porosity - welding mild steel, 7018 rod

[CNC Dan]

Dave thats the opposite way to think about it. In this case you want the heat and the light is "waste".

40% of a CFL's energy is light, 60% is waste heat. With a CFL used as a heater, 40% of the energy will be wasted. Incandescent is better for heat because 90% of energy used by an incandescent is waste heat. A heater that doesnt produce light would be better, but with an incandescent you're at 90%, thats pretty good.

LED would cost even less but there would be only 20% of your energy dollar going to heat, and 80% going to " waste light". : laughing:

Doesn't matter. When the light is absorbed, it gets turned into heat.
Total energy input in a closed box, ends up as heat.
Same if you put an electric motor in a box. Whatever power is drawn by the motor, ends up as heat, one way or another( resistance, friction, etc).

I would use an ' appliance bulb' such as used to light the inside of an oven, as it can take the heat better than most bulbs.

For longest life, get a reptile heater. Same base as a light bulb, but the filament runs much cooler(not white hot).

 

[Sodo]

I have to think about that. You're saying the Light energy converts to heat when it hits the box, or the welding rod? Its not changing to "work" or storing up or changing state or to chemical energy,,,,,. Hmmmmmmm you could be right.

But if you put a 23watt CFL in there, you will get somewhere between 13.8 and 23 watts of heat inside that box. Dan will say 23w.

If you put a 25 watt incandescent appliance bulb un there, you will get somewhere between 22.5 & 25 watts of heat in that box (& Dan will say 25w).

 

[CNC Dan]

I have to think about that. You're saying the Light energy converts to heat when it hits the box, or the welding rod? Its not changing to "work" or storing up or changing state or to chemical energy,,,,,. Hmmmmmmm you could be right.

Not unless there is a solar cell and battery it there.

But if you put a 23watt CFL in there, you will get somewhere between 13.8 and 23 watts of heat inside that box. Dan will say 23w.

If you put a 25 watt incandescent appliance bulb un there, you will get somewhere between 22.5 & 25 watts of heat in that box (& Dan will say 25w).

The watts of heat output will be equal to watts of electricty consumed, regardless of the source.

The CFL and LED "watts of light equivalent" arn't real watts, just something to help you chose a similar brightness.

Marketing old lightbulbs by watts they consumed is rather silly, when we have the measurement of lumens. But I guess we're stuck with it though.

 

[pat32rf]

I'd kill for some of that 8cents per kwh. Here in Ontario we are paying about 20 cents per kwh....and that is only because we are careful to avoid the peak rate times as much as we can....

 

[BukitCase]

Yeah, there are people down the road maybe 5 miles from us that're on a non-co-op commercial provider, and they pay about what you are - I think if I had to pay that much I'd be building a couple s-rotor turbines and some sine wave inverters... Steve

 

[dragoneggs]

For years I used an old smoker that was given to me. Just installed a heat lamp in the top.

Good idea. I love repurposed stuff that otherwise sits and rusts or goes to the landfill.

 

[jbwilson]

Regarding the OP poor fillet welds, I sometimes experience this. I think this happens if I hold the electrode too far away and lose control of the arc because it just bounces ariund between the teo legs. When this starts I cannot recover the situation and just have to stop, grind out the bad weld (that's why I stop quickly) and try again. It might also happen if the flux coating on the end of the rod is chipped or uneven resilting in biasing of the arc to one side. The uncontrolled arc means that the flux coating and the weld matal is mixed in the arc force resuting in slag inclusions. With fillet welds I turn up the amps a little more to reduce the prospect of extinguishing the arc with slag overrun, concentrate hard on keeping a short arc, and switch the electrode between the two legs while pausing briefly on the toes of the weld. It helps if the electrode is actually touching the metal at the toes of the fillet weld providing it doesn't drown the arc - some electrodes are better at this than others. In my case a bad weld is nearly always down to my poor tecnique rather than faulty rods or machine. My explanation is only a guess but I hope it resonates with the experienced welders here.
John

 

[Sodo]

Regarding the OP poor fillet welds, I sometimes experience this. I think this happens if I hold the electrode too far away and lose control of the arc because it just bounces ariund between the teo legs. When this starts I cannot recover the situation and just have to stop, grind out the bad weld (that's why I stop quickly) and try again. It might also happen if the flux coating on the end of the rod is chipped or uneven resilting in biasing of the arc to one side.

This sounds like what was happening. Pretty sure this weld is because I was using too much of the stick. I thought rather than start a new rod I could "make it" with the stub. The rod was getting pretty short & I was running it down to the last 1/4" of flux. MIG welder has little tolerance for "changing rods" :laughing:.

The porosity at the beginning of the weld is the part that surprises me.

The porosity at the finish of the weld seems reasonable due to lack of control. Can a boo-boo create porosity 3/4 inch upstream? I wonder if the stick gets "too hot" as it gets "too short"? As its getting short it has less surface to cool.

(both pics are the same weld oooops)

 

[jbwilson]

The porosity at the beginning of the weld is the part that surprises me.

The porosity at the finish of the weld seems reasonable due to lack of control. Can a boo-boo create porosity 3/4 inch upstream? I wonder if the stick gets "too hot" as it gets "too short"? As its getting short it has less surface to coo

Perhaps when the stick gets shorter there is less resistance between the stick and the work piece and therefore the current increases resulting in a stronger, stabler arc. I'm just guessing here. I certainly know that when the arc starts flaring, it means that I am just dumping a mix of electrode metal and flux onto a cold work piece and so I stop the weld.
John