Welding Tips and Tricks

I'm going to be welding a cast ally piece to the end of a stick of 2" OD ally 6061 tubing.

Any pointers before I take the plunge?

Jon

I like 5356 and 50Hz if yuor machine will do it. A single pass over the cast piece without filler helps me get a weld without porosity.

cj737, Great. I've got 3/32" 5356 but I can't adjust my PT185 to 50 Hz. So I'll stick with 60Hz, leave my balance at 70/30, no pulse, hit it with a 3/32" lanth electrode, normal Argon flow (15-20CFH) and see how I do.

I somehow got the idea that welding cast ally to 6061/6063 was a bit of a super-tricky activity. Sounds like it's pretty straightforward.

I'll post my results for feedback.

THKS!

Jon

What’s tricky is the cast ally is full of porosity and air bubbles. The heat from your torch will make those air bubbles expand and blow out. Provided this a clean, new casting, the impurities aren’t such an issue. But, if the casting is oil soaked, all hell will break loose as you hit it with heat.

Cast ally will flow under less heat than 6061. A tad more cleaning action is my approach. A 60* grind in the tungsten is what I use. Just get a first pass on, then clean it well. If you have any porosity, go back and wash the weld, adding filler as needed. You can also peen the weld if it gets out of hand to help.

cj - Got it. Fortunately this is a brand new casting so I probably won't have too much trouble with it in that sense.

When you say 60* grind on the tungsten, you mean a little blunter than usual, right? Or do you mean sharper? I'm assuming that I'd still cut a flat crayon end on the point anyway seeing as I'm welding ally.

And I'll bump up the cleaning action, as you suggest.

And sorry to keep going but what do you mean by "wash the weld" if I have porosity?

And "peen"? Maybe you mean using a ball peen hammer? But how?

I probably sound like a bit of a newb not knowing what these words and terms mean but if I don't understand the lingo, I'll never get the practical down. I'll never be able to do it.

This forum is a breath of fresh air for me and I find your advice particularly helpful.

Thanks in advance,

Jon

Yes, 60* is less sharp than the regular grind.
You can blunt the tip, I don’t. I ball it intentionally. After grinding, I set my AC Balance to 30, amps to 150. I smoothly ramp the pedal with the tungsten hovering just over top of a scrap piece of 3/8 plate I have. I watch the tip, when I get a small and consistent ball, I stop. Reset AC Balance to (desired) set my amps, and weld on.

Washing the weld means going back over it, with no filler. This will enable you to tie in the toes where you might have missed, clean up the weld aesthetically, and cook out some porosity. If you discover a large pore, some additional filler may be required. When I wash, (and I’m talking welds here, not my shower habits) I reverse my direction. I’m making new “ripples” so I want to get the best appearance that I’m capable of. Just make distinct, deliberate travel with the torch. Sometimes, I set my machine to PULSE for this as it gives a perfect freeze line and travel speed for me.

Peen, yes “hammer it”. If you have some round stock, grind a gentle taper into it, then round over the end. You’ve made basically a cold chisel with a round nose. A small brass hammer, tapping the weld between passes, or as you discover porosity. This helps “pack” the weld and drive out those ugly holes. With a new casting, you should be just fine.

Realize this: EVERYBODY welds differently. EVERY machine welds slightly differently. Pace of yuor travel, amount of filler, the action on the pedal, it all effects the outcome. Each person who welds, finds slight tweaks into getting the results they produce. What I do, may not work for you. How I setup my machine, may change as I weld. I might see something that I know I can conquer with a change in Balance, Freq, amperage, whatever. Maybe a different cup. You have to be willing to experiment and to ruin material before you get it dialed in. There is simply no substitute for hood time. And you will never produce great welds every time. No one can. Some days you got it, some you don’t. You might rip 60 gorgeous welds in a row, then as you go to finish the piece, you lay a weld that looks like crap! And you say, “WTF, who’s that guy welding behind me?” It happens, it’s welding.

What is important is strength of your weld. It must support its application. Beauty is secondary. You could have gorgeous looking welds that won’t hold a fly’s fart, but strong welds that Thor couldn’t bend. I’ll take the latter and work towards the former. So get some hood time, expect differing results, and don’t beat yourself up when they don’t turn out perfectly. They can be fixed with washing, a second pass, or a grinder.

Be patient and let things cool off. Heat saturation is probably the hardest thing to explain and teach to someone. Welding takes a lot time to perform, because temperature control is time-based. Really grainy welds in ally are a surefire sign of heat soaked material. Weld 4” on ally and stop. Air cool it with a hose or a quench bucket. Dry it, then proceed. Steel and stainless, let it cool naturally (10-15 minutes). You can weld farther on thick material, and on carbon, but the cooling time takes longer because you use more heat.

Sorry for the long-winded response. Hopefully it answers some questions and gives you a tad more insight that you may not have contemplated.

cj, You made me laugh! But this is all very good advice. Thanks for clarifying "wash" and "peen" - this makes total sense to me now.

I believe my main shortcoming is impatience. I can't always wait for the ally to cool and I'll keep going and ruin my weld. I sometimes dip my tungsten and keep right on welding because I don't have the time to stop and redress it and my weld comes out looking like #$%!@. These I realize are habits that will in the long run bring my welding career to a plataeu if not an end. So I'm working on correcting that.

Funny you should mention beautiful but weak welds, I happened to drop one of these frames that I'm making the other day. It was one that someone else had fabricated and yes - the welds were very pretty. But two of them cracked and the frame fell apart. I looked at these welds: no penetration, just a thin (but pretty) stack of dimes sitting on top of the metal. And they fell apart.

This is all good stuff that you've given me here, and some positive encouragement. This welding stuff, particularly on ally I think, is not going to come overnight. I need to slow down a bit, quick rushing and just make sure that I'm doing every step right.

Again, thanks for your more than welcome long-winded response!

I'll keep posting and I'll get some pix on here as well.

Going back under the hood now,

Jon