TIG filler wire size?

[Eicon]

Is there a rule of thumb when selecting the size of filler wire to use. Lets say I'm Tig welding 2'' sch.40 carbon pipe, it's about 1/4'' thick. What determines the size of the filler wire. 1/8'' wire or 3/32'' wire? Is it the root gap?

[NorthernLights]

I don't know what the rule of thumb is for filler size selection, but here's what I've gathered from both the Miller and Lincoln TIG calculators. Looks like it is ball park figure of 1/2 the material thickness. Filler size recommendation was the same for butt, lap, corner, and fillet welds, only amperage changed depending on the weld.

1/16" material = .045" or 1/16" filler
3/32"" material = 1/16" or 3/32" filler
1/8" material = 1/16" or 3/32" filler
3/16" material = 1/8" filler
1/4" material = 3/32" filler
1/2" material = 1/4" filler

These were for steel. Aluminum would use the larger of the two recommendations.

BTW, the Lincoln calculator offered the smaller size filler material. I don't know why they recommended smaller.

Hope this helps.

[HAWK]

Al rod size.

When tigging aluminum I like to use a filler rod one size bigger than the material at a minimum.

[Eicon]

check this

THANKS! But... I noticed NORHERNLIGHTS indicated 3/16'' material requires 1/8'' filler wire and 1/4'' material use 3/32'' filler wire. Is this correct, use the smaller filler wire for the thicker material being welded? I would think just the opposite.

[ASKANDY]

As a rule, don't use a filler larger than your base metal size. You would have to expend too much heat to melt the filler and would be too close to burning through the base metal. For your 1/16 use 040-1/16, 1/8" material likes 3/32 filler unless it's a large fillet then use the 1/8 but I think it's overkill. For your 1/4 wall sh40 I'd use 3/32 on the root and 1/8 fill or just use the 3/32 all the way.

Hope this helps.

Andy in Denver

[NorthernLights]

THANKS! But... I noticed NORHERNLIGHTS indicated 3/16'' material requires 1/8'' filler wire and 1/4'' material use 3/32'' filler wire. Is this correct, use the smaller filler wire for the thicker material being welded? I would think just the opposite.

I doubled checked the calculators and found that the Lincoln calculator did recommend 3/32" for 1/4" material. I made a mistake from the Miller calculator, they recommend 3/16" on 1/4". The calculators are great tools for finding a starting point, but individual preference and application may vary.

[Andrew J 649]

I was just going to start a thread when i found this, so i thought i'd add to it .
I'm in the middle of doing a large job all in 1/4" 5052 plate with some 3/16 too. Its 25 planter boxes (i know that might be a head scratcher for some.. but its what the architecture firm specified for a fancy roof terrace here.. so, not my idea). Ive been putting these together using 3/32" (5356). There are two different welds on these boxes, but this seems to work well for both. I got down to the end of my supply and was forced to switch to either 1/16" or 1/8". At first i was using the 1/16" but i found i had to feed in so fast to keep up that i couldn't place the filler accurately. So i tried the 1/8" and I'm finding it quite a bit easier. At 200-220 amps if i dart in and out sort of quickly, the puddle just takes in just the right amount. The part that makes it so easy is that the hand feed rate slows way down, so i can concentrate on exactly where the rod is being placed and less on finger work feed rate. The added stiffness of the thicker rod also makes it easier to feel the angle/orientation with a glove.
In the first photo the inset perforated bottom (for drainage) is 3/16", all else is 1/4". The second photo just shows my prep for the welds going up the sides, done with a router and 45 chamfer bit and template.

[ryanjones2150]

Beveling the ends as opposed to placing the plates properly for outside corner joints? Is that part of the specs as well? <br />
<br />
I prefer using as big of filler wire as I can get away with, especially on aluminum.

[Andrew J 649]

Thanks ryanjones2150 on the filler opinion. Your question about joint design sounds like a new discussion/topic, but it sounds like you don't approve. Keep in mind, the two front vertical corners are press brake formed, and the bevels are 2/3 depth of the material and 2" long x3 per joint.

[ryanjones2150]

If it's working for you then roll with it. But properly positioning your outside corner pieces eliminates the need for beveling like you're doing. I've never seen it done like that. Doesn't make it bad, just new to me. I'm sure someone else here has seen it done that way before.

[xryan]

Hey, you're the one doing the fabricating, but this Ryan also agrees with the other Ryan. Seems like too much work. Why bevel when you can just layout the plates for a nice 1/4" fillet along the edge. It would seem to me a whole lot faster and easier to just shorten the length 1/4" on each bent leg.

[ryanjones2150]

I was trying to post a picture of a properly positioned outside corner joint, but the forum app has disagreed with my technique and flat out refuses to comply.

[xryan]

Like so?

[ryanjones2150]

Precisely.

[ryanjones2150]

Showoff.