150 spoolmate

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billy c
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Re: 150 spoolmate

Post by billy c » Sun May 07, 2017 6:22 pm

Hi Kevin-
I will continue to make the adjustments you have recommended on my new practice samples. Today I prepared a few pieces so that my welds can be made on cooled material. I may also run down to one of the welding shops and see if they will sell me some scrap. They have lots of 1/8 " stock that they build docks and stair systems.
With the Millermatic 211 settings closer to correct and some guides to steady my hands for running the bead, this should make a huge difference in the quality of my results. I think I understand what you are saying about beginning and ending the bead so will work on that also.
Thanks again for your encouragement and guidance
Billy
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Bill Edmundson
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Re: 150 spoolmate

Post by Bill Edmundson » Sun May 07, 2017 7:17 pm

Down here a lot of the small fab shops will just give you scrap. They will even do some cutting for you. They do it all the time as public relations to help farmers, etc.

Of coarse, in Alabama we're all cousins!

Bill
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Kevin Morin
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Re: 150 spoolmate

Post by Kevin Morin » Sun May 07, 2017 7:58 pm

Billy C, in our neck of the woods scrappers go around to buy the off cuts so they're kind of used to recoup mat'l costs - not that they can't be found for lower cost than list price cut off a big sheet. The Local Metal Supplier (LMS) also will put the odd shapes in a remnant bin or rack and sell them for less $ than new- and that's another good place to check for odd shapes, thicknesses and alloys for practice.

Bill, that's some serious good will gesture for local shops to give away scrap or off cuts to their neighbors- a few pieces to one person here can make for hard feelings if the next guy gets told his request has already been given away!

When tuning your bead I'd like to remind you that there are several variables- wire feed speed, arc length, contact tip gap (makes a contribution to welding current), gas coverage, gun angle to the metal, travel speed and output voltage setting at the power supply. Now... that is more than one thing to go 'wrong' or need tuning.

What do you suppose would happen if you changed more than one of those variables between welds? Let's say you change the voltage/amperage/wattage up; the wire feed speed down, and your tip to work gap up just a bit? How would you ever (EVER?? ! ! !) be able to tell what effect you'd had on the next weld?

Rule of Thumb; only change on 'thing' at a time between test welds and concentrate on learning how that particular variable changes your welds- BEFORE you add another variable.

I'm pretty sure there is a computer programmer saying that if you have to solve any problem for more than two (worst case 3!) variables that the problem is considered : Unsolvable by computer.

It's critical to remember that the control circuits are trying to do their job and they consider that job to be: Keep the Voltage uniform- flat-constant-equal as possible. That is why the power supply for MIG is called a CV or constant voltage power supply. You may recall DC electricity is sort of summarized as V=IR or Voltage equals the current (I) times the resistance (R).

In a welding circuit R is the distance of the contact/copper tip to the work. (when welding its the arc length) So, if you're welding along and pull the gas cup upward 1/16th inch the R has gone up. What will the power supply do about that change? It is designed to reduce the I, or current, so the V stays the "same" as the preset. Going along any weld; the power supply is making its own adjustments to the weld output so the voltage can remain as flat as its circuits can make it. Steady rests, marked weld paths, and making only one adjust between welds all reduce the magnitude of the welds' changes- and allow you to begin associating these adjustments with your resulting welds.

Other welders can only help if you have the time to practice and the interest to post so we can all feedback what we see or answer questions you post. I'll try to field any welding question I can, and images of welds are always the key to reduce confusion when discussing a given bead.

Cheers,
Kevin Morin
Kenai, AK
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Bill Edmundson
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Re: 150 spoolmate

Post by Bill Edmundson » Sun May 07, 2017 9:10 pm

Kevin

They don't just give all the scrap away. But, if a farmer needs 3' of angle to fix his bush hog they'll give it to him. I don't know about aluminum fabricators down here though.

Bill
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billy c
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Re: 150 spoolmate

Post by billy c » Mon May 08, 2017 6:26 am

Bill- there are quite a few recycling centers for metal around here so the shops get most of the scrap picked up on a regular basis. I have done business with one shop over the years so hope they will have some stock for me a little cheaper than the sheet goods at the metal yards. Another thing I thought of is the dock companies that are around the lake. They take all the damaged aluminum and bring it back to their shops and are most likely not going to reuse it so that may be a source. Will start knocking on doors.
Kevin- I understand changing only one variable at a time and found that the 035 wire speed on my welder runs at a flat "6" thru quite a range of voltage settings (3rd line in from right in image below), so am keeping the wire speed as a constant for now and playing with the voltage only. Hope to get out there for some more practice time :)
...On yesterday's bead image I was running at 6.5/60
-Billy
Screen Shot 2017-05-08 at 9.17.08 AM.png
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Kevin Morin
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Re: 150 spoolmate

Post by Kevin Morin » Mon May 08, 2017 11:49 am

Billy C, good method of exploring one variable; when you've done that- kept the wire feed speed constant and explored the voltage up and down from the 'factory' setting? Then reverse the two- leave the voltage at some sweet spot and vary the wire.

Then do that with the gas cup/contact tip/arc length- that is make a WFS and V setting combo and move the cup up and down - one pass farther away, the next even farther and then some closer than the previous. Each variable wills show up as a contribution to the final profile.

Also, I'd encourage you to weld more practice beads on inside and outside corners than just flat on a padding plate. The reason is- there are few if any welds that are flat build up type welds- and the T fillet inside and a 90 outside joint- both provide their own guide lines' or edges of metal to use as a site guide for their beads.

practices only makes better if you're practicing the "right thing" !!

Cheers,
Kevin Morin
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