change to an upstairs machine room so after doing the butt welds we welded 5mm steel plate 100x200 over each face of upright way over engineers specs but he was very happy

I hadn't thought of fishplates, good idea for piece of mind.

Can you tell me what are those bits of metal added at the end of the weld in this video for?

[ame="http://www.youtube.com/watch?v=dHL2TctOfWA"]YouTube - I beam splice NR 232[/ame]

They are run on/run off tabs.

They are normally used in pressure vessel work to ensure no discontinuities at the end of a longitudinal joint in a cylinder.This is in the context of a fully penetrated and x rayed joint.

To my way of thinking the are perhaps unnecessary in a situation like this. Its not clear if it is a multi story building or what. I don't know the provenance of the video, it could be a back yard job

It runs against the grain too when seeing the man completing the vertical up weld then needing to dress it with the A/grinder Grrrr!!!!

To be fair its relative to whatever the application is and really I don't know what that is.

Grahame

It's off you tube and it appers to be a student's job from his comments. So those ad ons are so that the end of the weld does not burn a hole in.
So I suppose that after finish they will have to be cut off. Interesting.

Marc,
In case the graphic I sent you did not come through here it is here.

Grahame

It's all good, I got it.
That dog support at the top is a clever way to keep things in place.
Thanks again
Marc

I welded my fence up on the weekend (not the I beam yet) and took some photos. Unfortunatley I forgot my camera at the house so will have it back with more photos next week promise!

It was harder than I thought. and since I was working alone, shoveling around 2.4m long and 2.1m high security fence panels weighting easy 60 kilos, I had little time to practice plus my hands and arms were tired from the heavy load and so my hand was a bit stiff. Welding is like shooting, you need practice and you need a light relaxed hand or you miss or in this case mess up.

However I managed to do some decent weld and only a few needed total ground back and start again. I discovered that powder coated steel pipes are not only painted but also galvanised so the wirebrush I had attached to a small 100mm grinder was good to take the paint off but not for the galvo so had to use the grinder wheel.
I saw with interest how the weld got all bubbly like pomice when I had a gush of wind blowing my Argon away. I managed to do the caterpillar run and to blow a hole but I got it, sort of... in the end.
Still I don't understand exaclty what to change. I know what I want to achieve but not how to.
For example. if I have the crackling noise at too slow tempo, does it mean I have to increase the wire feed or that I have to be closer with the torch increase the amps or what?
Is it OK to stitch up a weld with a series of tacks or does it have to be one long run?
Since there is no flux to chip away it should be ok right?
With joining square pipes that are 2.5mm thick and 65mm wide, after the first 30mm things start getting heated up and if I keep on going the next thing is a crater. If I stop even a second and start again it seems to be good but of course I get a hickup that needs grinding back.
I had initially the gas at too low pressure (10). Later remembered that someone told me it was supposed to be around 20, so I increased the flow, yet I couldn't see any effect on my welding.
The selfdarkening helmet is a blessing once you get used to it blackening to any reflection even the hot tip of the wire.
I'll post some photos next week.

From what I know about MIG welding, either have it running dead silent (spray transfer) or having it sound like your cooking bacon Crank up the argon when there is a breeze.

The silent welding is disconcerting. I think something is not right. I feel all is right when the sparking noise is fast and not so loud.

Originally Posted by marc

i saw with interest how the weld got all bubbly like pomice when i had a gush of wind blowing my argon away. I managed to do the caterpillar run and to blow a hole but i got it, sort of... In the end. anything more than 7km breeze oR so,is too much-shielding is blown away- do not screw gas up more than 14/ lpm


still i don't understand exaclty what to change. I know what i want to achieve but not how to.
For example. If i have the crackling noise at too slow tempo, does it mean i have to increase the wire feed or that i have to be closer with the torch increase the amps or what?
increasing the wire feed will increase the amperage and rate of wire deposit
is it ok to stitch up a weld with a series of tacks or does it have to be one long run? if the metal is too thin for a full run -usually there is no other option
since there is no flux to chip away it should be ok right?
With joining square pipes that are 2.5mm thick and 65mm wide, after the first 30mm things start getting heated up and if i keep on going the next thing is a crater. If i stop even a second and start again it seems to be good but of course i get a hickup that needs grinding back.
don't try for complete runs --spread the heat do part runs on opposite sides- when cool go back and complete

i had initially the gas at too low pressure (10). Later remembered that someone told me it was supposed to be around 20, so i increased the flow, yet i couldn't see any effect on my welding.no more than 14 lpm
the selfdarkening helmet is a blessing once you get used to it blackening to any reflection even the hot tip of the wire.
I'll post some photos next week.

grahame

See above some of the first welding experiments with my new MIG. You can see the photos bigger if you look them up on my album called Marc's Photos on this forum.
It took me a while to get used to see with the self darkening helmet. Also the first and worst weldings I did with a 50/40 nozzle. Later I changed to a 50/22 and it made a lot of difference. Even when it gets dirty quicker, somehow it seems to work much better.
I am welding powder coated material that I sanded and painted with exterior paint. I grinded the welding areas but I was a bit too gentle and whilst welding I am still battling the galvo and the powdercoat residue.
What I miss most from the stick welder is the option of shouldering the cable and have a light hand. The torch is cumbersom and the hose is stiff. I try to find a postion that makes the torch feel free but it is not easy. I feel I want to hang the hose from the cieling with a long spring.
After a lot of changes and fiddleing with the settings and the speed of the wire and the gas and the amps, I had enough and I started to make changes in the distance I held the torch and the movements I give the torch and this made a lot more difference.
I now can get the welder to arc at the right speed and I can see much better the pool and I can tell ahead if it is about to blow a hole. I got a few full run that look rather smooth. This material is so dirty I have to hold my breath for fear of choking. I am sure that clean steel will be much better.
Below a photo of the beam I want to extend.
The measurements are 256mm high, 147 wide and is is made of 8 mm thick steel. I have to extend two beams. One by 300 mm and the other by 600mm Both will cantilever by the same amount. I am extending the beams in order to extend a veranda by the same lenght and bring it in line with the front section of the house. The two ends will also support the corrugated iron roof section over the veranda.


As you can see in the last photo the beam was not cut very stright, so I will have to dress it and make the other part match as best as I can since the post is right there and does not allow for any further cut back

G'day Mark, if you have an ajustable square you'll be able to replecate the other cut.
Sounds like your still getting used to the MIG. Keep going,you'll get there.
When I'm onsite and TIG welding we always set up humpys or welding screens to avoid the gas being blown away. You should be able to improvise with a tarp and some cable ties. This is very important so you dont get porosity in your weld on the beams. When you get to practise on beams take photos of each run you do ,I recon
you should use scrap plate to play around on until you get the settings right.
Cheers,Col.

Can I make a suggestion marc, not having a crack here but try slowing down a bit and as my old tradesman used to say treat it like its your last ****, not your first...