Tig weling 1" 25mm 55 thou 1.4mm tubeing help needed
Turbo Mini Forums

trying to sort the stupid coolant lines it aint happening for me this time i want to have the main part of the lines out of alu tube and just some simple rubber cuplings to the rad. water pump and head

seems what ever ive tried its eather to cold and whont weld both sides nice or it gets heat soaked and falls threw tryed pules and straight ac
must be that im just a crap welder i donno but ive done plenty of 3mm wall tubing with little trouble i want to use the 1.4mm wall as it will give more ID for coolant to flow vs 3mm wall

any tips for thin wall tube i think the main thing is heat soak as im not confident at hitting it with lots of amps and moveing fast i think the part soaks up and thats game over i tryed useing two 10mm plates of alu as heat sinks each side to try draw heat out but not really much help to me

im using the foot peddle and 1.4mm filler rods with a 2% Lanthanated 1.6mm

im tyring to do pie cuts to for a nice gradual bend but i think its a lack of skin and over heating issue as the 3mm 2" and 3" boost pipes ive done in that past have been no problem

its just frustrating as its about the last hing till i can have the mini properly on the road

Make sure the cuts touch so your not trying to bridge, also tack in a few places and do shorter welds.

With ally, clean clean clean! Make sure you clean the filler rod too,

If you do have to bridge a gap use a thicker rod and lay wire weld to avoid blowing the edges.

Check the required current but from memory your looking at about 50-70 amps for that

If you're doing pie cuts....

Cut from long tube, and leave the length on them. weld 1 piece..do another pie cut, weld long pieces together..etc etc

IMO trying to weld very short pieces together will result in lots of melted blobs on the table. At least if I try any small pieces that's what happens lol

For tight bends though either use silicone or alloy fabrication donuts are handy pieces to work from.

Edited by stevieturbo on 12th Apr, 2016.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

I use a larger tungsten for thin ally, a 3.2 I think, it doesn't concentrate the arc as much so makes things a bit more forgiving. Hard to say without seeing it happen, but I'd try a bit more amps. Soaking heat away into ally blocks is hindering you not helping, with ally its a case of getting it hot enough to weld as quick as poss, if you have a foot pedal then back off the juice a bit to avoid holes.
As above get it tacked up in a few places then fill in the gaps.

Reading again though, sounds like you are making hard work when it doesn't need to be. Either use thicker wall ally, or easier still use rubber/silicone bends joined with straight ally if needed.

If it's hard to heat both sides evenly, put a blunt point on the tungsten, and use high freq pulse (maybe 120+ Hz). That will help stop the arc favoring one side over the other and can also make the molten puddle seem more viscous at the point it wants to drop through. Change the AC balance further towards 'cleaning' can reduce burn through on thin stuff by putting less heat into the workpiece and more into the tungsten /arc.

All said, 1.4mm is going to be difficult though. If problems persist and you're having to redo each joint, just cheat. Lay a cold bead that just joins the two pieces and adds plenty of filler. Tidy it up with a file if you need to and once cooled, go back over at higher amps to melt it in properly. Not a great technique, but the result is of course the same.

With 1.5mm wall you want around 100A max. Filler rod should be no more than 1mm otherwise it cools the weld pool too much and ends up lumpy. You won't need the full 100A to weld, only to start the weld, after that you need to pulse the weld (I always pulse weld by foot for more control on thin stuff) pulse your foot down until you melt right through the join (should see a C shape form in puddle) then dip the filler rod and back off to 30% pedal, then move torch and repeat.

If you are holding your foot down and travelling with the pool then it will always start to melt away with heat soak unless you gradually back your foot off as you go round. It's much more constant to just pulse it, as this puts less heat into the job as well.

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1/4mile in 13.2sec @ 111 terminal on 15psi

When I try and use thin filler...it melts long before it gets anywhere near the bit I want to weld lol

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

That's because of the torch angle. 😉 it needs to nearly be perpendicular when doing ally. You can also move the torch back slightly as you dip the filler rod.

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www.fusionfabs.co.uk



1/4mile in 13.2sec @ 111 terminal on 15psi