As some of you know i wanted to teach myself how to TIG ally, so i bought a cheap tig set a while ago, and have just got round to having a go, now heres where hopefully someone might help,

have alook at the pics

now this material is 6mm dural, i started by just running a bead on the material to see how it pooled when welded, added a bit of rod etc and changed a few of the many settings on the plant




now i decided to join two pieces together, and heres where i have a problem, i know it will be something simple, i just dont know what,

after the peice has been welded the material goes pitted like and then after a few seconds shows a black 'crack' line down the middle and fractures why is this ?



also how much gas pressure should i be using ?

one ive got this sorted i can weld these to my bike frame

 

That plate is no where clean enough, you need a stanless steel wire brush and only use it on alloy, also try and pre heat the area. have you a setting for post flow of the gas ? IE after you have laid your weld down you keep the torch close to the work pice and flood it with gas. You are useing pure Argon gas and not a argon mix ?

 

I am no expert but of the two people I have observed when doing this type of
welding, they use a gas propane flame to heat up all parts before welding.

This is done so that all pieces cool down together at a similar rate reducing the chance of cracking while the weld is still weak when hot.

 

hi, yes i have post flow and is set for about 5 seconds to which i kept the torch at the end of the weld till it stopped, ok needs to be cleaner then, and a stainless brush just for the job, taken on board !

 

Markk andy gallacher is your man to teach you that!

 

i know hes very good at it, just a bit to far to go for a few lessons !

ive been up there a couple of times now, the next time i go up will be to collect my car hopefully, maybe i will ask him then

 

As above, prep work, pre heat will aid you alot.

What plant are you using?

are you using the pedal to sloop down the amps as you are going?

 

its a 200 amp chinese special only single phase and yes about the pedal

 

looks good initially mark,
heard that lots of times that your
stainless wire brush should only ever
touch ally (and clean ally) i.e use another for
buffing off dirt/corrosion then use the stainless
brush prior to welding.
keep us posted.

 

6mm is a tad heavy for 200 amp chinky my 200 amp fronius cost near 4k and it would struggle welding 3mm all day thou you can weld heavier for a short time

 

200 amps at what duty?

use acetone to clean your work and the rods!
ill get that book to you when i get 5, it does explain it all

 

but why would it crack in the middle andy ?

 

hmmm ill have to have a look at the spec sheet to find this maybe ?

 

theres not enough weld on and you never chamfered the edges of the plate

 

how much was the welder you bought and does it weld good with mild and stainless steel

 

this is the plant i bought

http://cgi.ebay.co.uk/AC-DC-TIG-WELD...QQcmdZViewItem

and welds steel/stainless very nicely

 

seems to good to be true too

 

80% duty according to the instructions mate