aluminium pipe help!!!!!

[milk]

need some help/tips to weld some pipe. got to weld some pipe 20mm od with 1mm wall to 50mm od with 8mm wall. small pipe comes off at around 45 degree's and then runs along the length of the thicker one with about 40mm max gap between the two. whats the best way to get a bead in between the two?

cheers Tom

 

[Jim_gsxr1000]

Tig and somone who has experance of aluminium welding

 

[milk]

Tig and somone who has experance of aluminium welding

well done so any tips then?

 

[Jim_gsxr1000]

No, i weld with tig, DC only tho, cant cope with getting the shocks from AC when you touch the filler rod to the tungsten by accedent!

 

[backpurge]

How much experience have you got

 

[milk]

i quite like the shocks wakes you up in the morning.got the outer edges just having trouble filling between the two pipes where the access is crap.

 

[milk]

How much experience have you got

about a weeks worth on alu.

 

[wheresmejumper]

long narrow cup,or huge gas lense might get you in there

 

[milk]

long narrow cup,or huge gas lense might get you in there

tried with a no 6 cup with about 5mm stick out but so far it's being a nightmare and at the moment i haven't a gas lense to try.

 

[wheresmejumper]

like these,often comes in handy

numbers 4,5,6,7 cost me about 4 quid from china

 

[milk]

think i'll have to get some. but got any suggestions for a quick fix as i was meant to have had this done yesterday and really need to get it done tomorrow as it's a sample for a job.

 

[wyn]

From time to time i need to weld this joint in 1" tubing...pic below...the angle between the tubes is around 40*.

I initially used the set up in the pic but now use a gas lens that lets me have the tungsten out around 10-15mm with no problems. WP20 torch

I also attack it more from the side (about 45* compared to the pic) and start at the tightest point and move out, then do the same from the other side.

It all got a touch too hot in the pic.

It will be tricky though 1mm to 8mm in aluminium.

 

[milk]

cheers pics quite helpful.it's certainly tested my patience today. will see how i get on tomorrow. the other think i thought about trying was to build it up with a few dabs of filler and leave it to cool and repeat until i've filled around that section.not looking forward to the 6 bar pressure test thats for sure

 

[Rrunnach]

A week welding al/al, then on to tricky work, a tall order, but no doubt you are capable.

1mm to 8mm WT, is a mare in it's own right, I would try a pre-heat on the 8mm, which of course conjurs up other probs with the 1mm WT.

If you want welds to hold 90psi/6bar, I would pre-heat......

 

[carlos420uk]

Get at least 4-6 good tacks on it before trying to weld.
Use a gas lens and long stick out with a bit of extra flow. Make sure your metal is clinically clean and wiped down with Acetone, same for the filler.

Arc up on the 8mm and get a little puddle started straight away (ie floor the pedal as much as possible, assuming you have one), then dab a little filler and try to wash it over onto the 1mm whilst keeping the Tungsten pointing mainly at the 8mm.
Once you have a solid tack joining the 2 you should be able to run a bead keeping the Tungsten pointing at the 8mm and carefully dabbing the filler on the 1mm. The filler should wash down onto the 8mm anyway providing it's the lower piece.
Watch for the top piece melting, and increase your travel and / or decrease amperage as you progress along the joint because heat will build up quickly.
If you dip or it starts getting out of control stop, re-clean / sharpen and try again.

If your using an invertor try a higher hz to concentrate the arc cone, I would start at around the 120-140 range.

Do some practise welds on the same thickness's of metal first.

I'm not the greatest at it in the world but that's how I'd attempt it.

 

[milk]

i know it's not the best quality but heres how my attempt went

 

[carlos420uk]

I think you could have done a lot worse mate

What is it?

 

[milk]

It's part of a pressure hose for shipping tankers

 

[Rrunnach]

Welds cold mate, which is why i suggested a preheat to 8mm wt. is it possible to have holes machined, then drop in and weld, this would allow preheat to 8mm wt only, then go like billy whizz"..........

 

[milk]

it's something i'll have to try.what kind of temp do you normally heat to? or doesn't it really matter.