No weld pool

[jordan1]

Just getting started with R-Tech161, just cannot get a pool on 4mm cast aluminium, ok on 1.5mm and that's it. Had a look through the posts and have done all I can, different tungstens [white] and heat settings. Any ideas guys, just can't move on without a puddle

 

[Paul.]

Not enough power, aluminium has around eight times the thermal conductivity of steel, so the surrounding material is sucking the heat away from the weld area. A massive difference between 1.6mm and 4mm, unless your cast ally part is very small you will either need to do some pre heating, or play the arc on the job until it melts, a small propane torch can be very handy for this kind of work, even better is an oxy-fuel set up.

 

[BrokenBiker]

from my small experience welding ally I would say it needs either preheat or a lot more power. im guessing you haven't got much more, if any more power so as Paul says, a blowtorch is needed.

I use the go systems propane butane mix and it works well with the bigger of the torch heads. will melt ally after a short while

 

[jordan1]

from my small experience welding ally I would say it needs either preheat or a lot more power. im guessing you haven't got much more, if any more power so as Paul says, a blowtorch is needed.

I use the go systems propane butane mix and it works well with the bigger of the torch heads. will melt ally after a short while

I have MAPP gas but don't want to put too much prolonged heat in as there are oil seals nearby, but would 160a be sufficient then?.

 

[wyn]

You'll have a job trying to keep the heat localised.....The seals will need to come out to get it hot enough to weld.

 

[brianblock]

I've welded 3mm no problem with 2.4 white tungsten and wire at 140 amps

 

[jordan1]

Not enough power, aluminium has around eight times the thermal conductivity of steel, so the surrounding material is sucking the heat away from the weld area. A massive difference between 1.6mm and 4mm, unless your cast ally part is very small you will either need to do some pre heating, or play the arc on the job until it melts, a small propane torch can be very handy for this kind of work, even better is an oxy-fuel set up.

Thanks for that, it is a new machine, is it possible that it has a fault and isn't putting out the ac power it should?.

 

[Paul.]

Thanks for that, it is a new machine, is it possible that it has a fault and isn't putting out the ac power it should?.

Any things possible, but I suspect its just that the casting needs warming up, I do quite a few repairs on engine casings etc and on the bigger ones often hit them with the welder flat out at 200 amps to start with, then as the material becomes soaked with heat you will need less power, this is where a pedal is handy,
Very often with old castings you will need to do a cleaning pass or two to burn out contamination, this can also be used as a preheat method, remember the melting point of ally is only around 600deg C, so a relatively few degrees temperature rise take the material a fair way towards a weldable state,
I have one customer who likes to do much of his own preparation, where possible he puts his casings in the oven for an hour or so (He's not married) then wraps them in a blanket for the short journey to my shop, they hold the heat quite well and it makes a big difference to the welding.

 

[dannyp]

get the work really clean then you can wind the AC balance down to put more heat into the work if you cant wind teh amps up anymore

 

[jordan1]

Have contacted supplier who tell me that the machine should tig ally that thickness, they say roughly 35a for every 1mm. may need checking out. Good point dannyp.
Thanks

 

[wheresmejumper]

i have a similar rtech welder,but 210 amps.did a cast aluminium lawnmower body repair that was 4mm and definately needed more than 160 amps,probably 190.
for smaller pieces i think 40 amps per mm is about right,but larger pieces need more,at least to pool