My first TIG...

[small.planes]

so, I got myself a TIG
My MIG set is 60 miles away (long story) and the OA set is empty.
Need to make a mounting bracket for a prototype projector, which weighs 5Kg, and of course its needed yesterday (forward planning not current strong point)...

Ive done all of fire it up to make sure it sparks, never even tried to join 2 bits of metal with it before today, think I did OK, though theres a long way to go for 'proper' TIG welds, and I can see why a foot pedal is a 'good thing'.
Theres good penetration (you can see the back sides of the welds in the tubes) and the whole thing is plenty strong (I tried to fail it with a vice and a bit of brute force)
As the bracket has some tight tolerances on the hole positions I drilled and tapped an old CI surface plate to hold the critical parts at the correct place whilst I welded the rest up. Lead to some awkward welds, position and things in the way wise.

and finally a close up of one of the welds:

I assume the poor finish is a lack of practice, and some incorrect settings?
Any pointers? IIRC I was running around 80A, but I have no idea on gas flow rate, my regulator has a flow meter, but due to the bottle neck being vertical and the (guess which country from) regulator needing a horizontal neck it doenst indicate flow... new (correct orientation) one is on order tomorrow.

I found that my OA experience really helped, I have welded in all sorts of awkward positions in cars with that, but a TIG torch is much different to hold, and (I discovered) I have a 'learned' tendency to move the torch away if its getting to hot, which of course doesnt work to well with a TIG set

Dave

 

[malcolm]

What type of gas did you use? Ought to be going for pure argon for TIG. The weld looks a bit blackened, though possibly that's something the tube you were welding.

 

[small.planes]

Yes its pure argon, I suspect the blackening is caused by me not cleaning and preping as thoroughly as I should. I gave the HRS a quick rub with some emery, but not the tube, and I didnt degrease it (ran out of degreaser...)

Dave

 

[rodofgod]

small.planes,

The weld itself is not a million miles away despite the un-melted stick of filler wire at the start! My main criticism at this stage would be the un-equal leg length! From the picture you've posted, it looks like all the weld is on the bottom half of the joint, with very little on the box section part! You really need to rectify this problem by adjusting your angles. Also aim to achieve a full length weld. By this I mean weld all the availible area. Also keep the arc tight, it's not like O/A welding, your relying on a gas shield to protect the weld, but it's no where near as forgiving as O/A welding

 

[small.planes]

Its an optical illusion, the tube has a rounded corner, which makes it look like the weld is more on the bottom than the tube. I havent managed to fill that little V area very well though. not sure how I do that better? Shorter arc length?
how would you cope with the lack of access (theres another tube right next to it)?
My welds are a little short as I didnt want to undercut the rails at the ends. any tips for avoiding this, or is it just not a problem with a TIG?

Most amazing part is all 6 bolt holes just lined up and the projector bolted straight on

I guess I was over worried about the possible distortion caused from the welding, seems TIG is better on this that OA, probably cause there is less 'excess' heat slopping around.

Dave