TIG Welding For Dummies

[Ji Gantor]

Yesterday I had to weld a side number plate bracket back onto a bike frame that was broken off at CD7.
The bike didn't hit the ground it was a fatigue crack.

After grinding the plate and frame I positioned the plate and held it in place with a welding magnet.
I then suited up and pressed the foot pedal.
The arc wandered like a drug induced nomad.
The arc melted some of the plate metal which then was drawn to the electrode.
After cleaning the electrode 4 times I removed the magnet to see if it had some part to play in this crazy situation.
The next time I pressed down on the foot control the arc was small and focused and the job was done without any more todo.

Since then I have discovered that magnets are a real problem when TIG welding.
There is a way to shift the pole away from the welding zone by introducing a length of 10 bar which absorbs the magnetism.

Magnets don't effect MIG welding.

Tight nuts

Ji

[Slakewell]

You cant use magnetic clamps to hold bits in place with DC. AC is not affected. If your stick welding and useing magnetic clamps on DC you will see the arc drawn to the magnet. Mig welding is simular thou it's much harder to see the affect.
Ji you do know how electric motors work? Its much the same princable.

[Ji Gantor]

Like many, I purchased my TIG welder to weld aluminium. As we know aluminium is not magnetic so mangets can not be used as holding devices. TIG welding ali is done in the AC mode as is all non ferrous metals. That said a magnet may not effect AC welding but a magnet is not much help holding non ferrous metals.
When I have used my TIG welder to fuse steel I normally just use viseclamps to hold the job.
So if you are like me and cross over to TIG welding steel which is in the DC mode don't use magnetic clamps.

I have used magnetic clamps for years to hold steel when MIG welding with out any problems. That said I don't suggest that the magnetic field has no influence on the process, but it must be very small.

Tight nuts

Ji

[Slakewell]

If your welding magnesium cases you must get a very good earth as close as possible to the area being repaired, sand the paint off and use vice grips on the case (I use a soft jaw set so I don't leave a mark) and then attach the earth clamp to the vice grips.
I don't understand why it happens but the arc can move around allot on magnesium maybe because of the lower amperage and can also earth out thou the case enough to blow a new hole.

[Ji Gantor]

Sweep up all magnesium filings after sanding as these can start fires if left in the corner of your work shop.
Magnesium if welded wrongly will catch fire so before fusion lets ask those that have welded it before.

Hi Slakewell,
When TIG welding magnesium what,
Amps do you use,
Filler rod,
and any other tips for those thinking of trying it.

Tight nuts

Ji

[Slakewell]

Ji the likely hood of setting fire to left over magnesium filings are about as good getting next weeks lotto numbers right.
You buy magnesium filler rods just like any other type ( I've only purchased the 5% silicon ones ) but you normally don't buy by the kilo there expensive and weigh nothing normally 20 will last a long time, they only come in 2.5mm any smaller they break too easy.
Mostly used for repair work (well that's all I have used them for) on say 2mm thickness cases somewhere around 10 to 15 amps depending on if your using a heat sink, try and use a copper or stainless steel heat sink if you can as you get allot of penetration, on Still chain saw cases little as 5 amps. Its not easy to make pretty as the filler rods are thicker than the material your welding. You also get a green flame and fumes as you weld. Follow the other tips and you should be ok.

[GMC]

The magnets can catch you out the first time you come across it.

Magnesium burns but Magnesium Alloy is less likely to burn, usually when it does it's becuase their is a pocket of high concentration of magnesium in a section.

Earth on the job is very important. As Slakewell says if you rely on the earth connecting through from the work bench you will create a hot spot that will arc out a small hole.

Don't get confused between Magnesium rods and Aluminium Alloy rods, they are like chalk and cheese.
The worst jobs I've had to repair are what others have stuffed up, and Mag cases can stuff up easliy.
Find some old cases to practice with to get a feel for it.

[Ji Gantor]

Not all crank cases, brake backing plates or wheel hubs are magnesium, most are aluminium.
Check your manual before welding.
Some times the manufacturer cast the word magnesium into the part.

Tight nuts

Ji

[Ji Gantor]

Depending on your usage you can buy filler rod by the packet or kilo or by the rod.
I don't use a lot of any one metal filler rod so I buy my filler rods individually.
When you do this you should start a system of keeping them clean and catalogued so you know which filler rod is which.
Bunnings sell these one meter long pipes with end caps that work great.
Try not to touch the filler rods to much as they will rust and add contamination to your bead.

Tight nuts

Ji

[Ji Gantor]

When you start welding different materials like steel, aluminium, stainless steel, titanium and a like you will need to purchase different electrodes and torch componants. Collets, end caps and nozzel cups need to be stored so they can be found quick for use.
Bunnings also sell these clear tackle type boxes that a great for the job.

Tight nuts

Ji   
 

[Ji Gantor]

Certain metals need to have an oxidation layer removed before welding. The best way to do this is with a stainless steel wire brush. These same metals will become contaminated if the wire brush has been used on a different metal. So for the best results use your S/S wire brush on only one type of metal and then store it in a sealed bag or box until next time.

Tight nuts

Ji

[Ji Gantor]

After wire brushing the job, clean the surface and your filler rod with acetone.
This will remove any residual contaminates prior to welding.

Tight nuts

Ji

[Ji Gantor]

Some filler rods have their nomination stamped or cast into the ends. This makes it easy to see what you have. Not all have this lable.

Tight nuts

Ji
 

[Ji Gantor]

Make sure all protective coatings are removed before welding.
Paint, Gal and anodising will effect the weld bead.

Try welding a coke can without sanding.
The anodising just kills the welding not to mention the deadly fumes.

Tight nuts

Ji

[Slakewell]

Anyone have any Magnesium tig rods for sale?