Alum welding

[HMW]

Here's a pic of a hydro trans I repaired a couple weeks ago. It was cracked around the drain plug. I have only been learning to TIG for about 3 years now and almost all on aluminum. Almost all the repairs I make are on this type of equipment. Nasty, oil filled, been in salt water or cast . I never really get to fabricate anything out of "new" aluminum so I think the learning curve may have been harder. I didn't know if anybody had any advice on getting the welds to look nicer. The welds I make always have held as this trans doesn't leak either...but.. Its not as nice looking as I would like it to be.

So, any thoughts are appreciated
ps: I just noticed that brown mark on the weld is a piece of grass ha ha ha. This machine has been used since I repaired it and is now back for a mounting bracket broke off but its steel. some people pretty rough on equipment
thanks

[shade tree welder]

aluminum welds

hey hmw i have the same problem with my welds ,they are not pretty and shiny like the pro"s . i am fairly new to tig welding ,but i have a motto:it mite not be pretty but down inside it is penetrated good and will hold", thats all that matters

[HMW]

Glad I'm not alone There might be some small ripples but nothing like what I see on here or commercial made items. Self taught is a slow way to learn, but I read alot and practice. Another issue I have is that, like the crack in the picture, My welds are usually short with no way to practice on that particular type of aluminum and cast is loads of fun. But.....I'm getting better. Really enjoy doing it,

[Fat-Fab.com]

You'll have a hard time getting the look you seek out of old cast AL. You'll probably be surprised as to the look of your weld on new material.

Aluminum when welded hot will not have that shiny look, it will be dull and flat looking. Moreover on old cast you need a lot of heat to float out the contaminants.

TJ

[swyman]

Fat-fab, that's it! I welded on a al. horse trailer the other day, same thing, nice and dirty and 1/8" and 1/4" thick. Using 3/32" tungston 1/16" 5356 filler @ 200 amps. Just messing around I turned it up to 230 amps and boy did it weld nicer! One thing though, what is max heat for 3/32" tungston?
Shane

[JonnyTIG]

HMW:

If you lightly grind the surface off the area to be welded it will remove some of the contaminates. Then, if you pre heat the joint area with the TIG torch, more oils and such will appear and burn off. Sometimes I do this and then weld the joint, only to find the weld still has black flakes in it, I use a die grinder to remove the contamiated weld, then usually the second weld comes out pretty good. Burning out the garbage in the cast sometimes has to be accompanied with mechanical removal. Cast Al seems to weld better when it's hot, so gettting the shiney beads (as stated in previous posts) is harder to do unless the base metal (casting) is very clean and thin enough to not require a lot of heat.

Your repair looks good to me

[dabeldesign]

A lot of preheat goes a long way with cast aluminum. Also, castings (especially transmissions and gearboxes that hold oil) get lot's of contaminates trapped in the surface; you'll see black flakes floating in your weld puddle...

[HMW]

Sometimes I do run the torch over the whole weld area to burn the "crap" out and that does help. Thats after wire brushing and cleaning with aluminum cleaner. Your right about the black stuff floating around. In this repair it did take alot of heat because of the thickness of the boss with the drain plug in it. Does much better when really hot. I'll keep after it and someday I'll get really good at it


Thanks for all the thoughts

[HMW]

Fat-fab, that's it! I welded on a al. horse trailer the other day, same thing, nice and dirty and 1/8" and 1/4" thick. Using 3/32" tungston 1/16" 5356 filler @ 200 amps. Just messing around I turned it up to 230 amps and boy did it weld nicer! One thing though, what is max heat for 3/32" tungston?
Shane

3/32" I think is 125amps, but I have put more than that on it for a little while. I have a sw180 and I leave it at max. So sometimes on thicker pieces of aluminum it takes a little while to get it hot enough. This is the first tig i have owned and it works great. I don't really know which model i want next???. Don't know if I want the dynasty or a bigger shop model, like the 250.

[dabeldesign]

Fat-fab, that's it! I welded on a al. horse trailer the other day, same thing, nice and dirty and 1/8" and 1/4" thick. Using 3/32" tungston 1/16" 5356 filler @ 200 amps. Just messing around I turned it up to 230 amps and boy did it weld nicer! One thing though, what is max heat for 3/32" tungston?
Shane

A general rule (which also applies to stick welding) is that you set the machine to one amp for every thousandth of an inch. For example: 1/8" tungsten= .125" diameter, so start out at about 125 amps. 3/32" is about .093 so 90-100 amps is about right. This is just a guideline but I think you'll find that 200 amps is a bit much for a 3/32" tungsten, especially if you have your foot all the way down on the pedal all the time. If you want more amps, switch to a bigger diameter tungsten that can handle it better...