[Tim]

Hello,
When do you preheat aluminum and how much heat do you have to put into it to create that first puddle? Do I need to get the base material to 350F first? Is there a chart somewhere which shows for example current/base metal temp for a given thickness?

The reason I ask is that when practicing on a 2x2x2" 1/8 alum diamond plate box, the first weld took forever. I was focused on maintaining an electrode/base material distance (avoiding contact) and I waited and waited and waited and resisted mashing the "pedal to the metal". After some very disappointing minutes, the material was puddling and I would say things were normal and I was seeing progress. After all the sides were tacked together, (and I assume, after the material heated up) I could run a puddle across the edges pretty easily and I could run a bead down the edges super easily.

I read the 1.5 amp per thousand thickness rule. No, I didn't apply it. I was set at 125amps? Do I need to set the current at 187 amps and have the pedal to the floor when started a bead? Should it take only 3 seconds to create a puddle on room temp base material? I thought it would burn through. No?

I guess I could figure this out in 100 years. But, I'm sure you guys would know off the top of your heads.

Thanks

[gurew]

aluminum is fun to weld, if you can get the skills to move quickly, you can turn up the amps, if you cant move fast then you need to set the amps lower

1/8" i personally would run 176amps

torch angle plays a big role in getting the puddle created, i usually light up and hold it there full pedal until i get the puddle i want, then i start moving along at a steady but fast pace. now with aluminum you dont have to move fast!! regardless of what anyone says...

[Tim]

Thanks Gurew,

You know what, it is fun. I like that puddle; it is unmistakable that you "are there" and the puddle follows the arc. Its a beautiful thing to see that.

OK - so ... for a air temp piece of aluminum which is what I'm wondering about:
- for 1/8", set it to 176amps
- point the torch down at a 90 degree angle
- establish an arc and "full throttle up" on the pedal
- (I'm guessing) 3 sec and I should see a puddle
- adjust the torch angle to (I'm guessing) 70 degrees
- dip, move, dip, move ... and
- (I'm guessing) let up on the pedal as the base material heats up (less amps required)
- adjust amps to maintain puddle for given speed.

So, you really dont care about the time spent on the cleaning action? You can speed it up from 10 sec to 3 seconds and there is no advantage to a longer cleaning action period. I thought it would just burn through.

Thanks very much. I really appreciate it.

[gurew]

welding is a skilled art. there are lots of "right" ways to accomplish what you want

sometimes i will pulse with the foot, others i will just go balls to the wall...really depends on the situation and what you feel comfortable with

i know that sucks hearing that practice and seat time is the best thing lol...but thats really the best thing you can do

[Tim]

Oh, that was funny. Developing a skill takes time ... who woulda thunk it?

There must be hundreds of variables !!! If you lived next door and walked over, I bet you could make 25 suggestions right off the bat.

Hey, thanks a bunch.

Tim

[gurew]

i can only suggest what ive learned via seat time

i think everyone ive talked to thats new seems to focus on the wrong things...the number 1 thing you should focus on is prepping the metal...cleanliness and fitment after that..everything else falls into place

[jakeru]

You probably won't need any pre-heating for your 1/8" thick, 2"x2"x2" aluminum cube.

To answer your question - I have pre-heated parts to successfully reduce distortion caused by the cooling weld bead. Often, a little distortion is manageable, but sometimes (welding next to a machined surface) distortion can be an issue.

The other benefit pre-heating can provide, especially with aluminum, is a reduced amount of heat from the tungsten necessary at the beginning of the weld. This can sometimes let you weld with a sharper, smaller diameter tungsten, or with a smaller machine than would be otherwise necessary. And it can reduce the time you spend with an arc struck at the beginning waiting for a puddle.

I don't see much good coming from waiting in one spot with an arc struck for a long time, so its best to avoid it if possible, and use more current. No sweat when you're learning though. If your tungsten is maxxed out (tip melting, or degrading like forming protrusions, etc), switch to a bigger tungsten, or a lower DCEP/cleaning setting (to take heat off the tungsten and put more into your work.) Sitting there waiting for an arc can be bad IMO, because it is more opportunity to touch your tungsten to the work (and make a mess), or get an uneven etched pattern, or excessively heat up your work, which can result in a less controllable (potentially "runaway" size) puddle happening as you get further along your weld bead. Often times to get enough current at full footpedal depression, we have them adjusted so we lose some fine control of low currents on the lower end. And a large tungsten, especially with a "used" tip, can have some issues at a really low current settings too. So, we often have limits of how far we can reduce the current while welding. When things are set up right, we should be able to complete the weld comfortably between the limits (upper AND lower) of what the footpedal and tungsten (and whatever other variables may be limiting...) allow.

You really don't need much DCEP/cleaning to get the job done on clean aluminum. So try turning the DCEP/cleaning setting down, and focus more heat into the work and take it off your tungsten. For 1/8" material, I would probably use a sharp&blunted 3/32" tungsten, and somewhere in the ballpark of 30%-20% DCEP. I'd probably set my machine at about 125 amps @ pedal full down, at least for starting out on room temp pieces. You can practice forming a puddle and maybe a dip or two on a piece of same thickness scrap, to make sure the heat is right. I like to aim for being able to get a puddle quickly at about 3/4" footpedal travel. Quite often during the "test puddle on scrap" step I like to do, I realize I forgot to open the argon bottle or something. Forgetting to switch from DC to AC can be a real doozie also. I'd initially press down enough to get a good arc start (minimize the high frequency "lightning", which can make unsightly scars on your surfaces), then over the next 1-2 seconds, gradually press down increasing the current until I get a puddle, ready to dip filler with the other hand, when a good sized puddle is reached, dip the filler in and move. Prepared to regulate (pull back especially) on the current to keep the puddle size roughly constant. For full penetration, I'd also try and melt a small melted "keyhole" and bridge it over with the filler rod. It will leave a little bulge inside where it melts through, but it will be strong and as close to fully penetrated as you're going to get by just welding from one side. If your filler hand is getting behind, or futzed up or whatever (I've had my filler glove work its way off), you can always pull back on the footpedal to shrink your puddle; its a little better than extinguishing the arc completely (avoids the white etch around the arc restarts.) You've just got to hold the torch still while your filler hand "catches up". If you are going for full penetration, at the "keyhole" puddle stage, you've got fractions of a second to fill it, or you'd better pull back quickly on the footpedal, or it will melt back and leave you with a hole. You can fill a hole, but it will cause a wider bead in that spot, which while can be perfectly functional, just won't look that great. But heck, you're learning, so if you make a hole, no big deal, try honing your skills on patching it closed, its kind of fun.

I recently did some .80" thick, fully penetrated corner joints. Hope this helps!

[gurew]

something i recently welded, i held the arc on start up for a little bit to pre-heat the area then got to work..no warpage, no issues. yada yada

also...something i learned, the balance settings are useless...you dont even need them the trick to that is....dun dun dun...you ready???

CLEAN YOUR METAL!!! brake cleaner first phase, wipe it down and clean it nice, then!! very important!! denatured alcohol!!!! clean off the brake cleaner very well....this works great for me, i produce the same bead quality time and time again just by prepping my metal the same everytime..no gaps, super tight EVEN fitment, and make sure its ULTRA clean... you will be damn amazed at how well your beads come out after you start cleaning better

[ogorir]

watch that brake cleaner, man... if you have any left on there when you light up, it WILL turn into phosgene gas which WILL cause neurological damage INSTANTLY if not just outright kill you. I'd really recommend finding another solvent that doesn't have a high probability of landing you 6 feet in a hole to clean your materials with.

[gurew]

nothing beats brake cleaner and denatured alcohol...clean off the brake cleaner and you are good to go....

learn to properly use the tools you use for work and you will never have an issue