[Otto Nobedder]

Countryboy,

The negative half of the cycle puts the heat to the aluminum, while the positive cycle, which does the cleaning action, puts heat into the tungsten, causing the balling. I've developed the habit of going as far negative on balance as I can (because I'm usually stuck with 3/32 tungsten, and sometimes need pulses of 200A or more), but this requires very clean metal. Jeff made some great recommendations on that. On small stuff, my final clean is often with a SS fine-wire brush in an angle die-grinder. Dremel tool would do fine, too.

Until you've accumulated some experience, I'd suggest watching for the "sagging ball", as Jeff mentioned, and set the balance a bit more "negative" at a time (re-grinding the tungsten, of course) until the ball is just small enough to stay centered. If this gets you too negative for good cleaning/good welds, move up one size on the tungsten, and begin from "balanced" again.

BTW, the "cleaning" action is solely to break through/push aside the oxide layer that begins forming the instant fresh aluminum surfaces see air. It doen't "clean" any missed crud from the puddle, that stuff either floats to the top or stays as an inclusion. That pepper could even be something drawn from the back side of what you're welding if you don't clean a half-inch of that surface too.

Just my two cents...

Steve S

[Otto Nobedder]

Also, my aluminum welds are sometimes "hazy". It's usually a gas-coverage issue... we have small torches at work (-25? I think), and I'm usually using a #5 cup. If I do the weld with the torch close to 90*, I get "shiny". If I have to "push" the torch because of the position/visibility, I don't get enough coverage behind the puddle, so the surface is still very hot when it sees air, and oxidizes rapidly. The fine-wire wheel (.006" stainless) shines them right up, though my stuff usually gets painted, so it doesn't matter.

Steve S

[countryboy1127]

Im definitely gonna do all that is stated from yourself and jeff .my lack of experience with aluminum has definitely given me a headache at times haha . Its something new and im trying to learn , I didn't realize it was so picky and tedious to tig weld .a lot different than mig welding it . I don't have to worry about painting it cause its a a frame and set of skimmer nets for a small shrimp boat so definitely not a production thing . I do however have my own integrity and standards that it must conform to and wont settle for less that . Ill be posting pictures of the finished product when its done and im sure ill have more questions before tbis is all over . I hope to be able to provide some feed back like you guys do and help some other people one day with my experience.

[TamJeff]

Actually, countryboy, your welds are "right there." Most of us have chalked up any of your remaining issues to every day quirks and familiarity issues. What happens to most aluminum welders is, you poke along and then everything occurs to you like the flip of a switch and you can't understand how you were ever having issues at all. What remains ends up typically being decided by your supplier.

Funny you said shrimp fishing parts. I was just approached to build frames for those about a month ago. There was also to be some rather thick (3/8-1/2") plate involved as well, as I remember telling my boss that we should order some helium if I was to make any time at these.

[countryboy1127]

Yea your rite thats how it always ends up happening . Yea their easy to build if you have the room to do it . Im building a small set for a personal boat not anything commercial driven . He's boat was already set up for it when he bought the boat just didn't get the frames and nets with it . The ones im building are gonna be 7X5s . Ill post pictures after im finished which should be mid week . Down here in south Louisiana you can make a little money during shrimp season , building new ones and repairing a lot of them .

[countryboy1127]

heres the finished project . not to bad I did however go over my quoted time frame of about 6 hours , but its my first paying welding job on my own . made a few rookie mistakes but am pleased witht he way it turned out when I have the nets put on and rigged up ill post more pics . once again thanks again guys for all your advice and help .

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[TamJeff]

Excellent. That had to be fun to do.

[Otto Nobedder]

Lookin' good, Countryboy!

There's always a learning curve the first time you do something, and it's rare two jobs like this will be the same.

When doing something for the first time, I like an old maxim from Thomas Edison. However long you think it will take, double it and add 10%. Sometimes this is remarkably close, but it almost guarantees you won't underestimate time on a job, even when you run into the unforseen. The number may be impractical for bidding, but should be in your mind when you bid, because rarely does everything go as you expect.

How many hours did you actually have in it, if you don't mind the question?

Steve S

[countryboy1127]

ill try and remember that for my next job . it really wasn't that bad , I only worked on it for a couple hours a day after my regular day job . total time was 34 hours . i bid the job for 28 so i had to eat a few hours but i just chalk it up to learning and i did make a few rookie mistakes .

[Otto Nobedder]

Ah, so you only went about 30ish% over on hours, on your first "solo".

That's actually VERY good. I've seen huge "fails" on first estimates, and this isn't one of them.

Next bid, I bet after you figure your time estimate, you'll add at least that 30% error, just to protect yourself.

It's all a learning curve, homing in on that balance between a bid that lands a job and a bid that doesn't bite you in the ass when you encounter problems.

Don't be afraid to include language in your bids that protects you from the unforseen. You can't protect yourself from YOU, but you can protect yourself from uncovering a previous inadequate/unsafe condition in what you're working on.

Steve S

[countryboy1127]

yea it wasn't to bad. i made few mistakes by second guessing things and mental errors. the customer did add some last minute changes as well which didn't help with the hours but it all worked out. ill definitely be adding a percentage of time to the next bid just for things like this . on the upside i did pick up 2 more jobs . one from this same customer.

[Otto Nobedder]

Don't know how it'd work, but you could consider offerring a rebate if you come in under your estimated hours...

It'd earn you a reputation, at least.

Steve S

[countryboy1127]

ill keep that in mind it would give you a good rep that's for sure .