well, it looks like i'll be on the phone again tomorrow. Nothing too serious though.
I had a good two and a half hours welding as i had a machine all to myself.
I knocked out three lap joints that were excellent on top, including the stop start in the middle of the weld. Penetration was showing itself on two of them, but Barry, tutor, said he'd like to see just a little bit more. I then did two or three fillet welds. Again Barry was very happy with the top, and although you could see a line along the back of the base plate, he wanted to see just a little bit more. Then i took a break and had a look through the course handbook. I noticed that it specifies the size of tube to be one inch O/D by one inch high welded onto the centre of a two inch square 1/8th thick plate. We have the plate, but the tube they have bought is 40mm O/D. thats about 1 inch and 9/16ths O/D.
I had two further attempts at the tube on plate. It did help to stand up, but i found i couldn't see what the tube at the plate was doing, so all too often it was because it had gone up in smoke.... I was having a lot of trouble getting the right torch angle. I'm used to having what i think, is a shorter torch at work and the head angle is flexible. The torches at college are about ten inches long, about an inch in diameter with a fixed head.
I'm used to resting my hand on the bench or something on the fixture or the job and i just can't seem to get comfortable
and get the right angle.
I think for next week i'm going to take a length of three inch or so diameter pipe from work to lift the plate and tube up off the desk to see if that helps.
Pulling the tungsten out further helped to get into the joint, but i was still getting too much of the tube melted away. If only i could keep a point on the tungsten... It would be just like welding steel
So after getting my spirit up with the lap, then down with the tube/plate, i thought i'd raise them up with another couple of fillets. THen i thought, why not have a bash at vertical up?
So i tacked two plates together, and then looked for a way of holding them in position. For some reason there were no 'arms' in the bay tonight. Being a practical guy, i improvised. I sat the base plate on top of the tube and rested it against an angle standing up behind it. It seemed safe enough, so i started.
I remember one of you guys saying you always kept your torch at 15 degrees. I got the weld pool started at the bottom but when i tried to dip the rod, it jut balled and ran away. You know your welding stinks when your material doesn't want to stick around!
So i aimed the torch downwards, which meant i was getting good penetration and i could dip the rod. Once i had gone about an inch i managed to aim the torch at right angles to the joint and welded in a sort of advbance, pause, aim the torch down a bit, dip the rod and then up again, melt right into the joint, pause, back, dip and so on. it was going pretty well, right up until the point the work fell straight forwards onto my tungsten... LOUD SWEARING ensued...
But i showed Barry and he said he'd seen worse.
So i tried it again, and this time i tacked the bottom corner onto the angle i'd just messed up, which meant it raised it up off the bench and was stable.
I cocked the start up by melting a hole into the upright bit and spent the first inch trying to fill the hole and get back to a normal bead. I was still having trouble dipping the rod now and then and at this point Barry appeared. He suggested sliding the rod downwards along the root of the joint into the puddle that way. I tried that on the next attempt, and after AGAIN cocking up the first inch and a half, i produced the next three inches of 'near perfect' line of dimes bead, right up ntil the last 3/4 of an inch when i stuck the rod to the weld and while trying to melt it with the torch lost concentration and nearly had a big lump 'fall out' due to the fact my foot was still at '100mph' on the pedal!
Conclusion:
Butt joint... I'll come back to that one...
I think i'll use the Jody method, but with a very small gap. I think i just need to get the right travel speed.
Tube to plate... It's scarey, VERY scarey, I'M SCARED!
Lap joint... NO problem.
Fillet joint... NO problem
Fillet joint vertical up... It's gonna be troublesome, but once i crack the first inch, NO problem.
The handbook lists the criteria that the candidate must be able to define...
At first glance a bit of panic set in, but now i've read through the 15 different points, most of it i know, some of it will need to be read up on so that i can say what it means to the examiner, and a few i'll have to research because i haven't got a clue. It would definately have helped to have this six weeks ago though.
I'll have to speak to Ben again tomorrow because as it stands we can't perform the tube to plate test without the required 25mm diameter tube, we still have no acid to etch the welds to check for penetration and Barry doesn't have the list of questions.
I'm in two minds about being given the questions, which is what Barry said he would do when he gets them.
Part of me is saying, "GIMME GIMME GIMME", and the other part is saying "no thanks, i'll just learn the subject properly...
Afterall, MY aim for doing this course is not to get a piece of paper, it's to learn how to tig weld aluminium, and if a byproduct of me getting that piece of paper is that i become a more knowledgable welder, then so be it!
then again... NO