think aluminum trouble

[dvice]

I have welded this job before...even though it was troublesome....for whatever reason. but today it just wont wet out!

this is an unknown allow of alluminum sheet..it was made into a guard. it is about .0625 thick

I am using a miller dialarc hfp 300 amp machine... I have it set for AC, 40-165 amps set at 40%, and i use a foot control!! I am using a genuine helicar torch , thats water cooled with a 3/32" dia pure tungsten electrode. the gas is argon set to about 30 psi

i have used several rods...in 1/16th dia of 4043.

the material wets for a split second only then glazes over and I cant get my filler rod to stick...then the whole surface starts to sink....you all know..

what can i do to get this material to wet out more so i can add filler???

with out caving in

thanks

bob

[John Renk]

I have had that problem with corroded aluminum, must be very clean unless rotted material from weather or salt.

[dvice]

I have sanded the mating surfaces and surrounding areas, as well as wire brushed with a ss brush...

I have a new belt sander belt and used that.,... si it should be clean..

bob

[MMW]

It could be corroded material. Like rusty steel but corroded aluminum. I fix some irrigation piping & that's exactly how it acts. If the material is corroded it will not weld. Even though you are sanding/grinding/wire brushing that usually doesn't remove the crappy stuff. Sometimes it just impregnates it more. Best bet is a die grinder with a carbide bit. Grind to clean then "butter" the joint as best you can. What kind of enviroment is it in, corrosive? Does it have to be liquid tight? A lot of times I wind up just putting patches over the top.

[cruizer]

30cfh would freeze the puddle pretty darn fast, Should be NO MORE than 20CFH

[mikesystem]

I have one of them dial arc and have had that problem a few times on nasty aluminum but 30 cfm is way to much