the first weld with a tig comments please

[lotus 30]

I have jumped in the deep end my first time using the adr 300 it ant easy on a fifty year old fuel tank, the bottom was rotted out it might of been easier to make a new one when i do the next side it should be better as i will have had some seat time cant feed the rod yet i have to keep stoping to feed the rod quite an art, comments please feel free, andy b

 

[FranV8]

Hmm, have you chosen to start welding aluminium? Quite a challenge, and if you don't mind me saying, serious running before you can walk, you need to practice runs on a scrap piece, then move onto some practice joints.

Back to what you've welded, looks like too much heat on the right, then opposite on the left, not enough and the bead is just sitting on top.

Good first start, but if you carry on like that, you're only going to embed bad habits.

 

[pedrobedro]

If you cut the plate to fit tightly you could get away with just laying the rod in position and melting it into place like on an outside corner joint.

 

[lotus 30]

Thank you yes just like me run before walking i will grind and re weld i suppose if i can weld the ali the rest should be easier, if it all goes bad i can fold a new tank, and new ali should be easier to weld, i have an old ali bodied car to repair so i am using this tank as a learning process, thanks again for the comments.

 

[langy]

Thank you yes just like me run before walking i will grind and re weld i suppose if i can weld the ali the rest should be easier, if it all goes bad i can fold a new tank, and new ali should be easier to weld, i have an old ali bodied car to repair so i am using this tank as a learning process, thanks again for the comments.

My advice would be to learn steel and stainless first, different technique to AC, I actually find aluminium welding easier than stainless.

 

[hotrodder]

What do the back of the welds look like? Outside corner welds are more prone to fatigue failure than butts or flanged joints, any lack of fusion/incomplete penetration will accelerate the process as fuel sloshes around flexing the tank skin. Granted this piece is about aircraft which is a few leagues beyond automotive stuff with regards to typical fuel capacities/tank sizes and the forces involved but the principle still applies... http://www.seqair.com/skunkworks/FuelSystem/Problems/Problems.html

Obviously if it's gonna hold fuel the welds need to be airtight. At the very least i'd practice with smaller stuff/offcuts untill you're at that level because chasing down leaks can get very boring in larger items when there's lots of 'em

 

[lotus 30]

Hotrodder That link very interesting when you consider the bottom of my boat tank was originally gas welded, would this anneal the tank during welding thus taking a lot of stress out of the tank,I have had some time away from the job to digest the comments given on the forum, we first timers do bare our soles posting rubbish welds on the forum but every day is a learning day and I do like to push myself to become more skilled, I think i will spend more time on prep for the next weld. again thanks to every one andy b

 

[hotrodder]

The annealing temp for aluminium/Al alloys is in the 340 - 410C range. Oxyfuel typically results in a larger area being annealed as the heat isn't as focused but the weld and HAZ will be softened regardless of process. The main advantage of oxyfuel is that flux is needed. The 'cathodic cleaning' that occurs with electrical welding can't reach the back of the joint whereas flux can. An example of the abuse a sound TIG weld should be able to take here...http://www.mig-welding.co.uk/forum/showpost.php?p=260327&postcount=3 and an example of a typical flaw here... oxide intrusion scroll down to page 111 and there's a etched weld cross section

 

[lotus 30]

again hotrodder thanks Back to the tank tomorrow the AC switch burnt out been making insulation bushes today
i will post the next attempt if the welder works thought not to try it tonight incase of blackout andy b

 

[SiPMerlin150]

You have been watching 'welding tips & tricks from youtube or Jody's website?

Never heard anyone else call it 'Seat time'...

His videos are good and I use his MIG technique too.

 

[jonnyBMX]

my suggestuion... as it is exactly what i have done, get some 3mm ally plate maye 200mm by 200m (is plenty) and run a load of beads as the welding tips and tricks video suggests try different lengths, thickness of electrodes and filler rods, amps, gas flows etc etc untill you hit a sweet spot for yourself... then write down the settings etc etc and keep practising untill its second nature... then you are ready to tackle joints

 

[lotus 30]

fixt the adr thanks to dave cackett

second attempt at tig comment's please i did struggle on times with rubbish bubbling up out of the old ali. then i ran out of argon i only have a 20ltr bottle what gas flow should i use i will have to get a flow meter. andy b

 

[lotus 30]

some other work on my lotus for your interest.

for your interest my lotus 30 chassis repair it is 1964 so some work is inevitable

 

[FranV8]

Beautiful car.

Gas flow, 5-7 lpm typical. Get a proper flow meter if possible, the ones that are just a gauge on the regulator are useless. Ideally the ones with a pointy "float" rather than a ball bearing.